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Title: Vegetable Teratology
An Account of the Principal Deviations from the Usual Construction of Plants
Author: Maxwell T. Masters
Release Date: November 6, 2007 [eBook #23354]
Language: English
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The Ray Society.
Instituted MDCCCXLIV.
[Illustration]
_This volume is issued to the Subscribers to the_ RAY SOCIETY _for
the Year_ 1868.
London:
MDCCCLXIX.
VEGETABLE TERATOLOGY,
An Account of the Principal Deviations from the Usual
Construction of Plants
by
MAXWELL T. MASTERS, M.D., F.L.S.
With Numerous Illustrations by E. M. Williams.
London:
Published for the Ray Society by
Robert Hardwicke, 192. Piccadilly.
MDCCCLXIX.
TO
JOSEPH DALTON HOOKER, M.D.,
D.C.L., LL.D., F.R.S., F.L.S., ETC. ETC.
DIRECTOR OF THE ROYAL GARDENS, KEW,
This Volume
IS
GRATEFULLY INSCRIBED.
TABLE OF CONTENTS.
PAGE
INTRODUCTION xxi
BOOK I.
DEVIATIONS FROM ORDINARY ARRANGEMENT 1
PART I.--UNION OF ORGANS 8
CHAPTER I.
COHESION 9
Cohesion between axes of same plant, 9--Fasciation, 11--Cohesion
of foliar organs, 21--Of margins of single organs, 21--Tubular
petals, 23--Cohesion of several organs by their margins, 25--Of
the sepals, 27--Of the petals, 28--Of the stamens, 29--Of the
pistils, 29--Ascidia or pitchers, 30.
CHAPTER II.
ADHESION 32
Adhesion of foliar organs, 32--Of leaves by their surfaces,
33--Of foliar to axile organs, 34--Of sepals to petals, 34--Of
stamens to petals, 34--Of stamens to pistils, 35--Miscellaneous
adhesions, 35--Of fruit to branch, 36--Synanthy, 36--Syncarpy,
45--Synspermy, 50--Between axes of different plants of same
species, 50--And of different species, 55--Synophty.
PART II.--INDEPENDENCE OF ORGANS 58
CHAPTER I.
FISSION 59
Fission of axile organs, 60--Of foliar organs, 61--Of petals,
66--Of stamens, 68--Of carpels, 68.
CHAPTER II.
DIALYSIS 69
Dialysis of margins of individual parts, 70--Of margins of parts
of same whorl-calyx, 70--Of corolla, 71--Of stamens, 73--Of
carpels, 73.
CHAPTER III.
SOLUTION 76
Solution of calyx from ovary, 77--Of stamens from petals, 82.
PART III.--ALTERATIONS OF POSITION 83
CHAPTER I.
DISPLACEMENT 84
Displacement of bulbs, 84--Of inflorescence, 85--Of leaves,
87--Of parts of flowers, 91--Of carpels, 96--Of placentas and
ovules, 96.
CHAPTER II.
PROLIFICATION 100
Prolification of the inflorescence, 102--Median foliar,
103--Median floral, 105--Lateral foliar, 106--Lateral floral,
107--Prolification of the flower, 115--Median foliar,
116--Median floral, 119--Axillary prolification, 138--Foliar,
141--Floral, 142--Complicated prolification, 151--Of embryo,
155.
CHAPTER III.
HETEROTAXY 156
Formation of adventitious roots, 156--Of shoots below the
cotyledons, 161--Adventitious leaves, 162--On scapes,
163--Production of leaves or scales in place of flower-buds,
164--Viviparous plants, 168--Formation of buds on leaves,
170--In pith, 171--On bulbs, 172--Production of gemmæ in place
of spores, 173--Of flowers on leaves, 174--Of flower-buds in
place of leaf-buds, 176--Of flowers on spines, 177--Of
flower-buds on petals, 177--On fruits, 178--In ovaries, 180--Of
stamens in ovaries, 182--Of pollen in ovules, 185--Homomorphic
flowers of Compositæ, 188--Heterotaxy affecting the
inflorescence, 188--Supra-soriferous ferns, 190.
CHAPTER IV.
HETEROGAMY 190
Change in the position of male and female flowers, 191--From
monoecious to dioecious condition, 193--From dioecious to
monoecious, 193--From hermaphroditism to unisexuality,
195--From unisexuality to hermaphroditism, 197--Pollen replaced
by ovules, 201.
CHAPTER V.
ALTERATIONS IN THE DIRECTION OF ORGANS 201
Fastigiation, 202--Eversion, 204--Altered direction of leaves,
205--Altered direction of flower, 206--Reflexion,
209--Gymnaxony, 211.
BOOK II.
DEVIATIONS FROM ORDINARY FORM 213
PART I.--STASIMORPHY 216
CHAPTER I.
PERSISTENCE OF JUVENILE FORMS 217
Stasimorphy in leaves of Conifers, 217--Regular peloria, 219.
PART II.--PLEIOMORPHY 228
CHAPTER I.
IRREGULAR PELORIA 228
PART III.--METAMORPHY 240
CHAPTER I.
PHYLLODY 241
Phyllody of bracts, 242--In inflorescence of Conifers, 245--Of
calyx, 245--Of corolla, 251--Of stamens, 253--Of pistils,
256--Of ovules, 262--Changes in nucleus of ovule, 269--Phyllody
of accessory organs, 272--Chloranthy, 273--General remarks on,
278.
CHAPTER II.
METAMORPHY OF FLORAL ORGANS 281
Sepalody of petals, 282--Petalody of calyx, calycanthemy,
283--Petalody of stamens, 285--Of anther, 291--Of connective,
293--Compound stamens, 294--Petalody of pistils, 296--Of ovules,
297--Of accessory organs, 297--Staminody of the bracts, 298--Of
sepals and petals, 298--Of pistils, 299--Of accessory organs,
301--Pistillody of perianth, 302--Of sepals, 302--Of stamens,
303--Of ovules, 310.
PART IV.--HETEROMORPHY 311
CHAPTER I.
DEFORMITIES 311
Formation of tubes, 312--In flower, 314--Spurs, 315--Contortion,
316--Spiral torsion, 319--Of leaf, 326--Adventitious tendrils,
326--Interrupted growth, 327--Cornute leaves, 328--Flattening,
328.
CHAPTER II.
POLYMORPHY 329
Heterophylly, 330--Dimorphism, 333--Sports or bud-variations,
336.
CHAPTER III.
ALTERATIONS OF COLOUR 337
Albinism, 337--Virescence, 338--Chromatism, 339.
BOOK III.
DEVIATIONS FROM ORDINARY NUMBER 340
PART I.--INCREASED NUMBER OF ORGANS 343
CHAPTER I.
MULTIPLICATION OF AXILE ORGANS--INFLORESCENCE 346
Multiplication of branches, 346--Plica, 346--Polyclady,
347--Multiplication of branches of inflorescence, 348--Of bulbs,
350--Of florets, 351.
CHAPTER II.
MULTIPLICATION OF FOLIAR ORGANS 352
Pleiophylly, 353--Multiplication of stipules, bracts, &c.,
357--Polyphylly, 358--Increased number of leaves in a whorl,
358--Polyphylly of bracts, 358--Of calyx, 358--Of corolla,
359--Of androecium, 361--Of gynoecium, 363--Of flower in
general, 365--Increased number of ovules and seeds, 367--Of
embryos, 369--Of cotyledons, 370--Pleiotaxy, or multiplication
of whorls, 371--Pleiotaxy of bracts, 371--Of calyx, 374--Of
perianth, 375--Of corolla (hose in hose), 376--Androecium,
379--Androecium of Orchids, 380--Pleiotaxy of gynoecium,
388--Increased number of flowers in an inflorescence, 391.
PART II.--DIMINISHED NUMBER OF ORGANS 392
CHAPTER I.
SUPPRESSION OF AXILE ORGANS 393
Acaulosia, 393--Non-development of peduncle, 393--Nature of
calyx-tube (Casimir de Candolle), 394--Suppression of columella,
395.
CHAPTER II.
SUPPRESSION OF FOLIAR ORGANS 395
Aphylly, 395--Meiophylly, 396--Of calyx or perianth, 396--Of
corolla, 397--Of androecium, 398--Of gynoecium, 399--Of
flower, 400--Meiotaxy, 403--Of calyx, 403--Of corolla, 403--Of
androecium, 405--Of gynoecium, 406--Of ovules or seeds,
407--Of flower, 408--General remarks on suppression, 409.
BOOK IV.
DEVIATIONS FROM ORDINARY SIZE AND CONSISTENCE 413
PART I--HYPERTROPHY 416
CHAPTER I.
ENLARGEMENT 417
Of axile organs, 418--Knaurs, 419--Enlargement of buds, 420--Of
flower-stalk, 421--In pears, 423--Of placenta, 424--Of leaves,
426--Development of parts usually abortive, 427--Enlargement of
perianth, 428--Of androecium, 430--Of gynoecium, 430--Of
fruit, 431--Alterations of consistence, 432.
CHAPTER II.
ELONGATION 488
Elongation of root, 434--Of inflorescence, 434--Of
flower-stalks, 435--Of leaves, 437--Of parts of flower, 438--Of
thalamus and placenta, 440--Apostasis, 440.
CHAPTER III.
ENATION 443
Excrescences from axile organs, warts, 444--Enation from leaves,
445--From sepals, 448--From petals, 448--Catacorolla,
451--Enation from stamens, 453--From carpels, 453.
PART II.--ATROPHY 454
CHAPTER I.
ABORTION 455
Abortion of axile organs, 455--Of receptacle, 457--Of leaves,
458--Of perianth, calyx, and corolla, 460--Of stamens, 463--Of
pollen, 463--Of pistil, fruit, &c., 464--Of ovules,
466--Depauperated ferns, 466--General remarks, 467.
CHAPTER II.
DEGENERATION 470
Formation of scales, 470--Of hairs, 472--Of glands, 473--Of
tendrils, 473.
GENERAL CONCLUSIONS.
General morphology of the leaf and axis, 476.--Homology,
476--Special morphology, 479--Calyx-tube, 480--Androecium,
482--Inferior ovary, 482--Placentation, 483--Structure of the
ovule, 484--Leaves of Conifers, 484--Relative position of
organs, 484--Law of alternation, 485--Co-relation,
486--Compensation, 488--Teratology and classification, 488.
APPENDIX.
Double flowers, varieties of, 491--Causes of production,
491--Relation to variegated foliage, 497--List of plants
producing, 499.
NOTE 508
INDEX TO SUBJECTS 511
INDEX OF NAMES OF PLANTS 517
LIST OF ILLUSTRATIONS.
FIG. PAGE
1. Diagram of regular pentamerous flower 4
2. Cohesion of branch _Dipsacus sylvestris_ 10
3. Fasciated lettuce ('Gard. Chron.') 11
4. Fasciation in _Asparagus_ 12
5. Fasciation in _Pinus Pinaster_ 13
6. Fasciation and spiral torsion in _Asparagus_
('Gard. Chron.') 14
7. Fasciation in scape of dandelion 16
8. Pitcher on leaf of _Pelargonium_ 22
9. Transition from flat to tubular segments of the perianth in
_Eranthis_ 24
10. Pitcher of _Crassula arborescens_ (C. Morren) 26
11. Gamopetalous corolla, _Papaver bracteatum_ 28
12. Adhesion of petaloid stamen to segment of perianth,
_Crocus_ 35
13. Adhesion of petal, stamen and carpel,
_Cheiranthus Cheiri_ 36
14. Synanthy. _Campanula Medium_ ('Gard. Chron.') 37
15, 16. Synanthic flowers of _Calanthe vestita_ 39
17. Synanthy in _Digitalis purpurea_ ('Gard. Chron.') 40
18. Synanthy in _Calceolaria_ 41
19, 20. Syncarpic apples 47
21. Adhesion of two stems of oak ('Gard. Chron.') 51
22. Adhesion of branches of elm ('Gard. Chron.') 52
23. Adhesion of two roots of carrot, one white, the other red
('Gard. Chron.') 53
24. Section through inverted and adherent mushrooms 54
25. Bifurcated male catkin, _Cedrus Libani_ 61
26. Bifurcated leaf, _Lamium album_ 62
27. Bifurcated leaf, _Pelargonium_ 63
28. Bifurcated frond, _Scolopendrium_ 64
29. Three-lobed lip of _Oncidium_ 68
30. Dialysis of corolla in _Correa_ 71
31. Dialysis of corolla in _Campanula_ (De Candolle) 72
32. Anomalous form of orange 74
33, 34. Disjoined carpels of orange (Maout) 75
35. Proliferous rose (Bell Salter) 78
36, 37. Apple flower, with detached calyx, &c. 79
38. Flower of _OEnanthe crocata_, with detached calyx, &c. 80
39. Anomalous bulbs of tulip 85
40. Displaced leaf of _Gesnera_ (C. Morren) 88
41. Leaves of _Pinus pinea_ 89
42. Deranged leaves of yew 90
43. Cohesion of sepals and displacement of parts of _Oncidium
cucullatum_ 92
44. Malformed flower of _Cypripedium_ 93
45. Diagram of the same 93
46. Diagram of natural structure in _Cypripedium_ 93
47. Diagram of malformed flower of _Lycaste Skinneri_ 93
48. Diagram of malformed flower of _Dendrobium nobile_ 94
49. Natural arrangement in same flower 94
50. Diagram of malformed violet 94
51. Monstrous flower of _Cerastium_ ('Gard. Chron.') 97
52. Inflorescence of _Polyanthus_, with tufts of leaves
at the summit 105
53. Lateral prolification in inflorescence of _Pelargonium_ 108
54. Paniculate inflorescence of _Plantago major_ 109
55. Branched spike and leafy bracts of the same 110
56. Inflorescence of _Plantago lanceolata_, with leaves
and secondary flower-stalks at its summit 111
57. Branched inflorescence of _Reseda Luteola_ 112
58. Thalamus of strawberry prolonged into a leafy branch
('American Agriculturist') 116
59. Flower of _Verbascum_, with dialysis of calyx and
corolla and prolonged thalamus 116
60. Median floral prolification of _Dianthus_ 120
61. Leafy carpels and prolification of _Daucus Carota_ 123
62. Median floral prolification of _Delphinium_ 126
63. Median prolification, &c., of _Orchis pyramidalis_ 128
64. Proliferous rose (Bell Salter) 130
65. Axillary floral prolification of _Nymphæa Lotus_
('Gard. Chron.') 144
66. Axillary floral prolification of _Dianthus_ 146
67. Proliferous rose 151
68. Proliferous rose ('Gard. Chron.') 152
69. Diagram of prolified orchid 153
70. Diagram of prolified orchis 154
71. Adventitious roots from petiole of celery 158
72. Germinating plant of mango 159
73, 74. Adventitious roots from leaves 160
75. Hip of rose bearing leaf 162
76. Leaves proceeding from the ovary of _Nymphæa_ sp. 162
77. Flower-stalk of dandelion, with leaves 163
78. Tuft of leaves in place of flowers in _Valeriana_ sp. 165
79. Scale-bearing spikelets of _Willdenovia_ 167
80. "Rose Willow" 167
81. Viviparous flowers of _Aira vivipara_ 169
82. Formation of shoot on leaf of _Episcia bicolor_ 171
83. Adventitious buds on root of sea-kale 172
84, 85. Production of adventitious bulbs in hyacinth ('Gard.
Chron.') 172
86. Adventitious buds on hyacinth ('Gard. Chron ') 173
87-92. Nepaul barley 174, 175
93. Formation of buds on fruit of _Opuntia_ 179
94. Flower-bud in the pod of _Sinapis_ 181
94*, 95. Adventitious pod in silique of _Cheiranthus_ 182
96, 97. Grapes, with adventitious fruits in interior 183
98. Stamens in ovary of _Bæckea diosmifolia_ 184
99. Pollen in ovule of passion flower (S. J. Salter) 185
100. Female flowers at the summit of the inflorescence of
_Carex acuta_ 192
101. Monoecious hop ('Gard. Chron.') 193
102. Superior ovary, &c, of fuchsia 198
103. Hermaphrodite flower of _Carica_ 199
104. Ovuliferous anthers of _Cucurbita_ sp. 200
105, 106. Prolonged inflorescence of fig 205
107. Hollow turnip, with inverted leaves 206
108. Normal flower of _Gloxinia_ 207
109. Regular peloria of _Gloxinia_ 207
110, 111. Structural details of erect _Gloxinia_ 208
112. Reflected corolla of azalea 209
113, 114. Enlarged and erect placenta of _Cuphea miniata_
(C. Morren) 210
115. Dimorphic leaves of _Juniperus sinensis_ 217
116. Regular peloria of _Delphinium_ 219
117. Structural details of the preceding 219
118. Regular peloria of violet 220
119. Double-flowered regular violet 220
120. Regular peloria of _Eccremocarpus scaber_ 222
121. Regular peloria of _Cattleya_ 223
122. Peloria of _Calceolaria_ 230
123. Peloric flower of _Aristolochia_ 232
124, 125. Peloric flowers of _Corydalis_ 236
126. Rose plantain 242
127. Leafy bracts in _Plantago major_ 243
128. Leafy scales of _Dahlia_ 244
129. Leafy sepals of rose 246
130. Leafy sepals of Fuchsia ('Gard. Chron.') 247
131. Leafy calyx of primrose 248
132. Leafy calyx of melon 248
133. Leafy sepals and petals of _Geranium_ 251
134. Leafy stamens of _Petunia_ 254
135, 136. Leafy anthers of _Jatropha_ (Müller) 255
137. Proliferous rose, with leafy carpels, &c. (Bell Salter) 257
138. Cucumber, with adventitious leaf attached (S. J. Salter) 258
139. Leafy carpels in flower of _Triumfetta_ 260
140. Leafy ovules of _Sinapis_ 264
141, 142. Leafy ovules of _Trifolium repens_ (Caspary) 265
143. Portion of leafy carpel of _Delphinium_, with ovules
(Cramer) 266
144, 145. Enlarged view of section of leafy carpel, &c., of
_Delphinium_ (Cramer) 267
146. Placentæ of _Dianthus_, bearing ovules and carpels
('Gard. Chron.') 268
147. Ovules passing into carpels, _Dianthus_
('Gard. Chron.') 268
148. Leafy shoot in place of ovule of _Gaillardia_ 270
149, 150. Leafy sepals, petals, &c., of _Epilobium_ 273
151. Leafy carpel of rose, with deformed ovules 274
152. Flower of St. Valery apple 282
153. Petaloid calyx of _Mimulus_ 284
154. Double stellate columbine 287
155. Four-winged filaments of Rhododendron 290
156. Diagram of malformed flower of _Catasetum_ 291
157. Petaloid stamen of _Viola_ 292
158. Double columbine 293
159. Petaloid stamens of _Hibiscus_ 293
160. Displaced coloured leaf, &c., of tulip 302
161. Supernumerary carpels in orange (Maout) 303
162. Pistilloid stamens of poppy 304
163. Pistilloid stamens of wallflower, &c. 306
164. Passage of stamen to carpel in lily 307
165. Transition of stamens to carpels,
_Sempervivum tectorum_ 309
166. Ascidia of cabbage 312
167. Stalked pitcher on lettuce leaf 313
168. Tubular petal of _Primula sinensis_ 315
169. Spurs on flower of _Calceolaria_ 316
170. Contorted stem of _Juncus_ 317
171. Contorted branch of _Cratægus_ 317
172. Spirally-twisted stem of teazel 321
173. Spirally-twisted stem _Galium_ 323
174. Spirally-twisted root ('Gard. Chron.') 324
175. Interrupted growth of radish (American Agriculturist) 327
176. Interrupted growth in apple 327
177. Polymorphous leaves of lilac 331
178. Adventitious growth on frond of _Pteris quadriaurita_ 333
179, 180. Coloured flower-stalks of feather hyacinth
(C. Morren) 347, 348
181. Multiplication of catkins, _Corylus_ 349
182. Branched inflorescence of broccoli ('Gard. Chron.') 351
183, 184. Supernumerary leaf of elm 353, 354
185. Supernumerary leaf of hazel 355
186. Multiplication of parts of flower in a plum ('Gard. Chron.') 366
187. Wheat-ear carnation 372
188. Multiplication of bracts in _Delphinium Consolida_ 373
189. Multiplication of bracts in _Pelargonium_ 373
190. Double white lily 376
191. Double flower of _Campanula rotundifolia_ 378
192. Diagram of usual arrangement of parts in _Orchis_
(Darwin) 381
193. Diagram of malformed flower of _Ophrys aranifera_ 385
194. Malformed flower of _Ophrys aranifera_ 385
195. Diagram of malformed flower of _Orchis mascula_
(Cramer) 386
196. Multiplication of carpels, Tulip 388
197. Section of St. Valery apple 388
198. Regular dimerous flower of _Calanthe vestita_ 402
199. Regular dimerous flower of _Odontoglossum Alexandræ_ 402
200. Hypertrophied branch of _Pelargonium_ 418
201. Tubers in the axils of leaves of the potato 420
202. Hypertrophied pedicels of ash 421
203, 204. Hypertrophy and elongation of flower-stalk, &c., in
pears 422, 423
205. Hypertrophied perianth, _Cocos nucifera_ 428
206. Elongation of flower-stalk, _Ranunculus acris_ 436
207. Linear leaf-lobes of parsley 438
208. Passage of pinnate to palmate leaves in horse-chestnut 439
209. Elongation of thalamus, apostasis, &c., in flower of
_Delphinium_ (Cramer) 441
210. Adventitious growths from cabbage leaf 445
211. Crested fronds of _Nephrodium molle_ 447
212. Supernumerary petals, &c., _Datura fastuosa_ 450
213. Supernumerary petaloid segments in flower of _Gloxinia_ 451
214. Catacorolla of _Gloxinia_ (E. Morren) 452
215. Atrophied leaves of cabbage 460
216. Abortion of petals, pansy 461
217. Flower of _Oncidium abortivum_ 462
218. Bladder plum 464
INTRODUCTION.
Till within a comparatively recent period but little study was given to
exceptional formations. They were considered as monsters to be shunned,
as lawless deviations from the ordinary rule, unworthy the attention of
botanists, or at best as objects of mere curiosity. By those whose
notions of structure and conformation did not extend beyond the details
necessary to distinguish one species from another, or to describe the
salient features of a plant in technical language; whose acquaintance
with botanical science might almost be said to consist in the
conventional application of a number of arbitrary terms, or in the
recollection of a number of names, teratology was regarded as a chaos
whose meaningless confusion it were vain to attempt to render
intelligible,--as a barren field not worth the labour of tillage.
The older botanists, it is true, often made them the basis of satirical
allusions to the political or religious questions of the day, especially
about the time of the Reformation, and the artists drew largely upon
their polemical sympathies in their representations of these anomalies.
Linnæus treated of them to some extent in his 'Philosophia,' but it is
mainly to Angustin Pyramus De Candolle that the credit is due of calling
attention to the importance of vegetable teratology. This great
botanist, not only indirectly, but from his personal research into the
nature of monstrosities, did more than any of his predecessors to rescue
them from the utter disregard, or at best the contemptuous indifference,
of the majority of botanists. De Candolle gave a special impetus to
morphology in general by giving in his adhesion to the morphological
hypotheses of Goethe. These were no mere figments of the poet's
imagination, as they were to a large extent based on the actual
investigation of normal and abnormal organisation by Goethe both alone,
and also in conjunction with Batsch and Jaeger.
De Candolle's example was contagious. Scarcely a botanist of any
eminence since his time but has contributed his quota to the records of
vegetable teratology, in proof of which the names of Humboldt, Robert
Brown, the De Jussieus, the Saint Hilaires, of Moquin-Tandon, of
Lindley, and many others, not to mention botanists still living, may be
cited. To students and amateurs the subject seems always to have
presented special attractions, probably from the singularity of the
appearances presented, and from the fact that in many cases the
examination of individual instances of malformation can be carried on,
to a large extent, without the lengthened or continuous investigation
and critical comparative study required by other departments of
botanical science. Be this as it may, teratology owes a very large
number of its records to this class of observers.
While the number of scattered papers on vegetable teratology in various
European languages is so great as to preclude the possibility of
collating them all, there is no general treatise on the subject in the
English language, with the exception of Hopkirk's 'Flora Anomala,' a
book now rarely met with, and withal very imperfect; and this
notwithstanding that Robert Brown early lent his sanction to the
doctrines of Goethe, and himself illustrated them by teratological
observations. In France, besides important papers of Turpin, Geoffroy de
Saint Hilaire, Brongniart, Kirschleger and others, to which frequent
allusion is made in the following pages, there is the classic work of
Moquin-Tandon, which was translated into German by Schauer. Germany has
also given us the monographs of Batsch, Jæger, Roeper, Engelmann,
Schimper, Braun, Fleischer, Wigand, and many others. Switzerland has
furnished the treatises of the De Candolles, and of Cramer; Belgium,
those of Morren, &c., all of which, as well as many others that might be
mentioned, are, with the exception of Moquin-Tandon's 'Eléments,' to be
considered as referring to limited portions only and not to the whole
subject.[1]
In the compilation of the present volume great use has been made of the
facts recorded in the works just cited, and especially in those of
Moquin-Tandon, Engelmann, and Morren. A very large number of
communications on teratological subjects in the various European
scientific publications have also been laid under contribution. In most
cases reference has been given to, and due acknowledgment made of, the
sources whence information has been gathered. Should any such reference
be omitted, the neglect must be attributed to inadvertence, not to
design. In selecting illustrations from the immense number of recorded
facts, the principle followed has been to choose those which seemed
either intrinsically the most important, or those which are recorded
with the most care. In addition to these public sources of information,
the author has availed himself of every opportunity that has offered
itself of examining cases of unusual conformation in plants. For many
such opportunities the author has to thank his friends and
correspondents. Nor has he less reason to be grateful for the
suggestions that they have made, and the information they have supplied.
In particular the writer is desirous of acknowledging his obligations to
the Society, under whose auspices this work is published, and to Mr. S.
J. Salter, to whom the book in some degree owes its origin.
The drawings, where not otherwise stated, have been executed either from
the author's own rough sketches, or from the actual specimens, by Mr. E.
M. Williams. A large number of woodcuts have also been kindly placed at
the disposal of the author by the proprietors of the 'Gardeners'
Chronicle.'[2]
As it is impossible to frame any but a purely arbitrary definition of
teratology or to trace the limits between variation and malformation, it
may suffice to say that vegetable teratology comprises the history of
the irregularities of growth and development in plants, and of the
causes producing them. These irregularities differ from variations
mainly in their wider deviation from the customary structure, in their
more frequent and more obvious dependence on external causes rather than
on inherent tendency, in their more sudden appearance, and lastly in
their smaller liability to be transmitted by inheritance.
What may be termed normal morphology includes the study of the form,
arrangement, size and other characteristic attributes of the several
parts of plants, their internal structure, and the precise relation one
form bears to another. In order the more thoroughly to investigate these
matters it is necessary to consider the mode of growth, and specially
the plan of evolution or development of each organ. This is the more
needful owing to the common origin of things ultimately very different
one from the other, and to the presence of organs which, in the adult
state, are identical or nearly so in aspect, but which nevertheless are
very unlike in the early stages of their existence.[3] Following Goethe,
these changes in the course of development are sometimes called
metamorphoses. In this way Agardh[4] admits three kinds of
metamorphosis, which he characterises as: 1st. Successive metamorphoses,
or those changes in the course of evolution which each individual organ
undergoes in its passage from the embryonic to the adult condition, or
from the simple and incomplete to the complex and perfect. 2. Ascending
metamorphoses, including those changes of form manifested in the same
adult organism by the several parts of which it consists--those parts
being typically identical or homologous, such as the parts of the
flower, or, in animals, the vertebræ, &c. 3. Collateral metamorphoses,
comprising those permutations of form and function manifested in
homologous organs in the different groups of organisms, classes, orders,
genera, species, &c.
Thus, in the first instance, we have a comparative examination of the
form of each or any separate part of the same individual at different
epochs in its life-history; in the second we have a similar comparison
instituted between the several parts of the same organism which
originally were identical in appearance, but which have in course of
evolution altered in character. In the third form we have the
comparative view not of one organ at different times, nor of the several
parts of one organism, but of the constituent elements pertaining to
those aggregates of individuals to which naturalists apply the terms
classes, orders, &c.
In successive metamorphosis we have a measure of the amount of change
and of the perfection of structure to which each separate organ attains.
In ascending metamorphosis we have a gauge of the extent of alteration
that may take place in the several homologous organs under existing
circumstances.
In collateral metamorphosis, in the same way, we have an illustration of
the degree of change possible in aggregates of organisms under existing
circumstances.
Now it is clear that from an investigation of all three classes just
mentioned, we shall be able to gain an idea of those points which are
common to all parts, to all individuals or to all aggregates, and those
that are peculiar to some of them, and, by eliminating the one from the
other, we shall arrive at conclusions which will be more or less
generally accurate or applicable, according to the ability of the
student and the extent to which the comparative analysis is earned. It
is thus that morphologists have been enabled to frame types or standards
of reference, and systematists to collocate the organisms they deal with
into groups. These standards and groups are more or less artificial
(none can be entirely natural) in proportion to the amount of knowledge
possessed by their framers, and the use they make of it.
From this point of view teratological metamorphosis of all three kinds
demands as much attention as that which is called normal. We can have no
thorough knowledge of an organ, of an individual which is an aggregate
of organs, or of an aggregate of individuals of whatever degree, unless
we know approximately, at least, what are the limits of each. It is not
possible to trace these limits accurately in the case of natural
science, but the larger our knowledge and the wider our generalisations,
the closer will be our approach to the truth.
The most satisfactory classification of malformations would be one
founded upon the nature of the causes inducing the several changes.
Thus, in all organised beings, there is a process of growth, mere
increase in bulk as it were, and a process of evolution or
metamorphosis, in accordance with which certain parts assume a
different form from the rest, in order the better to fit them for the
performance of different offices. Should growth and development be
uniform and regular, that is in accordance with what is habitual in any
particular species, there is no monstrosity, but if either growth or
development be in any way irregular, malformation results. Hence,
theoretically, the best way of grouping cases of malformation would be
according as they are the consequences of:--1st. Arrest of Growth;
2ndly. Excessive Growth; 3rdly. Arrest of Development; 4thly, of
Excessive or Irregular Development.
In practice, however, there are so many objections to this plan that it
has not been found practicable to carry it out. The inability arises to
a great extent from our ignorance of what should be attributed to arrest
of growth, what to excess of development, and so on. Moreover, a student
with a malformed plant before him must necessarily ascertain in what way
it is malformed before he can understand how it became so, and for this
purpose any scheme that will enable him readily to detect the kind of
monstrosity he is examining, even though it be confessedly artificial
and imperfect will be better than a more philosophical arrangement which
circumstances prevent him from employing.
The plan followed in this volume is a slight modification of that
adopted by Moquin-Tandon, and with several additions. In it the aim is
to place before the student certain salient and easily recognisable
points by reference to which the desired information can readily be
found. Under each subdivision will be found general explanatory remarks,
illustrative details, and usually a summary of the more important facts
and the inferences to be derived from them. Bibliographical references
and lists of the plants most frequently affected with particular
malformations are also given. In reference to both these points it must
be remembered that absolute completeness is not aimed at; had such
fullness of detail been possible of attainment it would have
necessitated for its publication a much larger volume than the
present.[5] It is hoped that both the lists of books and of plants are
sufficiently full for all general purposes.[6]
In the enumeration of plants affected with various malformations the !
denotes that the writer has himself seen examples of the deviation in
question in the particular plant named, while the prefix of the *
indicates that the malformation occurs with special frequency in the
particular plant to which the sign is attached.
Teratological alterations are rarely isolated phenomena, far more
generally they are associated with other and often compensatory changes.
Hence it is often necessary, in studying any given malformation, to
refer to two or more subdivisions, and in this way a certain amount of
repetition becomes unavoidable. The details of the several cases of
malformation given in these pages are generally arranged according to
their apparent degree of importance. Thus, in a case of prolification
associated with multiplication of the petals, the former change is a
greater deviation from the customary form than the latter, hence
reference should be made, in the first instance, to the sections
treating on prolification, and afterwards to those on multiplication. To
facilitate such research, numerous cross references are supplied.
In the investigation of teratological phenomena constant reference must
be made to the normal condition, and _vice versâ_, else neither the one
nor the other can be thoroughly understood. It cannot, however, be
overlooked that the form and arrangement called normal are often merely
those which are the most common, while the abnormal or unusual
arrangement is often more in consonance with that considered to be
typical than the ordinary one. Thus, too, it is often found that the
structural arrangements, which in one flower are normal, are in another
abnormal, in so far that they are not usual in that particular instance.
For purposes of reference, a standard of comparison is required; and
this standard, so long as its nature is not overlooked, may, indeed must
be, to some extent, an arbitrary one. Thus in the phanerogamous plants
there is assumed to exist, in all cases, an axis (stem, branches, roots,
thalamus, &c.), bearing leaves and flowers. These latter consist of four
whorls, calyx, corolla, stamens, and pistils, each whorl consisting of
so many separate pieces in determinate position and numbers, and of
regular proportionate size. A very close approach to such a flower
occurs normally in _Limnanthes_ and _Crassula_, and, indeed, in a large
proportion of all flowers in an early stage of development. To a
standard type, such as just mentioned, all the varied forms that are met
with, either in normal or abnormal morphology, may be referred by
bearing in mind the different modifications and adaptations that the
organs have to undergo in the course of their development. Some parts
after a time may cease to grow, others may grow in an inordinate degree,
and so on; and thus, great as may be the ultimate divergences from the
assumed standard, they may all readily be explained by the operation,
simply or conjointly, of some of the four principal causes of
malformation before alluded to. The fact that so many and such varied
changes can thus readily be explained is not only a matter of
convenience, but may be taken as evidence that the standard of reference
is not wholly arbitrary and artificial, but that it is a close
approximation to the truth.
It has already been said that an arrangement like that here considered
as typical is natural to some flowers in their adult state, and to a
vast number in their immature condition. It would be no extravagant
hypothesis to surmise that this was the primitive structure of the
flower in the higher plants. Variations from it may have arisen in
course of time, owing to the action of an inherent tendency to vary, or
from external circumstances and varied requirements which may have
induced corresponding adaptations, and which may have been transmitted
in accordance with the principle of hereditary transmission. This
hypothesis necessarily implies a prior simplicity of organisation, of
which, indeed, there is sufficient proof; many cases of malformation
can thus be considered as so many reversions to the ancestral form.
Thus, teratology often serves as an aid in the study of morphology in
general, and also in that of special groups of plants, and hence may
even be of assistance in the determination of affinities. In any case
the data supplied by teratology require to be used with caution and in
conjunction with those derived from the study of development and from
analogy. It is even possible that some malformations, especially when
they acquire a permanent nature and become capable of reproducing
themselves by seed, may be the starting-point of new species, as they
assuredly are of new races, and between a race and a species he would be
a bold man who would undertake to draw a hard and fast line.[7]
Discredit has been cast on teratology because it has been incautiously
used. At one time it was made to prove almost everything; what wonder
that by some, now-a-days, it is held to prove nothing. True the evidence
it affords is sometimes negative, often conflicting, but it is so rather
from imperfect interpretation than from any intrinsic worthlessness. If
misused the fault lies with the disciple, not with Nature.
Teratology as a guide to the solution of morphological problems has been
especially disparaged in contrast with organogeny, but unfairly so.
There is no reason to exalt or to disparage either at the expense of the
other. Both should receive the attention they demand. The study of
development shows the primitive condition and gradual evolution of parts
in any given individual or species; it carries us back some stages
further in the history of particular organisms, but so also does
teratology. Many cases of arrest of development show the mode of growth
and evolution more distinctly, and with much greater ease to the
observer, than does the investigation of the evolution of organs under
natural circumstances. Organogeny by no means necessarily, or always,
gives us an insight into the principles regulating the construction of
flowers in general. It gives us no archetype except in those
comparatively rare cases where primordial symmetry and regularity exist.
When an explanation of the irregularity of development in these early
stages of the plant's history is required, recourse must be had to the
inferences and deductions drawn from teratological investigations and
from the comparative study of allied forms precisely as in the case of
adult flowers.
The study of development is of the highest importance in the examination
of plants as individuals, but in regard to comparative anatomy and
morphology, and specially in its relation to the study of vegetable
homology it has no superiority over teratology. Those who hold the
contrary opinion do so, apparently, because they overlook the fact that
there is no distinction, save of degree, to be drawn between the laws
regulating normal organisation, and those by which so-called abnormal
formations are regulated.
It is sometimes said, and not wholly without truth, that teratology, as
it stands at present, is little more than a record of facts, but in
proportion as the laws that regulate normal growth are better
understood, so will the knowledge of those that govern the so-called
monstrous formations increase. Sufficient has been already said to
prove that there is no intrinsic difference between the laws of growth
in the two cases. As our knowledge increases we shall be enabled to
ascertain approximately of what extent of variation a given form is
capable, under given conditions, and to refer all formations now
considered anomalous to a few well-defined forms. Already teratology has
done much towards showing the erroneous nature of many morphological
statements that still pass current in our text-books, though their
fallacy has been demonstrated again and again. Thus organs are said to
be fused which were never separate, disjunctions and separations are
assigned to parts that were never joined, adhesions and cohesions are
spoken of in cases where, from the nature of things, neither adhesion
nor cohesion could have existed. Some organs are said to be atrophied
which were never larger and more fully developed than they now are, and
so on. So long as these expressions are used in a merely conventional
sense and for purposes of artificial classification or convenience, well
and good, but let us not delude ourselves that we are thus contributing
to the philosophical study either of the conformation of plants or of
the affinities existing between them. What hope is there that we shall
ever gain clear conceptions as to the former, as long as we tie
ourselves down to formulas which are the expressions of facts as they
appear to be, rather than as they really are? What chance is there of
our attaining to comprehensive and accurate views of the genealogy and
affinities of plants as long as we are restricted by false notions as to
the conformation and mutual relation of their parts?[8]
That teratology may serve the purposes of systematic botany to a greater
extent than might at first be supposed becomes obvious from a
consideration of such facts as are mentioned under the head of Peloria,
while the presence of rudimentary organs, or the occasional appearance
of additional parts, or other changes, may, and often do, afford a clue
to the relationship existing between plants--a relationship that might
otherwise be unsuspected. So, too, some of the alterations met with
appear susceptible of no other explanations than that they are
reversions to some pre-existing form, or, at any rate, that they are
manifestations of a phase of the plant affected different from that
which is habitual, and due, as it were, to a sort of allotropism.
The mutations and perversions of form, associated as they commonly are
with corresponding changes of function, show the connection between
teratology and physiology--a connection which is seen to be the more
intimate when viewed in the light afforded by the writings and
experiments of Gærtner, Sprengel, and St. Hilaire, and, in our own
times, especially by the writings and experiments of Mr. Darwin, whose
works on the 'Origin of Species,' and particularly on the 'Variation of
Animals and Plants under Domestication' comprise so large a collection
of facts for the use of students in most departments of biology. It
will suffice to allude, in support of these statements, to the writings
of Mr. Darwin on such subjects as rudimentary organs, the use or disuse
of certain parts according to circumstances, the frequently observed
tendency of some flowers to become structurally unisexual, the liability
of other flowers perfectly organised to become functionally imperfect,
at least so far as any reciprocal action of the organs of the same
flower is concerned, reversions, classification, general morphology, and
other subjects handled at once with such comprehensive breadth and
minute accuracy of detail by our great physiologist.
In the following pages alterations of function, unless attended by
corresponding alterations of form, are either only incidentally alluded
to, or are wholly passed over; such, for instance, as alterations in the
period of flowering, in the duration of the several organs, and so
forth.[9] Pathological changes, lesions caused by insect puncture or
other causes, also find no place in this book, unless the changes are of
such a character as to admit of definite comparison with normal
conformation. Usually such changes are entirely heteromorphous, and, as
it were, foreign to the natural organisation.
The practical applications of teratology deserve the attention of those
cultivators who are concerned in the embellishment of our gardens and
the supply of our tables. The florist lays down a certain arbitrary
standard of perfection, and attempts to make flowers conform to that
model. Whether it be in good taste or not to value all flowers, in
proportion as they accord with an artificial and comparatively inelastic
standard of this kind, we need not stop to enquire; suffice it to say,
that taking the matter in its broadest sense, the aim of the florist is
to produce large, symmetrical flowers, brightly and purely coloured, or
if parti-coloured, the colours must be distinct, harmonious, or
contrasted. When all this is done, the flower, in most instances,
becomes 'monstrous' of the eyes in the botanist, though all the more
interesting to the student of morphology on that account. In like manner
the double flowers, the "breaks," the "sports" which the florist
cultivates so anxiously, are all of them greater or less deviations from
the ordinary form, while the broccolies, the cabbages, and many other
products of our kitchen gardens and fields owe the estimation in which
they are held entirely to those peculiarities which, by an unhappy
application of words, are called monstrous by botanists. Grafting,
layering, the "striking" of cuttings, the formation of adventitious
roots and buds, processes on which the cultivator so greatly relies for
the propagation and extension of his plants, are also matters with which
teratology concerns itself. Again the difficulty experienced
occasionally in getting vines, strawberries, &c., to set properly, may
sometimes be accounted for by that inherent tendency which some plants
possess of exchanging an hermaphrodite for a unisexual condition.
For reasons then of direct practical utility, no less than on purely
scientific grounds, it is desirable to study these irregularities of
growth, their nature, limits, and inducing causes; and to this end it is
hoped the present work may, in some degree, contribute.
FOOTNOTES:
[1] An excellent summary of the history of Vegetable Teratology is given
in Kirschleger's 'Essai historique de la Tératologie Végétale,'
Strasburg, 1845.
[2] In some instances diagrams and formulæ are given in explanation of
the conformation of monstrous flowers; in general these require no
further explanation than is given in the text, unless it be to state
that the horizontal line--is intended to indicate the cohesion of the
parts over which it is placed, while the vertical line | signifies the
adhesion of the organs by whose side it is placed. The formula
S S S S S
------------------------
| P P P P P
|
| ST ST ST ST ST
shows that the sepals (S) are distinct, the petals (P) coherent, and the
stamens (ST) adherent to the petals.
[3] Wolff was the first to call attention to the great importance of the
study of development. He was followed by Turpin, Mirbel, Schleiden,
Payer, and others, and its value is now fully recognised by botanists.
[4] Agardh, "Theoria Syst. Plant.," p. xxiii.
[5] In the memoirs of Hopkirk, Kirschleger, Cramer, Hallier, and others,
malformations are arranged primarily according to the organs affected,
an arrangement which has only convenience to justify it. It is hoped
that the index and the headings to the paragraphs in the present volume
will suit the convenience of the reader as well as if the more
artificial plan just alluded to had been adopted.
[6] Cryptogamous plants are only incidentally alluded to in these pages,
owing to their wide difference in structure from flowering plants.
Attention may, also, here be called to a paper of M. de Seynes in a
recent number of the Bulletin of the Botanical Society of France, vol.
xiv, p. 290, tab. 5 et 6, in which numerous cases of malformation among
agarics are recorded. See also same publication, vol. iv, p. 744; vol.
v, p. 211; vol. vi, p. 496.
[7] On this subject see a paper of M. Naudin in the 'Comptes Rendus,'
1867, t. 64, pp. 929-933.
[8] It is probable that many terms and expressions calculated to mislead
in the way above mentioned are made use of in the following pages. The
inconsistency manifested by their use may be excused on the ground of
ignorance of the true structure, and by the circumstance that in many
cases facts alone are recorded without an explanation of them being
offered. Moreover, it is desirable to act in conformity with the usual
practice of botanical writers, and not to change established
terminology, even if suspected to convey false ideas, until the true
condition of affairs be thoroughly well ascertained by organogenetic
research or other means.
[9] A curious illustration of the latter class of alterations came under
the writer's notice last summer (1868), and which he has reason to
believe has not been previously recorded, viz. the persistence in an
unwithered state of the petals at the base of the ripe fruit, in a
strawberry. All the fruits on the particular plants alluded to were thus
provided as it were with a white frill. Whether this be a constant
occurrence in the particular variety is not known.
VEGETABLE TERATOLOGY.
BOOK I.
DEVIATIONS FROM THE ORDINARY ARRANGEMENT OF ORGANS.
As full details relating to the disposition or arrangement of the
general organs of flowering plants are given in all the ordinary
text-books, it is only necessary in this place to allude to the main
facts at present known, and which serve as the standard of comparison
with which all morphological changes are compared.
Even in the case of the roots, which appear to be very irregular in
their ramification, it has been found that, in the first instance at
least, the rootlets or fibrils are arranged in regular order one over
another, in a certain determinate number of vertical ranks, generally
either in two or in four, sometimes in three or in five series. This
regularity of arrangement (Rhizotaxy), first carefully studied by M.
Clos, is connected with the disposition of the fibro-vascular bundles in
the body of the root. This primitive regularity is soon lost as the
plant grows.
In the case of the leaves there are two principal modes of arrangement,
dependent, as it would seem, on their simultaneous or on their
successive development; thus, if two leaves on opposite sides of the
stem are developed at the same time, we have the arrangement called
opposite; if there are more than two, the disposition is then called
verticillate or whorled. On the other hand, if the leaves are developed
in succession, one after the other, they are found to emerge from the
stem in a spiral direction. In either case the leaves are arranged in a
certain regular manner, according to what are called the laws of
Phyllotaxis, which need not be entered into fully here; but in order the
better to estimate the teratological changes which take place, it may be
well to allude to the following circumstances relating to the
alternation of parts. The effect of this alternation is such, that no
two adjacent leaves stand directly over or in front one of the other,
but a little to one side or a little higher up. Now, in the alternate
arrangement the successive leaves of each spiral cycle alternate one
with another till the coil is completed. For the sake of clearness this
may be illustrated thus:--Suppose the spiral cycle to comprise five
leaves, numbered 1, 2, 3, 4, 5, then 2 would intervene between 1 and 3,
and so on, while the sixth leaf would be the commencement of a new
series, and would be placed exactly over 1. This arrangement may be thus
formularised:
6 7 8 9 10
1 2 3 4 5
In the verticillate or simultaneous arrangement of leaves the case is
somewhat different. Let us suppose a whorl of eight leaves, surmounted
by a similar whorl of eight. In such a case it will generally be found
that the whorls alternate one with another, as may be represented by
this symbol:
9 10 11 12 13 14 15 16
1 2 3 4 5 6 7 8
The simplest illustration of this arrangement is seen in the case of
decussate leaves, where those organs are placed in pairs, and the pairs
cross one another at right angles. This may be expressed by the
following symbol:
7 8
5 6
3 4
1 2
Thus, while in both the annular and the spiral modes of development the
individual members of each complete series necessarily alternate one
with another, in the former case the series themselves alternate, while
in the successive arrangement they are placed directly one over the
other. There are, of course, exceptions, but the rule is as has been
stated, and the effect is to prevent one leaf from interfering with the
development and growth of its neighbours.
In the case of the whorled or simultaneous arrangement the conditions of
growth must be uniform on all sides, but in the successive or spiral
disposition the conditions influencing growth act with unequal force, on
different sides of the stem, at the same time. In the whorl there is an
illustration of radiating symmetry, while in the spiral arrangement
there is a transition to the bilateral symmetry. There are frequent
passages from one to the other even under normal circumstances; thus,
while the one arrangement obtains in the ordinary leaves, the parts of
the flower may be disposed according to the other method. In the annular
disposition it generally happens that the rings are separated one from
the other by the development of the stem between them, the internodes
between the constituent leaves themselves of course being undeveloped;
on the other hand, in the spiral or successive arrangement there is no
such alternate growth and arrest of growth of the stem between the
leaves, or between successive cycles, but the growth is, under favorable
conditions, continuous--leaf is separated from leaf, and cycle from
cycle, by the continually elongating stem. Thus, the two modes of growth
correspond precisely with those observed in the case of definite and
indefinite inflorescence respectively.
[Illustration: FIG. 1.--Diagram showing the arrangement of parts in a
complete, regular, pentamerous flower: _s_, sepals; _p_, petals; _st_,
stamens; _o_, ovaries.]
The same arrangements, that are observed in the disposition of the
leaves, apply equally well to the several parts of the flower; thus, in
what is for convenience considered the typical flower, there is a calyx
of five or more distinct sepals, equal in size, and arranged in a whorl,
a corolla of a similar number of petals alternating with the sepals,
five stamens placed in the same position with reference to the petals,
and five carpels alternating with the stamens. Throughout this book this
arrangement is taken as the standard of reference. Nevertheless the
spiral order does occur in the floral leaves as well as in those of the
stem; it often happens, especially when the organs are numerous, that
they form spiral series; and the same holds good very generally, when
the parts of the flower are uneven in number, as in the very common
quincuncial arrangement of the sepals, &c.
To these general remarks, intended to show the agreement between the
disposition of the leaves of the stem and those of the flower, it is
merely necessary to add that the arrangement of the placentas, as well
as that of the ovules borne on them, is also definite, and takes place
according to methods explained in all the text-books, and on which,
therefore, it is not necessary to dilate in this place.
The branches of the stem or axis correspond for the most part in
disposition with that of the leaves from the axils of which they
originate, subject, however, to numerous disturbing causes, and to
alterations from the usual or typical order brought about by the
development of buds. These latter organs, as it seems, may be found in
almost any situation, though their ordinary position is in the axil of a
leaf or at the end of a stem or branch.
The points just mentioned are of primary importance in structural
botany, and as such are seized on not only by the morphologist, but by
the systematic botanist, who finds in them the characters by which he
may separate one group from another. Thanks to the labours of those
observers who have devoted their attention to that difficult but most
important branch of study, organogeny, or the investigation of the
development of the various organs, and to the researches of the students
of comparative anatomy or morphology, the main principles regulating the
arrangement and form of the organs of flowering plants seem to be fairly
well established, though in matters of detail much remains to be
cleared up, even in such important points as the share which the axis
takes in the construction of the flower and fruit, the nature of the
placenta, the construction of the ovules, and other points.
The facts already known justify the adoption of a standard or typical
arrangement as just mentioned. The intrinsic value of this type is shown
by the facility with which all varieties of form or arrangement may be
explained by reference to certain modifications of it. It must, however,
be considered as an abstraction, and should be looked on in the light
rather of a scaffolding, which enables us to see the building and its
several parts, than of the edifice itself, but which latter, from our
imperfect knowledge and limited powers, we could not see without some
such assistance.
The typical form may be, hypothetically at least, considered as the
primitive one transmitted by hereditary descent from generation to
generation, and modified to suit the requirements of the individual, or
in accordance with circumstances. If it be borne in mind that it is but
an artificial contrivance, more or less true--a means to an end, and not
the end itself--no harm will arise from its employment; and as knowledge
increases, or as circumstances demand, the hypothetical type can be
replaced by another more in accordance with the actual state of science.
Teratological changes in the arrangement of organs depend upon arrest of
growth, as when parts usually spirally arranged remain verticillate,
owing to the non-development of the internodes, or to excessive growth,
or development; but in many instances it is impossible, without
studying the development of the malformed flower, to ascertain whether
the altered arrangement is due to an excessive or to a diminished
action. Practically, however, it is of comparatively little importance
to know whether, say, the isolation of parts, that are usually combined
together, is congenital (_i.e._ the result of an arrest of growth
preventing their union), or whether it be due to a separation of parts
primitively undivided; the effect remains the same, though the cause may
have been very different.
The principal alterations to be mentioned under this head may therefore
be conveniently arranged under the following categories:--Union,
Independence, Displacement, Prolification, Heterotaxy, and Heterogamy.
PART I.
UNION OF ORGANS.
The union of parts, usually separate in their adult condition, is of
very common occurrence as a malformation. The instances of its
manifestation admit of being grouped under the heads of Cohesion, where
parts of the same whorl, or of the same organ, are united together; and
of Adhesion, where the union takes place between members of different
whorls, or between two or more ordinarily wholly detached and distinct
parts. In either case, the apparent union may be congenital (that is,
the result of a primitive integrity or a lack of separation), or it may
really consist in a coalition of parts originally distinct and separate.
In practice it is not always easy to distinguish between these two
different conditions. Indeed, in most cases it cannot be done without
tracing the development of the flower throughout all its stages. It is
needless to make more than a passing allusion to the frequency with
which both congenital integrity or subsequent coalescence of organs
exist under ordinary circumstances. Considered as a teratological
phenomenon, union admits of being grouped into several subdivisions,
such as Cohesion, Adhesion, Synanthy, Syncarpy, Synophty, &c. Each of
these subdivisions will be separately treated, but it maybe here said
that, in all or any case, the degree of fusion may be very slight, or it
may be so perfect that there may be a complete amalgamation of two or
more parts, while to all outward appearance the organ may be single.
The column of Orchids may be referred to as an illustration under
natural circumstances of the complete union of many usually distinct
parts.
In the uncertainty that exists in many cases as to the real nature of
the occurrence, it would be idle to attempt to explain the causes of
fusions. It is clear, however, that an arrest of development will tend
towards the maintenance of primordial integrity (congenital fusion), and
that pressure will induce the coalition of organs primarily distinct.
CHAPTER I.
COHESION.
Following Augustin Pyranius De Candolle, botanists have applied the term
cohesion to the coalescence of parts of the same organ or of members of
the same whorl; for instance, to the union of the sepals in a
gamosepalous calyx, or of the petals in a gamopetalous corolla. It may
arise either from a union between organs originally distinct, or more
frequently from a want of separation between parts, which under general
circumstances become divided during their development. Nothing is more
common as a normal occurrence, while viewed as a teratological
phenomenon it is also very frequent. For the purposes of convenience it
admits of subdivision into those cases wherein the union takes place
between the branches of the same plant, or between the margins of the
same leaf-organ, or between those of different members of the same
whorl.
=Cohesion between the axes of the same plant.=--This cohesion may occur
in various manners. Firstly. The branches of the main stem may become
united one to the other. Secondly. Two or more stems become joined
together. Thirdly. The branches become united to the stem; or, lastly,
the roots may become fused one with another.
[Illustration: FIG. 2--Cohesion of two branches in _Dipsacus
sylvestris_.]
The first of these is most commonly met with, doubtless owing to the
number of the branches and the facilities for their union. An
illustration of it is afforded by the figure (fig. 2), showing cohesion
affecting the branches of a teazle (_Dipsacus sylvestris_). Union of the
branches may be the result of an original cohesion of the buds, while in
other cases the fusion does not take place until after development has
proceeded to some extent. Of this latter kind illustrations are common
where the branches are in close approximation; if the bark be removed by
friction the two surfaces are very likely to become united (natural
grafting). Such a union of the branches is very common in the ivy, the
elder, the beech, and other plants. It may take place in various
directions, lengthwise, obliquely, or transversely, according to
circumstances. This mode of union belongs, perhaps, rather to the domain
of pathology than of teratology. Some of the instances that have been
recorded of very large trees, such as the chestnut of Mount Ætna, are
really cases where fusion has taken place between several of the
branches, or suckers, thrown out from the same original stem.[10] The
same process of grafting occurs sometimes in the roots, as in _Taxus
baccata_ mentioned by Moquin, and also in the aerial roots of many of
the tropical climbing plants, such as _Clusia rosea_, &c.
[Illustration: FIG. 3.--Fasciation in Lettuce.]
=Fasciation.=--In the preceding instances of union between the branches,
&c., the actual number of the fused parts is not increased; but if it
happen that an unusual number of buds be formed in close apposition, so
that they are liable to be compressed during their growth, union is very
likely to take place, the more so from the softness of the young
tissues. In this way it is probable that what is termed fasciation is
brought about. This is one of the most common of all malformations, and
seems to affect certain plants more frequently than others. In its
simplest form it consists of a flat, ribbon-like expansion of the stem
or branch; cylindrical below, the branches gradually lose their pristine
form, and assume the flattened condition.
[Illustration: FIG. 4.--Fasciation in _Asparagus_.]
[Illustration: FIG. 5.--Fasciated branch of _Pinus Pinaster_.]
Very generally the surface is striated by the prominence of the woody
fibres which, running parallel for a time, converge or diverge at the
summit according to the shape of the branch. If the rate of growth be
equal, or nearly so, on both sides, the stem retains its straight
direction, but it more generally happens that the growth on one side is
more rapid and more vigorous than on the other, and hence arises that
curvature of the fasciated branch so commonly met with, _e.g._ in the
ash (_Fraxinus_), wherein it has been likened to a shepherd's crook. It
is probable that almost any plant may present this change. It occurs
alike in herbaceous and in woody plants, originating in the latter case
while the branches are still soft. It may be remarked that, in the case
of herbaceous plants, the fasciation always affects the principal stem,
while, on the other hand, in the case of trees and shrubs the deformity
occurs most frequently in the branches; thus, while in the former it
may be said that the whole of the stem is more or less affected, in the
latter it is rare to see more than one or two branches of the same tree
thus deformed. It is a common thing for the fasciated branch to divide
at the summit into a number of subdivisions. These latter may be
deformed like the parent branch, or they may resume the ordinary aspect
of the twigs.
[Illustration: FIG. 6.--Fasciation and spiral torsion in the stem of
_Asparagus_.]
Sometimes the flattened stem is destitute of buds, at other times, these
organs are scattered irregularly over its surface or are crowded
together in a sort of crest along the apex. When, as often happens, the
deformity is accompanied with a twisting of the branch spirally, the
buds may be placed irregularly, or in other cases along the free edge of
the spiral curve. In a specimen of _Bupleurum falcatum_ mentioned by
Moquin the spiral arrangement of the leaves was replaced by a series of
perfect whorls, each consisting of five, six, seven, or eight segments,
and there was a flower-stalk in the axil of each leaf.
When flowers are borne on these fasciated stems they are generally
altered in structure; sometimes the thalamus itself becomes more or less
fasciated or flattened, and the different organs of the flower are
arranged on an elliptical axis. A case of this nature is described by
Schlechtendal ('Bot. Zeit.,' 1857, p. 880), in _Cytisus nigricans_, and
M. Moquin-Tandon describes an instance in the vine in one flower of
which sepals, petals, stamens, and ovary were abortive, while the
receptacle was hypertrophied and fasciated, and bore on its surface a
few adventitious buds.[11] The pedicels of _Streptocarpus Rexii_ have
also been observed in a fasciated state.[12]
It has been occasionally observed that the fasciated condition is
hereditary; thus, Moquin relates that some seeds of a fasciated
_Cirsium_ reproduced the same condition in the seedlings,[13] while a
similar tendency is inherited in the case of the cockscomb (_Celosia_).
With reference to the nature of the deformity in question there is a
difference of opinion; while most authors consider it to be due to the
causes before mentioned, Moquin was of opinion that fasciation was due
to a flattening of a single stem or branch. Linnæus, on the other hand,
considered such stems to be the result of the formation of an unusual
number of buds, the shoots resulting from which became coherent as
growth proceeded:--"_Fasciata dici solet planta cum plures caules
connascuntur, ut unus ex plurimis instar fasciæ evadat et compressus_"
(Linn., 'Phil. Bot.,' 274). A similar opinion was held by J. D. Major in
a singular book entitled 'De Plantâ, Monstrosa, Gottorpiensi,'
Schleswig, 1665, wherein the stem of a _Chrysanthemum_ is depicted in
the fasciated condition.
[Illustration: FIG. 7.--Fasciation in the scape of the Dandelion
(_Leontodon Taraxacum_).]
The striæ, which these stems almost invariably present, exhibit the
lines of junction, and the spiral or other curvatures and contraction,
which are so often met with, may be accounted for by the unequal growth
of one portion of the stem as contrasted with that of another. Against
this view Moquin cites the instances of one-stemmed plants, such as
_Androsace maxima_, but, on the other hand, those herbaceous plants
having usually but a single stem not unfrequently produce several which
may remain distinct, but not uncommonly become united together. Prof.
Hincks[14] cites cases of this kind in _Primula vulgaris_, _Hieracium
aureum_, and _Ranunculus bulbosus_. I have myself met with several cases
of the kind in _Primula veris_, in the Polyanthus, in the Daisy, and in
the _Leontodon Taraxacum_, in which latter a fusion of two or more
flower-stems bearing at the top a composite flower, and made up of two,
three, four, or more flowers combined together, and containing all the
organs that would be present in the same flowers if separate, is very
common.
Moquin's second objection is founded upon the fact that, in certain
fasciated stems, the branches are not increased in number or altered in
arrangement from what is usual; but however true this may be in
particular cases, it is quite certain that in the majority of instances
a large increase in the number of leaves and buds is a prominent
characteristic of fasciated stems.
Another argument used by the distinguished French botanist to show that
fasciated stems are not due to cohesion of two or more stems, is founded
on the fact that a transverse section of a fasciated stem generally
shows an elliptical outline with but a single central canal. On the
other hand, if two branches become united and a transverse section be
made, the form of the cut surface would be more or less like that of the
figure 8[Symbol: 8 turned 90°], although in old stems this may give
place to an elliptical outline, but even then traces of two medullary
canals may be found. This argument is very deceptive, for the appearance
of the transverse section must depend, not only on the intimacy of their
union, but also on the internal structure of the stems themselves. When
two flowers cohere without much pressure they exhibit uniting circles
somewhat resembling the figure of 8[Symbol: 8 turned 90°], but when more
completely combined they have an outline of a very elongated figure, and
something similar is to be expected in herbaceous stems. Even the
elongated pith of a transversely cut, woody, fasciated stem only marks
the intimate union of several branches, and Prof. Hincks, whose views
the writer entirely shares, has noticed instances of the union of two,
and of only two, stems where the internal appearance was the same as in
other fasciations.
Moquin, moreover, raises the objection that it is unlikely that several
branches should become united lengthwise in one plane only, and,
further, that in the greater number of fasciations all the other
branches which should be present are to be found--not one is wanting,
not one has disappeared, as might have been anticipated had fusion taken
place. In raising this objection, Moquin seems not sufficiently to have
considered the circumstance that the buds in these cases are in one
plane from the first, and are all about equal in point of age and size.
The last objection that Moquin raises to the opinion that fasciation is
the result of a grafting process is, that in such a case, examples
should be found wherein the branches are incompletely fused, and where
on a transverse section traces of the medullary canals belonging to each
branch should be visible. The arrangement of leaves or buds on the
surface should also in such a case indicate a fusion of several spiral
cycles or whorls. To this it may be replied that such cases are met with
very frequently indeed. A figure is given by De Candolle[15] of a stem
of _Spartium junceum_ having several branches only imperfectly
fasciated.
Fasciated stems, then, seem to be best explained, as is stated by Prof.
Hincks, "on the principle of adhesion arising in cases where from
superabundant nourishment, especially if accompanied by some check or
injury, numerous buds have been produced in close proximity, and the
supposition that these growths are produced by the dilatation of a
single stem is founded on a false analogy between fasciated stems and
certain other anomalous growths."
It will not, of course, be forgotten that this fasciated condition
occurs so frequently in some plants as almost to constitute their
natural state, _e.g._ _Sedum cristatum_, _Celosia_, &c. This condition
may be induced by the art of the gardener--"_Fit idem arte, si plures
caules enascentes cogantur penetrare coarctatum spatium et parturiri
tanquam ex angusto utero, sic sæpe in Ranunculo, Beta, Asparago,
Hesperide Pinu, Celosiâ, Tragopogone, Scorzonerâ Cotula foetida_,"
Linnæus op. cit.
Plot, in his 'History of Oxfordshire,' considers fasciation to arise
from the ascent of too much nourishment for one stalk and not enough for
two, "which accident of plants," says Plot, the German virtuosi ('Misc.
Curios. Med. Physic. Acad. Nat. Cur.,' Ann. i, Observ. 102,) "think only
to happen after hard and late winters, by reason whereof, indeed, the
sap, being restrained somewhat longer than ordinary, upon sudden thaws
may probably be sent up more forcibly, and so produce these fasciated
stalks, whereas the natural and graduated ascent would have produced
them but single." Prof. Hincks' explanation is, however, more near to
the truth, and his opinion is borne out by the frequency with which this
change is met with in certain plants which are frequently forced on
during their growth, as lettuce, asparagus, endive, &c., all of which
are very subject to this change. In the 'Transactions of the
Horticultural Society of London,' vol. iv, p. 321, Mr. Knight gives an
account of the cultivation of the cockscomb, so as to ensure the
production of the very large flower-stalks for which this plant is
admired. The principal points in the culture were the application of a
large quantity of stimulating manure and the maintenance of a high
temperature. One of them so grown measured eighteen inches in width.
The list which is appended is intended to show those plants in which
fasciation has been most frequently observed. It makes no pretension to
be complete, but is sufficiently so for the purpose indicated: the *
denotes the especial frequency of the change in question; the !
indicates that the writer has himself seen the plant, so marked,
affected in this way. The remainder have been copied from various
sources.
EXOGENS.
[Greek: alpha]. _Herbaceous._
Ranunculus tripartitus.
* bulbosus!
Philonotis.
Delphinium elatum.
* sp.!
Hesperis matronalis.
*Cheiranthus Cheiri!
*Matthiola incana!
*Brassica oleracea! var. pl. inflor.
Linum usitatissimum!
Althæa rosea!
Lavatera trimestris.
Geranii sp.
Tropæolum majus!
Viola odorata inflor.!
Reseda odorata!
Fragaria vesca.
Ervum lens.
Trifolium resupinatum.
repens!
pratense!
Saxifraga mutata.
irrigua.
Bupleurum falcatum.
Bunium flexuosum.
*Sedum reflexum!
cristatum!
Epilobium augustifolium!
Momordica Elaterium!
Gaura biennis.
Cotula foetida.
Barkhausia taraxacifolia.
Carlina vulgaris!
Apargia autumnalis.
*Leontodon Taraxacum inflor.!
Centaurea Scabiosa.
*Cichorium Intybus!
Hieracium Pilosella.
aureum.
umbellatum.
*Chrysanthemum Leucanthemum.
indicum!
Anthemis nobilis.
arvensis.
Cirsium lanceolatum.
Conyza squarrosa!
Inula dysenterica!
Tragopogon porrifolium.
Cnicus palustris.
Carduus arvensis!
Helianthus tuberosus!
annuus.
Cineraria palustris.
Helianthus sp.!
Dahlia variabilis.
Bellis perennis inflor.!
Coreopsis sp.!
Crepis virens.
Lactuca sativa!
Zinnia elegans.
*Campanula medium!
rapunculoides.
thyrsoidea.
Dipsacus pilosus.
fullonum.
silvestris.
Knautia arvensis.
Phyteuma orbiculare.
Jasione montana.
*Linaria purpurea!
Antirrhinum majus!
Veronica amethystea.
Veronica maritima.
sp.
Russellia juncea!
Digitalis purpurea!
Ajuga pyramidalis.
Hyssopus officinalis.
Dracocephalum moldavicum.
Myosotis scorpioides.
Echium pyrenaicum.
simplex.
Stapeliæ sp.
Lysimachia vulgaris!
Androsace maxima.
Primula veris inflor.!
denticulata inflor.!
Polemonium coeruleum.
Convolvulus sepium!
arvensis!
Plantago media.
*Euphorbia Characias.
exigua.
* Cyparissias.
Suæda maritima.
*Celosia sp.
Beta vulgaris inflor.!
Phytolacca sp.
[Greek: beta]. _Woody._
Berberis vulgaris.
Hibiscus syriacus!
Acer pseudo-platanus!
Dodonæa viscosa.
Sterculia platanifolia.
Euonymus japonicus!
Vitis vinifera inflor.!
Spartium Scoparium!
Spartium junceum!
Cytisus Laburnum.
nigricans.
Chorozema ilicifolium.
Amorpha sp.
Phaseolus sp.
Prunus sylvestris.
Laurocerasus!
Rosa sp.!
Spiræa sp.!
Cotoneaster microphylla!
Ailanthus glandulosus.
*Fraxinus Ornus!
* excelsior!
Melia Azedarach.
Xanthoxylum sp.!
Sambucus nigra.!
Aucuba japonica.
Erica sp. cult.
Jasminum nudiflorum!
officinale!
Olea europoea.
Punica Granatum.
Ilex aquifolium!
Daphne indica.
Daphne odora.
Suæda fruticosa.
Ulmus campestris.
Alnus incana.
Salix vitellina, &c.!
Thuja orientalis.
Pinus pinaster!
sylvestris!
Abies excelsa!
Taxus baccata.
Larix europoea.
ENDOGENS.
Lilium Martagon.
candidum!
*Fritillaria imperialis!
Asparagus officinalis!
Hyacinthus orientalis!
Tamus communis!
Narcissi sp.!
Gladiolus sp.
Zea Mays.
Filices.
See also--Moquin-Tandon, 'Elem. Ter. Veget.,' p. 146; C. O.
Weber, 'Verhandl. Nat. Hist.,' Vereins, f. d. Preuss., Rheinl.
und Westphal., 1860, p. 347, tab. vii; Hallier, 'Phytopathol.,'
p. 128; Boehmer, 'De plantis Fasciatis,' Wittenb., 1752.
=Cohesion of foliar organs.=--This takes place in several ways, and in
very various degrees; the simplest case is that characterised by the
cohesion of the margins of the same organ, as in the condition called
perfoliate in descriptive works, and which is due either to a cohesion
of the margins of the basal lobes of the leaf, or to the development of
the leaf in a sheathing or tubular manner. As an abnormal occurrence, I
have met with this perfoliation in a leaf of _Goodenia ovata_. The
condition in question is often loosely confounded with connation, or the
union of two leaves by their bases. In other cases the union takes place
between the margins of two or more leaves.
=Cohesion of margins of single organs.=--The leaves of Hazels may often
be found with their margins coherent at the base, so as to become
peltate, while in other cases, the disc of the leaf is so depressed that
a true pitcher is formed. This happens also in the Lime _Tilia_, in
which genus pitcher- or hood-like leaves (_folia cucullata_) may
frequently be met with. There are trees with leaves of this character in
the cemetery of a Cistercian Monastery at Sedlitz, on which it is said
that certain monks were once hung: hence the legend has arisen, that the
peculiar form of the leaf was given in order to perpetuate the memory of
the martyred monks. ('Bayer. Monogr. _Tiliæ_,' Berlin, 1861.) It is also
stated that this condition is not perpetuated by grafting.
[Illustration: FIG. 8.--Pitcher-shaped leaf of _Pelargonium_.]
I have in my possession a leaf of _Antirrhinum majus_, and also a
specimen of _Pelargonium_, wherein the blade of the leaf is funnel-like,
and the petiole is cylindrical, not compressed, and grooved on the upper
surface, as is usually the case. A comparison of the leaves of
_Pelargonium peltatum_ with those of _P. cucullatum_ ('Cav. Diss.,'
tab., 106) will show how easy the passage is from a peltate to a tubular
leaf. In these cases the tubular form may rather be due to dilatation
than to cohesion. M. Kickx[16] mentions an instance of the kind in the
leaves of a species of _Nicotiana_, and also figures the leaf of a rose
in which two opposite leaflets presented themselves in the form of
stalked cups. Schlechtendal[17] notices something of the same kind in
the leaf of _Amorpha fruticosa_; Treviranus[18] in that of _Aristolochia
Sipho_.
M. Puel[19] describes a leaf of _Polygonatum multiflorum_, the margins
of which were so completely united together, as only to leave a circular
aperture at the top, through which passed the ends of the leaves. The
Rev. Mr. Hincks, at the meeting of the British Association at Newcastle
(1838), showed a leaf of a Tulip, whose margins were so united that the
whole leaf served as a hood, and was carried upwards by the growing
flower like the calyptra of a Moss.
The margins of the stipules are also occasionally united, so as to form
a little horn-shaped tube. I have met with instances of this kind in the
common white clover, _Trifolium repens_, where on each side of the base
of the petiole the stipules had the form just indicated. That the bracts
also may assume this condition, may be inferred from the peculiar
horn-like structures of _Marcgraavia_, which appear to originate from the
union of the margins of the reflected leaf.
=Tubular petals= occur normally in some flowers, as _Helleborus_,
_Epimedium_, _Viola_, &c., and as an exceptional occurrence I have seen
them in _Ranunculus repens_, while in _Eranthis hyemalis_ transitions
may frequently be seen between the flat outer segments of the perianth
and the tubular petals. To Dr. Sankey, of Sandywell Park, I am indebted
for the flower of a Pelargonium, in which one of the petals had the
form of a cup supported on a long stalk. This cup-shaped organ was
placed at the back of the flower, and had the dark colour proper to the
petals in that situation. I have seen a petal of Clarkia similarly
tubular, while some of the cultivated varieties of _Primula sinensis_
exhibit tubular petals so perfect in shape as closely to resemble
perfect corollas.
[Illustration: FIG. 9.--_Eranthis hyemalis_. Transition from flat sepal
to tubular petal.]
Like the petals, the stamens, and even the styles, assume a hollow
tubular form. This change of form in the case of the stamens is, of
course, usually attended by the petaloid expansion of the filament, or
anther, and the more or less complete obliteration of the pollen sacs,
as in Fuchsias, and in some double-flowered Antirrhinums.[20] So also in
some semi-double varieties of _Narcissus poeticus_, and in _Aquilegia_.
By the late Professor Charles Morren, this affection of the stamens and
pistils was called _Solenaidie_,[21] but as a similar condition exists
in other organs, it hardly seems worth while to adopt a special term for
the phenomenon, as it presents itself in one set of organs.
In many of these cases it is difficult to say whether the cup-like or
tubular form is due to a dilatation or hollowing out of the organ
affected, or to a fusion of its edges. The arrangement of the veins will
in some cases supply the clue, and in others the regularity of form
will indicate the nature of the malformation, for in those instances
where the cup is the result of expansion, its margin is more likely to
be regular and even than in those where the hollow form is the result of
fusion.
=Cohesion of several organs by their margins:--leaves, &c.=--The union
of the margins of two or more different organs is of more common
occurrence than the preceding, the leaves being frequently subjected to
this change. Occasionally, the leaflets of a compound leaf have been
observed united by their margins, as in the strawberry, the white
trefoil, and others. Sometimes the union takes place by means of the
stalks only. I have an instance of this in a Pelargonium, in _Tropæolum
majus_, and _Strelitzia regina_; in other cases, the whole extent of the
leaf becomes joined to its neighbour, the leaves thus becoming
completely united by their edges, as in those of _Justicia_,
_oxyphylla_.[22] M. Clos[23] has observed the same thing in the leaves
of the lentil _Ervum lens_, conjoined with fasciation of the stem, and
many other examples might be given. Some of the recorded cases are
probably really due to fission of one leaf into two rather than to
fusion. Although usually the lower portions of the leaf are united
together, leaving the upper parts more or less detached, there are some
instances in which the margins of the leaf at their upper portion have
been noticed to be coherent, while their lower portions, with their
stalks, were completely free.[24]
Cohesion of the leaves frequently accompanies the union of the branches
and fasciation as might have been anticipated. Moquin cites the
fenestrated leaves of _Dracontium pertusum_, as well as some cases of a
similar kind that are occasionally met with, as instances of the
cohesion of the margins at the base and apex of the leaf, which thus
appears perforated. This appearance, however, is probably due to some
other cause. When the leaves are verticillate and numerous, and they
become coherent by their margins, they form a foliaceous tube around the
stem. When there are but two opposite leaves, and these become united by
their margins, we have a state of things precisely resembling that to
which the term connate is applied.
Fusion of the edges of the cotyledons also occasionally takes place, as
in _Ebenus cretica_.[25] It has also been observed in _Tithonia_, and is
of constant occurrence in the seed leaves of some _Mesembryanthema_.
This condition must be carefully distinguished from the very similar
appearance produced by quite a different cause, viz., the splitting of
one cotyledon into two, which gives rise to the appearance as if two
were partially united together.
Some of the ascidia or pitcher-like formations are due to the cohesion
of the margins of two leaves, as in a specimen of _Crassula
arborescens_, observed by C. Morren.
[Illustration: FIG. 10.--Two-leaved pitcher of _Crassula arborescens_,
after C. Morren.]
The stipules may also be fused together in different ways; their edges
sometimes cohere between the leaf and the stem, and thus form a solitary
intra-axillary stipule. At other times they become united in such a
manner as to produce a single notched stipule opposite to the leaf.
Again, in other cases, they are so united on each side of the stem, that
in place of four there seem only to exist two, common to the two leaves
as in the Hop.
To the Rev. M. J. Berkeley I am indebted for specimens of a curious
pitcher-like formation in the garden Pea. The structure in question
consisted of a stalked foliaceous cup proceeding from the inflorescence.
On examination of the ordinary inflorescence, there will be seen at the
base of the upper of two flowers a small rudimentary bract, having a
swollen circular or ring-like base, from which proceeds a small
awl-shaped process, representing the midrib of an abortive leaf. In some
of Mr. Berkeley's specimens, the stipules were developed as leafy
appendages at the base of the leaf-stalk or midrib, the latter retaining
its shortened form, while, in others, the two stipules had become
connate into a cup, and all trace of the midrib was lost. The cup in
question would thus seem to have been formed from the connation of two
stipules which are ordinarily abortive.
Cohesion of the bracts by their edges, so as to form a tubular
involucre, or by their surfaces, so as to form a cupule, is not of
uncommon occurrence, under natural conditions, and may be met with in
plants which ordinarily do not exhibit this appearance.
=Cohesion of the sepals= in a normally polypetalous calyx renders the
latter gamosepalous, and is not of uncommon occurrence, to a partial
extent, though rarely met with complete. I have observed a junction of
the sepals to be one of the commonest malformations among Orchids,
indeed such a state of things occurs normally in _Masdevallia
Cypripedium_, &c. An illustration of this occurrence is given by Mr. J.
T. Moggridge in _Ophrys insectifera_, in 'Seemann's Journal of Botany,'
1866, p. 168, tab. 47. In Orchids, this cohesion of sepals is very often
co-existent with other more important changes, such as absence of the
labellum, dislocation of the parts of the flower, &c.
[Illustration: FIG. 11.--Gamopetalous flower of _Papaver bracteatum_.]
=Cohesion of the petals.=--Linnæus mentions the occurrence of cohesion
of the petals in _Saponaria.[26]_ Moquin notices a Rose in which the
petals were united into a long tube, their upper portions were free and
bent downwards, forming a sort of irregular limb. An instance of the
polypetalous regular perianth of _Clematis viticella_ being changed into
a monopetalous irregular one, like the corolla of Labiates, is recorded
by Jaeger.[27] There is in cultivation a variety of _Papaver
bracteatum_, in which the petals are united by their margins so as to
form a large cup. Under normal circumstances, the petals become fused
together by their edges along their whole extent, at the base only, at
the apex only, as in the Vine, or at the base and apex, leaving the
central portions detached. Indications of the junction of the petals may
generally be traced by the arrangement of the veins, or by the notches
or lobes left by imperfect union. In Crocuses I have frequently met with
cohesion of the segments of the perianth, by means of their surfaces,
but the union was confined to the centre of the segment, leaving the
rest of the surfaces free.
=Cohesion of the stamens.=--Under natural circumstances, cohesion of the
stamens is said to take place either by the union of their filaments, so
as to form one, two, or more parcels (Monadelphia, Diadelphia,
Polyadelphia); at other times, by the cohesion of the anthers
(Syngenesia), in which latter case the union is generally very slight.
It must be remembered, however, that the so-called cohesion of the
filaments is in many cases due rather to the formation of compound
stamens, _i.e._ to the formation from one original staminal tubercle of
numerous secondary ones, so that the process is rather one of over
development than of fusion or of disjunction. These conditions may be
met with as accidental occurrences in plants or in flowers, not usually
showing this arrangement. Thus, for instance, Professor Andersson, of
Stockholm, describes a monstrosity of _Salix calyculata_, in which the
stamens were so united together as to form a tube open at the top like a
follicle.[28] This is an exaggerated degree of that fusion which exists
normally in _Salix monandra_, in Cucurbits and other plants.
=Cohesion of the pistils= is also of very frequent occurrence in plants,
under ordinary circumstances, but is less commonly met with than might
have been expected as a teratological phenomenon.
Further details relating to cohesion of the various parts of
the flower are cited in Moquin-Tandon, 'El. Ter. Veg.,' p. 248;
'Weber. Verhandl. Nat. Hist. Vereins f. d. Preuss. Rheinl. und
Westphal.,' 1860, p. 332, tabs. 6 et 7.
=Formation of ascidia or pitchers.=--In the preceding paragraphs, the
formation of tubular or horn-like structures, from the union of the
margins of one organ, or from the coalescence, or it may be from the
want of separation of various organs, has been alluded to, so that it
seems only necessary now, by way of summary, to mention the
classification of ascidia proposed by Professor Charles Morren[29], who
divides the structures in question into two heads, according as they are
formed from one or more leaves. The following list is arranged according
to the views of the Belgian savant, and comprises a few additional
illustrations. Those to which the ! is affixed have been seen by the
writer himself; the * indicates the more frequent occurrence of the
phenomenon in some than in other plants. Those plants, such as
_Nepenthes_, &c., which occur normally and constantly, are not here
included. Possibly some of the cases would be more properly classed
under dilatation or excavation.
ASCIDIA.
A. _Monophyllous_.
1. Sarracenia-like pitchers, formed by a single leaf, the edges
of which are united for the greater portion of their length,
but are disunited near the top, so as to leave an oblique
aperture.
*Brassica oleracea (several of the cultivated varieties)!
*Tilia europæa!
Pelargonium inquinans!
Staphylea pinnata.
Amorpha fruticosa.
Pisum sativum!
Lathyrus tuberosus.
Vicia sp.
Gleditschia sp.
Ceratonia siliqua.
Trifolium repens!
Cassia marylandica.
Mimosa Lophantha.
Rosa centifolia.
gallica.
Begonia sp.
Bellis perennis!
Nicotiana sp.
Goodenia ovata!
Antirrhinum majus!
Vinca rosea.
Polygonum orientale.
Aristolochia sipho?
Codiæum variegatum var.!
Spinacia oleracea.
Corylus avellana!
Polygonatum multiflorum.
Xanthosoma appendiculatum!
2. Calyptriform or hood-like pitchers, formed by the complete
union of the margins, and falling off by a transverse fissure
(as in the calyx of Escholtzia).
Tulipa Gesneriana.
B. _Polyphyllous._
1. Diphyllous, formed by the union of two leaves into a single
cup, tube, or funnel, &c.
Pisum sativum (stipules)!
Crassula arborescens.
Polygonatum multiflorum.
2. Triphyllous, formed by the union of three leaves.
Paris quadrifolia var.
Besides the above varieties of ascidia formed from the union of
one or more leaves, there are others which seem to be the
result of a peculiar excrescence or hypertrophy of the leaf.
Such are some of the curious pitcher-like structures met with
occasionally in the leaves of cabbages, lettuces, Aristolochia,
&c. See Hypertrophy, cup-like deformities, &c.
In addition to other publications previously mentioned,
reference may be made to the following treatises on the subject
of ascidia:--Bonnet, 'Rech. Us. Feuilles,' p. 216, tab. xxvi,
f. 1, _Brassica_; De Candolle, 'Trans. Hort. Soc.,' t. v, pl.
1, _Brassica_; Id., 'Org. Veget.,' I, 316; 'Bull. Soc. Bot.
Fr.,' I, p. 62, _Polygonatum_; 'Bull. Acad. Belg.,' 1851, p.
591, _Rosa_; Hoffmann, 'Tijdschrift v. Natuur. Geschied.,' vol.
viii, p. 318, tab. 9, _Ceratonia_; C. Mulder, 'Tijdschrift,
&c.,' vol. vi, p. 106, tab. 5, 6, _Trifolium_, _Mimosa_,
_Staphylea_;' Molkenboer,' p. 115, t. 4, _Brassica_.
FOOTNOTES:
[10] See a curious instance of this kind in the branches of _Pinus_.
'Regel. Garten Flora,' vol. 8, tab. 268.
[11] 'Bull. Soc. Bot. France,' 1860, p. 881.
[12] Ibid., 1861, p. 708.
[13] Ibid., 1860, p. 923.
[14] 'Proc. Linn. Soc.,' April 5, 1853.
[15] 'Organ. Végét.,' pl. iii, fig. 1.
[16] 'Bull. Acad. Roy. Bruxelles,' t. xviii, p. i and p. 591.
[17] 'Linnæa,' tom. 13, p. 383.
[18] 'Verhandl. Nat. Hist. Vereins,' 1859, Bonn, tom. xvi, tab. 3.
[19] 'Bull. Soc. Bot. Fr.,' vol. i, p. 62.
[20] 'Report of Internat. Bot. Congress,' London, 1866, p. 131, tab.
vii, figs. 10-13.
[21] 'Bull. Acad. Roy. Belg.,' t. xviii, 2nd part, p. 179.
[22] D. C., 'Organ. Végét.,' pl. xvii, fig. 3, and pl. xlviii, fig. 2.
[23] 'Mém. Acad. Toulouse,' 1862.
[24] Bonnet, 'Recherches Us. feuill.,' pl. xxi, fig. 2.
[25] De Candolle, 'Mém. Lég.,' pl. v, fig. 14.
[26] 'Phil. Bot.,' § 125.
[27] 'Nov. Act. Acad. Nat. Cur.,' 14, p. 642, t. xxxvii.
[28] 'Journal of the Linn. Soc. Bot.,' vol. iv, p. 55.
[29] 'Bull. Acad. Roy. Bruxelles,' 1838, t. v, p. 582. 'Bull. Acad. Roy.
Belg.,' 1852, t. xix, part iii, p. 437.
CHAPTER II.
ADHESION.
Adhesion, so called, occurs either from actual union of originally
distinct members of different whorls or from the non-occurrence of that
separation which usually takes place between them. It is thus in some
degree a graver deviation than cohesion, and is generally a consequence
of, or at least is coexistent with, more serious changes; thus if two
leaves of the same whorl are coherent the change is not very great, but
if two leaves belonging to different whorls, or two leaves in the same
spiral cycle are adherent, a deformation in the axis or a certain amount
of dislocation must almost necessarily exist. Adhesion as a normal
occurrence is usually the result of a lack of separation rather than of
union of parts primitively separate. Instances of adhesion between
different organs is seen under ordinary circumstances in the bract of
the Lime tree, which adheres to the peduncle, also in _Neuropeltis_,
while in _Erythrochiton hypophyllanthus_ the cymose peduncles are
adherent to the under surface of the leaf.
Adhesion between the axes of the same plant is sufficiently treated of
under the head of Cohesion, from which it is in this instance impossible
to make a distinction. Adhesion of the inflorescence is necessarily a
frequent accompaniment of fasciation and cohesion of the branches.
=Adhesion of foliar organs= may occur either between the margins or
between the surfaces of the affected parts; in the former case there is
almost necessarily more or less displacement and change of direction,
such as a twisting of the stem and a vertical rather than a horizontal
attachment of the foliar organ to it; hence it generally forms but a
part of other and more important deviations.
=Adhesion of leaves by their surfaces.=--The union of leaves by their
surfaces is not of very frequent occurrence, many of the instances cited
being truly referable to other conditions. Bonnet describes the union of
two lettuce leaves, and Turpin that of two leaves of _Agave americana_,
in which latter the upper surface of one leaf was adherent to the lower
surface of the leaf next above it, and I have myself met with similar
instances in the wallflower and in lettuce and cabbage leaves; other
instances have been mentioned in _Saxifraga_, _Gesnera_, _&c._[30]
In these cases, owing to the non-development of the internodes, the
nascent leaves are closely packed, and the conditions for adhesion are
favorable, but in most of the so-called cases of adhesion of leaf to
leaf by the surface, a preferable explanation is afforded either by an
exuberant development (hypertrophy) or by chorisis (see sections on
those subjects). Thus, when a leaf of this kind is apparently so united,
that the lower surface of one is adherent to the corresponding surface
of another, the phenomenon is probably due rather to extra development
or to fission. There is an exception to this, however, in the case of
two vertically-erect leaves on opposite sides of the stem; here the two
upper or inner surfaces may become adherent, as in an orange, where two
leaves were thus united, the terminal bud between them being suppressed
or abortive.
Adhesion between the membranous bract of _Narcissus poeticus_ and the
upper surface of the leaf is described by Moquin.[31] The same author
mentions having seen a remarkable example of adhesion in the involucels
of _Caucalis leptophylla_, the bracts of which were soldered to the
outer surface of the flowers. M. Bureau[32] mentions an instance
wherein the spathe of _Narcissus biflorus_ was partially twisted in such
a manner that the lower surface of its median nerve was adherent to the
corresponding surface of one of the sepals, mid-rib to mid-rib, thus
apparently confirming a law of G. de Hilaire, that when two parts of the
same individual unite, they generally do so by the corresponding
surfaces or edges, but the rule is probably not so general in its
application as has been supposed.
=Adhesion of foliar to axile organs.=--The appendicular organs may
likewise be found united to the axile ones. This union takes place in
many ways; sometimes the leaves do not become detached from the stem for
a considerable distance, as in the so-called decurrent leaves, at other
times the leaves are prolonged at their base into lobes, which are
directed along the stem, and are united with it. Turpin records a
tendril of a vine which was fused with the stem for some distance, and
bore leaves and other tendrils. Union of the leaf or bract with the
flower-stalk is not uncommon. It occurs normally in the Lime and other
plants.
=Adhesion of the sepals to the petals= is spoken of by Morren as
calyphyomy, [Greek: kalyx phyomai.][33] Moquin cites an instance in
_Geranium nodosum_, in which one petal was united by its lower surface
to one of the segments of the calyx. A similar circumstance has been
observed in _Petunia violacea_ by Morren. Duchartre describes an
instance wherein one of the outer sepals of _Cattleya Forbesii_ was
adherent to the labellum.[34]
=Adhesion of the stamens to the petals= is of common occurrence under
natural circumstances. Cassini has described a malformation of
_Centaurea collina_, in which two of the five stamens were completely
grafted with the corolla, the three others remaining perfectly free.
Adhesion of the petals to the column is not of infrequent occurrence
among Orchids. I have observed cases of the adhesion of the segments of
the perianth to the stamen in _Ophrys aranifera_, _Odontoglossum_, _sp_.
&c. It is the ordinary condition in _Gongora_ and some other genera. I
have seen it also in _Lilium lancifolium_. Some forms of _Crocus_,
occasionally met with, present a very singular appearance, owing to the
adhesion of the stamens to the outer segments of the perianth, the
former, moreover, being partially petaloid in aspect. M. de la Vaud[35]
speaks of a similar union in _Tigridia pavonia_. Morren[36] describes a
malformation of _Fuchsia_ wherein the petals were so completely adherent
to the stamens, that the former were dragged out of their ordinary
position, so as to become opposite to the sepals; the fusion was here so
complete that, no trace of it could be seen externally. It should be
remarked that it was the outer series of stamens that were thus
fused.[37]
[Illustration: FIG. 12.--_Crocus._ Adhesion of petaloid stamens to
perianth.]
=Adhesion of stamens to pistils.=--The stamens also may be united to the
pistils, as in gynandrous plants. Moquin speaks of such a case in a
_Scabious_; M. Clos in _Verbascum australe_.[38] I have seen cases of
the same kind in the Wallflower, Cowslip (_Primula veris_), Tulip,
Orange, in the garden Azalea and other plants.
=Miscellaneous adhesions.=--Sometimes organs, comparatively speaking,
widely separated one from the other, become united together. Miquel has
recorded the union of a stigma with the middle lobe of the lower lip of
the corolla of _Salvia pratensis_.[39] In the accompanying figure [fig.
13], taken from a double wallflower, there is shown an adhesion between
a petal and an open carpel on the one side, and a stamen on the other.
Moquin speaks of some pears, which were united, at an early stage, with
one or two small leaves borne by the peduncle and grafted to the fruit
by the whole of their upper surface. As the pear increased in size the
leaves became detached from it, leaving on the surface of the fruit an
impression of the same form as the leaf, and differing in colour from
the rest of the surface of the fruit. Traces of the principal nerves
were seen on the pear.
[Illustration: FIG. 13.--_Cheiranthus cheiri_. Adhesion of petal to
stamen and open carpel.]
It is curious to notice how very rare it is for the calyx to adhere to
the ovary in flowers where that organ is normally superior. The "_calyx
inferus_" seems scarcely ever to become "_calyx superus_," while, on the
other hand, the "_calyx normaliter superus_" frequently becomes inferior
from detachment from, or from want of union with the surface of the
ovary.
=Adhesion of fruit to branch.=--Of this Mr. Berkeley[40] cites an
instance in a vegetable marrow (_Cucumis_), where a female flower had
become confluent with the branch, at whose base it was placed, and also
with two or more flowers at the upper part of the same branch, so as to
make an oblique scar running down from the apex of the fruit to the
branch.
=Synanthy.=--Adhesion of two or more flowers takes place in various
ways; sometimes merely the stalks are united together, so that we have
a single peduncle, bearing at its extremity two flowers placed in
approximation very slightly adherent one to the other. In this manner I
have seen three flowers of the vegetable marrow on a common stalk, the
flowers themselves being only united at the extreme base. Occasionally
cases may be met with wherein the pedicels of a stalked flower become
adherent to the side of a sessile flower. I have noticed this commonly
in _Umbelliferæ_. Union of this kind occurs frequently in the common
cornel (_Cornus_), wherein one of the lower flowers becomes adherent to
one of the upper ones. In De Candolle's 'Organographie Végétale,' Plates
14 and 15, are figured cases of fusion of the flower stems of the
Hyacinth and of a _Centaurea_. In other cases the union involves not
only the stalk but the flowers themselves; thus fusion of the flowers is
a common accompaniment of fasciation, as was the case in the _Campanula_
figured in the cut (fig. 14).
[Illustration: FIG. 14.--Synanthic flowers of _Campanula medium_.]
Synanthy may take place without much derangement of the structure of
either flower, or the union may be attended with abortion or suppression
of some of the parts of one or both flowers. Occasionally this union is
carried to such an extent that a bloom appears to be single, when it is,
in reality, composed of two or more, the parts of which have become not
only fused, but, as it were, thrust into and completely incorporated one
with another, and in such a manner as to occupy the place of some parts
of the flower which have been suppressed. It must not be overlooked that
this adhesion of one flower to another is a very common occurrence under
natural circumstances, as in _Lonicera_, in the common tomato, in
_Pomax_, _Opercularia_, _Symphyomyrtus_, &c., while the large size of
some of the cultivated sunflowers is in like manner due to the union of
two or more flower-heads.
One of the simplest instances of synanthy is that mentioned by M.
Duchartre,[41] in which two flowers of a hyacinth were united together
simply by means of two segments of the perianth one from each flower. A
similar occurrence has been cited by M. Gay in _Narcissus chrysanthus_.
In like manner the blossoms of Fuchsias or Loniceras occasionally become
adherent merely by their surface, without involving any other change in
the conformation of the flowers. M. Maugin alludes to a case of this
kind in _Aristolochia Clematitis_.[42]
But it is more usual for some of the organs to be suppressed, so that
the number of existing parts is less than would be the case in two or
more uncombined flowers. A few illustrations will exemplify this. In two
flowers of _Matthiola incana_, that I observed to be joined together,
there were eight sepals, eight petals, and ten perfect stamens, eight
long and two short, instead of twelve. Closer examination showed that
the point of union between the two flowers occurred just where, under
ordinary circumstances, the two short stamens would be. In this instance
but little suppression had occurred. In similar flowers of _Narcissus
incomparabilis_ I remarked a ten-parted perianth, ten stamens within a
single cup, two styles, and a five-celled ovary. Here, then, it would
appear that two segments of the perianth, two stamens, and one carpel
were suppressed. In a Polyanthus there were nine sepals, nine petals,
nine stamens, and a double ovary.
[Illustration: FIG. 15.--Union of three flowers of _Calanthe vestita_.]
[Illustration: FIG. 16.--Shows the abortion of the central spur in
synanthic flowers of _Calanthe vestita_.]
As an illustration of a more complicated nature reference may be made to
three flowers of _Aconitum Napellus_, figured by A. de Chamisso,
'Linnæa,' vol. vii, 1832, p. 205, tab. vii, figs. 1, 2. In this specimen
the two outer blossoms had each four sepals present, namely, the upper
hooded one, one of the lateral sepals, and both of the inferior ones;
the central flower had only the upper sepal and one other, probably one
of the lower sepals; thus there were but ten sepals instead of fifteen.
The nectary-like petals, the stamens, and pistils were all present in
the lateral flowers, but were completely suppressed in the middle one. A
less degree of suppression was exemplified in a triple flower of
_Calanthe vestita_ sent me by Dr. Moore, of Glasnevin, in which all the
parts usually existing in three separate flowers were to be found, with
the exception of the spur belonging to the labellum of the middle flower
(figs. 15, 16).
One of the most common malformations in the Foxglove (_Digitalis_)
results from the fusion of several of the terminal flowers into one. In
these cases the number of parts is very variable in different instances;
the sepals are more or less blended together, and the corollas as well
as the stamens are usually free and distinct, the latter often of equal
length, so that the blossom, although truly complex, is, as to its
external form, less irregular than under natural circumstances. The
centre of these flowers is occupied by a two to five-celled pistil,
between the carpels of which, not unfrequently, the stem of the plant
projects, bearing on its sides bracts and rudimentary flowers. (See
Prolification.) An instance of this nature is figured in the 'Gardeners'
Chronicle,' 1850, p. 435, from which the cut (fig. 17) is borrowed.
[Illustration: FIG. 17.--Synanthy and other changes in a Foxglove.]
One of the most singular recorded instances of changes connected with
fusion of the flowers is that cited by Reinsch,[43] where two female
flowers of _Salix cinerea_ were so united with a male one as to produce
an hermaphrodite blossom.
It follows, from what has been said, that the number of parts that are
met with in these fused flowers varies according to the number of
blossoms and of the organs which have been suppressed. Comparatively
rarely do we find all the organs present; but when two flowers are
united together we find every possible variety between the number of
parts naturally belonging to the two flowers and that belonging to a
single one. Sometimes instances are met with wherein the calyx does not
present the normal number of parts, while the other parts of the flower
are in excess. I have seen in a _Calceolaria_ a single calyx, with the
ordinary number of sepals, enclosing two corollas, adherent simply by
their upper lips, and containing stamens and pistils in the usual way.
In this instance, then, the sepals of one flower must have been
suppressed, while no such suppression took place in the other parts of
the flower.
Professor Charles Morren paid special attention to the various methods
in which the flowers of Calceolarias may become fused, and to the
complications that ensue from the suppression of some parts, the
complete amalgamation of others, &c. Referring the reader to the Belgian
savant's papers for the full details of the changes observed, it is only
necessary to allude to a few of the most salient features.
[Illustration: FIG. 18.--Synanthic flowers of Calceolaria in which, with
two upper lips, there was but a single lower one.]
Sometimes the upper lips of two flowers are fused into one, the two
lower remaining distinct. In other cases, the upper lip disappears
altogether, while there are two lower lips placed opposite one another;,
of the stamens, sometimes the outermost, at other times the innermost
disappear.[44]
Occasionally there appears to be, as it were, a transference of the
parts of one flower to another. One of the simplest and most
intelligible cases of this kind is recorded by Wigand in the 'Flora' for
1856, in a compound flower of _Polygonatum anceps_, in which within a
twelve-parted perianth there were twelve stamens and two pistils, one
four-celled, the other two-celled; hence it would appear as if a carpel
belonging to one flower had become united to those constituting the
pistil of the adjacent one. Among Orchids this fusion of some of the
elements of different flowers, together with the suppression of others,
is carried to such an extent as to render the real structure difficult
to decipher. Sometimes flowers of _Ophrys aranifera_, at first sight
seeming normal as to the number, and almost so as regards the
arrangement of their parts, have yet, on examination, proved to be the
result of a confluence of two flowers. Mr. Moggridge has observed
similar phenomena in the same species at Mentone.
Sometimes the fusion affects flowers belonging to different branches of
the same inflorescence, as in _Centranthus ruber_, described by
Buchenau, 'Flora,' 1857, p. 293, and even a blossom of one generation of
axes may be united with a flower belonging to another generation. Thus
M. Michalet[45] speaks of a case wherein the terminal flower of
_Betonica alopecuros_ was affected with Peloria, and fused with an
adjacent one belonging to a secondary axis of inflorescence, and not yet
expanded. This latter flower had no calyx, but in its place were three
bracts, surrounding the corolla; this again was united to the calyx of
the terminal bloom in a most singular manner, the limb of the corolla
and that of the calyx being so joined one to the other as to form but a
single tube. It is not uncommon, as has been before stated, to find two
corollas enclosed within one calyx, but this is probably the only
recorded instance of the fusion of the calyx and corolla of two
different flowers belonging to two different axes.
From the preceding details, as well as from others which it is not
necessary to give in this place, it would appear that synanthy is more
liable to occur where the flowers are naturally crowded together[46]
than where they are remote; so too, the upper or younger portions of the
inflorescence are those most subject to this change. In like manner the
derangements consequent on the coalescence of flowers are often more
grave in the central organs, which are most exposed to pressure, and
have the least opportunities of resisting the effects of that agency,
than they are in the outer portions of the flowers where growth is less
restricted.
Morren in his papers on synanthic _Calceolarias_, before referred to,
considers that the direction in which fusion acts is centripetal, _e.g._
from the circumference towards the centre of the flower, thus reversing
the natural order of things. He considers that there is a radical
antagonism between the normal organizing forces and the teratological
disorganizing forces, and explains in this way the frequent sterility of
monsters from an imperfect formation of stamens, or pistils, or both.
The greater tendency in synanthic flowers of parts of one whorl to
adhere to the corresponding organs in another flower has often been
remarked, though the dislocation of parts may be so great as to prevent
this from being carried out in all cases. It appears also that synanthy
is more frequently met with among flowers which have an inferior ovary
than in those in which the relative position of the organ in question
is reversed. This remark applies particularly to individual cases; the
proportion as regards the genera may not be so large. The explanation of
this must of course depend on the circumstances of each particular case;
and it would be wrong to attempt to lay down a general rule, when
organogenists have not yet fully decided in what plants the inferior
ovary is an axial structure, and in what others the appearance is due to
the adhesion of the base of the calyx to the carpels.
The list which follows is not intended as a complete one, but it may
serve to show what plants are more particularly subject to this anomaly;
the * indicates unusual frequency of occurrence, the ! signifies that
the writer has himself seen instances in the plants named. Many of the
recorded cases of Synanthy are really cases of adhesion of the
inflorescence rather than of the flowers.
Ranunculus Lingua.
bulbosus!
Aconitum Napellus.
Delphinium sp.!
Matthiola incana!
Arabis sagittata.
Silene sp.
Reseda odorata!
Vitis vinifera.
Citrus aurantium.
*Fuchsia var. hort.!
OEnothera sp.
Saxifraga sp.
Podalyria myrtillifolia.
Prunus Armeniaca.
spinosa.
Pyrus Malus.
Persica vulgaris.
Cratægus monogyna.
Robinia pseudacacia.
Gleditschia triacanthos.
Syringa persica.
Cornus sanguinea.
Viburnum sp.
*Lonicera sp. plur!
Centranthus ruber!
Valantia cruciata.
Centaurea moschata.
Jacea.
Zinnia elegans.
Zinnia revoluta.
Helianthus sp.!
Spilanthes oleracea.
Dahlia.
*Leontodon Taraxacum!
Senecio Doria.
Cichorium Intybus.
Lactuca sativa.
Anthemis retusa.
*Campanula medium!
persicifolia.
Azalea indica!
Vinca minor.
Atropa Belladonna.
*Solanum Lycopersicum!
*Petunia violacea!
Galeopsis ochroleuca.
Betonica alopecuros.
*Digitalis purpurea!
*Antirrhinum majus!
*Linaria purpurea!
*Pedicularis sylvatica!
*Calceolaria var. hort.!
Scrophularia nodosa.
Salpiglossis straminea.
Streptocarpus Rexii.
*Gesnera var. hort.!
Æschynanthus sp.!
Thyrsacanthus rutilans!
Anagallis collina.
*Primula veris!
Auricula.
*Primula acaulis, var. umbellata!
elatior?
* sinensis!
Aristolochia Clematitis.
Blitum sp.
Chenopodium sp.
Rumex sp.
Salix cinerea.
*Hyacinthus orientalis!
Lilium bulbiferum!
croceum, et sp. alix, pl.
Tulipa, sp.
Polygonatum anceps.
Fritillaria imperalis!
Agave americana.
Iris versicolor.
sambucina.
Crocus, sp.
Colchicum autumnale.
Narcissus incomparabilis!
Tazetta.
biflorus.
chrysanthus.
*Ophrys aranifera!
Calanthe vestita!
Oncidium bicolor.
ornithorhyncum.
&c. &c.
In addition to the works before cited, additional information
on this subject may be gained from the following:--Jaeger,
'Missbilld.,' p. 92. v. Schlechtend, 'Bot. Zeit.,' 1856,
_Robinia_. Weber, 'Verhandl. Nat. Hist. Vereins. Preuss.
Rheinl.,' 1849, p. 290, _Primula_. Hincks, 'Rep. Brit. Assoc.
Newcastle,' 1838, _Salpiglossis_. Clos, 'Mém. Acad. Toulouse,'
vol. vi, 1862, _Anagallis_. Wigand, 'Flora,' 1856, tab. 8,
_Pedicularis_. Henfrey, 'Botan. Gazette,' i, p. 280, _Reseda_.
P. Reinsch, 'Flora,' 1860, tab. 7, _Petasites_. Weber,
Verhandl. Nat. Hist. Vereins. f.d. Preuss. Rheinl. u.
Westphal.,' 1860, p. 332, tabs. 6 et 7, _Prunus_, _Persica_,
_Campanula_, _Taraxacum_, _Saxifraga_, _Silene_, _Hyacinthus_,
_&c._ Miquel, 'Linnæa,' xi, p. 423, _Colchicum_. Michel,
'Traité du Citronnier,' tab. 6, _Citrus_.
=Syncarpy.=--In the preceding section it has been shown that the
carpels, like other parts of the flower, are subject to be united
together. This union may either take place between the carpels of a
single flower or between the pistils of different flowers. In the latter
case the other floral whorls are generally more or less altered. Where,
however, the ovary is, as it is called, inferior, it may happen that the
pistils of different flowers may coalesce more or less without much
alteration in the other parts of the flower, as happens normally in many
_Caprifoliaceæ_, _Rubiaceæ_, &c. &c. In some of these cases it must be
remembered that the real structure of the apparent fruit is not made out
beyond dispute, the main points of controversy being as to what, if any,
share the dilated fruit-stalk or axis takes in the formation of such
organs. Again, it will be borne in mind that in some cases the so-called
fruit is made up of a number of flowers all fused together, as in the
Mulberry or the Pineapple, in which plants what is, in ordinary
language, called the fruit really consists of the whole mass of flowers
constituting the inflorescence fused together. Union of the fruits may
also in some cases take place between the carpels after the fall of the
other floral whorls, particularly when the outer layers of the pericarp
assume a succulent condition, so that under the general head of syncarpy
really different conditions are almost necessarily grouped together,
and, in seeking to investigate the causes of the phenomenon, the
particular circumstances of each individual case must be taken into
account. Syncarpy takes place in various degrees; sometimes only the
stalks are joined; at other times the whole extent of the fruit, as in
cherries, &c. This peculiarity did not escape the observant mind of
Shakespeare--
"A double cherry seeming parted.
But yet a union in partition,
Two lovely berries moulded on one stem."
'Midsummer Night's Dream,' act iii, sc. 2.
A similar union has been observed in peaches, gooseberries, gourds,
melons, and a great many other fruits. In the Barbarossa grape I have
frequently seen a fusion of two, three, four or more berries quite at
the end of the bunch, so that the clusters were terminated by a compound
grape. Seringe has remarked sometimes two, sometimes three, fruits of
_Ranunculus tripartitus_ soldered together. He has also seen three
melons similarly joined.[47] Turpin mentions having seen a complete
union between the three smooth and leathery pericarps which are
naturally separate and enclosed within the spiny cupule of the
chestnut.[48] Poiteau and Turpin have figured and described in their
treatise on fruit trees, under the name of Néfle de Correa, four or five
medlars, joined together and surmounted by all the persistent leaflets
of the calyces.[49]
A very remarkable example of Syncarpy has been recorded by E. Koenig
in which nine strawberries were borne on one stem (_Fragaria
botryformis_),[50] and a similar malformation has been observed in the
Pineapple.
When two fruits are united together they may be of about equal size,
while in other cases one of the two is much smaller than the other. This
was the case in two cucumbers given to me by Mr. James Salter. These
were united together along their whole length excepting at the very
tips; the upper one of the two was much larger than the lower, and
contained three cells, the lower fruit was one-celled by suppression.
Both fruits were curved, the curvature being evidently due to the more
rapid growth of the upper as compared with the lower one.
[Illustration: FIG. 19.--Adhesion of two apples.]
[Illustration: FIG. 20.--Section of united apples.]
In many of these cases, where the fruits are united by their bases, the
summits become separated one from the other, so as to resemble the
letter V. Such divergence is of frequent occurrence where fruits are
united by their stalks, because, as growth goes on, the tendency must
necessarily be towards separation and divergence of the tips of the
fruit.
In some cases of Syncarpy the fusion and interpenetration of the carpels
is carried to such an extent that it is very difficult to trace on the
outer surface the lines of union. The fruit in these cases resembles a
single one of much larger size than usual. Moquin mentions a double
apple in which the connection was so close that the fruit was not very
different in form from what is customary, and a similar thing happens
with the tomato. In the case of stone-fruits it sometimes happens, not
only that the outer portions are adherent, but that the stones are so
likewise.
M. Roeper has observed two apples grafted together, one of which had
its stalk broken, and seemed evidently borne and nourished by the other
apple;[51] and a similar occurrence happens not infrequently in the
cucumber. Moquin has seen three united cherries having only a single
stalk jointed to the central fruit, the lateral cherries having each a
slight depression or cicatrix marking the situation of the suppressed
stalks. Schlotterbec has figured three apples presenting precisely
similar appearances.[52]
Fusion of two or more nuts (_Corylus_) is not uncommon; I have seen as
many as five so united.[53] In these cases the fruits may be united
together in a ring or in linear series.
In some _Leguminosæ_, contrary to the general rule in the order, more
than one carpel is found; thus peas, French beans, and other similar
plants, are occasionally met with having two or more pods within the
same calyx, and in _Gleditschia triacanthos_ and _Cæsalpinia digyna_
this is so commonly the case as to be considered almost the normal
state. (De Cand. 'Mem. Leg.,' pl. 2, fig. 6; pl. 3, fig. 2.) At times
these carpels become fused together, and it becomes difficult, when the
traces of the flower have disappeared, to ascertain whether these
carpels were formed in one flower, or whether they were the result of
the fusion of several blossoms. I have seen an instance of this kind in
a plum in which there were two carpels in the same flower, the one being
partially fused to the other. The nature of such cases may usually be
determined by an inspection of the peduncle which shows no traces of
fusion. (See chapter on Multiplication.)
When, however, the fruits are sessile, and they become grafted together,
the kind of syncarpy is difficult to distinguish. It, may, nevertheless,
be said as a general rule that the union brought about by the
approximation of two fruits, after the fall of the floral whorls, is
never so complete or so intimate as that determined by synanthy; and
also that in those cases where there are supernumerary carpels in the
flower, and those carpels become united together, they are rarely so
completely fused that their individuality is lost.
An analogous phenomenon takes place not uncommonly in mosses, the spore
capsules of which become united together in various ways and degrees.
Schimper[54] cites the following species as subject to this
anomaly:--_Buxbaumia indusiata_, _Leskea sericea_, _Hypnum lutescens_,
_Anomodon alternatus_, _Clinacium dendroides_, _Bryum cæspititium_,
_Brachythecium plumosum_, _Mnium serratum_, _Splachnum vasculosum_. It
has also been observed in _Trichostomum rigidulum_ and _Hypnum
triquetrum_.
In addition to the authorities already mentioned, the reader
may consult Moquin-Tandon, 'El. Ter. Veg.,' p. 270. Turpin.
'Mém. greffe. Ann. Sc. Nat.,' ser. i, t. xxiv, p. 334. De
Candolle, 'Organ. Veget.,' t. i. Duhamel, 'Phys. des Arbres,'
t. i, p. 304, tab. xiii, xiv. Weber. 'Verhandl. Nat. Hist.
Vereina f. d. Preuss. Rheinl. u. Westphal.,' 1860, p. 332, tab.
vi. et vii.
=Synspermy, or Union of the Seeds.=--Seeds may be united together in
various degrees, either by their integuments,[55] or by their inner
parts. Such union of the seeds, however, is of rare occurrence. It takes
place normally, to a slight extent, in certain cultivated forms of
cotton, wherein the seeds are aggregated together into a reniform mass,
whence the term kidney cotton. Union of the parts of the embryo is
treated under another head (see Synophty).
=Adhesion between the axes of different plants.=--Under this head may be
classed the union that takes place between the stems, branches, or roots
of different plants of the same species, and that which occurs between
individuals of different species; the first is not very different in its
nature from cohesion of the branches of the same plant (figs. 21, 22).
It finds its parallel, under natural circumstances, among the lower
cryptogams, in which it often happens that several individual plants,
originally distinct, become inseparably blended together into one mass.
In the gardening operations of inarching, and to some extent in budding,
this adhesion of axis to axis occurs, the union taking place the more
readily in proportion as the contact between the younger growing
portions of the two axes respectively is close. The huge size of some
trees has been, in some cases, attributed to the adnation of different
stems. This is said to be the case with the famous plane trees of
Bujukdere, near Constantinople, and in which nine trunks are more or
less united together.[56]
[Illustration: FIG. 21.--Adhesion of two distinct stems of oak, or
possibly cohesion of branches of the same tree. 'Gard. Chron.,' 1846, p.
252.]
A similar anastomosis may take place in the roots. Lindley cites a case
wherein two carrots, of the white Belgian and the red Surrey varieties
respectively, had grown so close to each other that each twisted half
round the other, so that they ultimately became soldered together; the
most singular thing with reference to this union was, that the red
carrot (fig. 23, _b_), with its small overgrown part above the
junction, took the colour and large dimensions of the white Belgian
(_d_), which, in like manner, with its larger head above the joining
(_a_), took the colour and small dimensions of the red one at and below
the union (_e d_). The respective qualities of the two roots were thus
transposed, while the upper portions or crowns were unaffected: the root
of one, naturally weak, became distended and enlarged by the abundant
matter poured into it by its new crown; and in like manner the root of
the other, naturally vigorous, was starved by insufficient food derived
from the new crown, and became diminutive and shrunken (see Synophty).
[Illustration: FIG. 22.--Adhesion of the branches of two elms. 'Gard.
Chron.,' 1849, p. 421.]
The explanation of the fact that the stumps of felled fir trees
occasionally continue to grow, and to deposit fresh zones of wood over
the stump, depends on similar facts. In _Abies pectinata_, says
Goeppert,[57] the roots of different individuals frequently unite; hence
if one be cut down, its stump may continue to live, being supplied with
nourishment from the adjacent trees to which it is adherent by means of
its roots.
[Illustration: FIG. 23.--Adhesion of two roots of carrot. 'Gard.
Chron.,' 1851, p. 67.]
A not uncommon malformation in mushrooms arises from the confluence of
their stalks (fig. 24), and when the union takes place by means of the
pilei, it sometimes happens, during growth, that the one fungus is
detached from its attachment to the ground, and is borne up with the
other, sometimes, even, being found in an inverted position on the top
of its fellow.[58]
The garden operations of budding, grafting and inarching have already
been alluded to as furnishing illustrations of adhesion, but it may be
well to refer briefly to certain other interesting examples of adhesion
induced artificially; thus, the employment of the root as a stock,
"root-grafting," is now largely practised with some plants, as affording
a quicker means of propagation than by cuttings; and a still more
curious illustration may be cited in the fact that it has also been
found possible to graft a scion on the leaf in the orange.[59]
[Illustration: FIG. 24.--Section through two adherent mushrooms, the
upper one inverted.]
Mr. Darwin, in his work on the 'Variation of Animals and Plants,' vol.
i, p. 395, alludes to the two following remarkable cases of
fusion:--"The author of 'Des Jacinthes' (Amsterdam, 1768, p. 124) says
that bulbs of blue and red hyacinths may be cut in two, and that they
will grow together, and throw up a united stem (and this Mr. Darwin has
himself seen), with flowers of the two colours on the opposite sides.
But the remarkable point is, that flowers are sometimes produced with
the two colours blended together." In the second case related by Mr.
Trail, about sixty blue and white potatoes were cut in halves through
the eyes or buds, and the halves were then joined, the other buds being
destroyed. Union took place, and some of the united tubers produced
white, others blue, while some produced tubers partly white and partly
blue.
=Adhesion of the axes of plants belonging to different species is a=
more singular occurrence than the former, and is of some interest as
connected with the operation of grafting. As a general rule
horticulturists are of opinion, and their opinion is borne out by facts,
that the operation of grafting, to be successful, must be practised on
plants of close botanical affinity. On the other hand, it is equally
true that some plants very closely allied cannot be propagated in this
manner. Contact between the younger growing tissues is essential to
successful grafting as practised by the gardener, and is probably quite
as necessary in those cases where the process takes place naturally.
Although there is little doubt but that some of the recorded instances
of natural or artificial grafting of plants of distant botanical
affinities are untrustworthy, yet the instances of adhesion between
widely different plants are too numerous and too well attested to allow
of doubt. Moreover, when parasitical plants are considered, such as the
Orobanches, the Cuscutas, and specially the mistleto (_Viscum_), which
may be found growing on plants of very varied botanical relationship,
the occurrence of occasional adhesion between plants of distant affinity
is not so much to be wondered at. Union between the haulms of wheat and
rye, and other grasses, has been recorded[60]. Moquin-Tandon[61] relates
a case wherein, by accident, a branch of a species of _Sophora_ passed
through the fork, made by two diverging branches of an elder
(_Sambucus_), growing in the Jardin des Plantes of Toulouse. The branch
of the _Sophora_ contracted a firm adhesion to the elder, and what is
remarkable is that, although the latter has much softer wood than the
former, yet the branch of the harder wooded tree was flattened, as if
subjected to great pressure[62]. It is possible that some of the cases
similar to those spoken of by Columella, Virgil[63], and other classical
writers, may have originated in the accidental admission of seeds into
the crevices of trees; in time the seeds grew, and as they did so, the
young plants contracted an adhesion to the supporting tree. Some of the
instances recorded by classical writers may be attributed to intentional
or accidental fallacy, as in the so-called "greffe des charlatans" of
more modern days.
Adhesion of the roots of different species has been effected
artificially, as between the carrot and the beet root, while Dr. Maclean
succeeded in engrafting, on a red beet, a scion of the white Silesian
variety of the same species. In all these cases, even in the most
successful grafts, the amount of adhesion is very slight; the union in
no degree warrants the term fusion, it is little but simple contact of
similar tissues, while new growing matter is formed all round the cut
surfaces, so that the latter become gradually imbedded in the newly
formed matter.
=Synophty or adhesion of the embryo.=--This often occurs partially in
the embryo plants of the common mistleto (_Viscum_), but is not of
common occurrence in other plants, even in such cases as the orange
(_Citrus_), the _Cycadeæ_, _Coniferæ_, &c., where there is frequently
more than one embryo in the seed. Alphonse De Candolle has described and
figured an instance of the kind in _Euphorbia helioscopia_, wherein two
embryo plants were completely grafted together throughout the whole
length of their axes, leaving merely the four cotyledons separate. A
similar adnation has been observed by the same botanist in _Lepidium
sativum_ and _Sinapis ramosa_, as well as in other plants.[64] I have
met with corresponding instances in _Antirrhinum majus_ and in _Cratægus
oxyacantha_, in the latter case complicated with the partial atrophy of
one of the four cotyledons. It is necessary to distinguish between such
cases and the fallacious appearances arising from a division of the
cotyledons. M. Morren has figured and described the union of two roots
of carrot (_Daucus_), which were also spirally twisted. He attributes
this union to the blending of two radicles, and applies the term
"rhizocollesy" to this union of the roots.[65] Mr. Thwaites cites a case
wherein two embryos were contained in one seed in a _Fuchsia_, and had
become adherent. What is still more remarkable, the two embryos were
different, a circumstance attributable to their hybrid origin, the seed
containing them being the result of the fertilisation of _Fuchsia
coccinea_ (quere _F. magellanica?_) by the pollen of _F. fulgens_.
FOOTNOTES:
[30] Wydler, 'Flora,' 1852, p. 737, tab. ix.
[31] 'El. Ter. Veg.,' p. 254.
[32] 'Bull. Soc. Bot. Fr.,' 1857, p. 451.
[33] 'Bull. Acad. Belg.,' vol. xix, part ii, p. 335.
[34] 'Bull. Soc. Bot. Fr.,' 1860, p. 25.
[35] 'Bull. Soc. Bot. Fr.,' 1861, p. 147.
[36] 'Bull. Acad. Belg.,' vol. xviii, part ii, p. 498.
[37] See also Prillieux, 'Bull. Soc. Bot. Fr.,' 1861, p. 195.
[38] 'Mém. Acad. Toulouse,' 5th Series, vol. iii.
[39] Linnæa, vol. ii. p. 607.
[40] 'Journal Roy. Hort. Soc.,' new ser., vol. i. 1866, p. 200.
[41] 'Bull. Soc. Bot. Fr.,' 1861, p. 159.
[42] Ibid., 1859, p. 467.
[43] 'Flora,' 1858, p. 65, tab. ii.
[44] C. Morren. 'Bull. Acad. Belg.,' vol. xv (Fuchsia, p. 89); vol.
xviii, p. 591. (Lobelia, p. 142); vol. xix, p. 352; vol. xx, p. 4.
[45] 'Bull. Soc. Bot. Fr.,' vol. vii, p. 625.
[46] Cramer, 'Bildungsabweichungen,' p. 56, tab. vii, fig. 10, figures a
case wherein the two central flowers of the capitulum of _Centaurea
Jacea_ were united together.
[47] 'Bull. Bot.' tab. iii, figs. 4-6.
[48] 'Mém. greffe Ann. Science Nat.,' ser. i, t. xxiv, p. 334.
[49] "Mespilus portentosa." Poit. et Turp., 'Pomol. Franc.,' liv, xxxi,
p. 202, pl. 202.
[50] Duchesne, 'Hist. Nat. Frais.,' p. 79.
[51] De Cand., 'Phys. Végét.,' tom. ii, p. 781.
[52] Sched. de monstr. plant. 'Act. Helv.,' tab. i, fig. 8.
[53] 'Mém. greffe,' loc. cit., tab. xxiv, p. 334.
[54] 'Bull. Soc. Bot. Franc.,' 8, pp. 73 and 351, tab. ii; and Röse.
'Bot. Zeit.,' x, p. 410.
[55] _Nymphæa lutea_, _Æsculus Hippocastanum_, &c. See Moquin, 'El.
Ter. Veg.,' p. 277.
[56] C. Martins, 'Promenade Botanique,' p. 8.
[57] 'Ann. Sc. Nat.,' t. xix, 1843, p. 141, tab. iv.
[58] 'Ann. Nat. Hist.,' ser. 2, vol. ix, tab. xvi. 'Phytologist,' 1857.
p. 352, &c.
[59] Quoted from the 'Revue Hortic.' in 'Gard. Chron.,' 1866, p. 386.
[60] Senebier, 'Phys Végét.,' t. iv, p. 426. The same author also cites
Romer as having found two plants of _Ranunculus_, from the stem of which
emerged a daisy. As it is not an uncommon practice to stick a daisy on a
buttercup, it is to be hoped no hoax was played off on M. Romer.
[61] 'El. Ter. Veg.,' p. 289.
[62] An instance of this kind is cited in Dr. Robson's memoir of the
late Charles Waterton, from which it appears that two trees, a spruce
fir and an elm, were originally planted side by side, and had been
annually twisted round each other, so that they had in places grown one
into the other, with the result of stunting the growth of both trees,
thus illustrating, according to the opinion of the eccentric naturalist
above cited, the incongruous union of Church and State!
[63] See Daubeny, 'Lectures on Roman Husbandry,' p. 156.
[64] A. P. De Candolle, 'Organ Végét.,' t. ii, p. 72, tab. liv, fig. 1.
[65] 'Bull. Acad. Belg.,' t. xx, part i, 1852, p. 43.
PART II.
INDEPENDENCE OR SEPARATION OF ORGANS.
Under this head are included all those instances wherein organs usually
entire, or more or less united, are, or appear to be, split or
disunited. It thus includes such cases as the division of an ordinarily
entire leaf into a lobed or partite one, as well as those characterised
by the separation of organs usually joined together. Union, as has been
stated in a previous chapter, is the result either of persistent
integrity or of a junction of originally separate organs, after their
formation; so in like manner, the separation or disjunction of parts may
arise from the absence of that process of union which is habitual in
some cases, or from an actual _bonâ fide_ separation of parts originally
united together. In the former case, the isolation of parts arises from
arrest of development, while in the latter it is due rather to luxuriant
growth. A knowledge, as well of the ordinary as of the unusual course,
of development in any particular flower is thus required in order to
ascertain with accuracy the true nature of the separation of parts. The
late Professor Morren[66] proposed the general term Monosy ([Greek:
monôsis]) for all these cases of abnormal isolation, subdividing the
group into two, as follows--1, Adesmy ([Greek: a-desmos]), including
those cases where the separation is congenital; and 2, Dialysis ([Greek:
dialyô]), comprising those instances where the isolation is truly a
result of the separation of parts previously joined together. Adesmy,
moreover, was by the Belgian savant said to be homologous when it
occurred between members of the same whorl, _e.g._ between the sepals of
an ordinary monosepalous calyx, or heterologous when the separation took
place between members of different whorls, as when the calyx is detached
from the ovary, &c. The former case would thus be the converse of
cohesion, the latter of adhesion.
To the adoption of these words there is this great objection, that we
can but rarely, in the present state of our knowledge, tell in which
group any particular illustration should be placed.
The terms adopted in the present work are, for the most part, not
necessarily intended to convey any idea as to the organogenetic history
of the parts affected. Where a single organ, that is usually entire,
becomes divided the term Fission is used; in cases where parts of the
same whorl become isolated, the word Dialysis is employed, and in the
same sense in which it is generally used by descriptive botanists, and
where the various whorls become detached one from the other, the
occurrence is distinguished by the application of the term Solution.
FOOTNOTES:
[66] 'Bull. Acad. Belg.,' t. xix, part iii, 1852, p. 315.
CHAPTER I.
FISSION.
When an organ becomes divided it receives at the hands of descriptive
botanists the appellations cleft, partite, or sect, according to the
depth of the division; hence in considering the teratological instances
of this nature, the term fission has suggested itself as an appropriate
one to be applied to the subdivision of an habitually entire or
undivided organ. It thus corresponds pretty nearly in its application
with the term Chorisis or "dédoublement," or with the "disjonctions qui
divisent les organes" of Moquin-Tandon.[67] It is usually, but not
always, a concomitant with hypertrophy, and dependent on luxuriance of
growth.
It must be understood therefore that the term, as generally applied,
does not so much indicate the cleavage of a persistent organ, as it does
the formation and development of two or more growing points instead of
one, whence results a branching or forking (di-tri-chotomy) of the
affected organ. In some instances it seems rather to be due to the
relative deficiency of cellular, as contrasted with fibro-vascular
tissue.
=Fission of axile organs.=--This condition is scarcely to be
distinguished from multiplication of the axile organs (which see). A
little attention, however, will generally show whether the unusual
number of branches is a consequence of the development of a large number
of distinct shoots, as happens, for instance, when a tree is pollarded,
or of a division of one. M. Fournier[68] gives as an illustration the
case of a specimen of _Ruscus aculeatus_ in which there occurred a
division of the foliaceous branches into two segments, reaching as far
as the insertion of the flower, but no further. He also mentions lateral
cleavage effected by a notching of the margin, the notch being anterior
to the flowers and always directed towards their insertion. In the
allied genus _Danaë_, Webb, 'Phyt. Canar.,' p. 320, describes the
fascicles of flowers as in "crenulis brevibus ad marginem ramulorum
dispositis." Sometimes, on the other hand, _Danaë_ has a fascicle of
flowers inserted on the middle of the upper surface, as in _Ruscus_.
Wigand mentions an instance in _Digitalis lutea_, where the upper part
of the stem was divided into six or seven racemes; possibly this was a
case of fasciation, but such a division of the inflorescence is by no
means uncommon in the spicate species of _Veronica_. I have also seen
it in _Plantago lanceolata_, _Reseda luteola_, _Campanula medium_,
_Epacris impressa_, and a bifurcation of the axis of the spikelet within
the outer glumes in _Lolium perenne_[69] and _Anthoxanthum odoratum_. In
the Kew Museum is preserved a cone of _Abies excelsa_,[70] dividing into
two divisions, each bearing bracts and scales. A similar thing
frequently occurs in the male catkins of _Cedrus Libani_ (fig. 25).
[Illustration: FIG. 25.--Bifurcated male inflorescence, _Cedrus
Libani_.]
This subdivision of axial organs is not unfrequently the result of some
injury or mutilation, thus Duval Jouve alludes to the frequency with
which branched stems are produced in the various species of _Equisetum_,
as a consequence of injuries to the main stem, but this is rather to be
considered as a multiplication of parts than as a subdivision of one.
[Illustration: FIG. 26.--Bifurcated leaf of _Lamium album_, &c.]
=Fission of foliar organs.=--Many leaves exhibit constantly the process
of fission, such as the _Salisburia adiantifolia_, and which is due
perhaps as much to the absence or relatively small proportion of
cellular as compared with vascular tissue, as to absolute fission. In
the same way we have laciniated leaves of the Persian lilac, _Syringa
persica_, and Moquin mentions instances in a species of _Mercurialis_
in which the leaves were deeply slashed. In _Chenopodium Quinoa_ the
leaves were so numerous and the clefts so deep, that the species was
hardly recognisable, while on a branch of _Rhus Cotinus_ observed by De
Candolle the lobes were so narrow and so fine as to give the plant the
aspect of an _Umbellifer_. Wigand ('Flora,' 1856, p. 706) speaks of the
leaves of _Dipsacus fullonum_ with bi-partite leaves; Moquin mentions
the occurrence of a leaf of an oleander bi-lobed at the summit, so as to
give the appearance of a fusion of two leaves. Steinheil has recorded an
instance in _Scabiosa atropurpurea_ in which one of the stem leaves
presented the following peculiarities. It was simple below, but divided
above into two equal lobes, provided each with a median nerve.[71]
Steinheil has also recorded a _Cerastium_ in which one of the leaves was
provided with two midribs; above this leaf was a group of ternate
leaves. I have seen similar instances in the common Elm, _Ulmus
campestris_, and also in the common nettle, _Urtica dioica_, the leaves
of which latter thus resembled those of _Urtica biloba_, which are
habitually bilobed at the summit. M. Clos[72] mentions an instance where
the terminal leaf and first bract of _Orchis sambucina_ were divided
into two segments. The same author also mentions the leaves of
_Anemiopsis californica_, which were divided in their upper halves each
into two lobes--also leaves of a lentil springing from a fasciated stem
and completely divided into two segments, but with only a single bud in
the axil. The axillary branches in like manner showed traces of
cleavage. Fig. 26 represents a case of this kind in _Lamium album_,
conjoined with suppression of the flowers on one side of the stem. I
have also in my herbarium a leaf of _Arum maculatum_, with a stalk
single at the base, but dividing into two separate stalks, each bearing
a hastate lamina, the form of which is so perfect that were it not from
the venation of the sheath it would be considered that there was here a
union of two leaves rather than a bifurcation of one. A garden
Pelargonium presented the same appearance.
[Illustration: FIG. 27.--Bifurcated leaf of _Pelargonium_.]
Fern fronds are particularly liable to this kind of subdivision, and
they exhibit it in almost every degree, from a simple bifurcation of the
frond to the formation of large tufts of small lobes all formed on the
same plan by the repeated forking of the pinnules. These may be
considered as cases of hypertrophy.
Moquin-Tandon, at a meeting of the Botanical Society of France (April
3rd, 1858) exhibited a leaf of _Cerasus Lauro-Cerasus_ divided in such a
manner as to resemble a leaf of _Citrus_ or of _Phyllarthron_. In this
case, therefore, the disunion must have taken place laterally, and not
from apex towards base, as is most common. The leaves of the common
horse-radish, _Cochlearia Armoracia_, are very subject to this pinnated
subdivision of the margin, and numerous other illustrations might be
given.
[Illustration: FIG. 28.--Bifurcated frond, _Scolopendrium vulgare_.]
A. Braun describes a singular case in a leaf of _Irina glabra_
wherein the blade of the leaf on one side was deeply and irregularly
laciniated, the other side remaining entire. (Verhandl., d. 35,
Naturforscherversammlung, tab. 3.) Laciniate varieties of plants are of
frequent occurrence in gardens where they are often cultivated for their
beauty or singularity; thus, there are laciniated alders, fern-leaved
beeches and limes, oak-leaved laburnums, &c. A list of several of these
is subjoined. A similar fission takes place constantly in the cotyledons
of some plants, sometimes, as in _Coniferæ_, to such an extent as to
give an appearance as if there were several cotyledons.[73]
It is not always easy to recognise, at a first glance, whether the
division be the result of disunion or of an incomplete union of two
leaves, but we may be guided by the number of leaves in the cycle or the
whorl. The number is complete in cases of partial disjunction, while in
cases of fusion it is incomplete. Again, in instances of disjunction,
there is only one point of origin, but, when two leaves are grafted
together, two such points may generally be detected at the base of the
leaf, or a transverse section of the leaf-stalk will show indications of
fusion. The number and position of the midribs will also serve as a
guide, as in cases of fusion there are generally two or more midribs,
according to the number of fused leaves; but as Moquin well remarks,
this latter character cannot be always depended upon, for the median
nerve may divide without any corresponding separation of the cellular
portions of the leaf. The author just quoted cites examples of this kind
in _Cardamine pratensis_, _Hedera Helix_, _Plantago major_, _Geranium
nodosum_.
The following list of plants commonly producing leaves that are cleft or
divided, to a greater extent than is usual in the species, is mainly
taken from one given by Schlechtendal, 'Bot. Zeit.,' 1844, p. 441, with
additions from other sources. The ! indicates that the author has
himself met with the deviation in question. Many are cultivated as
garden varieties under the names here given.
Trollius europæus dissectus.
Chelidonium majus laciniatum!
Glaucium luteum.
Brassica oleracea!
Tilia parvifolia laciniata.
asplenifolia!
Acer platanoides laciniatum.
crispum.
Æsculus Hippocastanum incisum!
asplenifolium.
Vitis vinifera apiifolia!
laciniosa.
Ilex Aquifolium!
Rhus Toxicodendron quercifolium.
Cotinus.
Ervum Lens.
Cytisus Laburnum quercifolium!
incisum.
Rubus fraticosus laciniatus!
Pyrcis communis.
Cerasus Lauro-cerasus.
Apium graveolens!
Pimpinella magna.
Saxifraga.
Cratægus Oxyacantha laciniata.
quercifolia!
Ribes nigrum.
Sambucus nigra laciniata!
racemosa laciniata.
Dipsacus fullonum.
Scabiosa atropurpurea!
Symphoricarpus racemosus.
Helianthus sp.!
Lonicera Periclymenum quercifolia!
Syringa persica laciniata!
Syringa vulgaris!
Nerium Oleander!
Lamium purpureum.
album!
Salvia officinalis.
Solanum Dulcamara!
Fraxinus excelsior crispa.
Veronica austriaca.
Polemonium cæruleum.
Juglans regia laciniata!
heterophylla.
filicifolia.
Anemiopsis californica.
Chenopodium Quinoa.
Ulmus americana incisa.
Fagus sylvatica heterophylla!
laciniata!
aspleniifolia!
incisa.
salicifolia!
Mercurialis perennis.
Urtica dioica.
Quercus Cerris laciniata!
pubescens filicina.
Betula populifolia laciniata.
alba dalecarlica.
Alnus incana laciniata!
glutinosa laciniata!
quercifolia.
oxyacanthifolia.
Corylus Avellana heterophylla!
laciniata!
urticifolia.
Carpinus Betulus incisa!
quercifolia.
heterophylla.
Castanea vesca heterophylla.
quercifolia.
incisa.
Populus alba acerifolia.
palmata.
quercifolia.
balsamifera.
Orchis sambucina.
Arum maculatum.
Filices sp. pl.
See also Schlechtendal, 'Bot. Zeit.,' tom. xiii, p. 823. A.
Braun, loc. supra citat. For Ferns too numerous for insertion,
see Moore, 'Nature-Printed Ferns,' 8vo ed., 2 vols. Clos, 'Mém.
Acad. Toulouse,' 1862, p. 51.
=Fission of the petals, &c.=--The floral leaves are subject to a similar
process of cleavage to that which has just been mentioned as taking
place in the leaves. This, indeed, occurs very often as a normal
occurrence as in the petals of mignonette (_Reseda_), or those of
_Alsine media_ and many other plants. Here, however, we have only to
allude to those instances in which the cleavage occurs in flowers whose
sepals or petals are usually entire. Under this category Moquin mentions
a petal of _Brassica oleracea_ completely split into two. Linné in his
'Flora Lapponica' (pp. 145 and 164) mentions quadrifid petals of
_Lychnis dioica_, and much divided petals of _Rubus arcticus_. Among
other plants subject to this division of sepals or petals may be
mentioned as having come within the writer's personal observation,
_Ranunculus Lingua_, _R. acris_, _Papaver somniferum_, and others of
this genus, _Saponaria sp._, _Dianthus_, _Narcissus_, &c.
In some of the garden varieties of _Cyclamen_ the corolla looks at first
sight as if double, and the plan of the flower is oblong or elliptical,
instead of circular. In these flowers each lobe of the corolla is
divided almost to the base into two lobes, so that there appear to be
ten lobes to the corolla instead of five, as usual. The stamens are
normal in form and number in these flowers.
In the paroquet tulips of gardeners the segments of the perianth are
deeply and irregularly gashed, the segments occasionally becoming rolled
up and their margins coherent so as to form little tubular spurs. I have
also noticed the segments of the perianth in _Crocus_ and _Colchicum_
deeply cleft, so much so sometimes, as to equal in this particular the
stigmas. In the flowers of a species of _Oncidium_, communicated to me
by Mr. Currey, the lip was divided into three segments perfectly
distinct one from the other, but confluent with the column; the two side
pieces had callosities at the upper edge close to the base, the central
piece had a similar wartlike process in its centre. In these flowers the
ovary, the stigma, and the anther were all in a rudimentary condition.
Some verbenas raised by Mr. Wills offer a curious illustration of this
condition. It will be remembered that some of the lobes or petals of a
verbena are normally divided at the base to a slight degree, but in the
flowers in question this is carried to such an extent that the enlarged
lobes are pushed into the centre of the flower and simulate, at a first
glance, a distinct and separate organ, though in reality it is but an
enlargement of what occurs normally.[74]
[Illustration: FIG. 29.--Flower of _Oncidium sp._ seen from the back.
The lip is divided into three unequal segments.]
Moquin mentions having seen the stamens of _Matthiola incana_ and
_Silene conica_ completely divided, each section bearing half an anther,
exactly as happens in _Polygalaceæ_. In tulips and lilies the same
author mentions division of the anther only, the filament remaining
entire, as happens naturally in many species of _Vaccinium_.
A division of the individual carpels occurs very frequently when those
organs become more or less leafy, as in _Trifolium repens_, and other
plants to be hereafter mentioned.
The instances given in this chapter have all been cases wherein the
division or the accessory growth has taken place in one plane only and
that plane the same as that of the affected organ, but there are other
examples, probably equally due to fissiparous division, where the new
growth is either parallel to, or even at angle with the primary organ.
Of such nature are some of those instances wherein two leaves appear to
be placed back to back. These partake of the nature of excrescences or
of exaggerated developments, and hence will be more fully treated of
under the head of hypertrophy. It must be remembered that in some of
these cases the fission may be a resumption of characters proper to the
species under natural conditions, but lost by cultivation or otherwise.
Thus, Mr. Buckman accounts for "finger-and-toe" in root-crops on the
principle of reversion to the wild form.
FOOTNOTES:
[67] Loc. cit., p. 295.
[68] 'Bull. Soc. Bot. France,' 1857, p. 758.
[69] Masters, 'Jourl. Linn. Soc.,' vol. vii, p. 121.
[70] Cramer, 'Bildungsabweichungen,' p. 4, tab. vi, fig. 4, figures a
case of the same kind in _Pinus Cembra_.
[71] 'Ann. des Science Nat.,' 2nd series, t. iv, p. 147, tab. v, figs. 3
and 4.
[72] 'Mém. Acad. Scien. Toulouse,' 5th series, vol. iii.
[73] Duchartre, 'Ann. Sc. Nat.,' 3rd series, 1848, vol. x, p. 207.
[74] Masters, 'Rep. Bot. Congress,' London, 1866, p. 136, tab. 7, f. 15,
16.
CHAPTER II.
DIALYSIS.
This term is here made use of in the same sense as in descriptive
botany, to indicate the isolation of parts of the same whorl; it is thus
the opposite of cohesion. Morren, as has been previously stated,
employed the word in a different sense, while Moquin-Tandon[75] included
cases of this description under the category of "Disjonctions qui
isolent les organes."
Dialysis, as here understood, may be the result of an arrest of
development, in consequence of which parts that under ordinary
circumstances would become fused, do not do so; or, on the other hand,
it may be the result of an actual separation between parts primitively
undivided. As it is not possible in every case to distinguish between
the effects of these two diverse causes, no attempt is here made to do
so.
=Dialysis of the margins of individual foliar organs.=--In cases where
the leaf or leaf-like organ is ordinarily tubular or horn-like in form,
owing to the cohesion of its edges, it may happen either from lack of
union or from actual separation of the previously united edges, that the
tubular shape is replaced by the ordinary flattened expansion. Thus, in
_Eranthis hyemalis_, wherein the petals (nectaries) are tubular and the
sepals flat, I have met with numerous instances of transition from the
one form to the other, as shown in fig. 9, p. 24.
It is, however, in the carpels that this separation occurs most
frequently. When these organs appear under the guise of leaves, as they
often do, their margins are disunited, so that the carpel becomes flat
or open. This happens in the strawberry (_Fragaria_), the columbine
(_Aquilegia_), in _Trifolium repens_, _Ranunculus Ficaria_, &c.[76]
=Dialysis of the parts of the same whorl:--calyx.=--The separation of an
ordinarily coherent series into its constituent parts is necessarily of
more common occurrence than the foregoing. As here understood, it is the
precise converse of cohesion, and it may be represented diagrammatically
by a dotted line above the letters denoting the sepals, petals, &c. When
this change happens in the calyx we have the gamosepalous condition
replaced by the polysepalous one, as thus represented:
.............
S S S S S
instead of
_____________
S S S S S
as in a calyx of five coherent sepals.
Detachment of this kind occurs not unfrequently, as in _Primula
vulgaris_, _Trifolium repens_, &c. In _Rosaceæ_ and _Pomaceæ_ this
separation of the calyx is of the more moment, as it has reference to
the structure of the inferior ovary, as will be more fully mentioned
hereafter. Here, however, a case recorded by M. J. E. Planchon may be
alluded to[77] wherein a quince fruit (_Cydonia_) was surmounted by five
leaves, the surface of the pome being marked by as many prominences,
which apparently corresponded to the five stalks of the calycine leaves.
In this specimen, then, the inferior position of the ovary appeared to
be not so much due to an expansion of the fruit stalk, as to the fusion
of the hypertrophied stalks of the sepals. Some of the malformations
among Cucurbits point to a similar structure. It is probable that in
many of these cases the so-called inferior ovary is partly axial partly
foliar, _i.e._, sepaline, and partly carpellary in its nature.
Dialysis of the sepals in calyces that are usually gamosepalous has been
most frequently observed in _Rosaceæ_, _Pomaceæ_, _Umbelliferæ_, less
commonly in _Leguminosæ_, also in the following genera:--_Primula_,
_Symphytum_, _Gentiana_, _Campanula_, &c.
[Illustration: FIG. 30.--Dialysis of the sepals and petals in _Correa_.]
=Dialysis of the corolla= is likewise of frequent occurrence, either
partially or to such an extent as to render the corolla truly
polypetalous. Among _Labiatæ_ the upper lip of the corolla may be often
met with partially cleft, as it is constantly in _Phlomis biloba_, or
more markedly among the _Lobeliaceæ_.
In the _Compositæ_, a similar separation of the petals is not
infrequent, thus showing frequent transitional stages between the
labiatifloral and tubulifloral divisions respectively. The ligulate
corollas also may often be found in Chrysanthemums, Dahlias, &c., more
or less deeply divided into their component parts.
A more complete separation occurs not unfrequently in _Campanula_,
_Rhododendron_, _Phlox_, _&c._ Figs. 30 and 31 illustrate dialysis of
the corolla; the first in _Correa_, the second in _Campanula_.
[Illustration: FIG. 31.--Dialysis of the corolla in _Campanula sp._,
after De Candolle.]
In the last-named genus, _C. rotundifolia_ has been found with
polypetalous flowers in a wild state in the mountains of Canton
Neufchatel, Switzerland, and gave rise to the creation of a new genus.
This form is now introduced into gardens.
It must be remembered that in some genera, where this separation of the
petals has been met with, there are species in which a similar isolation
occurs normally, as in _Rhododendron_. _R. linearilobum_, a Japanese
species, offers a good illustration of this.
The following list contains the names of the genera in which this
separation of the petals of an ordinarily gamopetalous flower takes
place most frequently.
Correa.
Campanula! sp. pl.
Polemonium.
Phlox!
Coboea!
Rhododendron!
Erica!
Rhodora.
Azalea!
Compositæ! sp. pl.
Lonicera!
Convolvulus!
Pharbitis.
Antirrhinum!
Verbascum!
Mimulus.
Digitalis!
Orobanche.
Solanum.
Nicotiana.
Gentiana!
Anagallis.
Primula!
Lamium!
Convallaria!
Lilium!
Colchicum!
&c. &c.
This list does not include those very numerous cases in which this
change is associated with more or less complete frondescence or leafy
condition of the petals.
=Dialysis of the stamens.=--A similar isolation of the stamens occurs
occasionally; for instance, when Mallows (_Malvaceæ_) become double, one
of the first stages of the process is often the disjunction of the
stamens, and a similar dissociation occurs in _Leguminosæ_ and
_Compositæ_, as in _Tragopogon_, as related by Kirschleger, in
_Hypochæris_ by Wigand, and in _Coreopsis_ by Schlechtendal.
=Dialysis of the carpels.=--In the case of the carpels this disunion is
more frequent than in the stamens. M. Seringe[78] figures carpels of
_Diplotaxis tenuifolia_ more or less completely separated one from the
other; indeed, this separation is very common amongst _Cruciferæ_ and
_Umbelliferæ_.
Generally speaking, the disunion is complicated with frondescence--but
not always so. I have, in my herbarium, specimens of _Convallaria
majalis_, _Commelyna sp._, and of _Lilium auratum_, in all of which the
three carpels are completely disjoined, and present three styles, three
stigmas, &c., without any other change. Engelmann[79] speaks of three
classes of this malformation. 1st, that in which the carpels separate
one from the other without opening, as in the lily just alluded to; 2nd,
that in which the ovary remains closed, but loses its internal
partitions, as in a case mentioned by Moquin in _Stachys sylvatica_, in
which, owing to imperfect disjunction, the two bi-lobed carpels were
changed into a nearly one-celled capsule;[80] and 3rd, those cases in
which the carpels are open and foliaceous.
[Illustration: FIG. 32.--Anomalous form of orange.]
Disjunction is more frequent in dry fruits than in fleshy ones. In the
latter instance it happens at an early stage of existence, and the
pericarp becomes more or less leafy, losing its faculty of becoming
fleshy, as in _Prunus Cerasus_ and _Amygdalus persica_; nevertheless,
fleshy fruits sometimes become disunited. I have seen a case similar to
that mentioned by M. Alphonse de Candolle in _Solanum esculentum_, in
which the pericarp became ruptured, and the placentas protruded. A like
occurrence has also been observed in a species of _Melastoma_.[81] This
is analogous to what happens in _Caulophyllum_ and _Slateria_.
Disjunction of the carpels is not rare in oranges. Sometimes this takes
place regularly, at other times irregularly; occasionally in such a
manner as to give the appearance of a hand and fingers to the fruit. Of
one of these, Ferrari,[82] in the curious volume below cited, speaks
thus: "Arbor profusissima, quia dat utraque manu; imo quia vere manus
dat in poma conversis; utque magis munifica sit poma ipsa convertit in
manus."
M. Duchartre[83] mentions a semi-double flower of orange with eight to
ten distinct carpels in a whorl, and occasionally several whorls one
above another. De Candolle[84] considers the rind of the orange as a
production from the receptacle, and this view is confirmed by the
specimens of Duchartre, in which the carpels were quite naked or had a
common envelope truncated, and open above to allow of the passage of the
styles and stigmas.
[Illustration: FIG. 33.--Orange. Showing disjunction of carpels, after
Maout.]
[Illustration: FIG. 34.--Section of orange shown in fig. 33 after
Maout.]
It frequently happens in conjunction with this separation of the carpels
one from the other, that a lack of union manifests itself between the
margins of the individual carpels themselves. Very numerous cases of
this kind have been recorded, and the double tulips of gardens may be
referred to as showing this condition very frequently. In connection
with this detachment of the carpels, a change in the mode of
placentation is often to be observed, or two or more kinds may be seen
in the same pistil, as in double-flowered saponarias, many Crucifers,
&c., as alluded to under the head of displacements of the placenta.
FOOTNOTES:
[75] _Loc. cit._, p. 298.
[76] Masters in Seemann's 'Journal of Botany,' 1867, p. 158.
[77] Bull. Soc. Bot. France,' t. xiii, 1866, p. 234.
[78] 'Bull. Bot.,' pl. i, figs. 8-12.
[79] 'De Anthol.,' p. 37.
[80] Moquin, loc. cit., p. 305.
[81] 'Neue Denkschr. der Allg. Schweiz. Gesell.,' band v, pl. ii. p. 5.
[82] 'Hesperides,' auctore Ferrario. Rome, 1646, fig. 415, pp. 213 and
215. See also Michel, 'Traité du Citronnier.'
[83] 'Ann. des Science Nat.,' 3rd series, 1844, vol. i, p. 294.
[84] 'Org. Véget.,' vol. ii., p. 41.
CHAPTER III.
SOLUTION.
The isolation or separation of different whorls that are ordinarily
adherent together is by no means of rare occurrence. Were it not that
the isolation is often congenital, the word detachment would be an
expressive one to apply to these cases, but as the change in question
occurs quite as often from a want of union, an arrest or stasis of
development, as from a _bonâ fide_ separation, the word solution seems
to be, on the whole, the best. It corresponds in application to the word
_liber_ (_calyx liber_, &c.), in general use by descriptive botanists.
As here employed, the term nearly corresponds with the "adesmie
hetérologue" of Morren. Moquin Tandon does not make any special
subdivision for the class of cases here grouped together, but places
them all under "Disjonctions qui isolent les organes." It seems,
however, desirable to have a separate word to express the converse
condition of adhesion, and for this purpose the term solution, as above
stated, is here employed. Diagrammatically, the condition may be
expressed by placing a dotted line at the side of the letters thus:
: s s s s s :
: c c c c c :
would indicate the disjunction of the sepals from the carpels (c), in
contradistinction to adhesion, which may be represented by the unbroken
line thus:
| s s s s s |
| c c c c c |
=Solution of the calyx from the ovary.=--Of all the instances of
adhesion which take place under ordinary circumstances, that between the
calyx and the ovary is perhaps the most common. The _calyx adhærens_ or
_superus_ is a structural characteristic to which all botanists attach
considerable importance; so that when exceptional cases occur in which
the calyx becomes detached from the ovary, becomes, that is, _inferus_
or _liber_, a proportionate degree of interest attaches to the
irregularity. It is not within the scope of the present work to inquire
whether this detachment be real or merely apparent, arising from a want
of union between parts ordinarily united together. This point must be
left to the organogenists to decide in each particular case. So also the
question as to what share, if any, the expanded and dilated flower-stalk
may take in what are usually called inferior ovaries, can be here only
incidentally touched upon.
Among _Rosaceæ_, the change in question is very common, especially in
conjunction with an elongation of the axis of the flower (apostasis) and
with prolification, though it is by no means always co-existent with
these malformations. When this alteration in the apparent relative
position of calyx and carpels occurs in roses (_Rosa_) the appearances
are generally such as to indicate that the "hip" of the rose is a
dilatation of the peduncle, continuous above with the coherent bases of
the sepals; this inference seems also to be borne out by what happens in
the _Pomaceæ_. In some cases in this sub-order, the calyx becomes
detached from the carpels, so that the latter organs become more or less
"superior," and distinct one from the other. This happens constantly in
the double-flowered thorn, _Cratægus Oxyacantha_, in some blossoms of
which the hollowed end of the peduncle still invests the base of the
carpels, leaving the upper portions detached. In apples flowers are
occasionally met with of greater size than usual and on longer stalks,
so that the whole looks more like a rose than an apple blossom. In these
cases it will usually be found that the calyx consists of distinct
sepals, without a trace of the ordinary swelling beneath the flower. The
petals are often more numerous than usual; the stamens variously
changed, and the carpels sometimes absent; at other times, as in the
instance figured in the adjacent woodcuts, figs. 36, 37, consisting of
separate, superior ovaries, sometimes destitute of ovules, or, at other
times, having two of these bodies.[85]
[Illustration: FIG. 35.--Proliferous Rose. Showing an absence of the
usual dilatation of the flower-stalk, and other changes.]
This condition accords precisely with the account of the development of
the flowers in _Pomaceæ_ as given by Payer, Caspary, and others, so that
the flowers above described would owe their deficiency of the swollen
receptacle to an arrest of development. M. Germain de Saint Pierre,
among other malformations of the rose, presented to the Botanical
Society of France in 1854[86] two specimens which are of special
interest as relating to this contested point. In the one, the swollen
portion beneath the flower was surmounted by five perfect leaves, as,
indeed, is not infrequent in such malformations; here, then, the calyx
could have had little or no share in the production of the swelling in
question. In the other, the swollen portion was actually above the
insertion of the sepals here represented by five perfect leaves.
[Illustration: FIG. 36.--Section through Apple blossom, showing
detachment of calyx from ovaries, absence of dilated flower-stalk, &c.]
[Illustration: FIG. 37.--Calyx detached from carpels in Apple.]
On the other hand, M. Planchon's specimen of the Quince before alluded
to, not to mention other instances, tends to show that the bases of the
sepals do sometimes enter into the composition of the pome. And, indeed,
in many of these cases it would be impossible to say where the axial or
receptacular portion ended, and the foliar portion began. As both from
normal organogeny as well as from unusual conformation contradictory
inferences may be drawn, it would obviously be unsafe to attempt the
explanation of the so-called calyx-tube in general from any particular
instances; so far as _Rosaceæ_ are concerned, there is so much variation
in the relative position of calyx and carpels under ordinary
circumstances, that it is no matter for surprise that similar
diversities should exist in teratological cases. A similar remark will
apply to _Saxifragaceæ_, _Cucurbitaceæ_, _Myrtaceæ_, _Bruniaceæ_,
_Rubiaceæ_, and other families of like conformation.
[Illustration: FIG. 38.--Flower of _OEnanthe crocata_, in which the
five sepals were completely detached from the ovaries, here three in
number and destitute of stylopods.]
In _Umbelliferæ_, a detachment of the calyx from the ovaries frequently
occurs, sometimes without any other change; at other times attended by
more serious alterations. So far as can be judged from exceptional
occurrences of this kind, it would appear that in this order the axis or
flower-stalk does not, in any material degree, enter into the
composition of the fruit.
In the Rubiaceous genus _Bikkhia_, as mentioned by Duchartre, the ovary
is completely inferior, but when the fruit arrives at maturity four
small leaves are detached from its surface which had previously adhered
to it, and which it seems reasonable to consider as the sepals.
In _Campanulaceæ_ a similar separation of calyx from the ovary may be
occasionally met with. On the other hand, the occasional formation of a
leaf on the inferior ovary of those plants would indicate the axial
nature of the fruit. In _Campanumæa_ and _Cyclodon_ the calyx is
inferior, while the corolla is superior. In the last-named genus this
peculiarity "is carried to the highest degree, the sepals being, in _C.
parviflorum_, placed on the peduncle of the flower far removed from the
base of the corolla and ovary, whilst in _C. truncatum_ and in
_Campanumæa_ they adhere to the base of the tube of the corolla."[87] In
this order, then, as in _Saxifragaceæ_, _Bruniaceæ_, &c., no hasty
conclusion should be drawn as to the nature of the fruit. In _Brunia
microphylla_ the ovary is superior, enclosed within but not adnate to
the cup-like calyx, to which latter, however, the petals and stamens are
attached.
In _Onagraceæ_ (_Jussieua_), as also in _Cactaceæ_ (_Opuntia_), buds
have been observed on the surface and edges of the inferior ovary.
Indeed, in the former genus, they have been produced artificially, but
as buds may be formed on foliar as well as on axial organs, the fact
cannot be made great use of in support either of the foliar or axial
nature of the inferior ovary. In _Epilobium_, I have met with four
perfect leaves at the summit of the ovary, in the place usually occupied
by the sepals. This would also favour the notion that the axis entered
into the constitution of the fruit in this genus.
Mr. B. Clarke, in his 'New Arrangement of Phanerogamous Plants,' p. 4,
cites a case wherein the perianth was completely detached from the
surface of the ovary in _Cannabis sativa_.
It must be borne in mind that some of the recorded instances of change
in the relative position of the calyx and pistil ought more properly to
be referred to a substitution of carpels for stamens, as in _Begonia_,
_Fuchsia_, &c. Among _Cucurbitaceæ_, examples have been recorded, both
of the detachment of the calyx from the ovary,[88] and of the partial
conversion of some of the anthers of the male flower to carpels.
The very singular mode of germination of _Sechium edule_ in which the
fruit, instead of rotting, becomes thickened into a kind of rhizome or
tuber, is a fact that should not be overlooked in investigating the true
nature of the fruit in this order.
The following are the genera in which the change has been most
frequently observed:
*Rosa!
*Pyrus!
*Cratægus!
*Daucus!
Pastinaca.
Torilis.
Apium.
OEnanthe!
Heracleum,
Athamanta.
Selinum.
Carum.
Imperatoria.
Rudbeckia!
*Campanula!
Lonicera!
Cucumis!
Cannabis.
=Solution of the stamens from the petals.=--A separation of the stamens
from the petals in flowers, wherein those organs are usually adherent
one to the other does not often occur unattended by other changes. It
has been observed in _Cobæa scandens_ (Turpin), in _Antirrhinum majus_,
and in many double flowers.
Partial detachment of the stamens from the styles occurs frequently in
semi-double flowers of _Orchis_.[89]
FOOTNOTES:
[85] 'Gard. Chron.,' 1865, p. 554; 1867, p. 599.
[86] 'Bull. Soc. Bot. Fr.' 1854, p. 303.
[87] Hook et Thoms, 'Præcurs. ad Flor. Ind.,' Journ. Linn. Soc., vol.
ii, 1858, p. 6.
[88] Lindley, 'Veget. Kingd.,' p. 315.
[89] Masters, 'Journal of Linnean Society,' 1866, vol. viii, p. 207. On
the subject of this chapter the reader should also consult
Moquin-Tandon, 1. c., p. 298. Engelmann, 'De Antholysi,' p. 37, tab. v.
C. Morren, 'Bull. Acad. Belg.,' xix, part 3, p. 318. Cramer,
'Bildungsabweichungen,' p. 64. Fleischer, 'Missbild. Cultur. Pflanzen.'
As to the nature of inferior ovaries, see also Payer, 'Bull. Soc. Bot.
Fr.' i, 1854, p. 283. Germain de Saint Pierre, _ibid._, p. 302. Caspary,
'Bull. Soc. Bot. Fr.,' t. vi, 1859, p. 235. Schleiden, 'Principles of
Botany,' English translation, p. 368. Duchartre, 'Elements de
Botanique,' p. 574. Le Maout et Decaisne, 'Traité général de Botanique,'
p. 57. Bentham, 'Journ. Linn. Soc.,' vol. x, p. 104 (Structure of
_Myrtaceæ_), and other treatises on Organography.
PART III.
ALTERATIONS OF POSITION.
Necessarily connected with changes in the arrangement of organs are
similar alterations in their position; so closely, indeed, that but for
convenience sake, it would be unnecessary to treat them separately.
There are, however, some anomalous developments affecting the relative
position of organs that could hardly be treated of under any of the
preceding paragraphs. There are, also, certain rare instances where an
organ is not so much displaced as misplaced; that is to say, it is
developed on or from a portion of the plant, which under usual
circumstances does not produce such an organ. In the former instance,
the altered position is due to or coexistent with other changes, but in
the latter case the new growth may spring from organs otherwise in
nowise different from ordinary. The word Displacement is here used to
signify the unusual position of an organ; while Heterotaxy may serve to
include those cases where a new growth makes its appearance in an
unwonted situation, as, for instance, a leaf-bud on a root, &c.
Prolification is also included under this heading, the unusual position
of the buds in these cases being of graver import than the mere increase
in number. Alterations in the position of the sexual organs are spoken
of under the head of Heterogamy.
CHAPTER I.
DISPLACEMENT.
Real or apparent displacement of organs from their usual position is an
almost necessary consequence of, or is, at least, coexistent with a
large number of teratological phenomena. It is obvious that abnormal
unions or disunions, suppressions, hypertrophies, &c., are very liable
to bring about or to be accompanied with changes in the position, either
of the parts directly affected or of adjoining organs.
In this place, then, it is merely necessary to allude to some of the
more important displacements, and to refer for further details to the
sections relating to those irregularities of growth on which the
displacement depends.
=Displacement of bulbs.=--I owe to the kindness of Mr. James Salter a
tulip bulb which had been dug up after flowering, and from the base of
which were suspended several small bulbs; and I have since seen another
specimen showing the same unusual arrangement. The explanation of these
formations seems to be that they correspond to the bulbils ordinarily
found in the axils of the scales of the parent organ, and which, in some
way or another, have been displaced and thrust into the ground.
Professor de Vriese figures something of the same kind in _Ixia
carminosa_.[90]
Of somewhat different nature to those above described was an anomaly
described by M. Gay at a meeting of the Botanical Society of France,
April 8th, 1859. The plant affected was _Leucoium æstivum_, and the
changes observed were apparently attributable to a simple separation of
two leaves that are usually contiguous. "Suppose," says M. Gay in
describing this malformation, "the first leaf of the terminal bud
separated by a long internode from the other leaves, which remain
closely packed; and further, suppose an evident thickening of the upper
portion of the lengthened internode, and there will be not only a single
bulb, bearing with the leaves of the present year all the remnants of
the leaves of the two preceding years, but two bulbs placed one above
another, on the same axis, separated by the length of the internode."
[Illustration: FIG. 39.--Unusual position of bulbs of tulip; the
parent-bulb cut open.]
The formation of bulbs in the axils of the leaves, as happens
occasionally in tulips, is further alluded to under the head of
hypertrophy.
=Displacements affecting the inflorescence.=--These are, for the most
part, dependent on hypertrophy, elongation, atrophy, spiral torsion,
&c., but there are a few instances of a different nature, which may here
be alluded to as not being coincident with any of the phenomena just
mentioned. Sometimes these deviations from the ordinary position have
the more interest as affecting characters used to distinguish genera;
thus one of the distinctions between rye-grass (_Lolium_) and wheat
(_Triticum_) resides in the relative position of the spikelets and the
main stem; in _Triticum_ the spikelets are placed with their backs
against the rachis, in _Lolium_ with one edge against it; but in a
specimen of rye-grass that has come under my own observation, the
arrangement was that of _Triticum_.
M. Kirschleger relates having found a specimen of _Leucanthemum
pratense_, in which the ligulate female flowers were growing singly in
the axils of the upper leaves of the stem.[91] The ordinary capitulum
would here seem to have been replaced by a spike or a raceme. A less
degree of this change wherein a few flowers may be found, as it were,
detached from the ordinary capitulum may often be observed in
_Compositæ_, _Dipsacaceæ_, &c. I have also met with specimens of _Lamium
album_ in which some of the fascicles or clusters of flowers in place of
being placed at the same level on opposite sides of the stem were placed
alternately one above another.
Caspary[92] mentions a flower of _Aldrovanda vesiculosa_, which was
elevated on a stalk that was adherent to the stem for a certain
distance, and then separated from it. This flower, with the leaf to
which it was axillary, evidently belonged to the whorl beneath, where
there was a corresponding deficiency. Another flower of the same plant
bore on its pedicel a small leaf, which was doubtless the bract raised
above its ordinary position.
M. Fournier mentions an instance in _Pelargonium grandiflorum_, where,
owing to the lengthening of the axis, the pedicels, instead of being
umbellate, had become racemose; and I owe to the kindness of Dr. Sankey
a somewhat similar specimen, but in a less perfect condition. Here there
was but a single flower, and that rudimentary, placed at the extremity
of the axis. There were several bracts beneath this flower disposed
spirally in the 1/3 arrangement, all being empty, excepting the terminal
one. In like manner, a head of flowers becomes sometimes converted into
an umbel.
=Displacement of leaves.=--A cohesion of parts will sometimes give rise
to an apparent displacement, but the true nature of the malformation
can, in general, be readily made out.
Steinheil[93] found a specimen of _Salvia Verbenaca_, the leaves of
which presented very curious examples of displacement arising from
cohesion. Two of these leaves placed at the base of a branch were
completely fused in their lower thirds, and divided into two distinct
lobes at the upper part; each of these lobes seemed to be as large as
the limb of an ordinary leaf. Above these was another very broad one,
apparently entire, but evidently produced by a complete cohesion of two.
This completely fused leaf alternated in position with the imperfectly
fused one below it; the alternation is explained by supposing that the
opposite leaves of each pair were directed one towards the other, and
became fused, and that thus resulted the displacement. The dislocation
of the organs took place in one direction for one pair of leaves, and in
another direction for the other pair, hence the alternation. Thus,
leaves normally opposite and decussate may, by fusion, become alternate.
A similar instance occurred to the writer in _Lysimachia vulgaris_,
wherein the changes arising from fusion and suppression of parts, &c.,
were very considerable; as far as the leaves were concerned they
presented the following arrangement in succession from below
upwards:--first verticillate, then opposite, then spirally alternate,
lastly opposite.[94] The term "diremption" has sometimes been applied to
cases where leaves are thus apparently dragged out of position.
In _Tradescantia virginica_ I have met with opposite connate leaves;
the altered position, however, being due to the union of two stems.
[Illustration: FIG. 40.--Large-coloured leaf occupying the position of
the inflorescence in _Gesnera_, after Morren.]
[Illustration: FIG. 41.--Ordinary arrangement of leaves in fascicles of
three in _Pinus pinea_ and unusual arrangement of leaves of same plant
in spires.]
Twisting of the stem is a frequent cause of the displacement of leaves
(see spiral torsion), as also hypertrophy, whether that excess of
development take place laterally or lengthwise (see elongation). Atrophy
or suppression will also frequently bring about an alteration in the
position of leaves; sometimes in such a manner that the place of the
suppressed organ is occupied by another one. One of the most curious
instances of displacement of leaves arising from suppression is that
mentioned by Morren,[95] where, in _Gesnera Geroltiana_, a large leaf
apparently occupied the extremity of the axis, a position which, under
ordinary circumstances, no leaf could assume. The explanation given by
the Belgian professor is, that the axis in this case, instead of
throwing off a pair of leaves, one on each side, had from some cause or
another produced only one; this one not only being much larger than
ordinary, but brightly coloured, thus assuming some of the
characteristics as well as the position of the inflorescence.
Alterations in the usual arrangement of leaves, however, are not always
dependent on or coexistent with other teratological changes, but may
simply depend on a natural elongation of the internodes, or on fission
or multiplication; for instance, in some conifers, such as the Larch,
(_Abies Larix_) or _Pinus pinea_, there may be found at different stages
in the growth of the branches leaves in crowded fascicles or tufts;
while, when growth is more rapid, the leaves may be disposed in a spiral
or alternate manner.
In the yew (_Taxus_) the leaves at the ends of the shoots not
unfrequently lose their usual distichous arrangement and become arranged
in a close spiral manner, the elongation of the shoot being arrested.
This appears to be the result of the injury effected by some insect.
[Illustration: FIG. 42.--Altered arrangement of leaves of yew, _Taxus
baccata_.]
So, too, the alteration from verticillate to spiral, or _vice versâ_,
may take place without any other notable change.[96] This may frequently
be seen in Rhododendrons.
=Displacement of the parts of the flower.=--This subject is partly
touched on in the chapters on solution, adhesion, and in those on
hypertrophy, elongation, prolification, &c., so that in this place it is
only requisite to offer a few general remarks, and to refer to other
sections for further details. Morren, in referring to displacement of
the floral organs, mentions an instance in a _Fuchsia_, wherein the four
petals in place of being alternate with the sepals were placed in front
of them, owing to the adhesion that had taken place between the petals
and the stamens. He speaks of this transposition as metaphery.[97] The
same author also gives an account of the displacement of several of the
organs of the flower in _Cypripedium insigne_, the displacement being
consequent, apparently, on a spiral torsion proceeding from right to
left, and involving the complete or partial suppression of several of
the organs of the flower. The dislocation of organs in a spiral
direction led Morren to apply the term "speiranthie" to similar
deviations from the usual construction. Changes of this kind among
_Orchidaceæ_ are by no means uncommon; the following may be cited by way
of illustration. In a specimen of _Oncidium cucullatum_ furnished me by
Mr. Anderson, well known for his success as a cultivator of these
plants, there was, associated with a cohesion of one sepal with another,
and probably dependent on the same cause, a displacement of the sepals
and petals--so that all were dragged out of place. This dislocation may
be better appreciated by the accompanying formula than even by the
woodcut. Let the usual arrangement be thus represented:
S
P ST P
L
S S
S standing for sepal, P for petal, L for lip, ST for stamen; then the
dislocated form may be represented thus:
S
P P
T
S
S_S
L
[Illustration: FIG. 43.--Flower of _Oncidium cucullatum_, showing union
of two lower sepals, displacement of column and lip, &c.]
In a specimen of _Cypripedium_ also furnished by Mr. Anderson the
appearance was as represented in the accompanying figure and diagrams,
figs. 44, 45. Referring to the plan of the natural arrangement at fig.
46, it will be seen that an explanation of the peculiar appearance of
the flower may be arrived at by supposing a disunion and lateral
displacement of the upper segment of the outer perianth together with
the complete absence of the lower one. In the second or inner whorl of
the perianth the lip is merely a little oblique on one side, but the
lateral petals are distorted, displaced, and adherent one to the other
and to the column, while the posterior shield-like rudimentary anther is
completely wanting.
[Illustration: FIG. 44.--Malformed flower of _Cypripedium_.]
[Illustration: FIG. 45.--Diagram of malformed _Cypripedium_. _o_, outer
segments; _i_, inner segments of perianth; _e_, lip; _s_, stigma; _a_,
anther.]
[Illustration: FIG. 46--- Diagram showing ordinary arrangement in
_Cypripedium_. _o_, outer, _i_, inner segments of perianth; _e_, lip,
_a_, anther, _a'_, abortive stamen; _s_, stigma.]
[Illustration: FIG. 47.--Plan of flower of _Lycaste Skinneri_ showing
displacement of organs.]
In a specimen of _Lycaste Skinneri_ similar changes were observed, as
shown in the plan, fig. 47. Here the posterior sepal was deficient, the
two lateral ones were present, one of them with a long tubular spur, _o
o_; of the two lateral petals, _i i_, one was twisted out of place, so
as partially to occupy the place of the deficient sepal; the lip was
represented by two three-lobed segments, _l_, one above and within the
other. The column and ovary of this flower were in their normal
condition.
Cohesion of two or more segments of the perianth is frequently
associated with displacements of this nature: thus, in a flower of
_Dendrobium nobile_, a diagram of which is given at fig. 48, the
uppermost sepal was coherent with one of the lateral ones, and at the
same time diminished in size, and, as it were, dragged out of position.
All the other organs of the flower are also more or less displaced,
forming a minor degree of the change already alluded to, and which
Morren termed speiranthy. The changes will be better appreciated by
comparing them with fig. 49, a diagram showing the natural arrangement
of parts in this species.
[Illustration: FIG. 48.--Plan of malformed flower of _Dendrobium
nobile_.]
[Illustration: FIG. 49.--Plan of natural arrangement in _Dendrobium
nobile_. The x x represent processes of the column, perhaps rudiments of
stamens.]
Sometimes the displacement seems consequent on hypertrophy of one of the
parts of the flower, the disproportionate size of one organ pushing the
others out of place. This was the case in a violet, fig. 50, in which
one of the sepals _s_ was greatly thickened, and the petals and stamens
were displaced in consequence.
[Illustration: FIG. 50.--Plan of flower of violet showing displacement
of petals, &c. At _b_ was a rudiment of a stamen.]
It is curious to observe in many of these cases that the transposed
organ not only occupies the place of a suppressed or abortive organ,
but frequently assumes its colour, and, to some extent, its function.
This has been alluded to in the case of the leaf of _Gesnera_ (see p.
88) and in Orchids this replacement seems to be very common; thus, in
addition to the cases before mentioned, in a flower of an Odontoglossum,
for which I am indebted to Professor Oliver, the two lateral sepals were
united together and occupied the position of the labellum, which was
absent. A similar occurrence happens occasionally in _Lycaste Skinneri_,
thus recalling the structure of _Masdevallia_, where the labellum is
normally very small. The arrangement in Lycaste may thus be symbolised:
S
P st P
+
S S
___
[Transcriber's note: The underscores represent a horizontal curly brace
in the original.]
the + indicating the position of the absent labellum.
Cases of this kind are the more interesting from their relation to the
fertilization of these flowers by insects; it seems as though, when the
labellum, which performs so important an office in attracting and
guiding insects, is deficient, its place is supplied by other means.
Displacement of the parts of the flower from elongation of the
receptacle is a not infrequent teratological occurrence, resulting
sometimes in the conversion of the verticillate into the spiral
arrangement. Instances of this are cited under Elongation,
Prolification, &c. In this place it is merely necessary to refer to a
curious circumstance that is met with in some double flowers, owing to
this separation of some parts of the flower and the cohesion or adhesion
of others. Thus, in some double flowers of _Primula sinensis_ and in the
Pea (_Pisum sativum_), I have seen a gradual passage of sepals to
petals, so that the calyx and corolla formed one continuous sheet,
winding spirally around the central axis of the flower, after the
fashion of a spiral tube.[98]
=Displacement of the carpels= arises from one or other of the causes
above alluded to, and when suppression takes place in this whorl it
generally happens that the place of the suppressed organ is occupied by
one of the remaining ones, which thus becomes partially dislocated.
=Displacement of the placentas and ovules= is a necessary result of many
of the changes to which the carpels are subject. The disjunction or
dialysis of the carpels, for instance, frequently renders axile
placentation marginal. Moreover, it frequently happens, when the carpels
become foliaceous and their margins are disconnected, that the ovules,
in place of being placed on the suture, or rather on the margins of the
altered carpel, are placed on the surface of the expanded carpel. Thus,
in some double flowers of _Ranunculus Ficaria_ that came under the
writer's notice the carpels were open, _i.e._ disunited at the margins,
and each bore two imperfect ovules upon its inner surface a little way
above the base, and midway between the edges of the carpel and the
midrib, the ovules being partly enclosed within a little depression or
pouch, similar to the pit on the petals. On closer examination the
ovules were found to spring from the two lateral divisions of the
midrib, the vascular cords of which were prolonged under the form of
barred or spiral fusiform tubes into the outer coating of the ovule. In
this instance, then, the ovules did not originate from the margins of
the leaf, nor from a prolonged axis, but they seemed to spring, in the
guise of little buds, from the inner surface of the carpellary leaf.[99]
The occurrence, also, of different forms of placentation in different
flowers on the same plant is no unusual thing in malformed flowers;
thus, in double flowers of _Saponaria officinalis_ I have met with
sutural, parietal, and free central placentation in the same plant.[100]
Professor Babington describes in the 'Gardeners' Chronicle,' 1844, p.
557, a curious flower of _Cerastium_, in which, in addition to other
changes, the five carpellary leaves "were partially turned in without
touching the placenta, which bears a cluster of ovules, and is perfectly
clear of all connection with those partitions" (fig. 51). See also
Lindley, 'Veg. Kingdom,' p. 497.
[Illustration: FIG. 51.--1. Monstrous flower of a _Cerastium_; sepals
and petals leafy. 2. Stamens and pistils separate. 3. Ovary cut open to
show the imperfect dissepiments and the attachment of the ovules. 4. A
deformed ovule.]
M. Baillon[101] records flowers of _Bunias_, some with ovules on the
margins of the carpels, others with a central branch bearing the ovules;
hence he concludes very justly that no fair inference can be drawn from
these facts as to the normal placentation of Cruciferæ.
The same excellent observer has recorded the occurrence of free central
placentation in malformed flowers of _Trifolium repens_.[102]
In malformed flowers of _Digitalis_ the change from axile to parietal
placentation may often be seen. Mr. Berkeley describes an instance of
this nature where the placentas were strictly parietal, and therefore
receded from the distinctive characters of the order, and approximated
to those of _Gesneraceæ_.
The same author alludes to certain changes in the same flower where two
open carpels "were soldered together laterally, as was clear by the
rudiments of two styles, the placenta being produced only at the two
united edges, the outer margins remaining in the normal condition. This
may possibly tend to the explanation of some cases of anomalous
placentation, for the only indication of the true nature of the
placentation is afforded by the two rudimentary styles, in the absence
of which the spongy receptacle of the seeds must have been supposed to
spring from the medial nerve."
In other cases the placentas were parietal above, but axile at the base
of the capsule, a striking instance of the facility with which axile
placentation becomes parietal, the change being here effected by the
prolongation of the axis, and the formation on it of a second whorl of
carpellary leaves.
In double flowers of _Primulaceæ_ similar alterations in the
placentation may often be observed. I have seen in _Primula sinensis_
sutural, parietal, axile, and free central placentation all on the same
plant; nay, even in the same capsule the ovules may be attached in
various ways, and transitions from one form of placentation to another
are not infrequent. The late Professor E. Forbes describes[103] an
instance of true foliar and true axile placentation in the same flower
in _Vinca minor_.
These and many similar changes, which it is not necessary further to
allude to, are not so much to be wondered at when it is borne in mind
how slight an alteration suffices to produce a change in the mode of
placentation, and how frequent is the production of adventitious buds or
of foliar outgrowths, as may be seen in the sections relating to those
subjects and to Substitutions.
It will be remembered, also, how, in certain natural orders, under
ordinary circumstances, considerable diversity in placentation exists,
according as the margins of the carpels are merely valvate or are
infolded so as to reach the centre. Often this diversity is due merely
to the changes that take place during growth; thus, the placentation of
_Caryophylleæ_, _Cucurbitaceæ_, _Papaveraceæ_, and many other orders,
varies according to the age of the carpel, and if any stasis or arrest
of development occurs the placentation becomes altered accordingly.
It is not necessary, in this place, to enter into the question whether
the placenta is, in all cases whatsoever, a dependence of the axis, as
Payer, Schleiden, and others, have maintained, or whether it be foliar
in some cases, axial in others. This question must be decided by the
organogenists; teratologically, however, there can be no doubt that
ovules may be formed from both foliar and axial organs, and, moreover,
that, owing to the variability above referred to, both in what are
called natural and in what are deemed abnormal conditions, it can rarely
happen that any safe inferences as to the normal or typical placentation
of any family of plants can be drawn from exceptional or monstrous
formations.
On the subject of placentation the following authors may be consulted:
R. Brown, 'Ann. Nat. Hist.,' 1843, vol. xi, 35. Brongniart,
'Ann. Sc. Nat.,' 1834, sér. 2. i, p. 308. Alph. De Candolle,
'Neue Denkschrift der Allg. Schweizer Gesellsch.,' Band v.
1841, p. 9. Duchartre, 'Ann. Sc. Nat.,' 3rd ser., 1844, vol.
ii, p. 290. Ibid., 'Elem. Bot.,' p. 574; 'Rev. Bot.,' 1846-7,
p. 213. Babington, 'Gard. Chron.,' 1844, p. 557. Lindley,
'Elements,' p. 89; 'Veg. King.,' pp. 313, 497, &c. Berkeley,
'Gard. Chron.,' 1850, p. 612. Unger, 'Nov. Act. Acad. Nat.
Cur.,' 1850; and in Henfrey's, 'Bot. Gazette,' 1851, p. 70.
Schleiden, 'Principles,' English edit., p. 385. Payer, 'Elem.
Bot.,' pp. 196, 211, 224. Baillon, 'Adansonia.' iii, p. 310.
tab. iv. Cramer, 'Bildungsabweichungen,' p. 20, &c. Clos, 'Ann.
Sc. Nat.,' 5th ser., iii, 313, as well as any of the general
treatises on botany. Reference may also be made to the chapters
on Prolification and Substitutions (in the case of the carpels
and ovules), and to the authorities therein cited.
FOOTNOTES:
[90] 'Tijdschr. voor. nat. Gesch.,' viii, 1841. tab. ii, p. 178.
[91] Communication to the Internat. Bot. Congress, Paris, 1867.
[92] 'Bot. Zeit.,' 1859, p. 117, tab. v.
[93] 'Ann. Sc. Nat.,' ser. 2, vol. iv, 1835, p. 143. tab. v.
[94] See Kirschleger, 'Flora.' 1844. p. 566 (_Scabiosa_).
[95] 'Bull. Acad. Belg.,' t. xvii. part ii, p. 387.
[96] 'Clos. Mem. Acad. Toulouse,' 5th ser., t. vi. pp. 51, 70.
[97] 'Bull. Acad. Roy. Belg.,' xviii. part ii, p. 505, and vol. xvii,
part i, p. 196, and vol. xix. part i. p. 260.
[98] See also Schlechtendal, 'Bot. Zeit.,' iv, p. 804. _Primula veris,
partibus perigonii spiræ in modum confluentibus._
[99] Seemann's 'Journal of Botany,' vol. v, 1867, p. 158.
[100] 'Journ. Linn. Soc.,' i, 1857, p. 161. _c. xylog._
[101] 'Adansonia,' ii, 306.
[102] 'Adansonia,' iv, p. 70, t. i.
[103] Henfrey's 'Bot. Gazette,' i, 265.
CHAPTER II.
PROLIFICATION.
Moquin-Tandon and other writers have classed the production of buds in
unwonted situations under the head of multiplication, but, as the
altered arrangement is of graver import than the mere increase in
number, it seems preferable to place these cases under this heading
rather than under that of alterations of number.
The adventitious bud may be a leaf-bud or a flower-bud; it may occupy
the centre of a flower, thus terminating the axis, or it may be axillary
to some or other of its component parts, or, again, it may be
extra-floral. In this last case the prolification is of the
inflorescence, and is hardly distinguishable from multiplication or
subdivision of the common flower-stalk. In accordance with these
differences we have median, axillary, and extra-floral prolification,
each admitting of subdivision into a leafy or a floral variety,
according to the nature of the adventitious bud. Under the head of each
variety certain special peculiarities are noticed, but it may here be
advisable to add a few general remarks on the subject.
Axillary prolification is a much less frequent malformation than the
median form. If only the number of orders and genera be reckoned, the
truth of this statement will be scarcely recognised; but if individual
cases could be estimated, the difference in frequency between the two
would be very much more obvious. This may, perhaps, be explained by the
fact that the branch has a greater tendency to grow in length than it
has to develop buds from the axils of the leaves. The flower is admitted
to be homologous with the branch, and it is also known that, up to a
certain time, the branch-bud or leaf-bud and the flower-bud do not
essentially differ.[104] At a later stage the difference between the two
is manifested, not only in the altered form of the lateral organs in the
flower-bud, but in the tendency to an arrest of growth, thus limiting
the length of the central axial portion. Now, in prolified flowers the
functions and, to a considerable extent, the appearance of a leaf-bud or
of a branch are assumed, and with them the tendency to grow in length is
developed. Median prolification, therefore, in this sense, is a further
step in retrograde metamorphosis than is the axillary form. To grow in
length, and to produce axillary buds, are alike attributes of the
branch; but the former is much more frequently called into play than the
latter; for the same reason, median prolification is more common than
the axillary form. This is borne out by the frequency with which
apostasis, or the separation of the floral whorls one from another, to a
greater degree than usual, is met with in prolified flowers.
In both forms the adventitious growth is much more frequently a
flower-bud or an inflorescence than a leaf-bud or a branch. This may be
due to the position of the flowers on a portion of the stem of the plant
especially devoted to the formation of flower-buds, to the more or less
complete exclusion of leaf-buds, _i.e._ on the inflorescence. This
conjecture is borne out by the comparative rarity with which
prolification has been observed in flowers that are solitary in the
axils of the ordinary leaves of the plant. If the lists of genera
appended hereto be perused, it will be seen that nearly all the cases
occur in genera where the inflorescence is distinctly separated from the
other branches of the stem. In direct proportion, then, to the degree in
which one region of the axis or certain branches of a plant are devoted
to the formation of flower-buds to the exclusion of leaf-buds, is the
frequency with which those flowers become affected with floral
prolification.
Flowers produced upon indefinite inflorescences are liable to be
affected with either form of prolification more frequently than those
borne upon definite inflorescences. Prolification in both varieties is
also more frequently met with in branched inflorescences than in those
in which the flowers are sessile; but the degree of branching seems less
material, inasmuch as this malformation is more commonly recorded as
occurring in racemes than in the more branched panicles, &c. From the
similar arrest of growth in length, in the case of the flower, to that
which occurs in the stem in the case of definite inflorescence, it might
have been expected that axillary prolification would be more frequent in
plants having a cymose arrangement of their flowers than in those whose
inflorescence is indefinite; such, however, is not the case. The reason
for this may be sought for in the lengthening of the floral axis, so
common in prolified flowers--a condition the reverse of that which
happens in the case of definite inflorescence.
Median prolification occurs frequently in double flowers; the axillary
variety, on the other hand, is most common in flowers whose lateral
organs have assumed more or less of the condition of leaves. The other
coincident changes are alluded to elsewhere or do not present useful
points of comparison, and may therefore be passed over.
=Prolification of the inflorescence.=--This consists in the formation of
leaf-buds or of an undue number of flower-buds on the inflorescence. It
must be distinguished from virescence, or the mere green colour of the
floral organs, and from chloranthy, in which all or the greater portion
of the parts of the flower are replaced by leaves. Prolification is, in
fact, a formation of supernumerary buds, leafy or floral, as the case
may be, these buds being sessile or stalked, the ordinary buds being not
necessarily changed. Prolification of the inflorescence, like the other
varieties, admits of subdivision, not only according to the foliar or
floral nature of the bud, but according to its position, terminal or
median and lateral.
Terminal prolification of the inflorescence, whether leafy or floral, is
hardly to be looked upon in the light of a malformation[105] seeing that
a similar condition is so commonly met with normally, as in _Epacris_,
_Metrosideros_, _Bromelia_, _Eucomis_, &c., wherein the leafy axis
projects beyond the inflorescence proper; or as in _Primula imperialis_,
in which plant, as also in luxuriant forms of _P. sinensis_, tier after
tier of flowers are placed in succession above the primary umbel.
Nevertheless, when we meet with such conditions in plants which, under
ordinary circumstances, do not manifest them, we must consider them as
coming under the domain of teratology.
=Median foliar prolification of the inflorescence= is frequently met
with in _Coniferæ_, and has of late attracted unwonted attention from
the researches of Caspary, Baillon, and others, on the morphology of
these plants. The scales and bracts of the cone in these abnormal
specimens frequently afford transitional forms of the greatest value in
enabling morphologists to comprehend the real nature of the floral
structure. It would be irrelevant here to enter into this subject;
suffice it merely to say that an examination of very numerous specimens
of this kind, in the common larch and in _Cryptomeria Japonica_, has
enabled me to verify nearly the whole of Caspary's observations. A
similar prolongation of the axis occurred in some of the male catkins of
_Castanea vesca_, each of which had a tuft of small leaves at their
extremity. In the common marigold and in _Lotus corniculatus_ I have
also seen instances of this kind. Kirschleger[106] describes a tuft of
leaves as occurring on the apex of the flowering spike after the
maturation of the fruit in _Plantago_, and a similar growth frequently
takes place in the common wallflower, in _Antirrhinum majus_, &c. In
cases where a renewal of growth in the axis of inflorescence has taken
place after the ripening of the fruit, the French botanists use the term
recrudescence, but the growth in question by no means always occurs
after the ripening of the fruit, but frequently before. Professor Braun
cites the case of a specimen of _Plantago lanceolata_, in which the
spike was surmounted by a tuft of leaves and roots, as well as a still
more singular instance in _Eryngium viviparum_, in which not only did
particular branches terminate in rosettes of leaves provided with roots,
but similar growths proceeded from the heads of flowers themselves.
Baron de Mélicoq[107] gives a case in _Primula variabilis_, in which at
the top of the flower-stalk, in the centre of six flowers, was placed a
complete plant in miniature, having three leaves, from the axil of one
of which proceeded a rudimentary flower. Mr. W. B. Jeffries also
forwarded me a polyanthus (fig. 52) in which the peduncle was surmounted
by a small plant, forming a crown above the ordinary flower-stalk, just
as the crown of the pineapple surmounts that fruit. A similar instance
was exhibited at the Scientific Committee of the Horticultural Society
on July 11th, 1868, by Mr. Wilson Saunders; the species in this case was
_P. cortusoides_. To Mr. R. Dean I am indebted for a similar proliferous
cyclamen, which seems similar to one mentioned by Schlechtendal.[108]
This author alludes to an analogous circumstance in the inflorescence of
_Cytisus nigricans_, where, however, the change was not so great as in
the preceding cases. The instances just cited all occur in plants having
an indefinite form of inflorescence; but the production of a tuft of
leaves or of a leafy shoot above or beyond the inflorescence is not
confined to plants with this habit of growth, for Jacquin figures and
describes an instance of this nature in the cymose flower-stems of a
Sempervivum. "_Hi racemi_," says he, "_ultra flores producuntur in
ramos, foliosos duo bifidos qui tandem trium unciarum longitudinem
adepti fuerunt_."[109]
[Illustration: FIG. 52.--Inflorescence of _Polyanthus_, bearing a tuft
of leaves at the top of the scape intermixed with the flowers.]
=Median floral prolification of the inflorescence=, wherein a new
inflorescence projects beyond the primary one, is not uncommon in plants
having their flowers arranged in close heads or umbels, as in the
common wild celery and other _Umbelliferæ_.[110] I have also met with
it in _Trifolium repens_, in the umbellate variety of the common
primrose, and in the scarlet geranium. Engelmann cites it in _Triticum
repens_, Roëper in _Euphorbia palustris_.[111]
=Lateral foliar prolification of the inflorescence= is of more common
occurrence than the preceding. I have met with it, amongst other plants,
frequently in _Brassica oleracea_, _Pelargonium zonale_, SCABIOSA,
BELLIS, and many other composites, also in _Leguminosæ_, e.g. _Lupinus_,
_Trifolium_, _Coronilla_, &c. Prof. Oliver forwarded me a specimen of
_Euphorbia geniculata_ in which, in addition to other changes, there was
a series of stalked buds bearing tufts of green scales, but without any
trace of stamens or pistil; these adventitious buds occurred within the
ordinary involucre of the plant, between it and the stamens. The pistil
was unaffected in some cases, while in some others it was entirely
wanting, the gynophore being surmounted by a cup-like involucre, divided
into three acutely pointed lobes, each with a midrib; these encircled a
series of stalked involucels, as before, and among which were scattered
a few stamens, some perfect, others partially frondescent.
In a specimen of _Scrophularia nodosa_ examined by me one of the lateral
buds on each of the cymes was represented, not by a flower, but by a
tuft of leaves, the other buds being unchanged. As the inflorescence was
much contracted in size, the appearance of the whole plant was greatly
changed.
Many of the instances of so-called viviparous plants, _e.g._, _Polygonum
viviparum_, may be cited under this head.[112] Many species of _Allium_,
_Lilium_, _Saxifraga_, _Begonia_, _Achimenes_, normally produce
leaf-buds or bulbs in the inflorescence; so, too, leafy shoots are
sometimes found in _Alisma natans_, _Juncus uliginosus_, _Chlorophytum
Sternbergianum_, &c. As an accidental occurrence, a similar thing has
been noticed in _Lychnis coronaria_, _Phaius grandifolius_, _Oncidium
cebolleta_, _Epidendrum elongatum_,[113] &c. &c.
Here, too, may be mentioned those cases wherein a leaf-bud is found upon
the surface of the so-called inferior ovary; generally a leaf only is
found, but a leaf-bud may also originate in this situation, and in
either case the inference is that the ovary is, in part at least, made
of the dilated and hollowed axis. Leaves may occasionally be found in
this way on the so-called calyx-tube or on the inferior ovaries of
roses, pears, apples, _Pereskia_, _Cratægus tanacetifolia_, &c.
The fruits of _Opuntia Salmania_ and of _O. fragilis_ ('Bull. Soc. Bot.
France,' vol. i, p. 306; vol. v, p. 115) have been observed to form
small fruit-like branches around their summits. This circumstance is
more fully treated of in the succeeding chapter relating to Heterotaxy.
=Lateral floral prolification of the inflorescence.=--This, which is
termed by Engelmann Ecblastesis foliorum sub floralium,[114] is much the
most common of all these deviations, and it is met with in every degree,
from the presence of a single supernumerary flower in the axil of a
bract to the existence of a small cluster or panicle of such flowers.
[Illustration: FIG. 53.--Lateral prolification in inflorescence of
_Pelargonium_.]
It is common in the _Anemone coronaria_ and _hortensis_, also in the
common scarlet _Pelargonium_ (fig. 53). It has been frequently recorded
in _Poterium sanguisorba_, and in _Sanguisorba officinalis_, and is
especially common in _Umbelliferæ_, _Dipsacaceæ_, and _Compositæ_; a
familiar illustration in the latter order is afforded by the
hen-and-chicken daisy. In some species of Compositæ, indeed, it is a
normal and constant occurrence, while in other cases, such as _Filago
germanica_, usually described as proliferous, there is not, strictly
speaking, any prolification, for the branching of the stalk takes place
below the inflorescence, and the branches originate from the axils of
ordinary leaves, not from the floral leaves or bracts. _Convolvulus
Sepium_ is very commonly subject to the production of flower-buds from
the axils of the floral leaves. The several species of Plantain
(_Plantago_) seem very liable to this and similar changes.
Schlechtendal[115] gives a summary of the various kinds of malformation
affecting the inflorescence in _Plantago_, and divides them into five
groups, as follows:--1st, bracteate, wherein the inferior bracts are
quite leaf-like, as is frequently seen in _Plantago major_. 2nd,
roseate; bracts leafy in tufts or rosettes, without flowers, as in the
so-called rose plantain, common in old-fashioned gardens in this
country. 3rd, polystachyate; spike-branched, bearing other spikes in the
axils of the bracts, as in _P. lanceolata_, _P. maritima_, &c. 4th,
proliferous, where the flower-stalk bears a rosette, a spike, or a head
with other rosettes. 5th, paniculate, in which the inflorescence has
become a much-branched pyramidal panicle, covered with little bracts,
and with very rudimentary flowers.[116] The first two groups belong
rather to frondescence of the bracts; but with regard to the whole of
them it will easily be surmised that intermediate forms occur, linking
one group to the other, and defying exact allocation in either. Thus, in
the borders of richly cultivated fields in the neighbourhood of London I
have frequently gathered specimens of _Plantago major_ with a branched
spike provided with large leafy bracts, the branches of the spike being
but little less in diameter than the ordinary single spike. These
specimens would therefore seem to be intermediate between
Schlechtendal's bracteate and polystachyate divisions. Wigand[117] also
describes an anomalous specimen of _Plantago major_ similar to those
just mentioned, but having small lateral spikes in place of large ones.
The instance quoted from Professor Braun would fall under the roseate
section, as would also that of Kirschleger, though we are expressly told
that the tuft of leaves in this last case was not developed until after
the ripening of the seed-vessel. One of the characters of the roseate
group, according to Schlechtendal, is the absence of flowers, but most
persons who have had the opportunity of watching the growth of the rose
plantain must have observed the occasional production of flowers,
sometimes stalked, in the axils of the leafy bracts, and at the same
time have noticed that the internodes become elongated, so that an
approach is made to the ordinary spike-like form of the inflorescence.
The proliferous group would include such specimens as that of _P.
lanceolata_ mentioned by Dr. Johnston,[118] wherein were several
spikes, some sessile, others stalked and pendent, the whole intermixed
with leaves and disposed in a rose-like manner. I have myself gathered
specimens of this nature, occurring in the same plant, at Shanklin, Isle
of Wight (fig. 56).
[Illustration: FIG. 54.--_Plantago major_, with panicled inflorescence.]
[Illustration: FIG. 55.--Inflorescence of _Plantago major_, with bracts
partly replaced by leaves and spike branched.]
[Illustration: FIG. 56.--Inflorescence of _Plantago lanceolata_, bearing
a tuft of leaves and flowers at the end of the flower-scape.]
It is rather singular that each species of _Plantago_ seems to have its
own perverse mode of growth; for instance, the bracteate, polystachyate
and paniculate forms are almost exclusively confined to _P. major_, the
roseate form to _P. media_, the proliferous form to _P. lanceolata_.
The instances wherein flower-buds originate from the surface of an
inferior ovary, as in those cases where the top of the stem is dilated
so as to form part of the fruit, would be properly classed under the
head of prolification of the inflorescence. As, however, there is still
some difference of opinion as to the correct morphological
interpretation to be put on some of these cases, it has been thought
better to include them under the head of heterotaxy than of
prolification.
[Illustration: FIG. 57.--Branched inflorescence of _Reseda luteola_.]
Some of the cases of prolification of the inflorescence resulting in a
branching of an ordinarily simple inflorescence, as in _Reseda luteola_
(fig. 57), might equally well be placed with fission or multiplication
of the axile organs. Branched spikes of this character are not so common
among Orchids as might be expected. Professor Reichenbach enumerates a
few instances in the Report of the International Botanical Congress of
London, 1866, p. 121, and the same author gives an illustration in his
'Orchidographia Europoea,' tab. 150.
In Grasses, as indeed in other plants with a spicate inflorescence, this
change occurs not unfrequently. The common Ray Grass (_Lolium_) is
especially subject to the change in question, and among cultivated
cereals, maize and wheat occasionally show this tendency to subdivision.
One variety of the latter grain is cultivated in hot countries under the
name of Egyptian wheat--_Triticum vulgare_, var. _compositum_.
Prolification of the inflorescence has been most frequently observed in
the following genera:
_Leafy_. _Floral_.
Ranunculaceæ Ranunculus. Ranunculus!
Anemone. Anemone.
Cruciferæ. *Brassica!
Caryophyllaceæ. Lychnis!
Dianthus!
Geraniaceæ. *Pelargonium! *Pelargonium!
Leguminosæ. *Trifolium! Trifolium!
Lotus! Lotus!
Coronilla!
Cytisus. Cytisus.
Rosaceæ. Poterium.
*Pyrus! *Pyrus!
*Cratægus! Cratægus!
*Rosa. Rosa!
Sanguisorba.
Philadelphaceæ. Philadelphus.
Crassulaceæ. Sempervivum.
Echeveria.
Crassula.
Ficoideæ. ?Tetragonia.
Cactaceæ. Opuntia. Opuntia.
Pereskia.
Saxifragaceæ. Saxifraga!
Umbelliferæ. Seseli.
*Apium!
Cnidium.
Chærophyllum.
Eryngium. Eryngium.
Silaus.
Heracleum! Heracleum!
Hydrocotyle. Hydrocotyle.
Daucus.
Carum.
Selinum.
Angelica!
Conium.
Astrantia.
OEnanthe. OEnanthe.
Begoniaceæ. Begonia!
Valerianaceæ. Valeriana.
Dipsacaceæ. *Scabiosa! *Scabiosa!
Knautia! Knautia!
Compositæ. *Bellis!
Centaurea.
Calendula. Calendula.
Anthemis.
Coreopsis.
Apargia.
Lampsana.
Carlina.
Arnoseris.
Tragopogon! Tragopogon!
Rudbeckia!
Senecio!
Carlina.
Bidens! Pyrethrum.
Filago.
Hedypnois.
Cirsium.
Lactuca.
Campanulaceæ. Prismatocarpus.
Lobeliaceæ. Jasione.
Ericaceæ. Azalea!
Convolvulaceæ. Convolvulus! Convolvulus!
Calystegia!
Scrophulariaceæ. Scrophularia!
Antirrhinum!
Gesneraceæ. Achimenes!
Primulaceæ. Primula! Primula!
Cyclamen! Cyclamen!
Plumbaginaceæ. Armeria.
Plantaginaceæ. *Plantago! *Plantago!
Polygonaceæ. Polygonum!
Euphorbiaceæ. Euphorbia!
Urticaceæ. Ficus.
Amentaceæ. Corylus!
Castanea! Castanea.
Coniferæ. *Larix!
*Cryptomeria!
Taxodium! Pinus.
Orchidaceæ. Phaius! Ophrys!
Epidendrum!
Oncidium!
Liliaceæ. *Allium!
*Ornithogalum!
*Lilium!
Amaryllidaceæ. Fourcroya
Alismaceæ. Alisma!
Palmaceæ. Cocos.
Juncaceæ. *Juncus!
Restiaceæ. Restio! Restio!
Elegia! Elegia!
Willdenovia! Willdenovia!
Cyperaceæ. Carex.
Graminaceæ. Dactylis.
*Lolium!
Festuca.
*Zea!
*Triticum!
*Hordeum!
Secale.
Phleum.
In addition to the papers already cited the following works may be
consulted with reference to prolification of the inflorescence:
Moquin-Tandon. 'El. Ter. Veg.,' p. 376. Engelmann, 'De
Antholysi,' §§ 85-87. Fleischer, 'Missbild. Versch. Cultur.
Pflanz.' For figures of Hen and Chicken Daisy (_Bellis
prolifera_). see Lobel, 'Ic.,' 477. Sweert, 'Florileg.,' pl.
98, f. 5. 'Hort. Eystett. Plant. Vern.,' fol. iv, f. i. &c. For
similar malformations in marigold (_Calendula_), see Lobel,
'Ic.,' 553. 'Act. Acad. Nat. Cur.,' vol. x, p. 208. Jaeger,
'Missbilld.,' 192-195. 'Hort. Eystett.,' pl. æstiv. fol. iii,
f. i. Klinsmann, 'Linnæa,' t. x, p. 607.
For monstrous plantains, in addition to previous citations, see
Camerarius, 'Epist.,' p. 261, _P. rosea_. Matthioli,
'Krauterb,' 245. Lobel, 'Stirp. Advers. Nov.,' p. 128, _P.
major paniculata._ J. Bauhin, 'Hist. Plant.,' i, p. 503 _b_.
Ibid., p. 503, _a_, _c_, _P. major rosea_, _bracteata
paniculata_, _prolifera_, &c. 'Hort. Eystett.,' pl. æstiv., t.
vii, f. 2, _P. rosea_ et _P. bracteata_. Lobel, 'Stirp. Hist.,'
p. 162. Dodonæus, 'Pempt.,' 1-4, cap. xxiii, P. major spica
multiplex, _i.e._ paniculata. Gerard, 'Herbal.' Clusius,
'Plant. Rar. Hist.,' lib. v, p. 109-10, _Plantago augustifolia
Gareti prolifera_. Marchand, 'Adansonia,' iv, p. 156.
_Coniferæ._--Richard, 'Mem. Conif.,' tab. xiii, f. 9. A. Braun,
'Das Individ.,' 1853, p. 65. De Cand., 'Organogr.,' tab. xxxvi.
Wigand, 'Bot. Untersuch.,' 154. Schlechtendal, 'Bot. Zeit.,'
1859, p. 239. Caspary, 'De Abiet. flor. fem. struct. morphol.'
Parlatore, 'Ann. Sc. Nat.,' 1862, vol. xvi, p. 215. Cramer,
'Bildungsabweich.,' p. 4, &c., &c.
_Gramineæ._--Bauhin, 'Pinax.,' 21. Morison, 'Hist. Plant.,' t.
i. Winckler, 'Ephem. Nat. Cur.,' dec. i, ann. 7, 8, p. 151.
Irmisch, 'Flora,' 1858, p. 40, &c.
See also under Chloranthy, Viviparous plants, &c.
=Prolification of the flower.=--In the preceding sections the formation
of adventitious buds of a leafy or floral nature on the inflorescence
has been considered. A similar production of buds may take place in the
flower itself, either from its centre or from the axil of some of its
constituent parts. Prolification of the flower is therefore median or
axillary, and the adventitious bud itself may be of a leafy or a floral
nature.
=Median leafy prolification.=--In this malformation the centre of the
flower is occupied by a bud or a branch; the growing point or
termination of the axis which ordinarily ceases to grow after the
formation of the carpels, takes on new growth. This is well shown in the
accompanying illustration (fig. 58), representing the thalamus of a
strawberry prolonged beyond the fruits into a small leaf-bearing branch.
[Illustration: FIG. 58.--Receptacle of strawberry prolonged into a leafy
branch. From the 'American Agriculturist.']
[Illustration: FIG. 59.--Flower of _Verbascum_ with five disunited
sepals, five similar green petals, and a prolonged branch in the centre
of the flower.]
In other cases the carpels are entirely absent and their place is
supplied by a leafy shoot as in a species of _Verbascum_, which came
under my own observation. In this case the petals were virescent, and
the stamens and pistils were entirely absent, hence in truth, the
so-called flower more nearly resembled a branch. In a flower of a May
Duke cherry, for which I am indebted to Mr. Salter, there was a gradual
change from the floral to the foliar condition; thus there were five
distinct lanceolate sepals, the arrangement of whose veins betokened
that they were leaf-sheaths rather than perfect leaves, ten petals
partly foliaceous and sheath-like as to their venation, one of them
funnel-shaped, but whether from dilatation or cohesion of the margins
could not be determined. The stamens were eight or ten in number, their
connectives prolonged into foliaceous or petaloid appendages, so that
the filament represented the stalk of the leaf. The pistil was entirely
absent and its place was supplied by a branch with numerous perfectly
formed stipulate leaves.
Some flowers of _Anagallis arvensis_ described by Dr. Marchand[119] are
so interesting and show so well the gradual stages by which this
malformation is arrived at, that it is desirable to cite the summary of
Dr. Marchand's researches as given in the 'Gardeners' Chronicle' by Mr.
Berkeley, taking that instance first in which the parts of the flower
departed least from the normal condition, and then the others in their
proper order. In all the parts there was a greater or less tendency to
assume a green tint; in some they were entirely green, in others the
brighter colours were confined to the more recently developed parts.
"1. In the first case then, the sepals and petals were in their normal
position, though rather more dilated than usual; the anthers were
fertile, the principal change existing in the ovary, the upper part of
which was wanting, so that the ovules were exposed seated on the central
placenta.
2. In the next step the calyx, more developed than usual, was separated
from the corolla by a long peduncle, and the ovary, which was ovate,
contained instead of a placenta a sort of plumule or young shoot.
3. In this case the corolla and calyx were distant from each other;
there was no trace of stamens, but the axis was continued from the
centre of the corolla, and ended in a leaf-bud.
4. The calyx and corolla nearly as before, but instead of stamens a
whorl of little leaves was developed, in the centre of which the axis
was continued, bearing at its tip two whorls of leaflets, alternately
three and three.
5. In this case two out of the five stamens were normal, the other three
changed into leaves, showing clearly the origin of the leaflets, in the
last case, which took the place of the stamens.
6. The ovary varied in different flowers. In some the placenta was
crowned with ovules; in others the ovules were replaced by a single
whorl of leaflets; in others there was every shade of change from
ordinary ovules to perfect leaflets; while in others, again, every ovule
was converted into a leaf with a long petiole.
7. In these flowers shoots were developed in the axils of the sepals, or
on the face of the petals between the point of their insertion and that
of the stamens, and, what is most curious, in the interior of the
ovaries round the foot of the placenta.
8. Here, again, a very singular condition presented itself: the calyx
and corolla separated from each other, the stamens partly developed, the
axis continued beyond the corolla, branched and bearing normal leaves so
as exactly to resemble an ordinary stem, while in consequence of the
calyx and corolla being bent down to the ground, adventitious roots were
developed from the axis on the under side above each of them. In another
case, where the calyx and corolla were approximated, the ovary was open
above, and sent out six shoots from within, perfectly developed, clearly
representing the central placenta and five axile buds, and each giving
out a number of adventitious roots at its base."
In other genera of the same order (_Primulaceæ_) an extension of the
placenta into a leafy branch has been observed, as in _Lysimachia_,
where in one case the prolonged placenta was removed and struck as a
cutting.[120]
In _Ericaceæ_ too, the axile placenta has been seen ovuliferous at the
base and prolonged above into a leafy branch.[121]
=Median floral prolification.=--This is of more frequent occurrence than
the preceding. The prolonged axis is more frequently terminated by a
flower-bud than by a leaf-bud, though it must be remarked, that the
lengthened and protruded stem frequently bears leaves upon its sides,
even if it terminate in a flower, and thus the new growth partakes of a
mixed leafy and floral nature. Instances of this kind have long been
familiar to observers, and have always excited attention from the
singularity of their appearance. In one of the old stained-glass
windows, apparently of Dutch manufacture, in the Bodleian Picture
Gallery at Oxford, is a representation of a _Ranunculus_ affected with
median floral prolification.[122] In pinks the affection is not
unfrequently met with. Fig. 60 shows an instance of the kind copied from
Schotterbec.
A singular instance of prolification in the central flower of one of the
verticillasters of _Phlomis fruticosa_ fell under my own notice; it was
a case wherein the calyx was torn on one side, and one of its lobes had
become petaloid. Between the calyx and the corolla were three or four
spathulate, hairy, bract-like organs; the corolla and stamens were
unchanged; but in place of the usual four-lobed ovary there was a single
carpel with a basilar style, terminated by a forked stigma. Occupying
the place of the other lobes of the pistil was an oblong woolly
flower-bud, consisting of calyx, corolla, and stamens, but with no trace
of pistil. I have been unable to find recorded any instance of
malformation among Labiates or Borages at all similar to this. It
differed from most other examples of prolification in that the axis was
not prolonged, the adventitious bud occupying precisely the position of
the three lobes of the ovary that were absent. The sole remaining carpel
had a style and a stigma as perfect in appearance as though the pistil
had been complete.
[Illustration: FIG. 60.--Flower of _Dianthus_ affected with median
floral prolification.]
In a flower of _Conostephium_ (_Epacridaceæ_) forwarded to me by Mr.
Bentham, there was a similar adventitious bud placed by the side of the
pistil, but as the latter contained the usual number of cells it is
probable that the supernumerary bud in this case originated rather from
the side than the end of the axis.
Certain families of plants present this deviation from their ordinary
structure with greater frequency than others: the following orders seem
to be the most frequently affected by it: _Ranunculaceæ_,
_Caryophyllaceæ_, _Rosaceæ_; while it is commonly met with in
_Scrophulariaceæ_, _Primulaceæ_ and _Umbelliferæ_. Of genera which seem
peculiarly liable to it may be mentioned the following: _Anemone_,
_Ranunculus_, _Cheiranthus_, _Dianthus_, _Dictamnus_, _Daucus_, _Rosa_,
_Geum_, _Pyrus_, _Trifolium_, _Antirrhinum_, _Digitalis_, _Primula_.
A reference to the subjoined list of genera affected by this
malformation, and the knowledge of its comparatively greater frequency
in some than in others of them, will show that it is more often met with
in plants having an indefinite form of inflorescence than in those
having a definite one. The change may affect some only, or the whole of
the flowers constituting an inflorescence; and though it is by no means
a constant occurrence, it very frequently happens that the central or
terminal flower in a definite inflorescence is alone affected, the
others remaining in their ordinary condition, as in pinks (_Dianthus_);
and in the indefinite forms of inflorescence, it is equally common that
the uppermost flower or flowers are the most liable to be thus affected.
In those plants which present this deviation from the ordinary condition
with the greatest frequency, it often happens that the axis is normally
more or less prolonged, either between the various whorls of the flower,
as in the case of the gynophore, &c., or into the cavity of the carpels,
as in the instances of free central placentation. To bear out this
assertion, the following instances taken from those genera having
definite inflorescence, and which are very commonly affected with
prolification, may be cited; thus, in _Anemone_ and _Ranunculus_ the
thalamus is prolonged to bear the numerous carpels; in _Dianthus_ there
is a marked internode separating the carpels from the other parts of the
flower; in _Primulaceæ_ central prolification is very common, and this
is one of the orders where the placenta seems from the researches of
Duchartre and others, to be truly a production of the axis within the
carpels;[123] in _Thesium_ also, another genus with free central
placenta, this malformation has been found.
So also among plants with indefinite inflorescence, prolification seems
very frequently to affect those wherein the axis is normally prolonged;
thus it is common in _Dictamnus_, which plant has an internode
supporting the pistil; it is frequent among _Umbelliferæ_, where the
carpophore may be truly considered an axile production; it is common
among _Rosaceæ_ and _Ranunculaceæ_, in many of which the axis or
thalamus is well-marked, and it is by no means infrequent in the flowers
of the Orange, where the floral internodes are also slightly elongated;
on the other hand, there is no case on record in _Magnoliaceæ_, and some
other orders where the floral part of the axis is at some point or other
elongated; still, on the whole, there can be but little doubt that there
is a real relation between prolification and the normal extension of the
floral internodes.
Under these circumstances, those instances wherein the parts of the
flower become separated one from the other by the elongation of the
internodes (apostatis), constitute a lesser degree of the same change,
which operates most completely in the formation of a new bud at the
extremity of the prolonged axis. Some specimens of _Geum rivale_ (a
plant very liable to become prolified) in my possession show this very
clearly. In the wild plant the thalamus is elevated on a short stalk; in
the abnormal ones the thalamus is simply upon a longer stalk than usual,
or in a more advanced stage of the deviation the lengthened thalamus
takes the form of a branch provided with leaves and terminated by a
flower; it is noticeable, also, in these specimens, that the sepals of
the lower flower have assumed entirely the dimensions and appearance of
leaves.
Median prolification has occasionally been recorded in flowers that
have, in their ordinary condition, but one carpel, as in _Leguminosæ_
and in _Santalaceæ_. In _Leguminosæ_, as also in _Amygdalus_, it would
seem as if the adventitious bud were strictly a lateral and axillary
production, and moreover that the carpel itself is not strictly terminal
but lateral in position, though apparently terminal from the abortion of
other carpels. In the only recorded instance that I am aware of, of this
malformation affecting the genus _Thesium_, the pistil was altogether
absent, and occupying its place was the new bud or branch.[124]
[Illustration: FIG. 61.--_Daucus Carota_, showing leafly carpels,
prolification, &c.]
As the carpels are not unfrequently absent in cases of median
prolification, it has been thought that the pistil in such cases was
metamorphosed into a stem bearing leaves or flowers. Setting aside the
physiological difficulties in the way of accepting such an opinion, an
examination of any number of cases is sufficient to refute it; for, as
Moquin well remarks, the carpels may frequently be found either in an
unaltered condition or more or less modified.
If the pistil be normally syncarpous, its constituent carpels, if
present at all in the prolified flower, become disjoined one from the
other to allow of the passage between them of the prolonged axis; thus
in some malformed flowers of _Daucus Carota_ gathered in Switzerland
(fig. 61), not only was the calyx partially detached from the pistil,
but the carpels themselves were leaf-like, disjoined, and unprovided
with ovules; between them rose a central prolongation of the axis, which
almost immediately divided into two branches, each terminated by a small
umbel of perfect flowers, surrounded by minute bracts.[125]
Not only are the carpels thus frequently separated one from the other by
the prolonged axis, but they undergo commonly a still further change in
becoming more or less completely foliaceous, as in the _Daucus_ just
mentioned, where the carpels were prolonged into two lance-shaped
leaves, whose margins in some cases were slightly incurved at the apex,
forcibly calling to mind the long "beaks" that some Umbelliferous genera
have terminating their fruits--for instance, _Scandix_. Dr. Norman, in
the fourth series of the 'Annales des Sciences,' vol. ix, has described
a prolification of the flower of _Anchusa ochroleuca_, in which the
pistil consisted of two leaves, situated antero-posteriorly on a long
internode, with a small terminal flower-bud between them; and numerous
similar instances might be cited.
In this place may also be noticed those instances wherein the placenta
elongates so much that the pericarp becomes ruptured to allow of the
protrusion of the placenta, although this prolongation is not attended
by the formation of new buds. Cases of this kind occurring in
_Melastoma_ and _Solanum_ have been put on record by M. Alph. de
Candolle.[126] This is a change analogous with that which occurs in some
species of _Leontice_ or _Caulophyllum_, as commented on by Robert
Brown. See 'Miscellaneous Botanical Works' of this author, Ray Society,
vol. i, p. 359.
If the pistil be apocarpous, and the carpels arranged spirally on an
elevated thalamus, it then frequently happens that the carpels,
especially the upper ones, become carried up with the prolonged axis,
more widely separated one from the other than below, and particularly
liable to undergo various petalloid or foliaceous changes as in
proliferous _Roses_, _Potentilla_, &c.
[Illustration: FIG. 62.--Median floral prolification, &c., in flower of
_Delphinium_.]
Fig. 62, copied from Cramer, shows an instance of this kind in
_Delphinium elatum_, where not only is the thalamus prolonged, and the
carpels separated, but from the axils of some of the latter which have
assumed from the disunion of their margins somewhat of the appearance of
leaves, other flowering branches proceed--axillary prolification. If, on
the other hand, the carpels be few in number, and placed in a
verticillate manner, the axis then generally passes upwards without any
change in the form or position of the carpels being apparent, as in a
proliferous columbine, figured in the 'Linnean Transactions,' vol.
xxiii, tab. 34, fig. 5.
When a flower with the ovary naturally inferior or adherent to the calyx
becomes prolified, a change in the relative position of the calyx and
ovary almost necessarily takes place, the latter becoming superior or
detached from the calyx; this has been already alluded to in
_Umbelliferæ_. In a species of _Campanula_ examined by me, the calyx was
free, the corolla double, the stamens with petaloid filaments, and in
the place of the pistil there was a bud consisting of several series of
green bracts, arranged in threes, and enclosing quite in the centre
three carpellary leaves detached from one another and the other parts of
the flower, and open along their margins, where the ovules were placed.
In other similar instances in the same species of _Campanula_, the
styles were present, forming below an imperfect tube which surrounded
the adventitious bud; in another, contrary to what occurs usually in
such cases, the ovary was present in its usual position, but surmounted
by a bud of leafy scales, enclosed within the base of a tube formed by
the union of the styles. A similar relative change in the position of
the calyx and the ovary takes place when the _Compositæ_ are affected
with central prolification, or even in that lesser degree of change
which merely consists in the separation and disunion of the parts of the
flower, but which in these flowers appear to be, as it were, the first
stage towards prolification. I owe to the kindness of Professor Oliver a
sketch of a species of _Rudbeckia_? showing this detachment of the calyx
from the ovary. In a monstrous _Fuchsia_ that I have had the opportunity
of recently examining, the calyx was similarly detached from the ovary
simultaneously with the extension of the axis. Here the petals were
increased in number and variously modified, the stamens also; while in
the centre and at the top of the flower, conjoined at the base with some
imperfect stamens, was a carpel open along its ovuliferous margins. Such
instances as these seem to be the first stages of a change which,
carried out more perfectly, would result in the formation of a new bud
on the extremity of the prolonged axis.
In _Orchidaceæ_, among which family I have now met with several
instances of prolification, the ovary seems usually to be absent. Fig.
63 shows a prolified flower of _Orchis pyramidalis_ in which the
perianth was nearly regular, the central portions of the flower absent,
and their place supplied by a new miniature raceme. This specimen was
forwarded to me by Dr. Moore, of Glasnevin.
[Illustration: FIG. 63.--Median prolification in _Orchis pyramidalis_,
the outer segments of the perianth regular and reflexed.]
As might be expected, it very rarely happens that median prolification
occurs without some other deviation in one or more parts of the flower
being simultaneously manifested. Some of these changes have been already
mentioned, but others are commonly met with, as, for instance, the
multiplication or doubling, as it is termed, of the petals; others,
though less frequent, are of more interest. Fusion of two or more
flowers in association with prolification is especially common in
cultivated specimens of _Digitalis purpurea_; the uppermost flowers of
the raceme become fused together so as to form one large, regular,
erect, cup-shaped corolla, to the tube of which the stamens are
attached, in greater number than ordinary, and all of equal length; the
bracts and sepals are confusedly arranged on the exterior of the flower;
while in the centre, in the place usually occupied by the pistil, there
rises a conical prolongation of the axis, bearing at its outer or lower
portion a number of open carpels, provided, it may be, with styles and
ovules; these enclose an inner series of scale-like bracts, from whose
axils proceed more or less perfect florets; so that in the most highly
developed stage a perfect raceme of flowers may be seen to spring from
the centre of a cup-shaped regular flower, whose lobes show its compound
character. All intermediate stages of this malformation may be found
from cases where there is a simple fusion of two flowers with a second
verticil of carpels within the outer, up to such cases as those which
have been just mentioned. It is worthy of special remark, that in all
these cases the flowers at the uppermost part of the raceme are alone
affected, and that, in addition to the prolification, there is fusion of
two or more flowers, and regularity in the form of the compound corolla
and stamens.
The calyx of a prolified flower is either unchanged, or it is modified
in harmony with the changes in the central part of the flower. If the
ovary be normally superior or free from the calyx, then the latter is
comparatively rarely altered; for instance, in proliferous pinks
(_Dianthus_) the calyx is seldom affected, except, indeed, in those
instances where the floral axis is prolonged, and produces from its side
a successive series of sepals, as in what is called the wheat-ear
carnation; but though these instances may be, as I believe, an imperfect
degree of prolification, they do not affect the general truth of the
above opinion, that the calyx, if it be free from the ovary, is but
rarely changed in a prolified flower; but that this is not a universal
rule is shown by proliferous flowers of _Geum rivale_, where the sepals
are usually large and leaf-like, as they likewise are frequently in
proliferous roses and pears.
[Illustration: FIG. 64.--Proliferous rose. Hip absent, sepals leafy,
stamens wanting, axis prolonged bearing supplementary flower, &c. (Bell
Salter).]
Proliferous roses have a special interest, inasmuch as they show very
conclusively that the so-called calyx-tube of these plants is merely a
concave and inverted thalamus, which, in prolified specimens, becomes
elongated (fig. 64) after the fashion of _Geum rivale_, &c.[127]
Occasionally from the middle of the outer surface of the urn-shaped
thalamus proceeds a perfect leaf, which could hardly be produced from
the united sepals or calyx-tube; a similar occurrence in a pear is
figured in Keith's 'Physiological Botany,' plate ix, fig. 12.
The change which the calyx undergoes when flowers with an habitually
adherent ovary become prolified, and wherein the calyx is disjoined from
the ovary, has been before mentioned, but it may also be stated that,
under such circumstances, the constituent sepals are frequently
separated one from the other, and not rarely assume more or less of the
appearance of leaves, as in proliferous flowers of _Umbelliferæ_,
_Campanulaceæ_, _Compositæ_, &c.
As to the corolla, it was long since noticed that prolification was
especially liable to occur in double flowers; indeed, Dr. Hill, who
published a treatise on this subject, setting forth the method of
artificially producing prolified flowers, deemed the doubling to be an
almost necessary precursor of prolification;[128] but, though frequently
so, it is not invariably the case that the flower so affected is
double--_e.g._ _Geum_. If double, the doubling may arise from actual
multiplication of the petals, or from the substitution of petals for
stamens and pistils, according to the particular plant affected.
Occasionally in prolified flowers the parts of the corolla, like those
of the calyx, become foliaceous, and in the case of proliferous pears
fleshy and succulent. There is in cultivation a kind of _Cheiranthus_?
in which there is a constant repetition of the calyx and corolla,
conjoined with an entire absence of the stamens and pistils; a short
internode separates each flower from the one above it, and thus
frequently ten or a dozen of these imperfect flowers may be seen on the
end of a flower-stalk, giving an appearance as if they were strung like
beads, at regular intervals, on a common stalk. I have seen a similar
instance in a less degree in a species of _Helianthemum_.
The stamens are subject to various changes in prolified flowers; they
assume, for instance, a leaf-like or petal-like condition, or take on
them more or less of a carpellary form, or they may be entirely absent;
but none of these changes seem to be at all necessarily connected with
the proliferous state of the flower. Of more interest is the alteration
in the position of these organs which sometimes necessarily accrues from
the elongation of the axis and the disjunction of the calyx; thus, in
proliferous roses the stamens become strictly hypogynous, instead of
remaining perigynous. In _Umbelliferæ_ the epigynous condition is
changed for the perigynous, &c.
The condition of the pistillary organs in prolified flowers has already
been alluded to. Hitherto those instances have been considered in which
either the carpels were absent, or the new bud proceeded from between
the carpels. There is also an interesting class of cases where the
prolification is strictly intra-carpellary; the axis is so slightly
prolonged that it does not protrude beyond the carpels, does not
separate them in any way, but is wholly enclosed within their cavity.
Doubtless, in many cases, this is merely a less perfect development of
that change in which the axis protrudes beyond the carpels. This
intra-carpellary prolification occurs most frequently in plants having a
free central placenta, though it is not confined to them, as it is
recorded among _Boragineæ_. A remarkable instance of this is described
by Mr. H. C. Watson in the first volume of Henfrey's 'Botanical
Gazette,' p. 88. In this specimen a raceme of small flowers was included
within the enlarged pericarp of a species of _Anchusa_. But the most
curious instances of this form of prolification are, no doubt, those
which are met with among _Primulaceæ_ and other orders with free central
placentation.
Duchartre, in his memoir on the organogeny of plants with a free central
placenta, in the 'Ann. des Sc. Nat.,' 3 sér., 1844, p. 290, among other
similar instances, mentions two flowers of _Cortusa Matthioli_, wherein
the placenta was ovuliferous at the base; but the upper portion, instead
of simply elongating itself into a sterile cone, had produced a little
flower with its parts slightly different from those of the normal
flowers. M. Alph. de Candolle has likewise described somewhat similar
deviations, and one in particular in _Primula Auricula_, where the
elongated placenta gave off long and dilated funiculi bearing ovules,
while other funiculi were destitute of these bodies, but were much
dilated and foliaceous in appearance.[129] In some flowers of
_Rhododendron_ I have observed a similar condition of the ovules, which,
moreover, in the primary flowers, were attached to the walls of the
carpels--parietal placentation.
In speaking of these as cases of intra-carpellary prolification, it is,
of course, impossible to overlook the fact that they differ in degree
only from those cases where the lengthened axis projects beyond the
cavity of the carpels; nevertheless they seem to demand special notice,
because in these particular plants the placenta or its prolongation
appears never to protrude beyond the carpels, or at least very rarely.
There are, however, numerous instances of such an extension of the
placenta and of prolification occurring among _Primulaceæ_ in
conjunction with the more or less complete arrest of growth of the
carpels.[130] An instance of this kind has come under my own notice in a
monstrosity of the chinese primrose, in which the carpels were reduced
to a hardly discernible rim surrounding an umbel of five rays, each
terminated by a small normally constituted flower-bud.
The ovules of a prolified flower are either unaffected, or they occur in
a rudimentary form, or, lastly, they may be present in the guise of
small leaves.
Under the term prolification of the fruit two or three distinct kinds of
malformation appear to have been included. The term seems usually to be
applied to those cases where from the centre of one fruit a branch
bearing leaves, flowers, or another fruit, is seen to project, as
happens occasionally in pears. Now, in many instances, not only the
fruit, is repeated, but also the outer portions of the flower, which
wither and fall away as the adventitious fruit ripens; so that at length
the phenomenon of one fruit projecting from another is produced. It is
obvious that this form of prolification in no wise differs from ordinary
central prolification. Sometimes some of the whorls of the adventitious
flower are suppressed; thus, M. Duchartre describes some orange blossoms
as presenting alternating series of stamens and pistils one above
another, while the calyces and corollas belonging to each series of
stamens and pistils were entirely suppressed.[131] In other cases,
doubtless, the carpellary whorl is alone repeated, the other whorls of
the adventitious flower being completely absent.
Another condition, apparently sometimes mistaken for prolification of
the fruit, is that in which the carpellary whorl becomes multiplied; so
that there is a second or even a third series within the outer whorl of
carpels. If the axis be at all prolonged, then these whorls are
separated one from the other, and produce in this way an appearance of
prolification. This happens frequently in oranges, as in the variety
called Mellarose.[132]
Moquin has given an explanation of the St. Valery Apples, wherein the
petals are sepaloid, the stamens absent, and where there is a double row
of carpels, by supposing these peculiarities to be due to "a
prolification combined with penetration and fusion of two or more
flowers," but it is surely more reasonable to conceive a second row of
carpels placed above the first by the prolongation of the central part
of the axis. Supposing this view to be correct, the inner calyx-like
whorl might be considered either as a repetition of the calycine whorl,
or it might be inferred that the corolla was present in the guise of a
second calyx.
Moquin-Tandon suggests another explanation--namely, that though the
stamens are absent in these curious flowers, at least in their ordinary
shape, they are represented by the lower row of carpels, which become,
in process of development, fused with the upper or true carpels. If this
were so, surely some intermediate conditions between stamen and carpel
would occasionally be present; but such does not appear to be the
case.[133]
In some of the instances of so-called proliferous pears the carpels
would seem to be entirely absent, and the dilated portion of the axis to
be alone repeated. Thus, the axis dilates to form the lower fruit
without any true carpels being produced, but at its summit a whorl of
leaves (sepals) is formed; above these another swelling of the axis
takes place also without the formation of carpels, and this, it may be,
is terminated in its turn by a branch producing leaves. In these cases
there is no true prolification, but simply an extension of the axis.
That the outer portion (so-called calyx-tube) of these fruits is really
an axile product there can now be little doubt; and, as if to show their
axile nature, they occasionally produce leaves from their sides, as
before mentioned. Moquin, in the tenth volume of the 'Bulletin of the
Botanical Society of France,' p. 73, says that when the case is one of
prolification the lower fruit is larger and is formed of a fleshy mass;
moreover, the line of demarcation between the fruits is more distinct,
and there are traces of the seed-bearing cavity in the interior, and of
calycine lobes at the top. On the other hand, if the case be one of
hypertrophy merely, the lowermost fruit is the smallest, and there is no
trace of seed-bearing cavity nor of sepals. See also under Hypertrophy.
Some other malformations usually referred to prolification of the fruit
seem due to branching of the inflorescence, as in _Plantago_, wheat,
maize; or to a simple extension of the axis beyond its ordinary limit,
as in some cones of firs, &c. It is obvious that the true fruits in
these cases are in no wise affected.
From these considerations it would appear better to abandon the use of
the expression prolification of the fruit, as unnecessary where it is
really applicable, and as delusive in the numerous other cases where it
is employed.
Median prolification of one or other kind has been met with in the
following genera:
_Leafy_. _Floral_.
Ranunculaceæ. Clematis.
Anemone! *Anemone!
Ranunculus! *Ranunculus!
Delphinium.
Caltha.
Aquilegia!
Cruciferæ. Bunias.
*Cheiranthus!
Erucago.
*Matthiola!
Sisymbrium!
Brassica!
Nasturtium.
Hesperis.
Sinapis!
Diplotaxis.
Lunaria.
Erysimum.
Alyssum.
Peltaria.
Cardamine!
Cleome.
Cistaceæ. Helianthemum!
Caryophylleæ. Dianthus! *Dianthus!
Silene!
Lychnis!
Violaceæ. Viola!
Tiliaceæ. Triumfetta!
Geraniaceæ. Geranium!
Sapindaceæ. Pavia! Pavia!
Malvaceæ. Paritium.
Hibiscus!
Malpighiaceæ. Byrsonima!
Rutaceæ. Genera not specified. *Dictamnus!
Resedaceæ. Reseda.
Caylussa!
Aurantiaceæ. *Citrus!
Vitaceæ. Vitis. Vitis.
Umbelliferæ. Heracleum.
Angelica.
Thysselinum.
*Athamanta.
*Daucus!
*Torilis.
Rosaceæ. *Rosa! *Rosa!
*Geum! *Geum!
Agrimonia. Amygdalus.
Prunus!
Spiræa! Spiræa!
Rubus.
*Pyrus! *Pyrus!
?Leguminosæ Trifolium!
Medicago!
Melilotus.
Pisum!
Cucurbitaceæ. Cucumis.
Passifloraceæ. Passiflora.
Philadelphaceæ. Philadelphus.
Onagraceæ. Epilobium!
Epacridaceæ. Epacris!
Ericaceæ. *Erica.
Rhododendron!
Convolvulaceæ. Convolvulus.
Gentianaceæ. Gentiana. Gentiana.
Apocynaceæ. Vinca.
Jasminaceæ. Jasminum!
Scrophulariaceæ. Verbascum! Antirrhinum!
*Digitalis!
*Linaria!
Veronica.
Orobanchaceæ. Orobanche.
Labiatæ. Genera not specified. Stachys.
Phlomis!
Hydrophyllaceæ. Hydrophyllum.
Boraginaceæ. Anchusa.
Symphytum.
Primulaceæ. *Dodecatheon. *Cortusa.
*Anagallis! *Anagallis!
*Primula.
Dipsacaceæ. Scabiosa.
Compositæ. Hieracium! Hieracium!
Cirsium. Cirsium.
Hypochæris. Calendula!
Spilanthes.
Carthamus.
Coreopsis.
Campanulaceæ. Campanula. *Campanula!
Polygonaceæ. Genera not specified. Rumex.
Santalaceæ. Thesium.
Liliaceæ. Genera not specified. Tulipa!
Hemerocallis!
Asphodelus.
Hyacinthus!
Iridaceæ. Iris.
Amaryllidaceæ. Narcissus!
Leucojum.
Orchidaceæ. Orchis!
Habenaria.
Cyperaceæ. Carex.
Gramineæ. Phleum.
=Axillary prolification= is the term applied to those cases wherein one
or more adventitious buds spring from the axils of one or more of the
parts of the flower. Engelmann makes use of the word ecblastesis to
denote the same condition. Both terms are open to the objection that
they do not clearly enable us to distinguish prolification occurring
within the flower from a similar state originating outside the flower,
within the bracts of the inflorescence. This latter condition, called by
Moquin-Tandon lateral prolification (see Prolification of the
Inflorescence), is as truly axillary as that to which the name is
restricted. In consequence of certain peculiarities in the structure of
some flowers, to be hereafter alluded to, it is not in all cases easy to
decide whether the new growth springs from the interior of the flower,
or from the inflorescence beneath the flower.
The accessory bud presents itself as a leaf-bud, a branch, a flower-bud,
or a miniature inflorescence; it may be sessile, but is far more
frequently stalked, and in more than half the number of cases it is a
flower-bud or an inflorescence. There may be one or more of these buds;
if two only, then they are usually placed directly opposite one to the
other, on the opposite sides of the flower.
It will be seen, from the appended list, that the orders and genera in
which this description of adventitious growth occurs most frequently are
the following:--_Cruciferæ_, especially the genus _Brassica_;
_Caryophyllaceæ_, e.g. _Dianthus_; _Resedaceæ_; _Leguminosæ_, e.g.
_Melilotus_, _Trifolium_, &c.; _Rosaceæ_, e.g. _Rosa_, _Potentilla_,
&c.; _Umbelliferæ_, and _Campanulaceæ_. For the most part, these are
groups also peculiarly liable to central prolification.
All the parts of the flower may be thus affected; but, as might have
been anticipated from the foliaceous nature of the sepals, the new bud
usually arises from within the axil of one of those organs. Next in
frequency to the calyx, the pistil is subjected to this change--the
carpels in such a case being disunited and leaf-like. The petals rank
next, and lastly the stamens; these latter, indeed, are usually, but not
invariably, absent, the new growth occupying their position. Hence it
may well be that when such is the case, there is no real axillary
prolification, but rather the substitution of a bud for a stamen.
Generally, however, the position of the accessory bud is such that it
may properly be referred to the axil of an undeveloped or rudimentary
stamen.
The largest number of instances of this malformation, not merely
generically, but also individually, occurs in plants the members of
whose floral whorls are not united one to the other; thus, it is far
more common in polypetalous plants than in gamopetalous ones. In the
prolified flowers belonging to the latter group, the sepals, if not
actually uncombined, are only united for a short distance. The same
relationship, but in a much less degree, exists in the case of median
prolification, as that aberration is likewise most commonly met with in
polypetalous flowers. Another feature of interest is the rarity with
which axillary prolification is found in irregular gamopetalous blooms.
It may be that the irregular and comparatively excessive growth in some
parts of these flowers, as compared with others, may operate in checking
any luxuriant tendency in other directions.
As in the case of median prolification, plants having an indefinite
inflorescence are more liable to be affected with ecblastesis than those
having a definite one. The degree of branching of the inflorescence may
be noticed, as this deformity is far more common in plants whose
peduncles are branched than in those which have either a solitary flower
or an unbranched flower-stalk. More than two thirds of the entire number
of genera cited as the subjects of this malformation have a branched
inflorescence of some form or other; and about two thirds of the cases
occur in genera having some form of indefinite inflorescence. If
individual instances could be accurately computed, the proportion would
be even higher.
Fully three fourths of the entire number of genera recorded as
occasionally the subjects of this irregularity possess in their usual
state some peculiarity of the thalamus; for instance, in about a third
of the whole number of genera the thalamus is more or less prolonged
between some or other of the floral whorl, e.g. _Caryophyllaceæ_,
_Potentilla_, _Anemone_, _Dictamnus_, _Umbelliferæ_, &c. About one
fourth of the genera have numerous stamens or numerous carpels, or both,
springing naturally from the thalamus. In others (about one sixth) the
thalamus is enlarged into a disc, or else presents one or more
glandular swellings, _e.g._ _Reseda_, _Nymphæa_, _Cruciferæ_. In the
last-named family, as has been already remarked, prolification is very
common. It would be interesting to ascertain precisely what part of an
inflorescence is most liable to this affection; but as information on
this point is but rarely given in the records of these cases, I can only
give the results of my own observations, which go to show that, in a
many-flowered inflorescence, those flowers at the outside, or at the
lower portion, seem to be more frequently the subjects of this change
than those situated elsewhere. This may probably be accounted for by the
fact that the malformation is met with most generally in plants with an
indefinite form of inflorescence, and therefore the lowermost or
outermost flowers are most fully nourished; the upper flowers being in a
less advanced condition, the change is more likely to be overlooked in
them; or it may be that from the unusual luxuriance in the lower
flowers, the upper ones may be either present in their ordinary
condition, or may be (as indeed frequently happens) stunted in the size
and proportion of their several parts.
=Axillary foliar prolification of the flower.=--The formation of an
adventitious leaf-bud in the axil of any of the parts of the flower is
not of such common occurrence as the development of a flower-bud in
similar situations, nor is it so frequent as median foliar
prolification. I have seen leafy shoots proceeding from the axils of the
sepals in the flowers of _Brassica_, and a similar occurrence has been
noticed in _Caltha palustris_, _Herreria parviflora_, and other plants.
Dr. Marchand's flowers of _Anagallis_, previously referred to at p. 117,
showed good illustrations of this occurrence, as also some specimens
described by Kirschleger in _A. phoenicea_.[134] Steinheil has figured
and described[135] a flower of _Scabiosa_ in which there was an
adventitious formation of leafy shoots in the axil of the outer calyx.
In some flowers, such as _Convolvulus_, _Anemone_, &c., the exact nature
of the sub-floral leaves is uncertain, _i.e._ it is open to doubt
whether the organs in question are bracts or leaves pertaining to the
inflorescence, or whether they are really parts of the flower. When
leafy shoots are formed in the axils of such organs, the adventitious
growth may be referred to extra-floral prolification, prolification of
the inflorescence that is, or to axillary prolification, according to
the view taken of the real nature of the sub-floral leaves. So far as
the mere occurrence of prolification is concerned, it is not very
material which view be adopted. The same remark applies to cases where
leaf-buds occur on the outer surface of inferior ovaries, as in
_Rosaceæ_, _Pomaceæ_, _Philadelphus_, or _Tetragonia expansa_, as
elsewhere mentioned.
It would seem more consistent with the general arrangements of parts,
that the adventitious buds should be formed more frequently outside than
within the flower proper.
Knight[136] figures and describes the occurrence of small tubers or
fleshy leaf-buds in the axils of the sepals of a potato, a curious
illustration of the real morphological nature of the tuber.
=Axillary floral prolification of the flower.=--As already stated, this
is of more common occurrence than the formation of a leaf-bud in a
similar situation. Any of the parts of the flower may thus subtend a
flower-bud, though probably the new buds more frequently originate in
the axils of the sepals than in the other whorls. In _Cruciferæ_ the
change in question is, relatively speaking, very common. In cauliflowers
and broccoli I have frequently met with stalked flowers proceeding from
the axils of the sepals, so also in some fuchsias I have seen a ring of
stalked flower-buds alternating with the petals, which, together with
the stamens and pistil, remained unaffected. The number of parts in the
supernumerary structures is generally less than the normal flowers.
In Mr. Herbert Spencer's 'Principles of Biology,' part iv, p. 37, are
figured and described some monstrous inflorescences in _Angelica_ and
other _Umbelliferæ_, from which, amongst other things, the author draws
the conclusion that there is no absolute distinction between leaf and
branch. Without staying for the moment to discuss this matter, it may
here be said that the Umbellifers in question apparently owe their
peculiarities rather to axillary prolification within the flower, or to
prolification of the inflorescence, than to an actual transformation of
a flower or any portion of a flower into an umbellule.[137]
In the 'Gardeners' Chronicle,' 1855, p. 551, an instance is figured of
the production of a supernumerary flower proceeding from the axil of a
stamen in a species of _Nymphæa_ (fig. 65). The ovary in this case was
wanting, but in its place was a tuft of small leaves. It is curious that
among Dr. Kirk's drawings of east tropical African plants now at Kew,
there should be one representing a precisely similar state of things.
The species in both instances was _Nymphæa Lotus_, or a cultivated
variety of it.
M. Wesmael[138] describes a very singular case of what appears to have
been referable to axillary prolification in the flowers of _Carex
acuta_. The rachillus is described as prolonged through the utricle by
the side of the stigmas, bearing on its side a bract, then a secondary
utricle, from the axil of which sprung a short stem surmounted by an
ovary. Wigand, 'Flora,' 1856, mentions a similar change in _Carex
glauca_. In this instance the base of the female inflorescence bore
lateral spikes, which projected from the utricles; some of these
adventitious spikes were female, others female below and male above,
others, again, wholly male.
[Illustration: FIG. 65.--Flower of _Nymphæa Lotus_, var., showing
axillary floral prolification. The section also shows the tuft of leaves
that occupied the place of the ovary.]
Various changes in the form and arrangement of the several floral whorls
accompany axillary prolification; some of these affect the particular
organ or organs implicated, and these only, while in other cases some
other parts of the flower likewise undergo modification. The changes
most commonly met with are such as may be classed under Goethe's theory
of retrograde metamorphosis; for instance, if a supplementary bud be
developed in the axil of a sepal, that sepal is likely to be more than
ordinarily leaf-like in appearance. The dislocation of the affected
sepal from its fellows is a very frequent occurrence; in cases of this
kind the detached sepal is placed below the others, thus approximating,
in position as well as in function, to the bracts. In some of the
instances of proliferous pears, on which I shall have occasion to
comment, the sepals are described as sharing in the succulent character
of the fruit.
The petals, under such circumstances, often exist in the guise of sepals
or of small leaves; and instances are recorded wherein the place of the
calyx and corolla was supplied by a succession of overlapping green
scales, from the axils of which the new buds arose. M. Germain de Saint
Pierre records such a case in _Trifolium repens_, wherein the calyx and
corolla were replaced by overlapping scales, in the axils of each one of
which arose a flower; above there was a row of stamens, and in the
centre a pistil in the guise of a trifoliate leaf.[139] Such instances
seem to afford an extreme degree of a more common change, viz., the
diminished size and contracted appearance of the sepals and petals when
affected with axillary prolification. They have also a close
relationship to such developments as we see in the wheat-ear carnation,
in certain species of the genus _Mæsa_ and others, wherein the calyx is
repeated over and again, to the partial or complete suppression of the
other parts of the flower. All these cases may be in part explained by
the operation of the principle of compensation.
So far as the androecium is concerned, the stamens either remain
unaltered, or they are present in a more or less petal-like condition;
but it far more frequently happens that the stamens are entirely
suppressed, the adventitious bud supplying their place; thus was it in
the _Dianthus_ represented in the adjoining woodcut, fig. 66, where the
stamens were entirely absent, and their places supplied by
flower-bearing branches. This _Dianthus_ has the more interest from its
similarity to the one described by Goethe, Metam. der Pflanzen, cap.
16, sect. 105; but in that instance median prolification also existed.
For my specimens I am indebted to Mr. T. Moore.
[Illustration: FIG. 66.--Flower of _Dianthus_ sp., calyx removed; petals
turned down so as to show the stalked flower-buds springing from their
axils.]
The pistil, too, is necessarily subject to very grave alterations when
affected with this malformation. It is separated into its constituent
carpels; and these assume a leaf-like aspect, and are in the great
majority of instances destitute of ovules. Indeed, virescence or
chloranthy is very intimately connected with this aberration, as might
have been anticipated, for if the parts of the flower assume more or
less of the condition of stem-leaves or bracts, it is quite natural to
expect that they will partake likewise of the attributes of leaves, even
at the expense of their own peculiar functions.
It occasionally happens that an adventitious bud arises from the axil of
a monocarpellary pistil. This takes place sometimes in _Leguminosæ_, and
seems to have been more frequently met with in _Trifolium repens_ than
in other plants. The species named is, as is well known, particularly
subject to a reversion of the outer whorls of the flower to leaves, and
even to a leaf-like condition of the pistil. There are on record
instances wherein a leaf-bud has been placed in the axil of a more or
less leaf-like carpel; while at other times a second imperfect carpel
has been met with in the axil of the first.[140] I have myself seen
numerous imperfectly developed cases of this kind.
It may be asked whether such cases are not more properly referable to
central prolification--whether the axis is not in such flowers
terminated by two, rather than by one carpel? It is, however, generally
admitted by morphologists that the solitary carpel of _Leguminosæ_ is
not terminal, but is the sole existing member of a whorl of carpels, all
the other members of which are suppressed as a general rule, though
exceptional instances of the presence of two and even of five carpels
have been described.[141]
Again, the adventitious bud or carpel is placed, not laterally to the
primary one, or opposite to it, on the same level, but slightly higher
up--in fact, in the axil of the primary carpellary leaf. Griffith
figures and describes[142] an instance of the kind in a species of
_Melilotus_. The stalk of the ovary is mentioned as having a sheathing
base, bearing in its axil a prolongation of the axis of inflorescence,
in the form of a short spike with hairy bracts and imperfect flowers,
the latter having a well-formed calyx and rudimentary petals and
stamens. Griffith infers, from this specimen, that the legume is not to
be considered as a terminal leaf.
_List of Genera in which Axillary Prolification has been observed._
Order Genus. Leaf-bud Flower-bud or From what organ.
or Branch Inflorescence
Ranunculaceæ Clematis Flower-bud Sepals.
Caltha Ditto Ditto.
Aconitum Ditto.
Delphinium Ditto Sepals, carpels,
&c.
Anemone! Ditto Involucre?
Nymphæaceæ Nymphæa! Fruit?
Nymphæa Flower Petal.
Cruciferæ *Brassica! Leaf-bud Flower-bud Sepals and
petals.
Brassica! Ditto Stamens.
Brassica! Ditto Ditto Pistil.
Cardamine! Ditto Sepals.
Matthiola! Ditto Sepals and
petals.
Cheiranthus! Ditto Sepals.
Erysimum Ditto Sepals and
pistils.
Lepidium! Ditto Petals and
stamens.
Arabis Ditto Sepals.
Diplotaxis Flower, Pistil, calyx
inflorescence and corolla.
Capsella
Capparidaceæ Cleome Flower-bud Sepals.
Resedaceæ *Reseda Ditto Ditto.
Caryophyllaceæ Arenaria Branch Ditto.
Agrostemma Leaf-bud Ditto.
*Lychnis Ditto
Stellaria Ditto
Silene Ditto
*Gypsophila Ditto Ditto Sepals and
stamens.
*Dianthus! Ditto Ditto Sepals.
Dianthus! Ditto Inflorescence Petals and
stamens.
Cucubalus Sepals
Saponaria! Sepals and
petals.
Malvaceæ Alcea Flower-bud Stamen.
Aurantiaceæ Citrus! Ditto Ditto.
Rutaceæ Dictamnus! Ditto Pistil leafy.
Tropæolaceæ Tropæolum! Ditto Petals.
Celastraceæ Celastrus Ditto Sepals.
Leguminosæ *Melilotus! Inflorescence Sepals and
petals.
Medicago Flower-bud Sepals.
Coronilla Ditto Ditto.
Trifolium! Ditto Second carpel Pistil.
axillary to
first
Melilotus! Ditto Ditto
Trifolium! Flower-bud Sepals and
petals.
Rosaceæ Pyrus! Fruit? Fruit?
Cerasus! Flower-bud Petals and
stamens.
Potentilla! Ditto Leafy carpels.
Cratægus! Ditto Petals.
*Rosa! Ditto Ditto Sepals, petals,
stamens and
pistil.
Myrtaceæ Lecythis Ditto Fruit?
Tetragoniaceæ Tetragonia? Ditto Ditto.
Cactaceæ Opuntia! Fruit-like Tufts of spines.
branch
Pereskia Ditto Sepals?
Echinocactus Ditto Ditto.
Philadelphaceæ Philadelphus Ditto Sepals.
Umbelliferæ *Athamanta Ditto Calyx.
*Daucus! Ditto Calyx and
pistil.
Bupleurum Ditto Calyx and
pistil.
Torilis Ditto Calyx and
pistil.
Apium Flower-bud Calyx and
pistil.
Pastinaca Ditto Ditto ditto.
Heracleum! Ditto Ditto ditto.
Angelica! Umbel Ditto ditto.
Campanulaceæ *Campanula! Branch Sepals.
Prismatocarpus Ditto Fruit Sepals, &c.
Gentianaceæ Gentiana! Flower-bud Sepals.
Convolvulaceæ *Convolvulus! Ditto Outer calyx.
Solanaceæ Solanum! Ditto Sepals.
Solanum Tubers Sepals and
petals.
Scrophulariaceæ *Digitalis! Ditto Petals, &c.
Veronica Raceme Calyx.
Primulaceæ Anagallis! Branch Ditto Petals.
Primula Ditto Petals and
carpels.
Polygonaceæ Rumex Ditto Sepals.
Santalaceæ Thesium Leaf-bud In place of
stamens and
pistils, both
absent.
Euphorbiaceæ? Euphorbia? Ditto Outer bracts?
Orchidaceæ Orchis! Flower-bud Perianth.
Amaryllidaceæ Leucoium Ditto Ditto.
Iridaceæ Iris Ditto Pistil.
Liliaceæ Herreria Ditto Sepals.
Hyacinthus Flower and Perianth.
raceme
Convallaria Flower-bud Ditto.
Allium Ditto Ditto.
Cyperaceæ Carex Inflorescence Utricle.
[Illustration: FIG. 67.--Proliferous Rose. Calyx leafy; petals normal,
some reflexed; stamens and pistil absent; in their places a branch with
leaves and flowers.]
[Illustration: FIG. 68.--Rose exhibiting median, axillary, lateral,
floral, and leafy prolification in same flower.]
=Complicated prolification.=--From what has been before stated it may be
seen that prolification of two or more kinds may coexist in the same
flower. Mixed leafy and floral prolification is not unfrequent in
proliferous roses, where a shoot is, as it were, prolonged through the
centre of the original flower and terminated by a second flower, or
even by a cluster, as is well shown in the accompanying figure (fig.
67). Median and axillary prolification, also, not unfrequently coexist
in the same flower; thus, in a proliferous rose forwarded to me by Mr.
W. Thomson (fig. 68), the following changes were observed:--the swollen
portion below the calyx, the "hip," was entirely absent; the sepals were
leaf-like in aspect, the petals unaffected; above the petals the axis
was prolonged for a short distance and then bore a circlet of miniature,
sessile roses, destitute, indeed, of calyx, but provided with numerous
petals, stamens, and pistils. Above these lateral flowers, the prolonged
axis bore a number of scales in many rows. The scales were in their turn
surmounted by a whorl of five perfect leaves, beyond which, again, the
axis was prolonged into a leafy shoot terminated by a flower bud, the
whole constituting a remarkably complicated admixture of elements
belonging to the flower, the bud, the inflorescence, and the
leafshoot.[143]
Proliferous flowers of Orchids also occasionally present great
complexity in the arrangement of their parts. An instance of this kind
was described by myself from specimens furnished by Dr. Moore, of
Glasnevin, in the 'Journal of the Linnean Society,' vol. ix, p. 349,
tabs. x, xi, and from which the following summary is extracted:
[Illustration: FIG. 69.--Proliferous Orchis. Diagram showing the
arrangement of the several organs in the seven outer circles of the
flower. Each whorl is numbered, and the position of the axillary buds
shown by the small circles.]
The primary flowers were composed of five distinct whorls, and of at
least two others less perfectly developed. These primary flowers did not
give rise to median formations, but they produced secondary buds in the
axils of the segments of the perianth. These latter buds were themselves
the subject of tertiary prolification of both kinds, median and
axillary. The tertiary median growths, like the primary flower, did not
develop median buds, but only lateral ones--quaternary axillary
prolification.
The accompanying diagrams are intended to show the plan of arrangement
in these flowers. Fig. 69 shows the disposition of parts in the primary
flower and the situation of the axillary buds. Fig. 70 shows the primary
flower without any central prolongation, but giving off axillary buds,
two of which are shown in the diagram, 2, 2; these are, each of them,
the subject of both median, 3, 3, and axillary prolification, 4', 4'.
[Illustration: FIG. 70.--Diagram to explain the construction of the
double-flowered _Orchis_.
1. The primary flower, with no median bud, the position of which, had it
been present, is shown by the dotted line.
2. Two axillary buds proceeding from 1, and themselves giving origin to
3, 3. Median buds, and 3', 3', axillary buds.
4' 4'. Axillary buds, proceeding from 3. No median bud is produced from
3; its situation, had it been present, is indicated by the dotted line.]
In _Narcissus major_ a similar combination of both forms of
prolification exists, as described by Morren.[144]
On the general subject of Prolification in flowers, in addition to the
authorities already cited, the reader may refer to the following among
many others:
Linnæus, 'Prolepsis,' §§ vi et vii. Goethe, 'Versuch.
Metamorph.,' cap. xv and xvi §§ 103-106. Moquin-Tandon,' El.
Ter. Veg.,' p. 362, &c. Engelmann, 'De Antholys.,' §§ 52-62,
&c. Cramer, 'Bildungsabweichungen,' &c. _Orchidaceæ_,
_Umbelliferæ_, _Compositæ_, _Leguminosæ_, _Primulaceæ_,
_Ranunculaceæ_. Fleischer, 'Missbild. Cultur Gewachs.'
Schlechtendal, 'Linnæa,' xv, p. 408, _Rosa_. 'Bot. Zeit.' vol.
xx, 1862, p. 382, _Cyclamen_. 'Bot. Zeit.,' vol. xx, p. 301,
_Asphodelus_; et _Lilium_. Seringe, 'Bull. Bot.,' i, t. xi, f.
7, 8, _Arabis_, _Diplotaxis_. Clos, 'Mem. Acad. Toulouse,' 5th
sér., 1862, _Papaver_. Wigand, 'Flora,' 1856, p. 716,
_Hypochæris_; et 'Bot. Untersuch.,' p. 19. Buchenau,'
Flora,' 1857, p. 295, _Reseda_. Roeper, 'Bot. Zeit.,' 1852, p.
427, _Orchis_. Presl., 'Linnæa,' vi, p. 599, tab. ix, figs.
5-8, _Sisymbrium_, Vrolik., 'Flora,' 1846, p. 97, t. i et ii,
id. 1844, t. i, _Digitalis_. See also Schlechtendal, 'Bot.
Zeit.,' vol. ix, 1851, p. 579. Klinsmann, 'Linnæa,' x, p. 604,
t. v, _Hesperis_. Fuckel, 'Flora,' 1848, p. 609. _Melilotus_.
De Candolle, 'Organogr.,' i, 396, t. 33. Turpin, 'Atlas de
Goethe,' p. 65, t. 5, figs. 12, 13. Fenzl. 'Sitzungsbericht d.
k. Akad. d. Wissensch. Wien.,' heft, iii, tabs. 3, 4, _Rosa_.
Kirschleger, 'Flora,' 1845, 613, _Dianthus_, _Rosa_.
'Institut.,' 1841, No. 413, p. 421, _Tragopogon_. Baron de
Melicoq., 'Ann. Sc. Nat.,' 3rd ser., vol. v. 1846, p. 61,
_Antirrhinum_. Reichenbach, 'Icon. Fl. Germ.,' tab. 100,
_Reseda_--"monstrosa anticipatio Euphorbiacearum et
Capparidearum." Duhamel, 'Phys. Arbres.,' liv. iii, cap. 3, p.
303, pl. xii, f. 306, _Rosa_. Caspary, 'Bull. Soc. Bot. Fr.,'
vol. vi, 1859, p. 235, Rev. Bibl., _Pyrus_. Eichler, 'Flora,'
1865, tab. ix, _Cleome_. Lindley, 'Elements of Botany,' p. 63,
&c., _Rosa_, _Epacris_, _Anagallis_, _Pyrus_. Irmish, 'Flora,'
1858, p. 38, _Pyrus_; and 'Bot. Zeit.,' xix, 1861, p. 342,
_Hyacinthus_. Duchartre, 'Bull. Soc. Bot. France,' 1861, p.
451, _Rosa_. Weber, 'Verhandl. Nat. Hist. Verein. Rhein.
Preuss., &c.' 1858 et 1860. Landrin, 'Mem. Soc. Sc. Nat. Seine
et Oise,' 1866?[145] Masters, 'Trans. Linn. Soc.,' vol. xxiii,
p. 359, tab. 34 and p. 481, tab. 54.
=Prolification of the embryo.=--This term was applied by Moquin-Tandon
to a peculiar condition of the almond (_Amygdalus_), in which, indeed,
it is not of unfrequent occurrence. In these cases one almond encloses
within its cotyledons a second embryo, and this, again, in some
instances, a third, the little plants being thus packed like so many
boxes one within the other. The supplementary embryos are, in the ripe
state at least, quite separate and detached one from another. These
cases differ from the ordinary instances wherein there is an increased
number of embryos in one seed in their position. In the latter case, as
often happens in the seeds of the orange, the new products are placed by
the side one of another.[146]
For other cases of prolification or the adventitious formation of buds
on leaves, roots, &c., see under Heterotaxy.
FOOTNOTES:
[104] Linn., 'Prolepsis,' § vii; Goethe, 'Metamorph.,' §§ 96, 103, 106.
[105] "Diaphysis inflorescentiarum." Engelmann, 'De Anthol.,' § 85.
[106] 'Flora,' 1844, p. 565.
[107] 'Ann. Sc. Nat.,' ser. 3, vol. v, 1846, p. 64.
[108] 'Bot Zeit.,' vol. xx, p. 382.
[109] 'Miscel. Austriac. Bot.,' vol. i, Vindob, 1778, p. 133.
[110] "_Umbellati dum prolificantur, augent umbellulam, ut ex umbellula
simplici altera exeat_." 'Linn. Phil. Bot.,' § 124.
[111] 'En. Euphorb.,' p. 36.
[112] Meisner. 'Mon. Gen. _Polygoni_ Prodrom.,' p. 20, tab. v, considers
the bulbils of this plant to be modifications of the pedicels of the
flower.
[113] See A. Braun. 'Ann. Scienc. Nat.,' 4th series, 1860, vol. xiv, p.
13.
[114] "_Prolificatio e latere ex calyci communi proles plurimos
pedunculatos emittens, fit in compositis aggregatis proprie dictis._"
'Linn. Phil. Bot.,' § 124.
[115] 'Bot. Zeit.,' 1857, p. 873. See also 'Verhandl. Nat. Hist.
Vereins. Preuss. Rheinl. u. Westphal.,' 1854, t. ix.
[116] "Pannicula spicatim sparsa onusta innumera foetura herbaceorum
flosculorum racematim cohærentium," 'Lobel. Stirp. Hist.,' p. 163. This
is the "Besome Plantain, or Plantain with spoky tufts," of Ray,
'Synopsis,' p. 314. Gerard's 'Herbal,' Ed. Johnson, p. 420. Parkinson,
'Theat. Bot.,' p. 494. Baxter, 'Loudon. Mag. Nat. Hist.,' vol. ix. p.
204, and vol. iii, p. 482. fig. 118.
[117] 'Flora.' 1856. p. 706.
[118] 'Flora of Berwick-on-Tweed,' vol. i. p. 38.
[119] 'Adansonia,' vol. iv. 1864, p. 150, tab. vii. 'Gard. Chron.,'
November 19th, 1864.
[120] 'Ann. Sc. Nat.,' ser. 3, tom. ii, p. 290; and 'Adansonia,' iii,
tab. iv; see also Bureau, in 'Bull. Soc. Bot. France,' x, p. 191.
[121] Baillon, 'Adansonia,' i, 286.
[122] See also figure in 'Hort. Eystett. Ic. Plant. Vern.,' fol. 15,
fig. 1. _Ranunculus asiaticus_.
[123] Duchartre, 'Ann. des sc. nat.,' 3me série, vol. ii, 1844, p. 293.
[124] Reissek, 'Linnæa,' vol. xvii, 1843, p. 641, tab. xix.
[125] The tube of the calyx in these specimens was traversed by ten
ribs, apparently corresponding to the primary ridges of the normal
fruit; these ribs were destitute of spines, and the bristly secondary
ridges were entirely absent. Those portions of the carpels which were
detached from the calyx had each three ribs, a central and two lateral
ones, which appeared to be continuous with the ribs of the calyx
below,--although in the case of the calyx there were ten, in the case of
the carpels six ribs, three to each. This diversity in number is thus
explained:--A circle of vascular tissue ran round the interior of the
calyx-tube, at its junction with the limb, and at the point of insertion
of the petals and stamens. The vascular circle seemed to be formed from
the confluence of the ten ribs from below. Of the five ribs in each half
of the calyx, the three central ones were joined together just at the
point of confluence with the vascular circle, above which they formed
but a single rib--that traversing the centre of the carpellary leaf; the
two lateral ribs of each half of the calyx seemed to be continuous,
above the vascular rim, with the lateral ribs of the carpel; these
lateral ribs were connected on either side with the central one by short
branches of communication. The disposition of the ten ribs may be thus
represented:--
1 1 1 1 1 1
3 2 3 2 3 3 2 3 2 3
1 1 1 1 1 1 1 1 1 1
The lower line of figures represents the calycine ribs, the middle row
shows how each of these ribs is divided at the vascular rim, and the
uppermost row shows their distribution above the rim. From this it will
be seen that six of the calycine ribs divide into three branches, one
prolonged upwards as a lateral or median rib into the carpellary leaf,
the other running horizontally to join with similar branches sent out
from the neighbouring rib; the four intermediate calycine ribs divide
into two branches only, which join the side branches of the first
mentioned, but have no direct upward prolongation into the carpel. The
ten ridges are placed opposite to the sepals and petals.
[126] 'Neue Denkschriften der allgemeine Schweizerischen Gesellschaft,'
band 5. 1841. tab. 2.
[127] Bell Salter, 'Gard. Chron.,' March 13th, 1847, and 'Ann. Nat.
Hist.,' 1847, vol. xix, p. 471. &c.
[128] 'The Origin and Production of Proliferous Flowers, with the
Culture at large for raising Double Flowers from Single, and Proliferous
from the Double.' By J. Hill, M.D. London, 1759.
[129] A. de Candolle, 'Neue Denkschriften,' op. cit., p. 9; also Unger
as cited in 'Botanical Gazette,' May, 1351. p. 70.
[130] Duchartre, op. cit.
[131] 'Ann. Sc. Nat.,' 1844, vol. i, p. 297.
[132] Maout, 'Leçons Elémentaires de Botanique,' vol. ii. p. 488;
Ferrari. 'Hesperides.' pls. 271, 315, 405.
[133] Moquin-Tandon, loc. cit., p. 386, &c.; see also Trécul, in the
'Bull. Soc. Bot. France,' tom. i, p, 307.
[134] 'Bull. Soc. Bot. Fr.,' 1863, vol. x, p. 461.
[135] 'Ann. Sc. Nat.,' 1835, p. 65. See also Le Maout, 'Leçons
Element.,' vol. ii, p. 426.
[136] 'Proc. Hort. Soc.,' vol. i, p. 39, fig. 2.
[137] See also 'Nat. Hist. Review,' 1865, p. 377.
[138] 'Acad. Roy. Belg.,' April 11th. 1863.
[139] 'Bull. Soc. Bot. Fr.,' tom. iii, 1856, p. 479.
[140] 'Linnæa,' vol. xv, p. 266, _c. ic._ Caspary, 'Schriften d.
Physik.-Oek. Gesell. zu Königsberg,' bd. ii, p. 5, tab. iii, fig. 39,
&c.
[141] Lindley, 'Veg. King.,' p. 545; also Clarke on the Position of
Carpels, Linn. Soc.,' December, 1850. 'Proc. Linn. Soc.,' ii, p. 105.
[142] 'Notulæ,' vol. i, Dicot. p. 127. 'Atlas,' pl. xliii.
[143] Moquin-Tandon gives the following references to cases of
proliferous roses, but some I have not been able to verify. 'Journ. des
Sav.,' 22 Mai 1679. Hottinger, 'Ephem. Nat. Cur.,' dec. 3 ann. 9 et 10,
p. 249. Marchant, 'Mem. Acad. Scienc. Paris.' 1707, p. 488. Preussius,
'Ephem. Nat. Cur.,' cent. 7 et 8. App. p. 83. Schuster, 'Act. Acad. Nat.
Cur.,' vol. vi, p. 185. Spadoni, 'Mem. Soc. Ital.,' t. v, p. 488. See
also at the end of this section for numerous other references.
[144] 'Bull. Acad. Belg.,' t. xx, part ii, p. 271. See also Bellynck,
'Bull. Soc. Bot. Belg.,' t. vi, ex. 'Bull. Soc. Bot. France,' t. xiv,
1867, Rev. Bibl., p. 241. _Orchis ustulata_.
[145] I have not been able to meet with this, but it is said to contain
a paper on prolification, with numerous bibliographical references.
[146] 'El. Ter. Veg.,' p. 364, Adnot.
CHAPTER III.
HETEROTAXY.
Under this category are here included a variety of deviations from the
ordinary arrangement and position of parts which cannot conveniently be
classed under the preceding or under other headings. The term heterotaxy
is intended to apply to the production of organs in situations where,
under usual circumstances, they would not be formed. It thus does not
include cases of substitution, where one part is replaced by another, or
more or less metamorphosed, nor cases of multiplication, nor of
prolification which are characterised not only by the production of
members in unwonted situations, but also in unwonted numbers. From the
very nature of the anomalies, and specially from the scanty knowledge we
possess concerning their mode of development, it is not possible to
allocate them in all cases correctly, and moreover many of them might as
well be placed in one group as in another.
=Formation of adventitious roots.=--This is of exceedingly common
occurrence in a vast number of plants, so much so that in most cases it
cannot be considered as in any way abnormal; there are, however, a few
instances where the formation of these organs may be considered to come
within the scope of teratology, or, at least, where their production is
the result of injury or of some unfavorable condition to which the plant
is exposed.
Thus the production of adventitious roots on the stem of the vine is
considered to be due to untoward circumstances impairing the proper
action of the ordinary subterranean roots. So, too, the formation of
roots on the upper portions of stems that are more or less decayed
below, as in old willows, is to be considered as an attempt to obtain
fresh supplies through a more vigorous and healthy channel.
A similar occurrence often arises as a consequence of some injury.
Virgil had this circumstance in view when he wrote
"_Quin et, caudicibus sectis, mirabile dictu,
Truditur e sicco radix oleagina ligno._"--'Georg.' Bk. ii.
I have seen many specimens of adventitious roots produced on the olive
in the way just mentioned.
In the 'Gardeners' Chronicle,' January 8th, 1853, p. 21, is described a
curious formation of roots in the fissure between two divisions of a
laburnum stem. In the same journal, January 1st, 1853, p. 4, Mr. Booth
mentions the case of a Cornish elm, the trunk of which was divided at
the top into two main divisions, and from the force of the wind or from
some other cause the stem was split down for several feet below the
fork. Around the edges of the fracture, layers of new bark were formed,
from which numerous roots issued, some measuring an inch in diameter and
descending into the cleft portion of the tree: similar instances must be
familiar to all observers.
It may happen that these roots sent down into the cavity of a decaying
trunk may, after a time, become completely concealed within it, by the
gradual formation and extension of new wood over the orifice of the
cavity formed by the death and decay of the old wood. Such is presumed
to be the explanation of a specimen of this kind in the possession of
the writer, and taken from a cavity in an apparently solid block of
rosewood; externally there were no marks to indicate the existence of a
central space, but when the block was sawn up for the use of the
cabinet-maker, this root-like structure was found in the centre and
attached to one end of the cavity.
The production of roots which ultimately serve as props to support the
branches, or as buttresses to compensate for the increasing weight of
branches and foliage, is also a familiar occurrence. The huge gnaurs and
burrs met with occasionally on some trees often produce great
quantities, not only of adventitious buds, but of roots also.
[Illustration: FIG. 71.--Production of adventitious roots from leaf
stalk of celery.]
The leaves, equally with the stems, have the power of emitting roots
under certain conditions, as when the leaves are in close contact with
moist soil or as the result of injury. This happens in some plants more
readily than in others--_Bryophyllum calycinum_ is a well-known
instance. Mr. Berkeley has described the formation of roots from the
fractured leaves of celery,[147] and also in a cabbage where a snail
"having gnawed a hole into the middle of a leaf at its junction with the
stem, a fascicle of roots was formed, bursting through the tissue lining
the cavity, and covered with abundant delicate hairs after the fashion
of ordinary radicles."
[Illustration: FIG. 72.--Germinating plant of mango, showing production
of roots from one of the cotyledons (from the Kew Museum).]
The production of adventitious roots is not limited to the ordinary
leaves of the plant, but may be manifested on the cotyledons; thus
Irmisch describes cases of this kind in the cotyledons of _Bunium
creticum_ and _Carum Bulbocastanum_.[148] I have figured and described
an analogous case in the cotyledons of the Mango (fig. 72).[149]
To this formation of adventitious roots the gardener owes the power he
has of propagating plants by cuttings, _i.e._, small portions of the
stem with a bud or buds attached, or in some cases from portions of the
leaves, of the roots themselves, or even of the fruit, as in the case of
the cactus (Baillon). Care also has to be exercised in grafting certain
fruit trees not to allow the grafted portion to be too close to the
ground, else the scion throws out roots into the soil, and the object of
the cultivator is defeated.
[Illustration: FIGS. 73 and 74 show formation of roots from leaves
induced by the art of the gardener.]
Layering is another garden operation dependent on the formation of these
organs, and advantage is also sometimes taken of this tendency of some
plants to produce roots when injured to reduce the dimensions of a plant
when getting too large for the house in which it is growing. By
gradually inducing the production of new roots from the central or upper
portions of the stem, it becomes possible, after a time, to sever the
connection between the original roots and the upper portion of the
trunk, and thus secure a shortened plant.
On the subject of adventitious roots, &c., reference may be
made to Trécul, 'Ann. Sc. Nat.,' 1846, t. v, p. 340, et vi, p.
303. Duchartre, 'Elements de Botanique,' p. 219. Lindley,
'Theory and Practice of Horticulture.' Thomson's 'Gardener's
Assistant,' pp. 374, _et seq._; and any of the ordinary
botanical text-books.
=Formation of adventitious buds on roots.=--One of the characteristics
by which roots are distinguished from stems in a general way consists in
the absence of buds; but, as is well known, they may be formed on the
roots under certain circumstances, and in certain plants, e.g., _Pyrus
Japonica_, _Anemone Japonica_, &c. What are termed suckers, owe their
origin to buds formed in this situation.
If roots be exposed or injured, they will frequently emit buds. The
well-known experiment of Duhamel, in which a willow was placed with the
branches in the soil and the roots in the air, and emitted new buds from
the latter and new roots from the former, depended on this production of
adventitious organs of either kind.
Gardeners often avail themselves of the power that the roots have of
producing buds to propagate plants by cuttings of the roots, but in many
of these cases the organ "parted" or cut is really an underground stem
and not a true root.
M. Claas Mulder has figured and described a case in the turnip-radish of
the unusual formation of a leafy shoot from the root, apparently after
injury.[150] From the figure it appears as if the lower portion of the
root had been split almost to the extremity, while the upper portion
seems to have a central cavity passing through it. From the angle,
formed by the split segments below, proceeds a tuft of leaves, some of
which appear to have traversed the central cavity and to have emerged
from the summit, mingling with the other leaves in that situation. The
production of a flower-bud has even been noticed on the root of a
species of _Impatiens_.
=Formation of shoots beneath the cotyledons.=--The tigellar or axial
portion of the embryo plant, as contrasted with the radicle proper, is
very variously developed in different cases; sometimes it is a mere
"collar" bearing the cotyledons, while at other times it is of
considerable size. Generally it does not give origin to shoots or leaves
other than the seed-leaves, but occasionally shoots may be seen
projecting from it below the level of the cotyledons. This happens
frequently in seedling plants of _Anagallis arvensis_, _Euphorbia_
_peplus_, and other species, _Linaria vulgaris_, some _Umbelliferæ_,
&c.[151]
=Adventitious formation of leaves.=--The term phyllomania has been
vaguely applied both to the production of an unwonted number of leaves
and to their development in unusual situations. Under the present
heading the latter class of cases are alone included. The extraordinary
tendency in some Begonias to develop leaves or leafy excrescences from
their surfaces is elsewhere alluded to, and is, in reality, a species of
hypertrophy or over-luxuriant growth.
In some flowers where the inferior ovary is supposed to be, in part at
least, formed by a dilatation of the top of the flower-stalk, leaves
have been met with proceeding from the surface of the ovary or fruit, as
in _Cratægus tanacetifolia_, roses, pears, gooseberries, &c. In a
specimen of _Nymphæa alba_ I have met with scale-like leaves projecting
from the surface of the fruit (or torus?), and which did not appear to
be metamorphosed stamens or styles (fig. 76).
[Illustration: FIG. 75.--Leaf proceeding from hip of the Rose.]
[Illustration: FIG. 76.--Leaves proceeding from the ovary of
_Nymphæa_.]
For other illustrations of increased leaf-formation, see Multiplication
of foliar organs.
[Illustration: FIG. 77.--_Leontodon_. Scape with two leaves; the bracts
of the involucre are also leafy.]
=Production of leaves on a usually leafless inflorescence.=--The
development of the bracts of an inflorescence to such an extent that
they resemble ordinary leaves is elsewhere alluded to as of common
occurrence. It happens far less frequently that leaves are developed on
an inflorescence usually destitute of them, without any metamorphosis or
substitution, and without any formation of adventitious buds, such as
happens in prolification. Such a partial change from a floriferous to a
foliiferous branch may be seen in a specimen of _Sambucus nigra_ in the
Smithian herbarium in the Linnean Society, where the ultimate branches
of the cyme bear small leaves. My attention was directed to this
specimen by the Rev. W. Newbould.
Jacquin figures an analogous case in _Sempervivum sediforme_,[152] in
which the branches of the inflorescence were prolonged into leafy
shoots.
Sometimes from the side of a flower-stalk or scape, which usually does
not bear leaves, those organs are produced. The common dandelion,
_Taraxacum_, sometimes offers an illustration of this, and also the
daisy (_Bellis_).[153] In a specimen of fasciated cowslip given me by
Mr. Edgeworth there was a similar formation of leaves on the flattened
stalk.
=Production of leaves or scales in place of flower-buds.=--The position
of the leaf and of the flower-buds respectively is, in most plants, well
defined, but occasionally it happens that the former is formed where,
under ordinary circumstances, the latter organ should be. This may
happen without the formation of any transitional organs between the two,
and without actual increase in the number of the buds. Where there is
evidently a passage from leaf-bud to flower-bud, or _vice versâ_, the
case would be one of metamorphy. If the number of buds be augmented, or
they be mixed with the flower-buds, then it would be referable to leafy
prolification of the inflorescence. There remains a class of cases
wherein there is a complete substitution of one structure for the other,
it may be without the slightest indication of transition between the
two, and without any admixture of leaf-buds among flower-buds, or any
absolute increase in the number of organs, as in Prolification. Such a
case is represented in fig. 78, which shows a portion of the stem of a
species of _Valeriana_, bearing at the summit, not an inflorescence, but
a tuft of leaves without the slightest indication of flowers.
Drs. Hooker and Thomson relate that in Northern India the flowers of
_Anemone rivularis_ are very generally absent, and their place supplied
by tufts or umbels of leaves.[154] In the collection of the late Mr. N.
B. Ward was a specimen of lupin in which the flowers were all absent,
and their place supplied by tufts of leaves.
[Illustration: FIG. 78.--Tuft of leaves replacing the inflorescence in a
species of _Valeriana_.]
A similar appearance has been noticed in _Compositæ_, and I owe to the
kindness of Professor Oliver the communication of a specimen of a
species of _Bidens_ from Peru, in which the capitula, instead of
consisting of florets, as usual, contained tufts of linear ciliolated
bracts within the involucre, without a trace of flowers. In the eleventh
volume of the 'Linnæa,' 1837, p. 301, Von Cesati figures and describes
an analogous case in _Carduus crispus_. The same author[1] records a
similar instance in the umbel of _Seseli coloratum_, where the place of
the flowers was occupied by stalked tufts of leaves. In the 'Gardeners'
Chronicle,' October 6th, 1860, p. 894, is mentioned an instance where
the blossoms of the pea were entirely absent, and their place supplied
by accumulations of small, ovate, green scales, thus presenting an
appearance similar to that brought about by the inordinate
multiplication of the sepals in the "wheat-ear carnation," and in the
Sweet William, and not unlike the condition met with in _Bryophyllum
proliferum_. In _Digitalis purpurea_ a similar anomaly is sometimes met
with.
In the apple I have observed leafy shoots bearing terminal tufts of
leaves where the flower should have been, so that what, under ordinary
circumstances would be a corymb of flowers, is here represented by a
series of tufts of leaves. In the cultivated azaleas also, leafy shoots
occupying the position of the flower may occasionally be met with.
In _Bouchea hyderabadensis_ I have seen the inflorescence more than
usually branched and covered with little tufts of bracts, without a
trace of true flower. A similar condition seems not infrequent in
_Gentiana Amarella_, as I have not only met with the plant myself in
this condition, but have been favoured with specimens by Mr. Pamplin,
Mr. Darwin, and others. In _Phyteuma spicatum_ an analogous appearance
has been recorded.
Among Griffith's collections from Affghanistan is a species of willow
(_Salix_) in which the inflorescence replaced by a much branched
panicle, bearing a quantity of minute bracts, in the axils of which
nestle numerous small buds. In another specimen the inflorescence
preserves its usual catkin-like shape, but the flowers are replaced by
little tufts of leaves. M. Germain de Saint Pierre mentions a case
wherein the flowers of _Alisma parnassifolia_ were completely replaced
by leaf-buds.[155]
[Illustration: FIG. 79.--Spikelets of _Willedenovia_, composed entirely
of scales to the exclusion of flowers.]
[Illustration: FIG. 80.--Rose Willow, _Salix_, sp.]
Here, also, may be mentioned the curious aggregations of scales which
occur in some grasses, in _Restiaceæ_, _Juncaceæ_, and other orders, in
which the inflorescence is made up of collections of scales or bracts
with no trace of floral structure. Fig. 79 shows this in a species of
_Willdenovia_, and a very good example is figured in a bamboo,
_Pseudostachyum polymorphum_, by General Munro.[156]
"Rose willows" (fig. 80) owe their peculiar appearance to a similar
cause, the scales of the catkin being here replaced by closely crowded
leaves. These aggregations of scales or leaves are not confined to the
inflorescence, but may be found in other parts of the plant, and may be
frequently met with in the willow, birch, oak, &c., generally as the
result of insect puncture. On the other hand, the production of leaves
or leaf-buds in place of flowers is, as is well known, generally the
consequence of an excess of nutrition, and of the continuance rather
than of the arrest of vegetative development.[157] It has even been
asserted that a flower-bud may be transformed into a leaf-bud by
removing the pistil at a very early stage of development, but this
statement requires further confirmation.[158]
=Viviparous plants.=--The spikelets of certain grasses are frequently
found with some of their constituent parts completely replaced by
leaves, like those of the stem, while the true flowers are usually
entirely absent. A shoot, in fact, is formed in place of a series of
flowers. In these cases it generally happens that the outermost glumes
are changed, sometimes, however, even the outer and inner paleæ are
wholly unchanged, while there is no trace of squamulæ or of stamens and
pistils within them, but in their place is a small shoot with miniature
leaves arranged in the ordinary manner.
The grasses most commonly affected in this manner are _Dactylis
glomerata!_, _Poa bulbosa!_, _Poa annua!_, _P. trivialis!_,
_pratensis!_, _alpina!_, _angustifolia_, and _laxa_, _Cynosurus
cristatus_, _Festuca nemoralis_, _F. ovina!_, _Glyceria fluitans!_, _Gl.
aquatica_, _Aira alpina!_, _cæspitosa!_, _Phleum phalaroides_, _Lolium
perenne!_, _Alopecurus pratensis!_, _Agrostis alba_, _Holcus mollis!_
[Illustration: FIG. 81.--Portion of panicle of _Aira vivipara_ and
separate floret.]
From an examination of the structure of viviparous grasses Von Mohl was
led to the conclusion that the lower palea is to be considered as a
bract, and not a perianthial leaf, because the base of the palea
surrounds the stem or axis of the spikelet entirely, and both its
margins cohere towards its lower extremity.[159]
A similar condition occurs not infrequently in _Polygonum viviparum_,
and in _Juncaceæ_, _Cyperaceæ_, &c.
In the genus _Allium_ an analogous formation of little buds or bulbils
takes place in lieu of flowers; this is specially the case with _A.
vineale_, the flowers of which are rarely seen.
Other illustrations of a similar character, where the adventitious
leaf-buds are mixed in amongst the flower-buds, are cited under the head
of Prolification of the Inflorescence.
=Formation of buds on leaves.=--The formation of little bulbs upon the
surfaces or edges of leaves, forming what are called viviparous leaves,
has long been familiar to botanists amongst Alliums. Professor Alexander
Braun,[160] who has paid much attention to this subject, divides cases
of this kind according to the position of the buds; thus, for instance,
they are sometimes formed upon the upper portion of the leaf or petiole,
as in many ferns, in _Nymphæa guineensis_, some _Arads_, &c. The same
condition has been met with as a teratological occurrence in the leaves
of _Cardamine pratensis_, _Hyacinthus Pouzolzii_, _Drosera
intermedia_,[161] _Arabis pumila_, _Chelidonium majus_, _Chirita
sinensis_,[162] _Episcia bicolor_,[163] _Zamia_, &c.[164] Many species
of _Begonia_ possess the power of emitting buds from the petioles and
veins of the leaf; the little ramenta or scales which so plentifully
beset the surface of some of these plants likewise, in some instances,
pass gradually into leaves. _B. phyllomaniaca_, Mart., is the species
best known as manifesting this tendency, but others have it also.[165]
Buds are also very often formed upon the margins of the leaf, the best
known instance of which occurs in _Bryophyllum calycinum_;
Weinmann[166] figures an instance of this kind in _Alchemilla minima_,
or they may occur upon the lower surface of the leaf, as in
_Ornithogalum scilloides_ and _longe-bracteatum_. M. Duchartre[167]
mentions a case in the tomato in which the leaves gave origin to small
leaf-bearing branches, which, of course, must have originated from buds,
just in the same way as in the _Drosera_ before mentioned.
[Illustration: FIG. 82.--Formation of shoot on leaf of _Episcia
bicolor_.]
Gardeners occasionally avail themselves of this formation of buds from
leaves to propagate plants, _e.g._ _Hoya_, _Gesnera_, _Gloxinia_, &c.
=Formation of buds in the pith.=--This is said to be a normal condition
in the curious _Stangeria paradoxa_,[168] and Mr. Berkeley records an
instance of this in sea-kale[169] (fig. 83) where the crown had been
injured, and buds were seen sprouting from its centre.
[Illustration: FIG. 83.--Adventitious buds in sea kale.]
[Illustration: FIG. 84.--Hyacinth bulb cut across to induce the
formation of new bulbs.]
[Illustration: FIG. 85.--Showing the formation of new bulbs on the cut
edges of an old hyacinth bulb.]
It will be remarked that the adventitious production of buds, like that
of roots, is very often consequent on decay or injury. The Dutch
bulb-growers have availed themselves of this latter circumstance in the
propagation of hyacinths. Mr. Fortune, who published some articles on
this subject in the 'Gardener's Chronicle,'[170] describes two special
modes as adopted by these skilful horticulturists--the one to make two
or three deep cuts at the base of the bulb, destroying the nascent
flower-stalk when, after a time, small bulbs are formed along the edges
of the cut surfaces (figs. 84, 85). The other method is effected by
scooping out the interior of the base of the bulb, thus leaving exposed
the cut ends of the sheathing leaves arranged concentrically; along
these lines the new bulbs are, after some time, formed in great numbers
(fig. 86).
[Illustration: FIG. 86.--Showing the production of small bulbs on the
inner surface of the scooped-out bulb of hyacinth.]
For the formation of supernumerary leaves on the surface of the normal
one, see Multiplication and Hypertrophy.
=Production of gemmæ in place of spores.=--An instance of this is
recorded by Dr. Montagne[171] in the case of a moss, _Encamptodon
perichætialis_, in which, in the interior of the capsule, in lieu of
spores numerous minute gemmæ of the same nature as those in the cup of
_Marchantia_ were seen.
=Formation of flowers on leaves.=--It is very doubtful whether a
flower-bud has ever been found actually on a leaf. Mere adhesion of the
pedicels of the leaf, such as happens in _Ruscus_, in _Helwingia_,
_Erythrochiton hypophyllanthus_, and a few other plants, is, of course,
not really to be considered in the light of an actual growth from the
leaf, and it is very doubtful in the present state of our knowledge
whether the case of the Nepaul barley should find a place here, but for
convenience sake it is placed in this section, as it is uncertain at
present where it properly belongs.
[Illustration: FIG. 87.--Three-lobed end of outer palea of Nepaul barley
bearing supplementary florets.]
[Illustration: FIG. 88.--Three spikelets of Nepaul barley.]
[Illustration: FIG. 89.--Lip of outer palea of Nepaul barley.]
[Illustration: FIG. 90.--Supplementary rachillus or outer palea of
Nepaul barley bearing florets.]
[Illustration: FIG. 91.--Diagram showing arrangement of supplementary
rachillus and florets.]
[Illustration: FIG. 92.--Supplementary floret of Nepaul barley; palea
removed.]
This curious plant has been described and figured by Irmisch in the
13th volume of the 'Linnæa,' p. 124, t. iv; also by Professor Henslow,
'Hooker's Journal of Botany,' 1849, vol. i, p. 33, tabs. 2, 3. The lower
palea of this plant forms an inverted flower-bud upon its midrib. In
some fresh specimens which I have lately examined I find the structure
to be as follows:--On each notch of the rachis there are three spikelets
(fig. 88), each one-flowered, and each provided with two linear glumes;
the outer palea in all cases is three-lobed at the summit, the central
lobe being oblong and hollow, forming a kind of hood (figs. 87-89), and
covered with hairs, which are directed downwards towards the centre of
the plant. The two lateral lobes are more pointed than the central one;
like it they are provided with hairs, but the hairs, in this case, are
turned away from the centre of the plant. The cavity of the side lobes
is generally empty, but that of the central lobe is occupied by a very
slender stalk, which is apparently the termination of the midrib, but
which is bent inwards at an acute angle, so as to occupy the hollow
space (figs. 90-91). On this slender axis are developed two florets,
more or less imperfect in their structure. Only one of the florets that
I have seen contained a perfect ovary. The tips of the lateral lobes of
the paleæ in the primary flower are sometimes extended into a long awn.
A similar awn may also be occasionally found on the tips of the paleæ of
the rudimentary florets. The occurrence of an adventitious axial
structure with rudimentary flowers has been adduced in support of the
opinion that the lower paleæ is, at least so far as its midrib is
concerned, an axial rather than a foliar structure, but in the present
uncertain state of our knowledge as to the morphology of grasses it is
hazardous to risk any explanation founded on so exceptional a case as
that of the Nepaul barley.[172]
=Production of flower-buds in place of leaf-buds.=--Under natural
circumstances this does not appear to be of so common occurrence as the
change above alluded to, but by the art of the gardener the change is
often effected. In rhododendrons and in peach trees and roses I have met
with this change occurring without human agency. The means adopted by
the gardener are such as check the luxuriance of the leaf-shoots,[173]
and this is effected in various ways, as by continuous "pinching" or
removal of the leaf-buds, by pruning, ringing the bark, confining the
roots, limiting the supply of nutriment, and other means all based on
the same principle. Some of the Cape bulbs (_Cyrtanthus_) are known not
to produce their flowers till their leaves have received, in some
manner, a check. Fires which often destroy the herbage thus have the
effect of throwing the plant into bloom. A very remarkable instance is
recorded of the production of flower-buds after an injury to the
leaf-buds in the 'Bulletin of the Botanical Society of France,' vol. ix,
p. 146. It appears that during the war of the French against the Arabs
in Algiers, the latter planted several hundreds of Agaves with a view to
obstruct the passage of the French cavalry. The soldiers hacked these
plants with their sabres, and cut out the central tuft of leaves, or the
heart, as gardeners call it. The following season almost every one of
these Agaves sent up their large handsome flower-spikes. It is well
known that, under ordinary circumstances, these plants do not flower
except at long intervals of time.
=Presence of flowers on spines.=--That the spine, as a contracted
branch, should occasionally produce flowers is not to be wondered at,
though the occurrence is by no means common. M. Baillon showed at a
meeting of the Botanical Society of France ('Bulletin,' vol. v, 1858, p.
316) a branched spine of _Gleditschia_ bearing a flower at the end of
each of the sub divisions. This was, therefore, strictly analogous with
those cases in which the peduncle is normally spiney.
=Formation of flower-bud on the petals.=--An instance of this, it is
believed, the only one on record, is cited in the 'Gardeners' Chronicle'
for 1865, p. 760, by the Rev. M. J. Berkeley, who describes the
formation of a flower-bud on the surface of a petal of _Clarkia
elegans_. Reasoning from analogy there seems no reason why buds should
not be formed on the petals as well as on the leaves.
=Formation of buds on fruits.=--This is a point of some moment with
reference to the share which the axis takes in the production of
"inferior" fruits. A very frequent malformation in pears is one wherein
a second pear proceeds from the centre of the first, and even a third
from the centre of the second.[174] Pears are occasionally also observed
arising either from the axils of the sepals of the primary pear or from
the axil of leaves originating on the outer surface of the fruits--using
the term fruit in its popular sense. These cases afford strong
confirmation of the view that the outer portion of the so-called fruit
in these plants is rather to be considered as an expansion and
hollowing-out of the flower-stalk, than as formed from the calyx-tube.
It is noteworthy that the true carpels and seeds are frequently entirely
absent in these cases.[175] Further reference to these fruits will be
made under the head of Hypertrophy.
M. Trécul has described and figured an instance in a species of
_Prismatocarpus_, in which a second flower proceeded from the axil of a
bract attached to the side of the fruit of the first flower.[176] A
similar growth was observed in the fruit of _Philadelphus speciosus_ by
M. A. Gris, who observed that the so-called calyx-tube was provided with
two small bracts, from the axil of one of which proceeded a small
flower-bud.[177]
[Illustration: FIG. 93.--Small buds projecting from the edges of the
fruit in _Opuntia_.]
The fruits of _Opuntia Salmiana_, _O. fragilis_,[178] _O. monacantha_,
and of some species of _Echinocactus_, have been observed to form small
fruit-like branches around their summits. M. Napoléon Doumet describes
the fruit as ripening as usual, but as being destitute of seeds in the
interior; after a little while the fruit begins to wither, and then a
circle of small buds, like those of the stem, may be seen at the top of
the fruit, each bud springing from the axil of a little tuft of wool and
spines found on the fruit. These little buds elongate into long shoots,
produce flowers the following year, which flowers exhibit the same
peculiarity. Gasparini and Tenore are said to have recorded the same
fact as long since as 1832. The specimen from which the figure (fig. 93)
was taken produced its fruits in the Royal Gardens at Kew, and is now
preserved in the museum of that establishment. The adventitious growth
in these cases appears to arise from the tufts of spines, which, it has
been suggested, are the homologues of the sepals. There can, however, be
little doubt that the outer and lower portion of the fruit of _Opuntia_
and its allies is a dilatation of the flower-stalk. This is borne out by
the fruits of _Pereskia_, which bear leaves on their surface arranged
spirally; indeed, the fruits of _Pereskia Bleo_ are mentioned as
producing buds from their summits, in the same way as the _Opuntia_
just cited. _P. Bleo_ is said, by M. Delavaud,[179] to present this
anomaly as a constant occurrence. On the summit of the primary fruit,
arising apparently from the axils of the sepals, or of small leafy
bracts in that situation, are a series of fruit-like branches, which, in
their turn, are surmounted by others, even to the fourth generation.
The fruits of _Tetragonia expansa_ frequently have attached to their
side a secondary flower or fruit in such a position as to lead to the
inference that it springs from the upper portion of the peduncle which
is dilated to invest the true carpels. In other instances it is due to
an adhesion of the pedicel to the side of the fruit. In either case the
production of an adventitious bud might be considered as an illustration
of prolification of the inflorescence, though not as was supposed by
Moquin and others of axillary prolification.[180]
Buds have also been produced artificially on the surface of some of the
fruits in the construction of which the axis is supposed to share; thus,
the unripe fruits of some species of _Lecythis_ were stated by Von
Martius, at a meeting of the German Naturalists at Carlsruhe, to produce
buds when placed in the earth. The fruit of these plants is probably of
the same nature as that of the _Pomaceæ_, and Baillon[181] succeeded in
producing buds on the surface of the inferior ovary of _Jussiæa_.
Some of the cases just mentioned have been considered to be instances of
prolification of the fruit, but the fruit has little to do with the
appearances in question.
=Formation of adventitious flowers and fruits within the ovary.=--This
generally arises either from substitution of a flower-bud for an ovule
or from prolification; there are certain cases, however, where the new
growth seems not to be either due to metamorphosis or to prolification
strictly.
The cut, fig. 94, represents a case where, in the dilated upper portion
of the ovary of _Sinapis arvensis_, two flower-buds were found
projecting from a raised central line, corresponding, as it would seem,
to the midrib, and not to the margins of the carpel. Similar cases have
occurred in _Nasturtium amphibium_, _Brassica Rapa_, and _Passiflora
quadrangularis_.
[Illustration: FIG. 94.--Distended pod of _Sinapis arvensis_ bearing in
the interior stalked flower buds.]
In Bromfield's 'Flora Vectensis,' p. 35, the following account is given
of an abnormal development in _Cardamine pratensis_: "On the lower part
of the corymb were several seed vessels on pedicels changed from their
usual linear to an ovate elliptical figure, so as to resemble a
silicula. These, on being opened, were found to contain petals of the
usual colour, which in the pods above had burst from their confinement
and appeared as semi-double flowers; the valves of the pod answering to
the true calyx. * * * From their verticillate arrangement it is evident
that these petaloid expansions were not transformed seeds, but simply a
development of the common axis within the ovary into an abortive whorl
of floral organs, besides which there were evident rudiments both of
stamens and germens in the centre of the bundle." Baillon[182] also
records a case of the same nature in _Sinapis arvensis_.
[Illustration: FIG. 94*.--Portion of the interior of the silicle in
_Cheiranthus Cheiri_, showing adventitious pod in the place of an
ovule.]
[Illustration: FIG. 95.--Adventitious pod from fig. 94, enlarged.]
Here, too, may also be mentioned the presence of an adventitious siliqua
within the ordinary one attached along the same line as the ovules, and
partially divided by a replum into two cavities. In this case there was
nothing to indicate the presence of floral envelopes (figs. 94, 95). A
similar occurrence has been brought under my notice in some grapes which
were observed to be cracking before they were perfectly ripe, and in
which adventitious fruits were found within the parent grape, occupying
the position of seeds (figs. 96, 97).
Similar anomalous growths are noticed under the heads of Substitution
and Prolification.
=Formation of stamens within the cavity of the ovary.=--The only
instance of this that has come under the author's observation occurred
in some flowers of _Bæckea diosmæfolia_, Rudge, for an examination of
which he is indebted to Mr. Bentham.
[Illustration: FIG. 96.--Section of Barbarossa grape showing
adventitious grape in the position of a seed.]
[Illustration: FIG. 97.--Grape with supplementary fruit in the interior]
In the normal flower there is a turbinate hollow calyx, whose limb is
divided into five serrated lobes; alternating with these latter, and
springing from the throat of the calyx, are the petals. Originating from
the same annular disk as the petals are the stamens, seven or eight in
number. The ovary is partially adherent, is surmounted by a style, and
has two or three loculi with an axile placenta, to which several small
curved ovules are attached. The malformed flowers did not present
anything peculiar in their outer parts, nor did the ovary, partially
immersed within the expanded top of the flower-stalk and the calyx-tube,
which is continuous with that organ, show externally any indication of
the change within. On cutting it across, however, in any direction,
numerous perfect stamens (filaments and anthers) were seen projecting
from the walls of the cavity (fig. 98). In most of the flowers the ovary
was one-celled; but in a few there was the usual axile placenta; yet
even in these latter cases the stamens originated from the walls of the
cavity, and not from the placenta. The stamens presented different
degrees of development; in some cases they were fully formed, the
anther-lobes open, and the pollen exposed; while in other instances the
filaments were involute or circinate, just as the ordinary stamens are
in the unexpanded flower-bud. In some cases imperfect stamens were
found, mere barren filaments, with or without rudimentary anthers at the
top. In no instance was there a perfect ovule, or, indeed, any trace of
ovules. The stamens appeared to be arranged irregularly on the walls of
the ovarian cavity; and while they were certainly more numerous at the
lower portion (that now generally considered to be formed by the
cup-like end of the pedicel), they were not wanting in the upper half of
the ovary (or that which is probably formed from the carpellary leaves).
[Illustration: FIG. 98.--1. Vertical section of flower of _Bæckea
diosmæfolia_, showing stamens within the ovary; magnified ten times. 2.
Transverse section of ovary. 3. Stamen. 4. Imperfect stamen.]
This case differs from most that have been recorded, and in which there
has been a more or less complete substitution of anther for carpel, or
where the tissues of the carpel have produced pollen, and so taken upon
themselves the appearance and functions of anthers. Instances of this
latter kind are not uncommon; but in the _Bæckea_ there were perfect
stamens proceeding from perfect and completely closed ovaries.
Moquin-Tandon[183] cites from Agardh an instance which seems more
closely to resemble the state of things in the _Bæckea_, and which
occurred in a double hyacinth, wherein both anthers and ovules were
borne on the same placenta. Probably, though the fact is not stated, the
ovary of the hyacinth was open; and we are told that the flower was
double--that it was, in fact, modified and changed in more organs than
one; while in the _Bæckea_ nothing at all unusual was observed till the
ovary was cut open. The style was present even in those flowers where
there was no axile placenta; hence in these cases it could not be, as
Lindley stated it to be in the closely allied _Babingtonia_, a
prolongation of the placenta.[184]
=Formation of pollen within the ovules.=--This has now been recorded in
two instances by Mr. S. J. A. Salter in _Passiflora cærulea_ and in _P.
palmata_,[185] and by the author in _Rosa arvensis_.[186]
[Illustration: FIG. 99.--Pollen within the ovule of _Passiflora_ (after
Salter).]
In the case of the passion-flower there were various malformations in
the ovaries, which were all more or less split open at the distal end,
indicating a tendency towards dialysis. The pollen-bearing ovules were
borne on the edges of these ovaries, and presented various intermediate
conditions between anthers and ovules, commencing at the distal
extremity of the carpel with a bi-lobed anther, and passing in series to
the base of the ovary, an antheroid body of ovule-like form, a modified
ovule containing pollen, an ovule departing from a perfectly natural
condition only in the development of a few grains of pollen in its
nucleus, and, finally, a perfect, normal ovule.
In the flowers of the Rose the stamens exhibited almost every
conceivable gradation between their ordinary form and that of the
carpels, while some of the ovules contained pollen in greater or less
abundance. Speaking generally, the most common state of things in these
flowers was the occurrence on the throat of the calyx, in the position
ordinarily occupied by the stamens, and sometimes mingled with those
organs, of twisted, ribbon-like filaments, which bore about the centre
one or more pendulous, anatropous ovules on their margins. Immediately
above the latter organs were the anther-lobes, more or less perfectly
developed, and surmounting these a long style, terminating in a fringed,
funnel-shaped stigma. Sometimes the ovules were perfect, at other times
the nucleus protruded through the foramen, while in a third set the
nucleus was included within the tegument, the ovules having in all
respects their natural external conformation, containing, however, not
only pollen-grains, but also a layer of those peculiar spheroidal cells,
including a fibrous deposit, which are among the normal constituents of
the anther. In one case, where the coat of the ovule was imperfect, and
allowed the nucleus to protrude, the pollen was evidently contained
within the central mass of the structure. In this instance the fibrous
cells were not detected, these being only found in cases where the
investment of the ovule was perfect; and hence it seems likely that the
fibrous cells were part of the coat of the ovule, while the pollen was
formed within the nucleus. In no case was any trace of embryo sac to be
seen.
The main interest, as Mr. Salter remarks, in these cases is
physiological; so far as structure alone is concerned, there does not
appear any reason why pollen-grains should not be developed in any
portion of the plant; the mother cells in which the pollen is formed not
differing, to all outward appearance, from any other cells, unless it be
in size.
The fundamental unity of construction in all the organs of plants could
hardly be better illustrated than by these cases; while, in spite of
their exceptional nature, they must be of great interest
physiologically, as showing the wide limits of possible variation which
thus may even involve the sex, "for an ovule to develop pollen within
its interior," says Mr. Salter, "is equivalent to an ovum in an animal
being converted into a capsule of spermatozoa. It is a conversion of
germ into sperm, the most complete violation of individuality and unity
of sex. * * * * The occurrence of an antheroid ovule and a normal ovule
on the same carpellary leaf realises the simplest and the most absolute
form of hermaphroditism."
It must, however, be remarked that the term substitution would be
preferable to conversion. There is, at present, no evidence to show that
the germinal vesicles were present in these cases; on the other hand, it
seems most probable that they were not, so that the presence of the
pollen-cells must be considered as simply adventitious. It can hardly be
that they were, in the first instance, germinal vesicles, which, in
course of time, became so modified as to assume the appearance of
pollen-grains. Between the nucleus of the ovule and the tubercle of
cellular tissue constituting the primordial anther, there is little or
no difference, so that it may be said that, for a time, there is no
distinction of sex in the nascent flower, but as development goes on,
the difference becomes perceptible. It cannot at present be stated what
precise circumstances induce the one mass to form mother-cells and
pollen-grains, and the other to develop an embryo sac and germinal
vesicles. Position and external circumstances may have some indirect
effect, and it may, perhaps, be significant that in all the instances of
polliniferous ovules, the ovular structures have been exposed on an open
carpel or otherwise, in place of being confined within the cavity of a
closed ovary, as under ordinary circumstances. Even among Conifers the
ovuligerous scales are so closely packed that there is little or no
exposure of the ovules. But, apart from all speculative notions as to
the relation between the structure and functions of the anther and of
the ovule respectively, and of the possibility or the reverse of
parthenogenesis, it will clearly be necessary in any future alleged
occurrence of the latter phenomenon to ascertain whether any or all of
the apparent ovules are, or are not, anthers in disguise.
=Homomorphic flowers of "Compositæ."=--In a large section of the
_Compositæ_ there is, as is well known, a distinction between the
florets of the "disc" and those of the "ray," the latter being ligulate,
the former tubular.
In what are erroneously called double flowers in this order, _e.g._ in
the Chrysanthemum, Dahlia, &c. &c., the florets are all ligulate. This
change is sometimes classed with peloria, but there is no abnormal
regularity in these cases. On the other hand, were the ligulate florets
to be all replaced by tubular ones, the term peloria would be more
strictly applicable. It will be remembered that in the sub-order
_Ligulifloræ_, the florets are naturally all ligulate, so that the
change above mentioned is not in itself a very grave one.
=Heterotaxy affecting the inflorescence.=--Under the head of
Prolification, Heterogamy, &c., various deviations from the normal
inflorescence are alluded to. In this place, therefore, it is only
necessary to mention certain rare deviations from the customary
arrangement of the inflorescence, such as the change from a definite
centrifugal form of inflorescence to an indefinite centripetal one. This
occurs occasionally in roses, where the shoot, instead of terminating in
a flower-bud, lengthens and bears the flower-bud on its sides as in a
raceme.
In the hyacinth, the inflorescence of which is properly indefinite, the
terminal flower may frequently be found to expand first, though in order
of development it may have been the last formed.
It occasionally happens that certain plants will, contrary to their
usual custom, bloom twice in the same season; this usually arises from
the premature development of buds which, under ordinary circumstances,
would not unfold till the following spring. In these instances of what
the French term "fleuraison anticipée," the position of inflorescence is
not changed, but there are other cases where the position of the
inflorescence is altered, as in the laburnum, where, in some seasons,
racemes may be seen springing from short lateral "spurs" along the sides
of the branches, as well as from the extremities of long shoots.
Of a similar nature are those cases wherein stems or branches usually
sterile become fertile; this happens in _Equisetaceæ_,[187] in
_Restiaceæ_, and other orders. In the equisetums, the condition in
question has been specially noticed to occur after prolonged drought.
_Equisetaceæ_ are likewise subject to an anomaly called by Duval Jouve
interruption of the spike, and wherein the scales bearing the spore
cases are separated by whorls of branches instead of forming one compact
unbroken spike as usual.
This alternation of the organs of vegetation and reproduction may also
be seen occasionally in _Typha_, and other plants.
Kirschleger describes a case in which the male catkins of _Salix
cinerea_ were placed at the ends of the branches instead of being
lateral productions; moreover the usual articulation was not formed, so
that the catkin was persistent instead of deciduous.[188]
=Supra-soriferous ferns.=--In the great majority of ferns the sori or
clusters of spore cases are placed on the under surface of the fronds;
nevertheless, a few cases are on record where the fructification is
produced on the upper as well as on the lower surface, and sometimes
abundantly so. This occasionally happens from the elongation of the
normally placed sorus, which thus extends to the margin, and returns on
the upper side, when the sori chance to be placed opposite to the
marginal crenatures. But it is also frequently the case that the sori
are produced on the upper side, distinctly within the margin, and where
there are no corresponding sori beneath. Those varieties which have the
margin crenated or lobed seem most liable to assume this abnormal
supra-soriferous condition. Among the ferns in which this condition has
been observed are the following: _Scolopendrium vulgare_, _Polypodium
anomalum_, Hook., _Asplenium Trichomanes_, _Cionidium Moorei_.[189]
FOOTNOTES:
[147] 'Gard. Chron.' 1852, p. 51.
[148] 'Flora.' 1858, pp. 32-42.
[149] 'Journ. Linn. Soc.,' vol. vi; "Botany," 1862, p. 24.
[150] 'Tijdschrift voor Natuur. Geschied,' 1836, vol. iii, tab. vii, p.
171.
[151] Roeper, 'Enum. Euphorb.,' p. 19. Bernhardi, 'Linnæa,' vii, p.
561, tab. xiv, f. 1. Wydler, "Subcotyled. sprossbildung," 'Flora,' 1850,
p. 337. Hooker, 'Trans. Linn. Soc.,' vol. xxiv, p. 20 (_Welwitschia_).
[152] 'Misc. Austriac. ad Bot.,' vol. i, p. 133, t. 5.
[153] See also Carrière, 'Revue Horticole,' 1866, p. 442; and as to
pears, Radlkofer in 'Bericht über die Thätigkert der Baierischen
Gartenbau Gesellschaft,' 1862, p. 74, t. i.
[154] 'Flora Indica,' p. 23.
[155] 'Bull. Soc. Bot. Fr.,' 1856, p. 53.
[156] 'Trans. Linn. Soc.' xxvi, p. 142, tab. iv, B.
[157] "Si arbusculam, quæ in ollâ antea posita, quotannis floruit et
fructus protulit, deinde deponamus in uberiori terra calidi caldarii,
proferet illa per plures annos multos ac frondosos ramos, sine ullo
fructu. Id quod argumento est, folia inde crescere, unde prius enati
sunt flores; quemadmodum vicissim, quod in folia nunc succrescit, id,
naturâ ita moderante, in flores mutatur, si eadem arbor iterum in ollâ
seritur."--Linnæus, 'Prolepsis,' § iii.
[158] 'Rev. Hortic.' May, 1868, 'Gardeners' Chronicle,' 1868, pp. 572,
737.
[159] Cited in 'Annals Nat. Hist.,' 1845, vol. xv, p. 177.
[160] 'Ann. Scienc. Nat.,' vol. xiv, 1860, p. 13.
[161] Naudin, 'Ann. Sc. Nat.,' 2nd ser., 1840, vol. xiv, p. 14, fig. 6,
pl. i (_Drosera_). St. Hilaire, 'Comptes Rendus,' ix, p. 437.
[162] Hance, 'Hook. Journ. Botany,' 1849, vol. i, p. 141, pl. v.
[163] Booth, 'Gard. Chron.,' Jan. 1st, 1853, p. 4.
[164] Lindley, 'Theory of Horticulture,' ed. 2, p. 273.
[165] 'Hook. Journ. of Botany,' 1852, iv, p. 206. See also the curious
_Begonia gemmipara_, 'Hook. fil. Illust. Himal. Plant.,' t. xiv.
[166] 'Phytanth.,' n. 36, _d._
[167] 'Ann. Scienc. Nat.,' 3rd series. 1853. vol. xix, p. 251, tab. 14.
[168] Carrière, 'Revue Horticole.' 1868, p. 184.
[169] 'Gard. Chron.,' 1858, p. 556.
[170] 1863, p. 556, &c.
[171] 'Ann. Nat. Hist.,' 1845, vol. xvi, p. 355.
[172] See also Lindley, 'Veg. Kingd.,' p. 109 et 116_a_, where the views
of Raspail, R. Brown, Mohl, Henslow, and others, are discussed.
[173] It has been observed that if a plant is supplied with copious
nourishment the flowering-period is delayed; but that moderate or even
scanty nourishment accelerates it. Goethe, 'Metam.,' § 30. See also
Wolff, 'Theoria Generationis,' 1759; Linn. 'Prolepsis,' §§ 3 and 10.
[174] Moquin-Tandon, p. 384; also Lindl., 'Elements of Botany,' p. 65,
fig. 130; "Theory of Horticulture," p. 86. 'Gard. Chron.,' 1851, p. 723;
Irmish, 'Flora,' 1858, p. 38, &c.
[175] Caspary, 'Bull. Soc. Bot. Fr.,' vol. vi, 1859, p. 235; also Payer,
ibid., vol. i, 1854. p. 283.
[176] Trécul, 'Ann. Sc. Nat.,' 2nd ser., vol. xx, p. 339.
[177] 'Bull. Soc. Bot. Fr.,' vol. vii, 1858, p. 331.
[178] 'Bull. Soc. Bot. Fr.,' vol. i. p. 306, vol. v, p. 115. 'Illustr.
Hortic.,' xii, 1865, Misc. 79. 'Rev. Horticole,' 1860 p. 204, et 1867 p.
43.
[179] 'Bull. Soc. Bot. Fr.,' 1858, p. 685.
[180] The structure of this flower is discussed at some length in a
paper by the author on axillary prolification. 'Trans. Linn. Soc.,' vol.
xxiii, p. 486, t. liv. fig. 3. See also 'Clos. Bull. Soc. Bot. Fr.,'
vol. v, 1855, p. 672. Seringe et Heyland, 'Bull. Bot.,' i, p. 8. 'Pallas
Enum. Plant. Hort. Demidoff,' append, c, ic.
[181] 'Adansonia,' i, 181.
[182] 'Adansonia.' vol. iii, p. 351, tab. xii.
[183] 'Elém. Térat. Végét.,' p, 218.
[184] Masters, 'Journ. Linn. Soc.,' vol. ix, 1866, p. 334.
[185] 'Trans. Linn. Soc.,' vol. xxiv, p. 143. tab. xxiv.
[186] 'Brit. Assoc. Report,' Dundee, 1867; and Seemann's 'Journal of
Botany,' 1867, p. 319, tab. lxxii, figs. B 1-9.
[187] Duval Jouve, 'Hist. Equiset. France.' 1864, p. 154.
[188] 'Flora,' t. xxiv, 1841, p. 340.
[189] Moore, 'Nature-Printed British Ferns,' 8vo edition, vol. ii. p.
135. tab. lxxxv, B, &c.
CHAPTER IV.
HETEROGAMY.
This term is here intended to apply to all those cases in which the
arrangement of the sexual organs is different from what it is
habitually. It is evident that in many instances there is no
malformation, no monstrosity, but rather a restoration of organs
habitually suppressed, a tendency towards structural completeness
rather than the reverse. It must be also understood that the following
remarks apply to structural points only, and are not intended to include
the question of function. The occurrence of heteromorphic unions renders
it necessary to keep in mind that plants hermaphrodite as to structure
are by no means necessarily so as to function.
The simplest case of this alteration in the relative position of the
sexes is that which occurs in monoecious plants, where the male and
female flowers have a definite position, but which in exceptional
instances is altered.
=Change in the relative position of male and female flowers= may thus
occur in any monoecious plant. Cultivated maize, _Zea Mays_,
frequently exhibits alterations of this kind; under ordinary
circumstances, the male inflorescence is a compound spike, occupying the
extremity of the stem, while the female flowers are borne in simple
spikes at a lower level, but specimens may now and then be found where
the sexes are mixed in the same inflorescence; the upper branching
panicle usually containing male flowers only, under these circumstances,
bears female flowers also.[190] In like manner, but less frequently, the
female inflorescence occasionally produces male flowers as well.
Among the species of _Carex_ it is a common thing for the terminal spike
to consist of male flowers at the top, and female flowers at the base;
the converse of this, where the female flowers are at the summit of the
spike, is much more uncommon. An illustration of this occurrence is
given in the figure (fig. 100). Among the _Coniferæ_ numerous instances
have been recorded of the presence of male and female flowers on the
same spike, thus Mr. now Professor Alexander Dickson exhibited at the
Botanical Society of Edinburgh in July, 1860, some malformed cones of
_Abies excelsa_, in which the inferior part of the axis was covered with
stamens, whilst the terminal portion produced bracts and scales like an
ordinary female cone. The stamens of the lower division were serially
continuous with the bracts above. Some of the lower scales of the female
portion were in the axils of the uppermost stamens, which last were
somewhat modified, the anther cells being diminished, whilst the
scale-like crest had become more elongated and pointed, in fact, more or
less resembling the ordinary bracts.[191] Mohl, Schleiden, and A. Braun
have observed similar cones in _Pinus alba_, and Cramer figures and
describes androgynous cones in _Larix microcarpa_. C. A. Meyer ('Bull.
Phys. Math.,' t. x, 1850) also describes some catkins of _Alnus
fruticosa_ which bore male flowers at the top, and female flowers at the
base.
[Illustration: FIG. 100.--Spike of _Carex acuta_, with female flowers at
the summit.]
On the subject of this section the reader may consult A.
Braun,. 'Das Individ.,' 1853, p. 65. Caspary, 'De Abietin.
flor. fem. struct. morphol.' Schleiden. 'Principles,' English
edition, p. 299. Mohl, 'Verm. Schrift.,' p. 45. Meyen in
'Wiegm. Archiv.,' 1838, p. 155. Cramer, 'Bildungsabweich,' p.
4, tab. v, figs. 13-17. Parlatore, 'Ann. Sc. Nat.,' ser. iv,
vol. xvi, p. 215, tab. 13A. See also under the head of
Prolification, Substitutions, &c.
=Change from the monoecious to the dioecious condition.=--This is of
less frequent occurrence than might have been anticipated. In the
'Gardeners' Chronicle,' 1847, pp. 541 and 558, several instances are
noted of walnut trees bearing female flowers to the exclusion of males.
The mulberry tree has also been noticed to produce female blossoms only,
while in other plants male flowers only are developed.
It seems probable that the age of the plant may have something to do
with this production of flowers of one sex to the exclusion of the
other.
=Change from the dioecious to the monoecious condition.--Androgynism.=--
This is of far more common occurrence than the preceding.
[Illustration: FIG. 101.--Monoecious inflorescence of Hop.]
In the hop (_Humulus Lupulus_), when monoecious, the female catkins
are usually borne on the ends of the branches as shown in the cut (fig.
101), and a similar thing has been noticed in _Urtica dioica_ by Clos,
'Bull. Soc. Bot. France,' vol. 9, p. 7.
Baillon ('Etudes du groupe des Euphorbiacées,' p. 205) mentions the
following species of that order as having been seen by him with
monoecious inflorescence: _Schismatopera distichophylla_, _Mozinna
peltata_, _Hermesia castaneifolia_. Oliver mentions ('Hook. Icon.
Plant.,' t. 1044) that in _Leitneria floridana_ the upper scales of the
male catkin occasionally subtend an ovary.
It would seem that external conditions have some effect in determining
the formation of one sex, as in some species of _Carex_, while in the
case of _Salix repens_, Hampe[192] says that when grown partially or for
a time under water, those twigs which are thrust up above the surface
bear female flowers, while those twigs that blossom after the water is
dried up, produce male flowers only.
Carrière[193] says that a plant of _Stauntonia latifolia_ which for some
years produced stamens only, now produces flowers of both sexes; it was
dioecious, but is now monoecious. The same author alludes to a
similar occurrence in _Juniperus Virginiana_. The hops is also said to
vary in sexual characteristics from time to time.[194] In addition to
the genera, already named, in which this production of flowers of both
sexes has been observed may be mentioned _Taxus! Gunnera! Urtica!
Mercurialis! Restio! Cannabis! Salix! Humulus!_ as well as others in
which the change is less frequent.
Among cryptogams a similar change occurs. As an illustration may be
cited _Leucobryum giganteum_, as quoted from Müller in Henfrey's
'Botanical Gazette,' i, p. 100.
As to androgynous willows, in addition to the references given
under the head of Substitution of stamens for pistils, see
Schlechtendal, 'Flora Berol.,' ii. p. 259. Tausch, 'Bot.
Zeit.,' 1833, i. p. 229. Koch, 'Synops. Flor. Germ.,' 740.
Host, 'Flor. Aust,.' ii, p. 641 (_S. mirabilis_). See also
Hegelmaier, 'Württemberg Naturwissenshaft Jahreshefte,' 1866,
p. 30. Other references to less accessible works are given in
'Linnæa,' xiv, p. 372.
=Change from hermaphroditism to unisexuality.=--Many flowers ordinarily
hermaphrodite as to structure, become unisexual by the abortion or
suppression of their stamens, or of their carpels, as the case may be.
This phenomenon is lessened in interest since the demonstration of the
fact by Darwin and others, that many plants, structurally hermaphrodite,
require for the full and perfect performance of their functions the
cooperation of the stamens and pistils, belonging to different
individuals of the same species.
Some of the _Ranunculaceæ_ constantly exhibit a tendency towards the
dioecious condition, and the rarity with which perfect seeds of
_Ranunculus Ficaria_ are formed is to be attributed, in great measure,
to the deficiency of pollen in the anthers of these flowers. _Ranunculus
auricomus_ also is frequently sterile. Specimens of _Ranunculus
bulbosus_ may be met with in which every flower is furnished with
carpels, most of which have evidently been fertilised, although there
are no perfect stamens in the flowers.
Knight and other vegetable physiologists have been of opinion that a
high temperature favours the production of stamens, while a lower degree
of heat is considered more favorable to the production of pistils, and
in this way the occurrence of "blind" strawberries has been accounted
for. Mr. R. Thompson, writing on this subject, speaks of a plantation of
Hautbois strawberries which in one season were wholly sterile, and
accounts for the circumstance as follows: the plants were taken from the
bearing beds the year previous, and were planted in a rich well-manured
border, in which they started rapidly into too great luxuriance, the
growth being to leaves rather than to fruit. The following season these
same plants bore a most abundant crop, hence these plants were
accidentally prevented from perfecting their female organs.[195]
Mr. Darwin[196] cites from various sources the following details
relating to strawberries which it may be useful to insert in this place,
as throwing some light upon the production of unisexual flowers.
"Several English varieties, which in this country are free from any such
tendency, when cultivated in rich soils under the climate of North
America commonly produce plants with separate sexes. Thus, a whole acre
of Keen's seedlings in the United States has been observed to be almost
sterile in the absence of male flowers; but the more general rule is,
that the male plants over-run the females.... The most successful
cultivators in Ohio plant, for every seven rows of pistillate flowers,
one row of hermaphrodites, which afford pollen for both kinds; but the
hermaphrodites, owing to their expenditure in the production of pollen,
bear less fruit than the female plants."
_Stratiotes aloides_ has been said to produce its carpels with greater
abundance towards the northern limits of its geographical distribution,
and its stamens, on the other hand, are stated to be more frequently
developed in more southern districts.
_Honckenya peploides_ affords another illustration of the sexual
arrangements in the flower being altered as it would seem by climatal
conditions. Thus, in the United States, according to Professor Asa Gray,
the flowers are frequently hermaphrodite, while in this country they are
usually sub-dioecious.[197]
Treviranus[198] says that the flowers of _Hippuris_ and _Callitriche_
are apt to be hermaphrodite in summer, but female only at a later
period.
For further remarks on this subject, see sections relating to
suppression of stamens and pistils.
=Change from unisexuality to hermaphroditism.=--This occurrence depends
on one of two causes, either organs are developed (stamens or pistils as
the case may be), which are habitually absent in the particular flower;
or some of the stamens may be more or less completely converted into or
replaced by pistils, or _vice versâ_.
The first condition is the opposite of suppression; it is, as it were, a
restoration of symmetry, and might be included under the head of regular
peloria, inasmuch as certain organs which habitually undergo suppression
at a certain stage in their development, by exception, go on growing,
and produce a perfect, instead of an imperfect flower. In teratological
records it is not always stated clearly to which of the two above-named
causes the unusual hermaphroditism belongs, though it is generally easy
to ascertain this point. Very many, perhaps all, diclinous flowers may,
under certain conditions, become perfect, at least structurally. I have
myself seen hermaphrodite flowers in _Cucurbita_,[199] _Mercurialis_,
_Cannabis_, _Zea Mays_, and _Aucuba japonica_, as well as in many
_Restiaceæ_, notably _Cannamois virgata_ and _Lepyrodia hermaphrodita_.
_Spinacia oleracea_, _Rhodiola rosea_, _Cachrys taurica_, and _Empetrum
nigrum_ are also occasionally hermaphrodite.
Gubler[200] alludes to a similar occurrence in _Pistacia Lentiscus_,
wherein, however, he adds that there was a deficiency of pollen in the
flowers.
Schnizlein[201] observed hermaphrodite flowers in the beech, _Fagus
sylvatica_, the ovaries being smaller than usual, and the stamens
epigynous.
Baillon[202] enumerates the following _Euphorbiaceæ_ as having
exceptionally produced hermaphrodite flowers, _Crozophora tinctoria_,
_Suregada_ sp., _Phyllanthus longifolius_, _Breynia_ sp., _Philyra
brasiliensis_, _Ricinus communis_, _Conceveiba macrophylla_, _Cluytia
semperflorens_, _Wall_, non _Roxb_. _Mercurialis annua_ and
_Cleistanthus polystachyus_.
In some of these cases the hermaphroditism is due to the development of
anthers on the usually barren staminodes, though, in other cases, the
stamens would seem to be separate, independent formations, as they do
not occupy the same relative position that the ordinary stamens would do
if developed.[203]
[Illustration: FIG. 102.--Flower of _Fuchsia_ in which the calyx was
leafy, the petals normal (reflexed in the figure), the stamens partially
converted into ovaries, the ordinary inferior ovary being absent. See
Substitution.]
Robert Brown[204] observed stamens within the utricle of _Carex acuta_,
and Gay is stated by Moquin ('El. Ter. Veg.,' p. 343) to have observed
a similar occurrence in _Carex glauca_.
Paasch[205] observed a similar occurrence in _C. cæspitosa_, and
Schauer, in _C. paludosa_,[206] though in the latter instance the case
seems to have been one of transformation or substitution rather than one
of hermaphroditism.
The second cause of this pseudo-hermaphroditism is due either to the
more or less perfect mutation of male and female organs, or it may be to
the complete absence of one and its replacement by another, as when out
of many stamens, one or more are deficient, and their places occupied by
carpels. This happens very frequently in willows and poplars, and has
been seen in the beech.[207]
[Illustration: FIG. 103.--Hermaphrodite flower of _Carica Papaya_.]
In _Begonia frigida_[208] the anomaly is increased by the position of
the ovaries above, the perianth, a position due, not to any solution or
detachment of the latter from the former, but simply to the presence of
ovaries where, under ordinary circumstances, stamens only are formed,
as happened also in a garden variety of a _Fuchsia_, wherein, however,
the change was less perfect than in the _Begonia_, and in which, as the
flower is naturally hermaphrodite, the alteration is of the less
importance.
[Illustration FIG. 104.--Ovuliferous anthers--_Cucurbita_.]
In hermaphrodite flowers of _Carica Papaya_ (fig. 103) there is a single
row of five stamens instead of two rows of five each as in the normal
male flowers, the position of the second or inner row of stamens being
occupied by five carpels, which, however, are not adherent to the
corolla as the stamens are, thus, supposing the arrangement of parts in
the normal male flowers to be as follows:
---------------------------
s s s s s
---------------------------
| p p p p p
| st st st st st
| st st st st st
|
That of the hermaphrodite blossoms would be, in brief, as follows:
| 5 s
|------------
| 5 p
| 5 st
| 5 c
|
One of the most curious cases of this kind recorded is one mentioned by
Mr. Berkeley,[209] wherein a large white-seeded gourd presented a
majority of flowers in which the pollen was replaced by ovules. It would
seem probable from the appearances presented by the figure that these
ovules were, some of them, polliniferous, like those of the
_Passiflora_, &c., described at p. 185, but nothing is stated on the
subject.
See also section on Regular Peloria, Substitution, Pistillody of the
stamens, &c.
FOOTNOTES:
[190] See also Clos., 'Mem. Acad. Toulouse,' sixth ser., t. iii, pp.
294-305. Scott, 'Trans. Bot. Soc. Edinburgh,' t. viii, p. 60. Wigand,
'Flora,' 1856, p. 707.
[191] Professor Dickson concludes from the examination of these
structures that the male cone, consisting of simple stamens developed on
one common axis, must be regarded as a simple male flower, while the
axillary scales of the female cone are by him compared with the
flattened shoots of _Ruscus_.
[192] 'Linnæa,' xiv, 367.
[193] Rev. Hortic.,' January, 1867.
[194] See Royle, 'Man. Materia Medica,' ed. 1, p. 567.
[195] Thomson, 'Gardener's Assistant,' p. 577.
[196] 'Variation of Animals and Plants,' i, 353.
[197] Babington, 'Ann. Nat. Hist.,' vol. ix, 1852, p. 156.
[198] 'Phys. der Gewächse,' ii, p. 323.
[199] See also Schlechtendal, 'Linnæa,' viii, p. 623, and Lindley, 'Veg.
Kingd.,' p. 315.
[200] 'Bull. Soc. Bot. France,' vol. ix, p. 81.
[201] Cited in Henfrey, 'Bot. Gazette.' 3, p. 11.
[202] Baillon. 'Etudes du Groupe des Euphorbiacées,' p. 205, tab. xv,
fig. 19, tab. xix, fig. 31.
[203] See also Guillemin, 'Mém. Soc. Nat. Hist. Paris,' I, p. 16;
hermaphrodite flowers in _Euphorbia esula_.
[204] 'Prod. Flor. N. Holl.,' p. 242.
[205] 'Bot. Zeit.,' 1837, p. 335.
[206] 'Pflanz, Terat.,' von Moquin-Tandon, p. 208.
[207] Schnizlein, loc. cit.
[208] 'Bot. Mag.,' tab. 5160, fig. 4. See also 'Gard. Chron.,' 1860, pp.
146, 170; 1861, p. 1092.
[209] 'Gard. Chron.,' 1851, p. 499.
CHAPTER V.
ALTERATIONS IN THE DIRECTION OF ORGANS.
The deviations from the ordinary direction of organs partake for the
most part more of the nature of variations than of absolute malposition
or displacement. It must also be borne in mind how frequently the
direction of the leaves, or of the flower, varies according to the
stage of development which it has arrived at, to unequal or
disproportionate growth of some parts, or to the presence of some
impediment either accidental or resulting from the natural growth of the
plant. These and other causes tend to alter the direction of parts very
materially.
=Change in the direction of axile organs, roots, stems, &c.=--The roots
frequently exhibit good illustrations of the effect of the causes above
mentioned in altering the natural direction. The roots are put out of
their course by meeting with any obstacle in their way. Almost the only
exception to the rule in accordance with which roots descend under
natural circumstances, is that furnished by _Trapa natans_, the roots of
which in germination are directed upwards towards the surface of the
water. So in _Sechium edule_, the seed of which germinates while still
in the fruit, the roots are necessarily, owing to the inverted position
of the embryo, directed upwards in the first instance.
A downward direction of the stem or branches occurs in many weak-stemmed
plants growing upon rocks or walls, or in trees with very long slender
branches as in _Salix Babylonica_, and the condition may often be
produced artificially as in the weeping ash.
The opposite change occurs in what are termed fastigiate varieties,
where the branches, in place of assuming more or less of a horizontal
direction, become erect and nearly parallel with the main stem as in the
Lombardy poplar, which is supposed to be merely a form of the black
Italian poplar.
M. de Selys-Longchamps has described a similar occurrence in another
species of Poplar (_P. virginiana_ Desf.), and amongst a number of
seedling plants fastigiate varieties may frequently be found, which may
be perpetuated by cuttings or grafts, or sometimes even by seed; hence
the origin of fastigiate varieties of elms, oaks, thorns, chestnuts, and
other plants which may be met with in the nurseries.
Sometimes when the top of the main stem is destroyed by disease or
accident, one of the heretofore lateral shoots takes its place, and
continues the development of the tree in the original direction. It is
often an object with the gardener to restore the symmetry of an injured
tree so that its beauty may ultimately not be impaired.[210]
Climate appears sometimes to have some influence on the direction of
branches, thus Dr. Falconer, as quoted by Darwin,[211] relates that in
the hotter parts of India "the English Ribston-pippin apple, a Himalayan
oak, a Prunus and a Pyrus all assume a fastigiate or pyramidal habit,
and this fact is the more interesting as a Chinese tropical species of
_Pyrus_ naturally has this habit of growth. Nevertheless many of the
fastigiate varieties seen in gardens have originated in this country by
variation of seeds or buds."
M. Carrière has also recorded a curious circumstance with reference to
the fastigiate variety of the false acacia _Robinia pseudacacia_; he
states that if a cutting or a graft be taken from the upper portion of
the tree, the fastigiate habit will be reproduced, and the branches will
be furrowed and covered with short prickles; but if the plant be
multiplied by detaching portions of the root-stock, then instead of
getting a pyramidal tree with erect branches, a spreading bushy shrub is
produced, with more or less horizontal, cylindrical branches, destitute
of prickles.[212]
=Eversion of the axis.=--In the case of the fig, the peculiar
inflorescence is usually explained on the supposition that the
termination of the axis becomes concave, during growth, bearing the true
flowers in the hollow thus formed. The cavity in this case would
probably be due not to any real process of excavation, but to a
disproportionate growth of the outer as contrasted with the central
parts of the fig. Some species of _Sempervivum_ have a similar mode of
growth, so that ultimately a kind of tube is formed, lined by the
leaves, the central and innermost being the youngest. The hip of the
Rose may be explained in a similar manner by the greater proportionate
growth of the outer as contrasted with the central portions of the apex
of the flower-stalk. In cases of median prolification, already referred
to, the process is reversed, the central portions then elongate into a
shoot and no cavity is formed. A fig observed by Zuccarini (figs. 105,
106) appears to have been formed in a similar manner, the flower-bearing
summit of the stalk not being contracted as usual, the flowers projected
beyond the orifice of the fig. If this view be correct the case would be
one rather of lengthening of the axis than of absolute eversion since it
was never inverted.
[Illustration: FIG. 105.--Fig showing prolonged inflorescence and
projecting flowers.]
[Illustration: FIG. 106.--Section of the same.]
=Altered direction of leaves.=--The leaves partake more or less of the
altered direction of the axis, as in fastigiate elms, but this is not
universally the case, for though the stem is bent downwards the leaves
may be placed in the opposite direction; thus in some specimens of
_Galium Aparine_ growing on the side of a cliff from which there had
been a fall of chalk, the stems, owing apparently to the landslip, were
pendent, but the leaves were abruptly bent upwards.
One of the most singular instances of an inverted direction of the
leaves is that presented by a turnip (fig. 107) presented to the Museum
of King's College, London, by the late Professor Edward Forbes. The
turnip is hollow in the interior and the majority of the leaves
springing from its apex instead of ascending into the light and air
become bent downwards so as to occupy the cavity, and in such a manner
as to bring to mind the position of an inverted embryo in a seed.
[Illustration: FIG. 107.--Hollow turnip, showing some of the leaves
inverted and occupying the cavity.]
=Altered direction of the flower and its parts.=--The changes which take
place in the relative position either of the flower as a whole or of its
several parts during growth are well known, as also are the relations
which some of these movements bear to the process of fertilisation, so
that but little space need here be given to the subject beyond what is
necessary to point out the frequent changes of direction which
necessarily accompany various deviations from the ordinary form and
arrangement of parts.
In cases where an habitually irregular flower becomes regular, the
change in form is frequently associated with an alteration in direction
both of the flower as a whole and, to a greater or less extent, of its
individual members, for instance of _Gloxinia_, the normal flowers of
which are irregular and pendent, there is now in common cultivation a
peloriate race in which the flowers are regular in form and erect in
position.
[Illustration: FIG. 108.--Flower of normal _Gloxinia_.]
[Illustration: FIG. 109.--Flower of _Gloxinia_, erect and regular
(regular _Peloria_).]
Fig. 108 shows the usual irregular form of _Gloxinia_, with which may be
contrasted figs. 109, 110 and 111.
Fig. 109 shows the regular erect form; fig. 110 the calyx of the same
flower; while in fig. 111 are shown the stamens and style of the two
plants respectively. In the upper figure the style of the peloriate
variety is shown as nearly straight, and the stamens undergo a
corresponding change. No doubt the relative fertility and capacity for
impregnation of the two varieties is affected in proportion to the
change of form. The Gloxinia affords an instance of regular congenital
peloria in which the regularity of form and the erect direction are due
to an arrest, not of growth, but of development, in consequence of which
the changes that ordinarily ensue during the progress of the flower from
its juvenile to its fully formed condition do not take place.
[Illustration: FIG. 110.--Calyx of erect _Gloxinia_.]
[Illustration: FIG. 111.--Stamens of erect regular, and of pendent
irregular-flowered _Gloxinia_.]
A similar alteration accompanies this form of peloria in other flowers
(see Peloria). A change in direction may result also from other
circumstances than those just alluded to. Abortion or suppression of
organs will induce such an alteration; thus in a flower of _Pelargonium_
now before me three of the five carpels, from some cause or other, are
abortive and much smaller than usual, and the style and the beak-like
torus are bent downwards towards the stunted carpels instead of being,
as they usually are, straight.
Amongst orchids, where the pedicel of the flower or the ovary is
normally twisted, so that the labellum occupies the anterior or inferior
part of the flower, it frequently happens, in cases of peloria and other
changes, that the primitive position is retained, the twist does not
take place, and so with other resupinate flowers. In Azaleas a curious
deflexion of the parts of the flower may occasionally be met with. Fig.
112 shows an instance of this in which the corolla, the stamens and the
style were abruptly bent downwards: as young flowers of this singular
variety have not been examined it is difficult to form an opinion as to
the cause of this variation. In one plant the change occurred in
connection with the suppression of all the flowers but one in the
cluster, or rather the place of the flowers was occupied by an equal
number of leafy shoots.
[Illustration: FIG. 112.--Flower of _Azalea_, showing the corolla
reflected.]
Moquin[213] mentions a flower of _Rosa alpina_ in which two of the
petals were erect, while the remaining ones were much larger and
expanded horizontally. The same author quotes from M. Desmoulins the
case of a species of _Orobanche_, in which a disjunction of the petals
constituting the upper lip took place, thus liberating the style and
allowing it to assume a vertical direction.
[Illustration: FIG. 113.--Flower of _Cuphea miniata_ enlarged, showing
protrusion and hypertrophy of an erect placenta, after Morren.]
[Illustration: FIG. 114.--Placenta from the flower shown at fig. 113;
the ovary is membranous and torn, the placenta, erect and ovuliferous,
after Morren.]
M. Carrière[214] has described an instance wherein two apples were
joined together, a larger and a smaller one; the former was directed
away from the centre of the tree as usual, while the smaller one was
pointed in exactly the opposite direction. The larger fruit had the
customary parchment-like carpels, the smaller was destitute of them.
Sometimes the direction assumed by one flower as an abnormal occurrence
is the same as that which is proper to an allied species or genus under
natural circumstances; thus flowers of the vine (_Vitis_) have been met
with in which the petals were spreading like a star (_fleurs
avalidouires_), as in the genus _Cissus_.[215]
Morren describes a curious condition in some flowers of _Cuphea
miniata_, in which the placenta protruded through an orifice in the
ovary, and losing the horizontal direction became erect (figs. 113,
114). A similar occurrence happened in _Lobelia erinus_. To this
condition the Belgian savant gave the name of gymnaxony.[216]
FOOTNOTES:
[210] The following details as to the method pursued by Mr. McNab, of
the Edinburgh Botanic Garden, may not be uninteresting in this place.
They are from the pen of Mr. Anderson, and originally appeared in the
'Gardeners' Chronicle.'
"The mode of inducing leaders to proceed from laterals is a matter of
comparatively little concern among the generality of deciduous trees,
for they are often provided with subsidiary branches around the leader,
at an angle of elevation scarcely less perpendicular, but the laterals
of all Conifers stand, as nearly as possible, at right angles. Imagine
the consternation of most people when the leader of, say, _Picea
nobilis_, _P. Nordmanniana_, or _P. Lowii_ is destroyed."
In a specimen of the latter plant the leader had been mischievously
destroyed, to remedy which Mr. McNab adopted means which Mr. Anderson
goes on to describe. "Looking from the leader downward to the first tier
of laterals, there appeared to have been a number of adventitious
leaf-buds created, owing to the coronal bud being destroyed. These were
allowed to plump up unmolested until the return of spring, when every
one was scarified or rubbed off but the one nearest the extremity. To
assist its development and restrain the action of the numerous laterals,
every one was cut back in autumn, and this restraint upon the sap acted
so favorably upon the incipient leader as to give it the strength and
stamina of the original leader, so that nothing detrimental was evident
twelve months after the accident had happened, and only a practical eye
could detect that there had been any mishap at all. This beautifully
simple process saved the baby tree.
"Another example of retrieving lost leaders may be quoted as
illustrative of many in similar circumstances. _Pícea Webbiana_ had its
leader completely destroyed down to the first tier of laterals. There
was no such provision left for inducing leaf-buds as was the case with
_P. Lowii_ above referred to. Resort must, therefore, be had to one of
the best favoured laterals, but how is it to be coaxed from the
horizontal position of a lateral to the perpendicular position of a
leader? The uninitiated in these matters, and, in fact, practical
gardeners generally, would at once reply, by supporting to a stake with
the all-powerful Cuba or bast-matting. But no. A far simpler method than
that, namely, by fore-shortening all the laterals of the upper tier but
the one selected for a leader. Nature becomes the handmaid of art here;
for without the slightest prop the lateral gradually raises itself
erect, and takes the place of the lost leader. All that the operator
requires to attend to is the amputation of the laterals until this
adventitious fellow has gained a supremacy. Singular provision in nature
this, which, thanks to the undivided attention of a careful observer,
has been fully appreciated and utilized."
[211] 'Variation of Animals and Plants,' ii, p. 277.
[212] Quoted in 'Gard. Chron.,' 1867, p. 654.
[213] Loc. cit., p. 315.
[214] 'Rev. Hortic.,' 1868, p. 110.
[215] Planchon and Marès, 'Ann. Sc. Nat.,' 5 ser., tom. vi, 1866, p.
228, tab. xii.
[216] 'Bull. Acad. Belg.,' xviii, part ii, p. 293.
BOOK II.
DEVIATIONS FROM THE ORDINARY FORM OF ORGANS.
In a morphological point of view the form of the various parts or organs
of plants and the changes to which they are subjected during their
development are only second in importance to the diversities of
arrangement and, indeed, in some cases, do not in any degree hold a
second place.
Taken together, the arrangement, form, and number of the several parts
of the flower, make up what has been termed the symmetry of the
flower.[217] Referring to the assumed standard of comparison, see p. 4,
it will be seen that in the typically regular flower all the various
organs are supposed to be regular in their dimensions and form. At one
time it was even supposed that all flowers, no matter how irregular
they subsequently became, began by being strictly symmetrical or
regular, and that subsequent alterations were produced by inequality of
growth or development. The researches of organogenists have, however,
dispelled this idea of unvarying primordial regularity, by showing that
in many cases flowers are irregular from the very first, that some begin
by being irregular, and subsequently become regular, and even in some
cases resume their original condition during the course of their
development.[218] Under these circumstances an artificial standard of
comparison becomes almost an absolute necessity for the time being.
Changes of form very generally, but not always, are accompanied with a
change in regularity: thus a flower habitually bi-lateral may assume the
characters of radiating symmetry and _vice versâ_. Increase or decrease
of size very frequently also are co-existent with an alteration in the
usual form.
In the case of the arrangement of organs it is often difficult or
impossible, in the present state of our knowledge, to determine whether
a given arrangement is congenital or acquired subsequently to the first
development, whether for instance an isolation of parts be due to
primordial separation or to a subsequent disunion of originally combined
organs, see p. 58. With reference to the changes in the form of organs,
however, it is in general more easy to ascertain the proximate cause of
the appearance, and thus teratological changes of form may be grouped
according as they are due to, 1, arrest of development; 2, undue or
excessive development; 3, perverted development; and 4, irregular
development; hence the use of the following terms--Stasimorphy,
Pleiomorphy, Metamorphy, and Heteromorphy--to include teratological
changes really or apparently due to one or other of the causes above
mentioned. The classification here adopted is of course to a
considerable extent an arbitrary one and subject to correction or
modification, as the knowledge of the development of the flowers in the
various genera of plants advances.
FOOTNOTES:
[217] The word symmetry has been used in very different senses by
different botanists, sometimes as synonymous with "regularity," at other
times to express the assumed typical form of a flower. Payer understands
it to be that arrangement of parts which permits of the whole flower
being divided vertically into two symmetrical halves (bi-lateral
symmetry). Others, again, have applied the term symmetry to the number
of the parts of the flower, reserving the terms "regularity" or
"irregularity" for the form. It is here used in a general sense to
express the plan of the flower, and thus includes the arrangement, form,
and number of its component elements.
[218] See Baillon, 'Adansonia,' v, 176.
PART I.
STASIMORPHY.[219]
Deviations from the ordinary form of organs arising from stasis or
arrest of development are included under this heading.
There are many cases in which the forms proper to a juvenile condition
of the plant are retained for a much longer period than ordinary, or
even throughout the life of the individual growth goes on, but
"development" is checked. Such conditions may even be propagated by seed
or bud. It is a very general thing for botanists to consider these cases
as reversions to a simpler, primitive type, and this may be so; but on
the other hand, they may be degenerations from a complex type, or they
may have no direct relation to any antecedent condition. Stasimorphic
changes affecting principally the relative size of organs--such, for
instance, as the non-development of internodes, or the atrophy or
suppression of parts will be found mentioned in the sections relating to
those subjects. In the present part those alterations which affect the
form of organs principally are treated of.
FOOTNOTES:
[219] [Greek: Stasis-morphôsis].
CHAPTER I.
PERSISTENCE OF JUVENILE FORMS.
The retention in adult life of a form characteristic of an early stage
of development, and therefore usually transient, may be manifested in
any of the organs of the plant. As these cases are for the most part
treated under separate headings, it is here only necessary to allude to
a few, which it is difficult to allocate satisfactorily, while the
reader may be referred for other instances of like nature to the
sections on Peloria, Atrophy, Suppression, Dimorphy, Substitutions, &c.
[Illustration: FIG. 115.--_Juniperus sinensis_. Two forms of leaves on
branches of the same shrub.]
=Stasimorphy in the leaves of conifers.=--In many conifers the leaves
produced in the young state of the plant are different, both in
arrangement and form, from those subsequently developed (see pp. 89,
90). But it occasionally happens that the plant continues to form
throughout its existence leaves such as are usually produced only in a
young state; thus M. Gubler ('Bull. Soc. Bot., Fr.,' vol. viii, 1861, p.
527) describes a plant of _Pinus pinea_ in which the primordial, usually
transitory, foliage was permanent, leaves of the ordinary shape not
being developed at all. It more often happens that some only of the
leaves retain their young form while others assume other shapes, see
fig. 115. This happens frequently in the larch and constantly in the
Chinese juniper when it has arrived at a considerable age. In _Cupressus
funebris_ two forms of leaves may often be found on the same plant, the
one representing the juvenile state, the other the more developed
condition. What is very singular, is that a cutting taken from the
branch with leaves of the young form grows up into a shrub bearing
leaves of no other shape, so that an ordinary observer unacquainted with
the history of the plant would imagine that he had to deal with two
distinct species. This fact is the more interesting when compared with
the alternation of generations which takes place among the lower
animals.
The regular development of all the parts of the flower in a plant
habitually producing irregular flowers is referred to under the head of
Peloria, but it still remains to consider those examples in which some
only of the parts of the flower are affected in this manner.[220] Most
of these cases are elsewhere referred to in this volume under the
particular form of malformation assumed; but the following case may here
be noticed as not coming under any of the previous heads. It is an
instance recorded by Professor Babington ('Phytologist,' August, 1853),
and in which the pod of _Medicago maculata_, which is usually rolled up
like a snail shell and provided with spines, was sickle-shaped and
unarmed.
FOOTNOTES:
[220] See a paper of Professor C. Morren's on "Floral Stesomy" in 'Bull.
Acad. Belg.,' t. xix, part ii, p. 519.
CHAPTER II.
REGULAR PELORIA.
[Illustration: FIG. 116.--Regular Peloria, _Delphinium_.]
[Illustration: FIG. 117.--Sepal, petal, &c., of regular-flowered
_Delphinium_.]
[Illustration: FIG. 118--Regular peloria, _Viola_.]
[Illustration: FIG. 119--Double Violet, flower regular, petals
multiplied, stamens and pistils petaloid.]
When an habitually irregular flower becomes regular, it does so in one
of two ways; either by the non-development of the irregular portions, or
by the formation of irregular parts in increased number, so that the
symmetry of the flower is rendered perfect, as in the original peloria
of Linnæus, and which may be called irregular peloria, while the former
case may be called regular peloria. This latter appearance is therefore
congenital, and due to an arrest of development.[221] As the true nature
of these cases has not been in all cases recognised (even Moquin places
them under the head of deformities--they being less entitled to rank in
that class than are the usual flowers), it may be well to cite a few
instances taken from various families. In _Delphinium peregrinum_ I have
met with perfectly regular flowers having five sepals and five oblong
stalked petals, and a similar occurrence has been noted in other
species of this genus. Baillon,[222] in referring to these flowers,
points out the resemblance that they bear to the double varieties of
_Nigella_. In the stellate columbines (_Aquilegia_) of gardens the
tubular petals are replaced by flat ones often in increased numbers. In
violets both forms of peloria occur, that in which there is an unusual
number of spurs, and that in which there are no spurs (var. anectaria).
In the more perfect forms of regular peloria occurring in the last-named
genus the following changes may be noticed: 1, an alteration in the
direction of the flower so that it remains in an erect position, and is
not bent downwards as usual; 2, equality of proportion in the sepals and
petals; 3, absence of spurs, as also of hairs on the lateral petals; 4,
equal stamens whose anthers are sometimes entirely destitute of the
prolonged crest which forms so prominent a feature under ordinary
circumstances; 5, erect, not curved styles, and the stigmas not
prolonged into a beak, but having a more or less capitate form; ovary
with three or five cells, ovules normal.
These are cases where the change in question is most strongly marked,
the bi-lateral is completely replaced by the radiating symmetry. The
absence of the usual nectary, and of hairs on the side petals, the
alterations in the form of the style, etc., all show how much the
process of fertilisation must be altered from that which occurs under
ordinary circumstances. In some of the double violets now cultivated in
gardens, a similar regularity of proportion in the parts of the flower
may be seen combined with the substitution of petals for stamens and
pistils, and with the development of an increased number of petal-like
organs.[223] Between these cases and the ordinary spurred forms as well
as those with an increased number of spurs, many intermediate forms may
be met with. That such regularity should occur in this family is not to
be wondered at seeing that there is a whole subdivision of the order
(_Alsodeiæ_) in which regular flowers are the rule.
In cultivated Pelargoniums the central flower of the umbel or "truss"
frequently retains its regularity of proportion, so as closely to
approximate to the normal condition in the allied genus _Geranium_; this
resemblance is rendered greater by the fact that, under such
circumstances, the patches of darker colour characteristic of the
ordinary flower are completely wanting; the flower is as uniform in
colour as in shape. Even the nectary which is adherent to the upper
surface of the pedicel in the normal flower disappears--sometimes
completely, at other tunes partially. The direction of the stamens and
style, and even that of the whole flower, becomes altered from the
inclined to the vertical position. In addition to these changes, which
are those most commonly met with, the number of the parts of the flower
is sometimes augmented, and a tendency to pass from the verticillate to
the spiral arrangement manifested. Schlechtendal mentions some flowers
of _Tropæolum majus_ in which the flowers were perfectly regular and
devoid of spurs[224], while in the double varieties, now commonly grown
in greenhouses, the condition of parts is precisely the same as in the
double violet before alluded to. Among the _Papilionaceæ_ the Laburnum
and others have been noticed to produce occasionally a perfectly regular
flower in the centre, or at the extremity of the inflorescence, though
the peloria in this flower is usually irregular. In the Gentianaceous
genus _Halenia_, _H. heterantha_ is remarkable for the absence of spurs.
Amongst _Gesneraceæ_, _Bignoniaceæ_, _Scrophulariaceæ_, and other
families of like structure, regular peloria is not uncommon. Fig. 120
represents a case of this kind in _Eccremocarpus scaber_, conjoined, as
is frequently the case, with dialysis or separation of the petals.[225]
Many of the cultivated Gloxinias also show erect, regular, five
stamened flowers, but these are probably cases of irregular peloria.
[Illustration: FIG. 120.--Regular peloria, _Eccremocarpus scaber_.]
A solitary flower of _Pedicularis sylvatica_ was found by the Marquis of
Stafford near Dunrobin Castle in Sutherlandshire, in which the usual
ringent form of the corolla was replaced by the form called
salver-shaped. There were six stamens, four long and two short. Sir W.
Hooker and Mr. Borrer are stated to have found a similar flower in the
same locality in 1809.[226]
The passage of ligulate to tubular corollas among _Compositæ_ is not of
such common occurrence as is the converse change. I owe to Mr. Berkeley
the communication of a capitulum of a species of _Bidens_, in which
there was a transition from the form of ligulate corollas to those that
were deeply divided into three, four, or five oblong lobes. These then
were instances of regular peloria.
[Illustration: FIG. 121.--Flower of _Cattleya marginata_. Lip replaced
by a flat petal.]
In _Orchidaceæ_ a similar change is not by any means infrequent; in a
few, indeed, a regular flower is the normal character, as in
_Dendrobium normale_, _Oncidium heteranthum_, _Thelymitra_, etc. Fig.
121, reduced from a cut in the 'Gardeners' Chronicle,' 1854, p. 804,
represents an instance of this kind in _Cattleya marginata_.
From the same journal the following account of a case of peloria in
_Phalænopsis Schilleriana_ is also cited as a good illustration of this
peculiar change. The terminal flower differed entirely from all the
others; instead of the peculiar labellum there were three petals all
exactly alike, and three sepals also exactly alike; the petals resembled
those of the other flowers of the spike, and the upper sepal also; but
the two lower sepals had no spots, and were not reflexed as in the
ordinary way: thus, these six parts of the flower were all in one plane,
and being close together at their edges, made almost a full round
flower; the column and pollen-glands were unaffected. Professor
Reichenbach also exhibited at the Amsterdam Botanical Congress, of 1865,
a flower of _Selenipedium caudatum_ with a flat lip.
M. Gris[227] has placed on record some interesting cases of peloria of
this kind in _Zingiber zerumbet_; in the more complete forms the
androecium or staminal series was composed of six distinct pieces, the
three inner of which were fertile, while in the ordinary flower the
androecium is composed of two pieces, "a lip" and a fertile stamen.
"Is it not a matter of regret," says M. Gris, "to be obliged to call the
latter the normal flower?"
Under this head may likewise be mentioned those cases in which the
normal, or at least the typical symmetry of the flower is restored by
the formation of parts usually suppressed; thus Moquin cites an abnormal
flower of _Atriplex[228] hortensis_ described by M. Fenzl as having a
true calyx within the two bracts that usually alone encircle the
stamens. Adanson, also cited by Moquin, found a specimen of _Bocconia_
with a corolla. _Arum maculatum_ has likewise been met with provided
with a genuine perianth as in _Acorus_ and other Orontiads. The unusual
development of the sexual organs in diclinous flowers has been alluded
to under the head of heterogamy, and other cases where the symmetry of
the flower is rendered regular, by the development of parts ordinarily
suppressed, will be found in the chapters relating to deviations from
the usual number of organs.
This change, or rather this persistence of a form that is usually
transient, is generally accompanied by some other alterations. Change of
direction, as has been already mentioned, is one of the most common of
these; separation of the petals (_Antirrhinum_, _Verbascum_, &c.), and
even their appearance in leaf-like guise, are not infrequent
(_Delphinium_, _Antirrhinum_, _Verbascum_, &c.) At other times
multiplication or increased number of the whorls of petals takes place,
often, but not always, at the expense of the sexual organs of the
flower. Perhaps even more frequent is the increased number of parts in
the same whorl in cases of regular peloria; thus, in the Pelargoniums
before alluded to, the parts of the flower are frequently regulated by
the number six instead of five.
This form of peloria is most generally met with in flowers that are
placed at the end or in the centre of the inflorescence, or in such
flowers as occur singly at the end of the flower-stalk, as in
_Tropæolum_, _Viola_, &c. It would hence seem as if the freedom from
pressure or restriction on one side allowed the flower to develop
equally in all directions, and thus to produce regularity of form.
It is obvious, from what has been before said, that the process of
fertilisation is in many cases interfered with and altered by the change
in the conformation or the flower.
From overlooking the occasional existence of this form of peloria, new
genera have sometimes been formed on insufficient grounds. The genus
_Aceranthus_, for instance, consists of species of _Epimedium_ in which
the customary spurs are not formed.[229]
The occurrence both of regular and irregular peloria on the same plant
has frequently been observed in _Linaria_. It has also been remarked
that the seedlings raised from these forms are not always constant;
thus, the late Mr. Crocker, formerly foreman in the Royal Gardens, Kew,
informed me that he fertilised some flowers of a drooping Gloxinia with
their own pollen, and that when the seedlings blossomed a large number
of them produced the erect regular flowers.
From what has been already said it will be seen that regular peloria is
closely allied to what Morren called epanody, or a return to the normal
condition. The reversion of a monstrous form to the normal one, as, for
instance, when the fern-leaved beech reverts to the normal type, was
called by the same author epistrophy.[230]
The following are the genera in which regular peloria has been most
often observed. It must, however, be remarked that in some of the
flowers recorded as peloric there is no indication as to which form of
peloria the case should be referred to. For other illustrations refer to
chapters on Heterogamy, Number, Irregular Peloria, &c.
*Delphinium peregrinum!
*Nigella damascena!
*Aquilegia vulgaris!
*Viola odorata!
hirta.
Epimedium, sp.
*Pelargonium zonale!
* inquinans!
Tropæolum majus!
*Wistaria sinensis.
Lupinus.
*Cytisus Laburnum!
Trifolium repens!
*Compositæ, gen. pl.!
Lonicera Periclymenum!
Streptocarpus Rexii.
*Digitalis purpurea.
*Scrophularia aquatica.
*Pentstemon.
*Linaria vulgaris!
*Antirrhinum majus!
Verbascum nigrum!
Columnea Schiedeana.
Halenia heterantha.
Galeobdolon luteum.
Prunella vulgaris!
Salvia, sp.!
Teucrium campanulatum.
Betonica alopecuros.
Eccremocarpus scaber.
Pedicularis sylvatica.
Zingiber Zerumbet.
Phalænopsis amabilis!
Phalænopsis Schilleriana.
Habenaria.
*Orchis morio.
mascula.
*Dendrobium, sp.
Atriplex, sp.
Cattleya Mossiæ!
marginata.
Calanthe vestita!
Oncidium, sp.!
Selenipedium caudatum.
Arum maculatum.
In addition to the references already given, further information on this
subject may be gained from consulting the following publications. See
also Irregular Peloria.
Giraud, 'Bot. Soc. Edinb.,' Dec. 12, 1839, _Antirrhinum_.
Dareste, 'Ann. Sc. Nat.,' ser. 2, 1842, xviii, p. 220,
_Delphinium_. C. Morren, 'Fuchsia,' p. 90, _Calceolaria_,
'Bull. Acad. Belg.,' xx, part ii, p. 57; and E. Morren, 'Bull.
Acad. Belg.,' 2nd ser., xix. p. 224, _Gloxinia_. Richard, 'Mém.
Soc. d'hist. nat.,' ii, p. 212, tab. 3. Lindley, 'Journ. Linn.
Soc.,' iii, p. 9, _Dendrobium_. Michalet, 'Bull. Soc, Bot.
France,' vii, p. 625, _Betonica_. Gubler, 'Bull. Soc. Bot.
Fr.,' ix, 81, 'Des anomalies aberrantes et regularisantes.'
Reichenbach fil. 'De pollinis orchid. genesi ac structura,'
1852, _Oncidium_. Clos, 'Mém. Acad. Toulouse,' vi, 1862,
_Salvia_. Caspary, 'Verhandl. Phys. OEkon. Gesell.
Königsberg,' 1860, i, 59, _Columnea_. Bureau, 'Bull. Soc. Bot.
Fr.,' 1861, vol. viii, p. 710, _Streptocarpus_. Darwin,
'Variation of Animals and Plants,' ii, pp. 59 and 396. Godron,
'Ex. Bull. Bot. Soc. Fr.,' xiv, p. 165, 'Rev. Bibl.,'
_Wistaria_. Marchand, 'Adansonia,' iv, p. 172, _Lonicera_.
Baillon, 'Adansonia,' v, p. 177, 'Sur la regularité transitoire
de quelques fleurs irreg.,' shows that during the development
of some flowers which begin and end by being irregular, there
is an intermediate state when all the parts are regular. Helye,
'Revue Horticole,' Sept., 1868, p. 327. In this last paper,
published as this sheet is going through the press, the author
states that he has raised from seed three generations of plants
of _Antirrhinum_ with regular spur-less flowers. The original
wild plant was only partially peloric, but all the flowers
produced on its descendants were regular.
FOOTNOTES:
[221] "On the existence of two forms of Peloria," by M. T. Masters.
'Nat. Hist. Review,' April, 1863.
[222] Baillon, 'Adansonia,' iv. p. 149.
[223] Similar cases are figured in 'Hort. Eystettens. Ic. Pl. Vern.'
fol. 4, f. 1, 2. _Viola martia_ multiplici flore.
[224] 'Linnæa,' 1837, p. 128.
[225] M. Bureau, 'Bull. Soc. Bot. Fr.,' ix, p. 91, describes two genera
of _Bignoniaceæ_ in which the flowers are _normally_ regular and six
parted.
[226] See 'Trans. Linn. Soc.,' vol. x. p. 227.
[227] 'Ann. Sc. Nat.,' ser. 4, 1859. tom. xi, p. 264, tab. 3.
[228] 'El. Ter. Veg.,' p. 342.
[229] Marchand, 'Adansonia,' vol. iv, p. 127.
[230] 'Bull. Acad. Belg.,' xvii. p. 17. "Fuchsia," p. 169.
PART II.
PLEIOMORPHY.[231]
Most irregular flowers owe their irregularity to an unequal development
of some of their organs as compared with that of others. When such
flowers become exceptionally regular they do so either because
development does not keep pace with growth, and a regular flower is thus
the result of an arrest of the former process (regular peloria), or
because the comparatively excessive development, which usually occurs in
a few parts is, in exceptional cases manifested by all, hence the flower
becomes regular from the increase in number of its irregular elements.
These latter cases, then, are due to an excess of development, hence the
application of the term pleiomorphy. It must be understood that mere
increase in the number of the organs of a flower is not included under
this head, but under that of deviations from the ordinary number of
parts.
FOOTNOTES:
[231] [Greek: Pleios-morphôsis].
CHAPTER I.
IRREGULAR PELORIA.
The term peloria was originally given by Linné to a malformation of
_Linaria vulgaris_, with five spurs and five stamens, which was first
found in 1742 near Upsal. This was considered so marvellous a
circumstance that the term peloria, from the Greek [Greek: pelôr], a
prodigy, was applied to it.[232] After a time other irregular flowers
were found in like condition, and so the term peloria became applied to
all cases wherein, on a plant habitually producing irregular flowers,
regular ones were formed. The fact that this regularity might arise from
two totally different causes was overlooked, or at least not fully
recognised, even by Moquin-Tandon himself. Where a flower retains
throughout life the same relative size in its parts that it had when
those parts first originated the result is, of course, a regular flower,
as happens in violets and other plants. This kind of peloria may for
distinction sake be called regular or congenital peloria (see chapter on
that subject); but where a flower becomes regular by the increase in
number of its irregular portions, as in the _Linaria_ already alluded
to, where not only one petal is spurred, but all five of them are
furnished with such appendages, and which are the result of an irregular
development of those organs, the peloria is evidently not congenital,
but occurs at a more or less advanced stage of development. To this
latter form of peloria it is proposed to give the distinctive epithet of
irregular.
Peloria is either complete or incomplete; it is complete when the flower
appears perfectly symmetrical, it is incomplete when only a portion of
the flower is thus rendered regular. It is very common, for instance, to
find violets or Linarias with two or three spurs, and these intermediate
stages are very interesting, as they serve to show in what way the
irregularity is brought about. In _Antirrhinum_, _Linaria_, &c.,
intermediate forms show very clearly that it is to the repetition of the
form usually assumed by the petals of the lower lip that the condition
is due. This is also obvious in peloric flowers of the _Calceolaria_.
The perfect peloria of this flower is in general erect, with five
regular sepals, a regular corolla contracted at the base and at the
apex, but distended in the centre so as to resemble a lady's sleeve,
tight at the shoulder and wrist, and puffed in the centre!
[Illustration: FIG. 122.--Peloric flower of _Calceolaria_.]
Morren[233] describes a form intermediate between the ordinary
slipper-shaped corolla and the perfect peloria just described, and which
he calls sigmoid peloria. This flower is intermediate in direction
between the erect peloria and the ordinary reflected flower. The tube is
curved like a swan's neck and is dilated in front into two hollow
bosses, such as we see in the lower lip of an ordinary flower; beyond
these it is contracted and is prolonged into a slender beak terminating
in two hollow teeth, between which is the narrow orifice of the
corolla. The colour at the base of the tube inside is as in the perfect
peloria; while round the summit of the tube, in both cases, the
intensity of colour is greatest on the outside. Now, in a normal flower
the deepest colour is within just opposite the orifice of the corolla;
this deep colour is also seen outside of the central and most elevated
portions of the lower lip. In the peloria the deep colour at the base of
the tube represents that which is near the orifice under ordinary
circumstances, while the outer patch of colour at the apex corresponds
to that formed on the upper surface of the lower lip. On the other hand,
in peloric flowers of _Cytisus Laburnum_, _Clitoria Ternatea_,
_Trifolium repens_, and other Papilionaceæ, it is the "standard," the
form of which is repeated. In the case of peloric aconites[234] the
lateral and sometimes the inferior coloured sepals assume the hooded
form usually peculiar to the upper sepal only, the number of the petals
or nectaries being correspondingly increased. Balsams become peloric by
the augmentation in the number of spurs.[235] So when orchids are
affected with irregular peloria it is the form of the labellum that is
repeated, the accessory lips being sometimes the representatives of
stamens, which are usually suppressed in these flowers,[236] but at
other times the appearance is due simply to the fact that all three
petals assume the form usually confined to the lip, the staminal column
being unaffected, except that its direction and relative position with
reference to the other parts of the flower is different from ordinary.
This was the case in some flowers of _Phalænopsis equestris_ sent to me
by Mr. Wentworth Buller. Fig. 123 represents a flower of _Aristolochia
caudata_ with two lips, for which I am indebted to Mr. W. H. Baxter.
From these cases it is evident that the flowers in question become
regular by the repetition of the irregular parts.
[Illustration: FIG. 123.--Two-lipped flower of _Aristolochia caudata_.]
It is probable that peloria may occur in any habitually irregular
flower, and that, if more attention were directed to the subject,
illustrations might be obtained from a larger number of natural families
than can be done at present. It is, however, necessary to exercise
discrimination, and not to attribute to peloria all the cases that at
first sight appear to be so referable. Thus, Professor Dickson exhibited
at the Botanical Society of Edinburgh, December 13th, 1860, four
abnormal flowers of the common Indian cress (_Tropæolum majus_), each
presenting a supernumerary spur. On these he remarked that "in
_Tropæolum_ the posterior part of the receptacle between the insertion
of the petals and that of the stamens is dilated so as to form the spur
which is so characteristic in the genus. The position of the spur in a
line with the posterior sepal has led many botanists to consider it as a
process of that sepal, but the fact of its being situated within the
insertion of the petals is conclusive as to its receptacular origin. In
the flowers exhibited the supernumerary spur (as if to show its want of
connection with any sepal) was placed exactly between a lateral sepal
and one of the anterior sepals, sometimes on the one side of the flower
and sometimes on the other. These additional spurs were precisely
similar to the normal ones, except that they were a little shorter. This
abnormality, although at first sight seeming to indicate a pelorian
tendency, is no approximation to regularity, from the fact of the extra
spur being differently placed, with regard to the sepals, from the
normal one."
Peloria of this kind, when perfect, is very often associated with other
alterations. Change of direction is one of the most common of these; the
usually drooping flower becomes erect, the stamens and style also are
changed in direction, while, not unfrequently, either the one or the
other (most often the stamens) are entirely suppressed. With this
suppression an increase in the size of the flower very generally
coincides. The number of parts is also frequently increased; thus, in
_Antirrhinum majus_ the corolla, when subjected to peloria, is very
generally six-parted, and has six stamens. Fusion of one or more flowers
is also a common accompaniment of peloria, as in _Digitalis purpurea_,
in which plant prolification often adds increased complexity to the
flower.
It has been stated by Moquin and others that the uppermost flower of an
inflorescence is the most subject to peloria; the uppermost flower of
_Teucrium campanulatum_, for instance, is very generally regular. In
_Calceolaria_ it is the central terminal flower which is usually
peloriated; on the other hand, in _Linaria_ and _Antirrhinum_ the lower
flowers, or those on the secondary branches, are quite as often affected
as the primary ones. Cassini considered that the spur of _Linaria_ was
developed from the lower petal rather than from the upper ones, because
there is more room on the side of the flower farthest from the stem than
on the opposite side. With reference to this point, M. Godron remarks
that in habitually irregular flowers the apex of the peduncle is
oblique, and hence the flowers are bent downwards or spread
horizontally, but if the receptacle be quite flat and level then the
flower is regular. The oblique position causes some of the organs to
press on others, and hence induces abortion and suppression of some
parts and increased growth in others that are not subjected to pressure.
In a terminal peloriated flower of aconite, described by this
naturalist, the flower was removed so far from the nearest bracts that
all its parts had the chance of growing regularly. In ordinary cases M.
Godron considers that the compression of the lateral bracts is the cause
of the irregularity of the androecium and of the receptacle.[237]
It has also been somewhat too generally stated that peloria occurs
principally on luxuriant vigorous plants. It seems quite as often to
happen in plants characterised by their deficiencies in this respect. On
this point M. de Melicoq[238] says, referring to _Linaria vulgaris_
affected with peloria, that on the weakest plants the peloriated flower
was at the top of the stem; while in stronger plants, with more numerous
flowers and larger foliage, the peloriated flowers were principally to
be found in the centre and at the base of the inflorescence, and their
pedicels were much longer than usual.
Linné, as has been already stated, considered these flowers to be
sterile, and only capable of multiplication by division of the root, but
Willdenow obtained seeds from the _Linaria_ which reproduced the
anomaly when sown in rich soil. Baron Melicoq obtained similar
results.[239] Mr. Darwin[240] raised sixteen seedling plants of a
peloric _Antirrhinum_, artificially fertilised by its own pollen, all of
which were as perfectly peloric as the parent plant. On the other hand,
the same observer alludes to the tendency that these peloric plants have
to revert to the usual form, as shown by the fact that when the peloric
flowers were crossed with pollen from flowers of the ordinary shape, and
_vice versâ_, not one of the seedlings, in either case, bore peloric
flowers. Hence, says Mr. Darwin, there is in these flowers "a strong
latent tendency to become peloric, and there is also a still greater
tendency in all peloric plants to reacquire their normal irregular
structure." So that there are two opposed latent tendencies in the same
plant. A similar remark has been made with reference to malformations in
general by other observers.
It would be very interesting if some competent naturalist would collect
information as to whether any variations in degree of fertility exist in
the three forms of flowers in _Linaria_, viz. the ordinary one-spurred
form, which is intermediate between the spur-less and the five-spurred
form. It must be remembered, however, that in the latter cases the
stamens are often deficient. In the _Compositæ_, where there are regular
flowers in the disc and irregular ones in the ray, sexual differences,
as is well known, accompany the diversities in form.
To Mr. Darwin the author is indebted for the communication of some
flowers of _Corydalis tuberosa_ (figs. 124, 125), provided with two
spurs of nearly equal size. To these flowers allusion is made in the
work already quoted[241] in the following terms:--"_Corydalis tuberosa_
properly has one of its two nectaries colourless, destitute of nectar,
only half the size of the other, and therefore to a certain extent in a
rudimentary state; the pistil is curved towards the perfect nectary, and
the hood formed of the inner petals slips off the pistil and stamens in
one direction alone, so that when a bee sucks the perfect nectary the
stigma and stamens are exposed and rubbed against the insect's body. In
several closely allied genera, as in _Dielytra_, there are two perfect
nectaries; the pistil is straight, and the hood slips off on either
side, according as the bee sucks either nectary." In the flowers of
_Corydalis_, which were provided with two perfect nectaries containing
nectar, Mr. Darwin considers that there has been a redevelopment of a
partially aborted organ, accompanied by a change in the direction of the
pistil, which becomes straight, while the hood formed by the petals
slips off in either direction, "so that these flowers have acquired the
perfect structure, so well adapted for insect agency, of _Dielytra_ and
its allies."
[Illustration: FIG. 124.--Two-spurred flowers of _Corydalis_.]
[Illustration: FIG. 125.--Section through two-spurred flowers of
_Corydalis_, Magnified.]
Peloria, then, is especially interesting physiologically as well as
morphologically; it is also of value in a systematic point of view, as
showing how closely the deviations from the ordinary form of one plant
represent the ordinary condition of another; thus, the peloric
Calceolarias resemble the flowers of _Fabiana_, and De Candolle,[242]
comparing the peloric flowers of _Scrophulariaceæ_ with those of
_Solanaceæ_, concluded that the former natural order was only an
habitual alteration from the type of the latter. Peloric flowers of
_Papilionaceæ_ in this way are indistinguishable from those of
_Rosaceæ_. In like manner we may trace an analogy between the normal
one-spurred _Delphinium_ and the five-spurred columbine (_Aquilegia_),
an analogy strengthened by such a case as that of the five-spurred
flower of _Delphinium elatum_ described by Godron.[243] The _Corydalis_,
before referred to, is another illustration of the same fact, the
structure being the same as in _Dielytra_, &c.
The ordinary irregular flowers may possibly be degenerated descendants
of a more completely organized ancestor, and some of the cases of
peloria may therefore be instances of reversion; some ancient _Linaria_
may, perhaps, have had all its petals spur-shaped, and the cases of
irregular peloria now found may be reversions to that original form.
When both regular and irregular forms of peloria occur on the same
plant, as they frequently do in _Linaria_, the one may be perhaps
considered as a reversion to a very early condition, the other to a
later state, when all the petals were irregularly formed. But before we
can assert the truth of this surmise we must have better evidence as to
what the original condition really was than we have at present.
The proximate cause of irregular peloria has been considered to be
excess of nourishment, but evidence as to this point is very
conflicting. Willdenow states that "radices peloriæ, solo sterili
plantatæ, degenerant in Linariam," ('Sp. Plant.,' iii, p. 254); but this
opinion is counterbalanced by that of others, while the frequent
existence of both forms on the same plant, at the same time, seems to
negative the supposition of any direct effect from external
circumstances.
The following are the plants in which irregular peloria has been most
often observed:
Aconitum Napellus.
Delphinium elatum!
Corydalis tuberosa.
*Viola odorata!
hirta.
Impatiens Balsamina.
Clitoria Ternatea.
Cytisus Laburnum!
Trifolium repens!
Lupinus polyphyllus!
*Gloxinia, var. cult.!
*Linaria vulgaris!
spuria.
Elatine.
triphylla.
æruginea.
triornithophora.
pilosa.
chalepensis.
cymbalaria!
purpurea!
decumbens.
Pelisseriana.
origanifolia.
Digitalis orientalis.
* purpurea!
Calceolaria crenatiflora.
rugosa.
* var. cult.!
Chelone barbata.
*Antirrhinum majus!
Rhinanthus crista galli.
Pedicularis sylvatica.
Pedicularis euphrasioides.
Scrophularia aquatica!
Sesamum indicum.
Lamium.
Mentha.
Sideritis.
Nepeta diffusa.
Galeopsis Ladanum.
Tetrahit.
Galeobdolon luteum.
Teucrium campanulatum!
Plectranthus fruticosus.
Cleonia lusitanica.
Dracocephalum austriacum.
Phlomis fruticosa!
Vitex incisa.
Aristolochia, sp.!
Ophrys aranifera!
Orchis simia.
pyramidalis!
latifolia!
morio!
papilionacea.
mascula.
latiflora.
conopsea.
Habenaria bifolia.
Corallorhiza innata.
Aceras anthropophora.
Cattleya Moasiæ!
Phalænopsis equestris!
Pogonia ophioglossoides!
The literature of peloria is very extensive. The following are the
principal papers, not already mentioned, which relate to the subject,
arranged under the genera, placing those first which are most subject to
this anomaly (see also Regular Peloria).
_Linaria_.--Adanson, 'Fam. Plant.,' t. i, p. 110. Jussien,
'Gen. Plant.,' p. 120. Poiret, 'Encycl. Method, Suppl.,' t.
iii, Jaeger, 'Missbilld. der Gewachs.,' pp. 94, 97, and 313.
Cassini, 'Op. Phytol.,' t. ii, p. 331. Ratzebourg, 'Animadv. ad
pelor. spectand.,' 1825. Turpin. 'Ic. Veget.,' tab. xx, f. 16.
Curtis, 'Flor. Londin.,' i, 118. Hopkirk, 'Flora Anom.,' pl.
vii, figs. 1, 2, 3. Haller, 'Act. Helvet.,' 2, p. 25, t. iv. De
Candolle, 'Flore Franc.,' t. iii, p. 583. Sowerby, 'Engl.
Bot.,' iv, 260, ed. Syme, tab. 963. Chavannes, 'Mon.
Antirrhin.' Delavaud, 'Bull. Soc. Bot. France,' 1858, p. 689;
id., 1860, p. 175. Heufler, 'Linnæa,' xvii, tab. ii. Weber,
'Verhandl. des Nat. Hist. Vereins. f. d. Rh. Preuss.,' 1850,
tab. i, figs. 1-8. 'Verh. Nat. Hist. Ver. Rh. Preus.,' 1849,
vol. vi, p. 290, tab. xiii.--_Antirrhinum_, Clos, 'Mém. Acad.
Toulous.,' vi, 1862. Chavannes, 'Mon. Antirrh.,' p. 62.
Fresenius, 'Mus. Senkenb.,' ii, t. iv, fig. 10. 'Bot. Soc.
Edinb.,' 1851, July 10.--_Calceolaria_, Chamisso, 'Linnæa,' t.
vii, p. 206. Guillemin, 'Archiv. Bot.,' t. ii, p. 1 et 136.
Schlechtendal, 'Linnæa,' xii, p. 686. Ernst Meyer, 'Linnæa,'
xvi, 26, tab. iii. Morren, 'Bull. Acad. Belg.,' t. xv, n. 7, et
t. xviii, p. 583. 'Gard. Chron.,' 1850, p. 389; ibid., 1866, p.
612.--_Viola_, Leers, 'Flor. Herborn.,' p. 145. De Candolle,
'Organ. Veget.,' t. i, p. 519, pl. xlv. Forbes, 'Proc. Linn.
Soc.,' June 6, 1848, p. 382. Hildebrand, 'Bot. Zeit.,' 1862,
vol. xx, tab. viii.--_Orchidaceæ_, His, 'Jourl. Phys.,' 65, p.
241. Wydler, 'Arch. Bot.,' t. ii, p. 310, tab. xvi. R. Brown,
'Obs. organ. Orchid.,' p. 698. A. Richard, 'Mém. soc. d'hist.
nat.,' t. i, p. 212. Greville, 'Flora Edinens.,' p. 87
(_Corallorhiza_). Curtis, 'Flora Londinensis,' t. lxxxii.
Morren, C., 'Bull. Acad. Roy. Belg.,' t. xix, part ii, p. 171.
Clos, 'Mém. Acad. Sc. Toulous.,' 5 ser., vol. iii. Caspary,
'Schrift. K. Gesellsch. Königsberg,' 1860, i, 59. Masters,
'Jourl. Linn. Soc.,' vol. viii, p. 208 (_Ophrys_, _Pogonia_).
Duchartre, 'Bull. Soc. Bot. Fr.,' vol. vii, 1860, p. 26,
_Cattleya_. Cramer, 'Bildungsabweich.'--_Limosella_, Baillon,
'Adansonia,' i, p. 305. (Flower normally irregular, becoming
regular "à force d'irregularité.")--_Chelone_, Chamisso,
'Linnæa,' vii, p. 206,--_Clitoria_, Bonavia, 'Gard. Chron.,'
1868, p. 1013. In this latter communication, published as this
sheet is passing through the press, the author gives an
interesting account of the transitional stages between the
ordinary papilionaceous condition and the regular form which is
like that of a Rosaceous plant. The peloric form is stated to
be transmitted by seed.
For other references see Moq.-Tandon, 'El. Terat. Veget.,' p.
186. Hallier, 'Phytopathol.,' p. 151.
FOOTNOTES:
[232] 'Amoen. Acad.,' i, p. 55, t. iii (1744):--The following note
refers to Linné's notion that these forms were due to hybridization. It
is extracted from Gmelin's edition of the 'Systema Naturæ,' 1791, p.
931. "_Linariæ_ proles hybrida, ejusdemque qualitatis et constans,
radicibus infinite sese multiplicans charactere fructificationis
diversissima, corolla regulari, quinque-corniculata, pentandra, ut genus
proprium absolute constitueret et distinctissimum, nisi fructus
frequentissime abortiret. Naturæ prodigium. Ita quidem a Linné.
Verisimilor autem videtur ea opinio, quæ peloriam pro peculiari
degeneratione monstrosa floris habet, in quam inclinare hoc genus
(Linaria) præ aliis, similis a forma deflexio in aliis speciebus, e.g.
_spurio Elatine_, _cymbalaria_, observata, ... Merk., 'Goett. gel.
Anz.,' 1774, n. 121. Linck, 'Annal. Naturg.,' i, p. 32."
[233] 'Bull. Acad. Belg.,' xviii, part i, p. 591. Lobelia, p. 137.
[234] See also Seringe, 'Esquisse d'une Monogr. du genre _Aconitum_,' p.
124.
[235] Schlotterbec, 'Act. Helvet.,' t. ii, pl. i, Roeper. Balsam, p. 10,
note.
[236] Masters. "Peloria, &c., _Ophrys aranifera_," 'Journ. Linn. Soc.,'
viii, p. 207.
[237] Godron, "Mém. sur les Fumarieès à fl. irreg.," 'Ann. Sc. Nat.,'
sér. 5, vol. ii, tab. xvii, p. 280.
[238] 'Bull. Soc. Bot. France,' vol. v, 1858, p. 701.
[239] 'Bull. Soc. Bot. France,' vol. vi, 1859, p. 717.
[240] 'Variation of Anim. and Plants,' ii, p. 70.
[241] Loc. cit., p. 59.
[242] 'Théor. Elém.,' ed. 2, p. 266.
[243] Cited in 'Bull. Soc. Bot. France,' vol. xiii (Rev. Bibl.), p. 81.
PART III.
METAMORPHY.
Much of the objection with which Goethe's famous essay on the
'Metamorphosis of Plants' was met on its publication may be traced to a
misapprehension of the sense in which Goethe employed the word. As used
by him, it had nearly the same signification as now applied to the word
development by organogenists. It does not necessarily imply that there
has been a change in any particular organ, but rather that there has
been, to some extent, a change in the plan of construction, in
accordance with which a deviation from the customary form results. The
particular organ was never anything else than what it is; it has not
been metamorphosed in the ordinary sense of the word; for instance, in a
double flower, where the stamens are, as it is said, changed or
metamorphosed into petals, no absolute change really has taken
place--the petal was never a stamen, although it occupies the position
of the latter, and may be considered a substitute for it.
The term metamorphosis, then, really implies an alteration in the
organizing force, taking effect at a very early period of the life of
the flower, at or before the period when the primitive aggregation of
cells, of which it is at that time composed, becomes separated or
"differentiated" into the several parts of the flower. In other words,
the "development" of the flower pursues a different course from what is
usual. In the preceding sections the effects of arrest and of excess in
this process have been partly treated of; other deviations arising from
similar causes will be mentioned elsewhere, but, under the present
heading, are specially included cases not of merely diminished or
increased, but of perverted development; the natural process is here not
necessarily checked or enhanced, but it is changed. Hence, in the
present work, the term metamorphy is employed to distinguish cases where
the ordinary course of development has been perverted or changed. As it
is applied solely for teratological purposes, the ordinary acceptation
of the term, as nearly synonymous with "development," is not interfered
with.
In order to avoid other possible misapprehensions, the terms retrograde
and progressive metamorphosis employed by Goethe are not herein used,
their place being, to a great extent, supplied by the more intelligible
expressions arrest or excess of development.[244]
FOOTNOTES:
[244] See Goethe, 'Versuch. der Metam. der Pflanzen,' 1790. English
translation by Emily M. Cox, in Seemann's 'Journal of Botany,' vol. i,
1863, p. 327. For a brief sketch of the origin and progress of the
theory of vegetable morphology, prior to the publications of Wolff,
Linné, and Goethe, as well as for an attempt to show what share each of
these authors had in the establishment of the doctrine, the reader is
referred to an article in the 'Brit. and For. Medico-Chirurgical
Review,' January, 1862, entitled "Vegetable Morphology: its History and
Present Condition," by Maxwell T. Masters.
CHAPTER I.
PHYLLODY.
This condition, wherein true leaves are substituted for some other
organs,[245] must be distinguished from Virescence, q. v., in which the
parts affected have simply the green colour of leaves, without their
form or structure. The appearance of perfect leaves, in place of other
organs, is frequently looked on as due to retrograde metamorphosis, or
to an arrest of development. But this is not strictly correct; for
instance, suppose a petal, which is very generally merely the sheath of
a leaf, with the addition of colouring matter, to be replaced by a
perfect leaf, one in which all three constituent parts, sheath, stalk,
and blade, are present, it surely can hardly be said that there has been
any retrogression or arrest of development in the formation of a
complete in place of an incomplete organ. The term retrograde here is
used in a purely theoretical sense, and cannot be held to imply any
actual degradation. Morphologically, as has been stated, the case is one
of advance rather than the reverse, and hence the assignment of
instances of this nature to a perversion of development, rather than to
a diminution or to an exaltation of that process, seems most consistent
with truth. The affected organs have really undergone no actual change,
simply the direction of the organising force has been altered at a very
early state, so that the usual differentiation of parts has not taken
place.
[Illustration: FIG. 126.--'Rose plantain,' _Plantago media var._, spike
contracted; bracts leafy.]
=Phyllody of the bracts.=--As bracts are very generally imperfect
organs, so their replacement by perfect leaves is not attributable to
arrest of development or retrograde metamorphosis, but the reverse. The
bracts of some species of _Plantago_[246] are very subject to this
change. Thus, in the rose plantain of gardens, _P. media_ (fig. 126),
the bracts are leafy and the axis depressed or not elongated, so that it
is surmounted by a rosette of small leafy organs. A similar condition of
the bracts, unattended with arrest of growth in the axis, is common in
_P. major_ (fig. 127) and in _P. lanceolata_ (see p. 108). It also
occurs in the bracts of _Corydalis solida_, _Amorpha fruticosa_, _Ajuga
reptans_, _Parthenium inodorum_, _Centaurea Jacea_, in the involucral
bracts of the dandelion, the daisy, and many other composites. In the
'Gardeners Chronicle,' 1852, p. 579, is figured a dahlia in which the
bracts of the involucre and the scales of the receptacle had all assumed
the form, texture, and venation of leaves.[247]
[Illustration: FIG. 127.--Leaf-like bracts in _Plantago major_.]
[Illustration: FIG. 128.--Dahlia. Scales of receptacle leafy.]
In _Umbelliferæ_ the substitution of leaves for involucral bracts is not
infrequent. It has been observed among other plants in _Angelica
Razoulzii_, _Carum carui_, _Daucus Carota_, &c. The scales of the hop
(_Humulus Lupulus_) not infrequently manifest this change, as do also
the bracts of many amentaceous plants, _e.g._ in the male catkins of
the walnut, the female catkins of the alder,[248] of some willows,[249]
&c. The bracts of some _Euphorbiaceæ_, as _E. pusilla_, _E. Lathyris_,
_E. Cyparissias_, have been observed to undergo a similar
alteration.[250]
Amongst monocotyledons an analogous change occurs not unfrequently, as
in some commelynaceous plants, _e.g._ _Tradescantia_, in _Musa_, &c.
The spathe of _Arum maculatum_ is sometimes represented by a stalked
leaf similar to that which occurs, under ordinary circumstances, in
_Spathiphyllum_, but in which genus the spadix is more or less adherent
to the leaf-like spathe.[251] In _Schoenus cephalotes_ a similar
exaggerated development of the bracts is figured by Rottboell.[252]
=Phyllody in inflorescence of Conifers.=--This demands passing notice by
reason of the interest attaching to the morphological construction of
these plants. The elongation of the axis which occurs in the female
cones has been already alluded to under the head of prolification of the
inflorescence. This change is frequently associated with a more or less
foliaceous condition of the bracts, which, indeed, may be seen to be
serially continuous, both above and below, with the ordinary leaves. The
scales, too, become notched and bipartite, and show, between the lobes,
the rudiment of a bud, which in a further stage becomes developed into a
shoot bearing leaves. Such a change has been described by Parlatore in
_Abies Brunoniana_, and examples may frequently be met with in the larch
(_Larix europæa_), and specially in _Cryptomeria japonica_.[253] The
scales of the male catkins of conifers likewise occasionally assume the
appearance of leaves; this may be seen in monstrous catkins of
_Araucaria_, as also in _Podocarpeæ_ and _Cupressineæ_ (Eichler).
=Phyllody of the calyx.=--Sepals under ordinary circumstances are so
like leaves, that it is not wonderful that they are often replaced by
those organs.[254] A singular instance of this has been mentioned as
occurring in _Cakile maritima_, wherein the sepals were found by M.
Fournier to be pinnatifid like the ordinary leaves of the plant.[255]
The sepals of _Ranunculaceæ_ and _Rosaceæ_, for example, _Rosa_, _Geum_,
are particularly liable to this change.
[Illustration: FIG. 129.--Flower of rose, sepals replaced by five
perfect leaves; axis prolonged through the flower in the form of a leafy
branch.]
In a species of _Geranium_ recently examined the sepals presented
themselves in the form of three-lobed leaflets; so in fuchsias and in
_Epilobium hirsutum_ the sepals occasionally are not distinguishable
from ordinary leaves (fig. 130). In roses, the change in question is a
very frequent accompaniment of prolification (fig. 129). In the peach
also this replacement of the sepals is sometimes carried to such an
extent, that five perfect, bistipulate leaves occur in the place of the
calyx, but when this is the case it usually happens that the pistil is
abortive.
[Illustration: FIG. 130.--Fuchsia, with one of the sepals leaf-like.]
De Candolle[256] figures a curious instance wherein the pappus of
_Podospermum laciniatum_ was replaced by five linear, foliaceous lobes.
A similar change has been noticed in other composites, as in _Tragopogon
pratense_. Engelmann mentions as subject to this hypertrophy of the
pappus, as it may be termed, _Scorzonera octangularis_ and _Senecio
vulgaris_. Wigand has observed a similar transformation in a species of
_Centranthus_ (_Valerianaceæ_).
In some cases the phyllody of the sepals has a special interest, as
bearing on the question whether what is termed calyx-tube is or is not a
portion of the calyx, and whether the sepals are modifications of the
blade or of the sheath of the leaf. Thus in the primrose the phyllodic
sepals seem to show clearly that the sepals are in that plant of a
laminar nature (fig. 131). The so-called calyx-tube of roses is
elsewhere alluded to. The leaf-like organs sometimes seen at the apex of
a cucumber would seem to support the view that there was really a
calyx-tube in _Cucurbitaceæ_ adherent to the carpels. It is also shown
in the cut, fig. 132, borrowed from the 'Gardeners' Chronicle,' 1859,
p. 654.
[Illustration: FIG. 131.--Primrose. Calyx of foliaceous segments.]
[Illustration: FIG. 132.--Leafy calyx of melon.]
Under ordinary circumstances, the sepals may be considered as the
representatives of the sheath of the leaf (cataphyllary) or of the blade
(euphyllary), the arrangement of the veins being different in the two
cases; thus, in the vagina or sheath, there are generally several large
veins of about equal size, either convergent towards the apex, or
divergent; on the other hand, in the blade, there is usually but one
central vein, the midrib, larger than the rest, and the smaller veins
come off at a less acute angle, and are more reticulated.[257]
Now, when phyllomorphy occurs in sepals which ordinarily are vaginal, it
is obvious that the case is one, not merely of increased relative
growth, but also of the appearance or development of an organ habitually
suppressed; on the other hand, when phyllomorphy occurs in sepals which
usually are laminar in form and nervation, the case is one of unusual
growth or hypertrophy, and not of the development of an organ habitually
suppressed, so that the amount of change is greater in the former than
in the latter instance.
Under normal circumstances it will be found that laminar venation is
most common in gamosepalous and vaginal venation in polysepalous
calyces. And the same holds good in cases where the calyx is abnormally
leafy. The complete leaf development shows itself more frequently among
the monosepalous plants than in the polysepalous ones, as shown even in
the subjoined list of species. This statement would be more fully
verified were it possible to state the frequency with which the
condition occurred in _individual plants_, when it would be found that
phyllody of the calyx occurs much more often in individual gamosepalous
plants than in polysepalous ones.
Phyllody of the calyx has been most often observed in the following
plants:
Ranunculus acris!
Delphinium Ajacis.
Caltha palustris.
Anemone Pulsatilla.
sylvestris!
nemorosa!
hortensis!
coronaria!
*Papaver orientale.
Escholtzia crocea.
Cakile maritima.
Diplotaxis tenuifolia.
Thlaspi arvense.
Cheiranthus Cheiri.
incanus.
Sinapis arvensis.
Brassica oleracea!
Peltaria alliacea.
*Sisymbrium officinale.
Caryophyllaceæ,[258] sp. pl.
Geranium, sp.!
*Fuchsia, var. hort.!
Epilobium hirsutum!
Cucurbita Pepo!
*Rosa, var. hort.!
Potentilla nepalensis.
Fragaria sp.
Geum rivale.
Amygdalus communis.
Persica vulgaris.
Cerasus!
Pyrus Malus.
Daucus Carota.
Athamanta Cervaria.
*Trifolium repens!
Centranthus macrosiphon.
Tragopogon pratense.
orientale.
Scorzonera octangularis.
Hypochæris radicata.
*Senecio vulgaris!
Podospermum laciniatum.
Cirsium arvense.
Carduus heterophyllus
tataricus.
Campanula, sp.
Convolvulus sepium.
*Primula officinalis, var. cult!
acaulis.
elatior.
Gentiana campestris.
*Petunia violacea!
Lycium europæum.
Laurus Sassafras.
Tulipa Gesneriana.
Convallaria maialis.
Colchicum autumnale! (virescent?)
Consult also Turpin, 'Atlas de Goethe,' t. iv, f. 12, _Lycium_.
Engelmann, 'De Anthol.,' § 35, p. 31. This author figures
phyllodic sepals in _Senecio vulgaris_, tab. v, figs. 24-26;
_Campanula_, tab. iii, f. 15, 16; _Athamanta cervaria_, tab. v,
f. 14. Lindley, 'Elements of Botany,' 1847, pp. 64, 73, &c.
'Gard. Chron.,' 1858, p. 685; 1859, p. 654, _Cucurbita_.
Petunnikoff, 'Bull. Soc. Imp. Moscow,' 1862, _Cirsium_. Braun,
'Rejuvenescence,' Ray Society's Transl. See succeeding
paragraphs.
=Phyllody of the corolla.=--The petals also are frequently replaced by
leaves, though in many of the recorded instances the change has been one
of colour only; these latter are strictly cases of virescence. M.
Seringe[259] speaks of a flower of _Peltaria alliacea_ in which the
calyx was petal-like, while the corolla was leafy as if there had been
transposition of the two organs, a very rare, if not unparalleled,
instance. In a flower of _Campanula Medium_, provided, as is often the
case, with a double corolla, the outer corolla was slit down on one
side, the edges of the cleft being leafy.
[Illustration: FIG. 133.--Sepals and petals to leaves. _Geranium_.]
The frondescent petals are very often completely disjoined, as in
_Verbascum nigrum_, and _Lonicera Periclymenum_, in which, moreover,
median prolification generally coexists. In the case of _Tropæolum
majus_, the ordinary leaves of which are peltate and orbicular, the
petals when frondescent have not the peltate arrangement, but are
spathulate, and provided with very long, narrow stalks, so that, in some
cases, they are, more properly speaking, enlarged virescent petals than
true leaves; in other instances, however, the arrangement of the veins
is more like that of the true leaves than that of the petals.
As might be expected, frondescence of the petals is frequently
accompanied by other changes of a similar nature in other parts of the
flower, and sometimes by the abortion of the sexual organs. Thus, in
_Actæa spicata_, as observed by Fresenius, the petals were replaced by
true petiolate, palminerved, lobed leaves, the stamens and pistils
being abortive. In _Ranunculus_ the leaves that appear in the place of
the petals have no scale at their base, and in _Tropæolum_ the calyx (or
receptacle) is free from the usual spur.
The absolute frequency of this occurrence seems to be greatest in those
flowers which are normally polypetalous. The petals of these flowers, as
a general rule, are more like the leaf-sheaths than the leaf-blades as
to their venation, hence it would seem that the phyllomorphic condition
in these petals is a manifestation of a greater degree of organizing
force than that which occurs in those cases where the petals are
normally present in the form of contracted blades or laminæ. (See the
remarks in the preceding section.)
Frondescence of the petals has been observed most frequently in the
following cases; some, perhaps, were cases merely of virescence, q. v.;
see also under Chloranthy, Prolification.
Ranunculus repens!
Delphinium Ajacis.
crassicaule.
Aquilegia vulgaris.
Actæa spicata.
*Brassica oleracea!
Diplotaxis muralis.
Hesperis matronalis.
Thlaspi bursa pastoris.
Sisymbrium tenuifolium.
Turritis glabra.
Raphanus sativus.
Peltaria alliacea.
Alyssum incanum.
Erysimum Barbarea.
officinale!
cheiranthoides.
Cheiranthus Cheiri.
*Dictamnus Fraxinella!
Lychnis sylvestris.
dioica!
Alsine media.
Cerastium vulgatum!
triviale.
Reseda lutea.
Phyteuma.
Malva sylvestris.
*Tropæolum majus!
Geranium, sp.!
Triumfetta, sp.!
Epilobium hirsutum!
OEnothera striata.
Rubus, sp.
*Rosa, var. cult.!
*Trifolium repens!
Spiræa oblongifolia.
Amygdalus communis.
*Rosa!
Cerasus vulgaris!
Persica vulgaris!
Potentilla nepalensis.
Geum rivale.
Daucus Carota!
Heracleum Sphondylium.
Torilis Anthriscus.
Echinophora maritima.
Campanula rapunculoides.
glomerata.
Phyteuma spicatum.
Calendula officinalis.
Cirsium tricephalodes.
Senecio vulgaris.
Scabiosa columbaria.
agrestis.
Lonicera xylosteum.
Periclymenum.
Gentiana Amarella.
Gilia glomeriflora.
*Symphytum officinale.
Petunia violacea!
Verbascum, sp.
Antirrhinum majus!
Stachys sylvatica.
*Anagallis phoenicea?
Primula sinensis!
Polemonium coeruleum.
See Moquin-Tandon, 'El. Terat. Veg.,' p. 203. Engelmann, 'De
Anthol.,' § 38 _et seq._; tab. ii, figs. 8-14, _Gilia_; tab. v,
23-26, _Senecio_; tab. v, f. 1-13, _Torilis_; tab. iv, f. 3,
_Erysimum_. 'Bull. Soc. Bot. Fr.,' vol. ii, 1855, p. 479,
_Primula sinensis_. Giraud, 'Edinb. Phil. Magazine,' 1839,
_Antirrhinum_. Jaeger, 'Act. Acad. Cæs. Nat. Cur.,' vol. xiii,
2, p. 1, tab. xli, _Tropæolum_. Bischoff, 'Lehrbuch,' 11, 2, p.
27, _note_, _Tropæolum_. Fresenius, 'Mus. Senkenb.,' ii, 35,
tab. 4, fig. 5, _Actæa_. See also succeeding paragraphs and
sections in Chloranthy, Virescence, &c.
=Phyllody of the stamens= happens less frequently than the corresponding
condition in the neighbouring organs. The structure of the anther is so
much removed from that of the leaf, that the change of the stamen from
its ordinary condition to that of a leaf must be regarded as indicating
a greater degree of perverted development than that which occurs in
those cases where less highly differentiated organs, such as the sepals,
petals, and pistils, are thus altered.[260]
In all cases it is desirable to ascertain, if possible, what parts of
the stamen are thus transformed. In some Petunias the filaments are
unchanged, but in place of the anther is a small lamina, representing
precisely the blade of an ordinary leaf. Sometimes the connective only
is replaced by a leaf. One of the most interesting cases of this kind
that has fallen under the writer's observation was in _Euphorbia
geniculata_, in which, in addition to other changes mentioned under
prolification of the inflorescence, some of the stamens were partly
frondescent, half the anther being perfect, the other half leaf-like.
Another filament bore just above the usual joint three leaflets, two
lateral ones, somewhat conduplicate, and a third central one, half
anther, half leaflet.
[Illustration: FIG. 134.--Flower of a _Petunia_, opened to show the
stamens partially replaced by stalked leaves.]
In the case of frondescent flowers of _Tropæolum majus_ the stamens are
usually absent or atrophied, but in other instances the filament is
present as usual, representing the stalk of the leaf, and surmounted by
a small lamina, but this latter, in place of being nearly flat, is
pinched up in the centre from back to front, and surmounted by a
two-lobed anther, so that the general appearance of the whole structure
is that of a central anther, supported at the base on each side by two
concave leaf-lobes, or it might be compared with a three-lobed leaf, the
terminal lobe represented by the anther.
In _Jatropha Pohliana_, Müll. (_Adenorophium luxurians_, Pohl.), a
singular condition has been observed by M. Müller (Argov.). In this
flower the anther, in place of being represented by the flat blade of a
single leaf, had the appearance as if two such blades were present and
coherent one with the other by their midribs, along their upper or inner
surfaces, which were directed towards the centre of the flower (fig.
136), thus resembling the cases of adhesion of leaves by their surfaces
already referred to (p. 33). In other cases, in the same plant, the
anther appeared as if formed by two collateral leaves, the faces looking
towards the circumference of the flower, and their margins so folded
together as to represent an open anther lobe (fig. 135). These cases are
apparently due, not to the formation and adhesion of two leaves, but
rather to the exuberant development of one leaf into two blades.[261]
The bearings of these and other similar malformations on the morphology
of the anther are alluded to under the head of petalody of the anther.
[Illustration: FIG. 135.--Phylloid anther of _Jatropha_, after Müller
(Arg.).]
[Illustration: FIG. 136.--Leaf-like anther of _Jatropha Pohliana_, after
Müller.]
Phyllody of the stamens has been most often observed in the following
plants:
Anemone nemorosa.
coronaria.
Delphinium crassicaule.
Nymphæa dentata.
Tropæolum majus!
Dictamnus albus.
*Trifolium repens!
Torilis anthriscus.
Heracleum Sphondylium.
Daucus Carota
Epilobium hirsutum!
*Rosa, var. cult.!
Lonicera Periclymenum.
Anagallis arvensis.
Primula sinensis!
Petunia, var. cult.
Jatropha Pohliana.
Euphorbia goniculata.
In addition to the foregoing there are very numerous instances of
similar substitution in chloranthic flowers. In the above list only
those cases are given wherein the leafy change is confined to the
stamens, or, at least, to a few only of the other parts of the flower.
=Phyllody of the pistils.=[262]--This is of more common occurrence than
is the corresponding change in the case of the stamens. It is of
interest, as it sometimes serves to illustrate the morphological nature
of the pistil. Of this the double-flowering cherry is a well-known
illustration, the pistil being here represented by two small foliar
laminæ, whose midribs are prolonged with a short style, terminated by an
imperfect stigma. It is usually the basal portion of the pistil, the
ovary, which is thus specially affected, the margins being also often
disunited so as to expose the ovules. These latter organs may be absent
or they may themselves be the subjects of foliaceous development.
Moquin[263] relates having found in the neighbourhood of Montpellier a
flower of a tulip the ovary of which was represented by true leaves,
which bore on their margins the ovules, and thus presented a striking
analogy with the carpels of those Sterculias, like _S. platanifolia_,
which are foliaceous in texture and open very early in the course of
their development. A similar occurrence has also been frequently
noticed in the Columbine and also in _Cruciferæ_ and _Umbelliferæ_. M.
Germain de St. Pierre mentions an instance wherein the carpels of _Salix
Babylonica_ were converted into two leaves, provided with stipules. All
the flowers of the catkins were similarly changed, so that it became
permanent, and resembled a branch.
[Illustration: FIG. 137.--Rose, in which the axial portion of the flower
was elongated and the carpels were more or less replaced by leaves.]
Substitutions of this kind form the green "eyes" or centres of certain
varieties of _Ranunculus_ and _Anemone_.
In proliferous roses, or in cases where the central axis of the flower
is prolonged, it frequently happens that the pistils are more or less
replaced by leaves. Fig. 137, from a specimen of Dr. Bell Salter's,
given in the 'Gardeners' Chronicle,' shows the passage, from below
upwards, of the ordinary carpels to perfect leaves; the so-called
calyx-tube being completely deficient and the ovaries entirely superior.
Like most similar specimens, this one bears out the notion that what is
called the calyx-tube in roses is really an expansion and dilatation of
the top of the flower-stalk.
[Illustration: FIG. 138.--Cucumber with leaf attached.]
Fig. 138, for which I am indebted to Mr. S. J. Salter, represents a very
singular conformation in the cucumber, described by that gentleman in
'Henfrey's Botanical Gazette,' i, p. 208, and considered by him to be
due to the foliaceous condition of one of the three carpels of which the
fruit is composed. The portion near the peduncle was binary, while the
distal extremity of the fruit was ternary. The main difficulties
attending the acceptance of this explanation reside in the peculiar
reversed position of the leaf, and in the fact that the fruit of the
_Cucurbitaceæ_ is probably of axial nature, the dilated and succulent
end of the peduncle adhering to and usually concealing the carpels; in
some cases, however, these latter project beyond the axial portion,
leaving no doubt as to the true nature of the structure in these
particular instances.
Admitting the axial nature of the fruit, it might be supposed that in
Mr. Salter's cucumber an adventitious leaf had been given off from the
axis, but even on that supposition the reversed position offers a
difficulty, and there still remains to be explained the fact that the
proximal part of the fruit was binary in its constitution, the distal
end ternary.
M. Norman[264] mentions a case wherein the carpels of _Anchusa
ochroleuca_ were replaced by two leaves; from this he draws the
inference that the pistil of borages and labiates is really composed of
two leaves, placed fore and aft, the margins of the leaves being
congenitally fused. This tallies well with the account given of the
development of these plants by Payer, Germain de St. Pierre, and others.
In an Indian species of _Triumfetta_, not only were the petals
virescent, but the ovary also was much enlarged, and in some flowers it
was divided half way down into five lanceolate leaves (fig. 139), the
sepals and stamens being in their normal condition.
In the preceding instances the foliaceous condition has pervaded the
entire pistil, or at any rate the basal portion or ovary, and it may be
noticed that the ovary is thus shown to consist in some cases of the
sheath of the leaf, as in _Aquilegia_; in other cases of the blade, as
in _Cerasus_, _Daucus_, &c.
[Illustration: FIG. 139.--Flower of _Triumfetta_, sp., carpels
represented by five leaves.]
There are cases, however, in which a part only of the pistillary
structure thus becomes foliaceous. Linnæus, 'Prolepsis,' § 9, mentions
some flowers of _Carduus heterophyllus_ and _C. tataricus_ in which the
style had grown into two green leaflets, and in which the calyx and
corolla were also leaf-like. A very singular instance is recorded by
Baillon,[265] wherein the pistil of _Trifolium repens_ consisted of
three carpels, either separate, or combined so as to form a one-celled
ovary with three parietal, pluri-ovulate placentæ; the ovary in these
flowers was formed of the basal vaginiform part of the leaf; the three
styles were formed by the petioles, while the stigmas were represented
by trifoliolate leaves. The back of the leaf in these cases is usually
directed away from the centre of the flower. When this change occurs it
is commonly attended by an increased number of parts, as in the trefoil
just mentioned, or in the double cherry, where usually two foliaceous
carpels may be met with, and sometimes more.
The change is also of interest when it affects such orders as the
_Umbelliferæ_, which have their ovaries inferior under ordinary
circumstances; but when these organs assume a leafy condition they
become superior also, _i.e._ they are detached from the calyx.
As regards the position of the ovules in these foliaceous pistils, they
may be placed, as in _Aquilegia_, _Delphinium_, &c., on the edges of the
carpel or on the surface, as in some flowers of _Ranunculus repens_ and
_R. Ficaria_. A similar position of the ovules is recorded in the case
of the vine (_Vitis_), where the pistil consisted of leaves bearing the
ovules on their inner surface.[266] The supposed causes of this and
other similar malformations are alluded to under the head of chloranthy,
but it may be here remarked that semi-double flowers, fertilised by the
pollen of similar flowers, are said to produce flowers with a centre of
small green leaves, this central tuft resulting from the expansion and
frondescence of the pistils.
As this condition rarely occurs without corresponding changes in other
parts of the flower, further remarks on this subject will be found in
the chapter relating to Chloranthy.
Phyllody of the pistil has been most frequently recorded in the
following plants:
Pæonia officinalis.
Ranunculus repens!
*Aquilegia vulgaris!
Delphinium elatum.
crassicaule.
Ajacis.
amænum.
Nymphæa dentata.
Sinapis arvensis!
Diplotaxis tenuifolia.
*Brassica oleracea!
*Sisymbrium officinale!
Dianthus. sp
Reseda Phyteuma.
Triumfetta, sp.!
Lychnis dioica.
Cerastium, sp.!
*Dictamnus Fraxinella!
Cerasus avium.
vulgaris!
*Rosa, var. cult.!
*Daucus Carota!
Heracleum, sp.
Epilobium hirsutum!
Lathyrus latifolius.
*Trifolium repens!
hybridum.
Melilotus, sp.
Medicago, sp.
Lonicera Periclymenum.
Carduus heterophyllus.
tataricus.
Scrophularia aquatica.
Symphytum officinale.
Anchusa ochroleuca.
paniculata.
*Primula sinensis!
Salix babylonica.
Hyacinthus, sp.
Tulipa, sp.
Some of the above are probably cases of mere virescence rather than of
phyllody. For further illustrations, references to authorities, &c., see
under Chloranthy, Virescence, Prolification, &c.
=Phyllody of the ovules.=--Pending the settlement of the existing
differences of opinion with reference to the morphological nature of the
ovule and its component parts, much interest attaches to the
malformations to which they are occasionally subject. Considered purely
in a teratological point of view, it seems clear that the ovular coats
are usually, if not always, of foliar nature, while the central nucleus
is an axial organ; but if this be so there still remains the question
whether the leafy coats of the ovule are processes of the carpel itself,
or distinct independent formations, like the scales of a leaf-bud; as to
this latter point, the evidence is at present very conflicting. Prof.
Al. Braun, who has devoted much attention to the subject, describes and
figures ovules of _Nigella_ and _Adonis_, wherein the outer coat of the
ovule was converted into a leafy, lobed mass, like the ordinary leaves,
and these he considers to be a portion, not of the carpel, but of the
ovular bud; he, however, hesitates to pronounce an opinion on the nature
of the pedicel of the ovule. In _Primulaceæ_, wherein ovular changes are
very common, the leafy coat of the ovule would seem, from the nature of
the placenta, to be independent of the carpel. Morren, who studied the
changes in the ovules of _Primula sinensis_, applied the term
lepyrophylly ([Greek: lepyron], a scale) to the foliaceous condition of
the testa in this plant. Unger[267] describes a series of malformations
in _Primula sinensis_, consisting chiefly of reversions of the part of
the flower to leaves. The carpels were entirely absent in this case, and
the place of the free central placenta was occupied by a circle of
leaves, sometimes bearing imperfect ovules on their edges. An instance
of a similar kind has been described by A. de Candolle.[268]
In these flowers the placenta seemed to be composed of several funiculi
soldered together, and bearing imperfect ovules. In other cases no
traces of ovules are visible, but the funiculi are in a foliaceous
condition. Moquin also alludes to a case of the same nature in _Cortusa
Mathioli_, in which the funiculi bore little rounded leaves. Brongniart
has described some malformations of _Primula sinensis_ in which the
ovules were transformed wholly or partially into small leaves with three
to five lobes.[269] Dr. Marchand[270] mentions similar changes in
_Anagallis arvensis_ and _Lonicera Periclymenum_.
Cramer[271] figures ovules of _Primula sinensis_ in the form of stalked
leaves, often becoming infolded at the margins, and giving origin to a
small nucleus on their inner surface.
M. Tassi[272] records an instance in _Symphytum officinale_ wherein the
ovules were replaced by two small linear leaves arising entirely from
the axis, and not from the carpels.
In most of the foregoing illustrations the foliar portion of the ovule
must have been independent of the carpel; this independence is less
manifest, though probably as real in the cases now to be mentioned. In
_Sinapis_ and in _Brassica oleracea_ foliaceous ovules may occasionally
be seen, attached to the placenta by long stalks. No trace of the
nucleus is visible in these specimens.
[Illustration: FIG. 140.--_Sinapis_, replum and ovules; the dotted line
shows the position of the carpels.]
Griffith, in alluding to a similar case in _Sinapis_,[273] describes the
ovules as foliaceous, and having their backs turned away from the axis,
the raphe being next to the axis and representing the midrib the funicle
corresponding to the petiole. The outer tegument of the ovule, according
to Griffith, is a leaf united along its margins, but always more or less
open at its apex. No inversion can, therefore, really take place in
anatropous ovules, but the blade of the leaf is bent back on the
funicle, with which its margins also cohere.
Caspary, in an elaborate paper on phyllomorphy occurring in _Trifolium
repens_, figures foliaceous ovules springing from the edge of an open,
leafy carpel. The nucleus of the ovule, in these cases, appears to
originate as a little bud from the surface of the leafy ovule (figs.
141, 142).
[Illustration: FIG. 141.--Leafy ovules, &c., _Trifolium repens_.]
In a species of _Triumfetta_ (see p. 260), of which I examined dried
specimens, the ovary was open and partly foliaceous; it bore on its
infolded margins ten erect leaflets, representing so many ovules; each
leaflet was conduplicate, the back being turned towards the placenta.
[Illustration: FIG. 142.--Leafy ovules of _Trifolium repens_, showing
formation of nucleus, &c. After Caspary.]
On the other hand, there are cases in which the leafy coat of the ovule,
in place of being a distinct organ, seems to originate from the margin
of the carpellary leaf itself--to be, as it were, a lobule or small
process of the carpel, and not an absolutely new growth. Thus,
Planchon[274], from an examination of some monstrous flowers of _Drosera
intermedia_, was led to the inference that the ovules are analogous to
hairs on the margins of the leaves. This acute botanist was enabled to
trace all the gradations between the simple cup formed by the
confluence of four glanduliferous hairs and the concave leaf and the
perfect ovule.
Brongniart[275] records ovules of _Delphinium elatum_ existing in the
form of marginal lobes of the carpellary leaf itself; so that each ovule
corresponds to a lobe or large tooth of this leaf, the funiculus, as
well as the raphe, being formed by the median nerve of the lateral lobe.
M. Clos[276] mentions a similar instance in _Aquilegia Skinneri_; and
another is figured in Lindley's 'Elements of Botany,' p. 88, f. 180.
[Illustration: FIG. 143.--Portion of an open foliaceous carpel of
_Delphinium_, with ovules on the lobules.]
Cramer[277], from an examination of several ovular malformations, as
well as from the investigation of the mode of evolution of the ovules,
is led to a similar conclusion with reference to the production of
ovules from the modified lobes of the carpellary leaf. Figs. 143-145,
copied from Cramer, show how the nucleus of the ovule is formed as a new
growth from the surface of the lobes of the leaf in _Delphinium elatum_.
[Illustration: FIG. 144.--Section through marginal lobe of carpel
(_Delphinium_), showing the nucleus (_n_).]
[Illustration: FIG. 145.--Section through marginal lobe of carpel,
showing nucleus and tegument (_Delphinium_).]
[Illustration: FIG. 146.--1. Placenta of _Dianthus_, bearing ovules and
carpels. 2. One of the ovaries separated.]
[Illustration: FIG. 147.--Ovules of _Dianthus_ passing into carpels.]
One of the most singular instances of ovular malformation in record is
that cited by the Rev. M. J. Berkeley, in the 'Gardener's Chronicle,'
September 28th, 1850, p. 612. The plant was a carnation, and its
placenta bore, not only ovules, but also carpels (fig. 146), the latter
originating in a perverted development of the former, so that many
intermediate stages could be traced between the ordinary ovule and the
ovary (fig. 147, 1, _a_, 2, _b_). Some of these carpels, thus derived
from the ovules, themselves bore secondary ovules on a marginal
placenta, as shown in the sections at _c_, _d_, _e_. Could such a change
occur in the animal kingdom, there would be the unfertilised ovum
converted into an ovary, and this again bearing Graafian vesicles! In
Mr. Berkeley's carnation the change was not so great, seeing that the
nucleus of the ovule was not developed, and sufficient evidence has been
above given as to the foliar nature of the primine, while for a leaf to
be folded up so as to form a carpel is an ordinary occurrence.
It is worthy of remark that in these foliaceous ovules there is never
more than one coat, the secondine and other integuments do not make
their appearance in these cases, and that very generally the change in
question accompanies a similar foliaceous condition in the carpel, the
margins of which are more or less disunited.
Prof. A. Braun remarks that up to this date no such change has been
observed in the ovules of Monocotyledons.
=Changes in the nucleus of the ovule.=--The preceding remarks have had
reference especially to the ovular coats, but it is desirable also to
allude to certain points connected with the nucleus. Very frequently,
when the coat of the ovule is phylloid, as before described, the nucleus
is altogether wanting, though sometimes it is present as a small
cellular papilla; very rarely is it to be found in its perfect state.
Occasionally the nucleus is present in the guise of a small elongated
branch. Wigand cites ovular buds in every stage of progress into a
branch, sometimes even bearing indications of anthers. Wydler has
observed a similar occurrence in ovules of _Alliaria officinalis_, and
Schimper has described and figured specimens of _Nigella damascena_ in
which the outer coats of the ovule were but little changed, while the
nucleus was replaced by a leafy shoot. On one of the leaves of this
latter was found an imperfect ovule--an ovule on an ovule!
Fig. 148 shows a floret of a species of _Gaillardia_, in which the ovule
was replaced by a leafy shoot which had made its way through a chink in
the ovary. In this specimen, however, there was no evidence to show
whether the shoot in question was a perverted development of the
nucleus, or whether it was wholly independent of the ovule.
[Illustration: FIG. 148.--Floret of _Gaillardia_, showing leafy shoot
occupying the place of the ovule.]
From this occasional elongation of the nucleus, as well as from the
foliar nature of the ovular coats, Prof. Alex. Braun arrives at the
conclusion that the ovule is to be looked on as a bud, the ovular
coatings, so often variable in number, representing the scales of the
bud, the nucleus corresponding to the end of the axis or growing point.
Griffith had previously expressed the same opinion from his observations
on malformed ovules of _Sinapis_ and _Lonicera_, while Caspary's
conclusions from the foliaceous ovules of _Trifolum repens_ are somewhat
similar. The latter observer considers that the funiculus, with the
integuments, is the equivalent of a leaflet, the petiolule or midrib of
which answers to the funiculus, and its hollow expansion to the
integument. The nucleus itself is considered to be a new formation
analogous to a shoot.
M. van Tieghem's conclusion[278] from the examination, of flowers of
_Tropæolum majus_, in which the ovules were replaced by perfect peltate
leaves, is that the ovules are foliar productions springing, not
directly from a prolonged floral axis, as in _Primulaceæ_, but from
branches of the axis arising from the axils of the carpellary leaves.
Phyllody of the ovules has been met with most often in the following
species:
*Aquilegia vulgaris!
Skinneri.
Delphinium crassicaule.
elatum.
dictyocarpum.
Ajacis.
Nigella damascena.
Adonis autumnalis.
Cheiranthus Cheiri!
Nasturtium, sp.
Sisymbrium officinale!
Brassica napus!
* olcracea!
*Alliaria officinalis!
Sinapis arvensis!
Turritis, sp.
Thlaspi arvense.
Erucastrum Pollichii.
Stellaria media.
*Reseda lutea.
Drosera intermedia.
Agrostemma Githago.
Stellaria media.
Triumfetta, sp.!
Tropæolum majus!
Dictamnus albus.
Fraxinella!
Caram carui
Pastinaca sativa.
Torilis anthriscus.
Thysselinum palustre.
Epilobium palustre.
Rosa, sp.
Fragaria alpina.
*Trifolium repens!
Medicago maculata.
Desmodium canadense.
Melilotus macrorhiza.
Lonicera, sp.
Gaillardia!
Crepis, sp.
Phyteuma odorata.
Symphytum Zeyheri.
* officinale.
Stachys sylvatica.
Anagallia arvensis.
phoenicea.
Lysimachia ephemerum.
*Primula sinensis!
Auricula.
prænitens.
Gilia glomeruliflora.
Rumex arifolius.
scutatus.
Salix capræa.
The following list of publications relating to ovular malformations is
copied from A. Braun, 'Ueber Polyembryonie und Keimung von Cælobogyne'
(Appendix),[279] to which are also added some others not alluded to by
that author and not specially referred to in the preceding pages:
Jaeger, 'Missbilld. d. Gewächse,' p. 78, 79, f. 47. Roeper,
'Enum. Euphorb.,' 1824. p. 45, _Delphinium_.--Schimper,
'Flora,' 1829, pp. 437-8, et 'Mag. fur Pharmacie de Geiger,'
1829-30, pl. iv-vi, text wanting, _Primula_, _Reseda_,
_Cheiranthus_.--Engelmann, 'De Antholysi,' 1832.--Valentin,
'Act. Acad. Nat. Cur.,' 1839, p. 225, _Lysimachia_.--Unger,
'Act. Acad. Nat. Cur.,' xxii, 11, 1850, p. 543, t. 5 B,
_Primula_.--'Flora (B. Z.)', 1842, p. 369, t. ii,
_Trifolium_.--Brongniart, 'Ann. Sc. Nat.,' 1834, ii, p. 308;
also 'Archives Mus. d'Hist. Nat.,' 1844, t. iv, p. 43, pl. iv,
v, _Primula_.--Reissek, 'Linnæa,' xvii, 1843,
_Alliaria_.--Wydler, 'Denkshrift. d. Regensb. Bot. Gesell.,'
1855, iv, s. 77, t. vii, _Alliaria_.--Wigand. 'Grundlegung der
Pflanzen Teratol.,' 1850, p. 39, _Turritis_.--Wigand, 'Bot.
Untersuchungen,' 1853, p. 23, _Rosa_, _Turritis_,
_Crepis_.--Germain de St. Pierre, 'L'lnstitut,' 1853, n. 1051,
p. 351.--Rossmann, "Entwicklung der Eiknospen aus dem
Fruchtblatte," &c., 'Flora,' 1855, pp. 647 and 705.--Dareste,
'Ann. Sc. Nat.,' 1842, p. 220, _Delphinium_.--Fresenius, 'Mus.
Senkenb.,' ii, p. 39, t. iv, f. 9, _Primula_.--Schultz, 'Flora
o. d. Bot. Zeit.,' 1834, xvii, p. 121, _Nasturtium_.--Seringe
and Heyland, 'Bull. Bot.,' 1-7, _Diplotaxis_.--Clos, 'Mem.
Acad. Toulouse,' vi, 1862, _Delphinium_.--Morren, C., 'Bull.
Acad. Belg.,' xix, part ii, p. 519, _Primula_.--Caspary,
'Schrift. d. Physik. OEk. Gesell. zu Königsberg,' band ii, p.
51, tabs. ii, iii. Fleischer, 'Ueber Missbildungen
Verschiedener Cultur Pflanzen.,' &c., Esslingen, 1862. Cramer,
'Bildungsabweich,' p. 68, &c. &c., _Trifolium._--Moquin-Tandon,
'El. Terat. Veg.,' p. 206, _Cortusa_.--Guillard, 'Bull. Soc.
Bot. Fr.,' 1857, vol. iv, p. 761, _Stellaria_.--Moelkenboer,
'Tijdschrift v. Natuurl. Geschied.,' 1843, p. 355, t. vi, vii,
_Primula_.--Van Tieghem, 'Bull. Soc. Bot. Fr.,' 1865, p, 411,
_Tropæolum_.
=Phyllody in accessory organs.=--In addition to the ordinary organs of
the plant, what are termed the accessory organs, such as hairs, spines,
&c., sometimes become foliaceous. It is not to be wondered at that
spines, when they represent the framework of a leaf, become sometimes
clothed with cellular tissue, and thus become indeed true leaves. This
happens occasionally in _Berberis;_ a similar thing occurs in the
stipules of some _Leguminosæ_; the scales of some begonias; the tendrils
of _Bignonia_, _Cobæa_, &c.
The presence of two small green laminæ on the outer side of the two
posterior stamens in _Antirrhinum majus_ has also been met with. The
adventitious organs appeared as if they were developments from the
thalamus--a kind of foliaceous disc, in fact.
[Illustration: FIG. 149.--Leafy petal of _Epilobium_.]
[Illustration: FIG. 150.--Chloranthy, &c. _Epilobium hirsutum_.]
=Chloranthy.=--The term phyllomorphy is applied to the individual parts
of the flower which assume the form and appearance of leaves. By
chloranthy it is to be understood that all, or the great majority of the
organs of the flower assume these conditions.[280] In chloranthy, as
here defined, there is no unusual number of buds, as there is in
prolification, but the appearance of the flower-bud is so changed as to
make it resemble more closely a leaf-bud than a flower-bud. There is not
necessarily any increase in the number, or any alteration in the
position of the buds, but the form and appearance of the latter differ
from what is usual. Chloranthy, then, is a more complete form of
frondescence. Owing to the vagueness with which the word has been
applied by various authors, it becomes very difficult to ascertain
whether the recorded instances of chloranthy were really illustrations
of what is here meant by that term, or whether they were cases of mere
virescence (green colour, without other perceptible change), or of
prolification (formation of adventitious buds). It is, therefore, quite
possible that some of the instances to be now mentioned were not
strictly cases of chloranthy.
[Illustration: FIG. 151.--_a._ Open leafy carpel of "green rose," with
two deformed ovules. _b._ Ovule separate. _c._ Primine removed. _d._
Secondine and nucleus, with the bulbous end that projects through the
micropyle.]
Seringe[281] has described a malformation in _Diplotaxis tenuifolia_ in
which all the floral organs were replaced by sixteen distinct leaflets
which had preserved their proper relative position. The _Cruciferæ_, of
which family the last-named plant is a member, are particularly liable
to this malformation, as also are the _Rosaceæ_, as will be seen from
the following illustrations. Roses indeed often exhibit alterations of
this kind as the commencement of prolification. There is also in
cultivation a rose[282] called the green rose, "Rose bengale à fleurs
vertes," in which all the parts of the flower are represented by leaves.
One of the most remarkable features in this plant is, that the carpels
have often two ovules on their margins. Now, Payer, in his
"Organogénie," has shown that at a certain period of the development of
the ordinary rose flower the ovary contains two collateral ovules, of
which one becomes in process of time suppressed.[283] _Geum coccineum_
has been found by Wigand with its flowers in this condition.[284]
Lindley[285] figures a very interesting illustration in _Potentilla
nepalensis_, in which some of the flowers have their component parts
leafy, in others the receptacle lengthens, till in extreme cases the
whole of the floral apparatus is represented by a branch bearing a
rosette of leaves.
A particular variety of the Alpine strawberry is also described as
occasionally subject to this transformation. In these flowers the calyx
remains normal, while all the other parts of the flower, even to the
coating of the ovule, assume a leaf-like condition.[286]
Among _Leguminosæ_ a partial leafy condition (frondescence), or a more
complete degree of the same change, (chloranthy) is not infrequent,
particularly in _Trifolium repens_. In this species the changes are so
common, so various and important, that they may be alluded to in some
little detail. M. Germain de Saint Pierre,[287] in commenting on the
frequency with which the flowers of this plant are more or less
frondescent, remarks that although all the flowers on one plant may be
affected, they are all changed in the same manner, but on different
specimens different degrees of transformation are found. In all the
corolla and stamens are comparatively little removed from the ordinary
form, the calyx and pistil, however, have a particular tendency to
assume a foliar condition. The author just cited arranges the
malformations of this plant under three heads, as follows:
1. Calyx-teeth larger than usual, sometimes dentate at the
margin; petals more or less regular and disposed to run away
from the papilionaceous form; filaments free; anthers normal;
carpel transformed into a true leaf with a long stalk provided
at the base, with two stipules, terminal leaflet, solitary,
green, with no trace of ovules. Sometimes a second carpellary
leaf, similar to the first, is formed; in other cases the
central axis of the flower is occasionally prolonged into a
head of young flowers--median prolification. In some few
instances the calyx is not at all altered, but the carpellary
leaf is trifoliolate, or even quinquefoliolate, the corolla
being then absent. The heads of flowers in this first form have
the aspect of little tufts of leaves.
2. Each of the teeth of the calyx is represented by a long
stalk, terminated by a single articulated leaflet, the
bi-labiate form of the calyx is still recognisable; the two
upper petals are united, the three lower separate; the tube of
the calyx is not deformed and seems to be formed of the
petioles of the sepals united by their stipules. In this second
class of cases the corolla is papilionaceous, the filaments
free, the carpellary leaf on a long stalk provided with
stipules, its blade more or less like the usual carpel, with
its margins disunited or more commonly united with the ovules
in the interior, sometimes represented by a foliaceous, dentate
primine only. In one case the carpel was closed above, gaping
below, where it gave origin to several leaflets, the lower ones
oval, dentate, like ordinary leaflets, the upper ones merely
lanceolate, leafy lobes, representing the primine reduced to a
foliaceous condition. Inflorescence--a head with leafy flowers
on long stalks, which are longer at the circumference than in
the centre.
3. Calyx-teeth lance-shaped, acuminate; corolla more or less
regular, arrested in its development and scarcely exceeding the
tube of the calyx within which it is crumpled up; stamens but
little changed; carpellary leaf on a short stalk, not exceeding
the calyx tube, but the ovarian portion very long, and provided
with abortive ovules.
These three groups will be found to include most of the forms
under which frondescence of the clover blossoms occurs, but
there are, of course, intermediate forms not readily to be
grouped under either of the above heads. Such are the cases
brought under the notice of the British Association at
Birmingham in 1849 by Mr. R. Austen, in some of which the
petals and stamens even were represented by leaves.
Although, on the whole, chloranthy is most frequent in the families
already alluded to, yet it is by no means confined to them, as the
examples now to be given amply show. Specimens of _Nymphæa Lotus_ have
been seen in which all the parts of the flower, even to the stigmas,
were leafy, while the ovules were entirely wanting.
Planchon[288] figures and describes a flower of _Drosera intermedia_
that had passed into a chloranthic condition, excepting the calyx, which
was unchanged; the petals, like the valves of the ovary, were provided
with stipules, and were circinate in vernation.
M. A. Viaud-Grand-Marais[289] records an interesting example of
chloranthy, in which the sepals, petals, pistils, and ovules of
_Anagallis arvensis_ were all foliaceous. Similar changes have not
unfrequently been met with in _Dictamnus Fraxinella_.
M. Germain de Saint Pierre has also recorded the following deviations in
the flowers of _Rumex arifolius_ and _R. scutatus_; in these specimens
the calyx was normal, the petals large, foliaceous, shaped like the
stem-leaves, the stamens were absent, the three carpels fused into a
triangular leafy pod, as long again as the perianth, the stigmas normal
or wanting, the ovule represented by a thick funicle, terminated by a
foliaceous appendage analogous to the primine.[290]
In grasses it frequently happens that the flowers are replaced by
leaf-buds; this condition is alluded to elsewhere under the head of
viviparous grasses, but in this place may be mentioned a less degree of
change, and which seems to have been a genuine case of chloranthy in
_Glyceria fluitans_, the spikelet of which, as observed by Wigand,[291]
consisted below of the ordinary unchanged glumes, but the remaining
paleæ as well as the lodicles and stamens were represented by ligulate
leaves. The plant, it is stated, was affected by a parasitic fungus. On
the other hand, General Munro, in his valuable monograph of the
_Bambusaceæ_,[292] refers to an illustration in which "the lowest glumes
generally, and the lowest paleæ occasionally, had the appearance of
miniature leaves, with vaginæ, ligules and cilia, enveloping, however,
perfect fertile spiculæ; as progress is made towards the top of the
spike, the ligule first, then the cilia, and finally, the leaf-like
extension disappears, and the uppermost glumes assume the ordinary shape
and form of those organs."
=General remarks on chloranthy and frondescence.=--Moquin remarks with
justice that the position of the flowers on the axis is of importance
with reference to the existence of chloranthy. Terminal flowers are more
subject to it than lateral ones, and if the latter, by accident, become
terminal, they seem peculiarly liable to assume a foliaceous condition.
Kirschleger says, that in _Rubus_ there are two sorts of chloranthy,
according as the anomaly affects the ordinary flowering branches, or the
leafy shoots of the year, the summits of which, instead of developing in
the customary manner, terminate each in one vast and long inflorescence,
very loose and indeterminate, and with axillary flowers.[293]
On the whole, taking in consideration cases of partial frondescence, as
well as those in which most of the parts of the flower are affected,
phyllody would seem to be most common in the petals and carpels, least
so in the case of the stamens and sepals. It is more common among
polysepalous and polypetalous plants than in those in which the sepals
or petals are united together.
The causes assigned for these phenomena are chiefly those of a nature to
debilitate or injure the plant; thus it has been frequently observed to
follow the puncture of an insect. M. Guillard[294] gives an instance in
_Stellaria media_ where the condition appeared to be due to the attacks
of an insect _Thrips fasciata_. Still more commonly it arises from the
attacks of parasitic fungi, _e.g._ _Uredo candida_, in Crucifers, &c.
In other cases it has been observed when the plants have been growing in
very damp places, or in very wet seasons, or in the shade, or where the
plant has been much trampled on. This happens frequently with _Trifolium
repens_. The frequency with which the change is encountered in this
particular species is very remarkable; it is difficult to see why one
species should be so much more subject to the kind of change than
another of nearly identical conformation.
It might at first be supposed that the same causes that bring about the
complete substitution of leaf-buds for flower-buds (see Heterotaxy)
would operate also in the partial substitution of leaves for other parts
of the flower, but it will be seen that the inducing cause, whether
similar or not in the two cases respectively, acts at different times;
in the one case, it is not brought into play until the rudiments of the
flower are already formed, whereas in the other the influence is exerted
prior to the formation of the flower. So that while the formation of
leaf-buds in place of flower-buds may be and generally is due to an
excess of nutrition, inducing over activity of the vegetative organs,
the production of phyllomorphic or chloranthic flowers may be owing
rather to a perversion of development arising from injury or from some
debilitating agency. The discrepancies in the assigned causes for the
conditions above mentioned may, therefore, in great measure, be
attributed to the different periods at which the causes in question
operate.
The following list may serve as a guide to the plants most frequently
the subjects of chloranthy, but reference should also be made to
preceding and subsequent sections, and to that relating to prolification
of the inflorescence.
Aquilegia vulgaris.
Chelidonium majus.
Corydalis aurea.
Nymphæa Lotus!
*Brassica oleracea!
Bunias.
Hesperis matronalis.
*Sinapis arvensis!
Sisymbrium officinale.
Erucastrum canariense.
Diplotaxis tenuifolia.
Lychnis dioica!
Cerastium glomeratum!
triviale.
Stellaria media.
Poterium polygamum.
Torilis anthriscus.
Seseli, sp.
Selinum caruifolium.
Epilobium hirsutum!
Begonia fuchsioides.
Gomphia, sp.
Scabiosa Columbaria.
Dipsacus fullonum.
Matricaria Parthenium.
Calendula officinalis.
Campanula pyramidalis.
Reseda odorata!
Vitis vinifera.
Dictamnus Fraxinella!
Triumfetta, sp.!
*Tropæolum majus!
Rhamnus Frangula.
*Trifolium repens!
Lupinus, sp.
Rosa diversifolia!
Potentilla nepalensis.
argentea.
Fragaria vesca!
Geum rivale.
Rubus fruticosus.
cæsius.
Saxifraga foliosa.
Verbascum phlomoides.
Scrophularia nodosa.
aquatica!
*Primula sinensis!
Lysimachia Ephemerum.
Anagallis arvensis.
Webbiana.
Nicotiana rustica.
Anchusa ochroleuca.
Myosotis cæspitosa.
Stachys sylvatica.
Gilia capitata.
Euphorbia segetalis.
Rumex arifolius.
scutatus.
Juncus lampocarpus.
uliginosus.
In addition to the publications before cited the following may be named
as containing valuable information on the subject of this chapter.
Jæger, 'Missbild. Gewächs.,' 1814, p. 83, _Trifolium repens_.
For other accounts of similar malformations in the same plant,
see Schmitz, 'Linnæa,' xv, p. 268. Unger, 'Flora' (B. Z.) xxv,
p. 369. Caspary, 'Schrift. der. Physik. ökon. Gesellsch. zu
Königsberg,' 2, 1861, p. 51, tabs. ii, iii. Fleischer,
'Missbilld. verschied. Cult. Pflanz.,' 1862, p. 55, &c., t. v,
vii, &c. For _Primula_ see Brongniart, 'Ann. Sc. Nat.,' ser. 2,
t. i, p. 308. A. P. and Alph. De Candolle in 'Neue
Denkschrift.' Morren, C., 'Bull. Acad. Roy. Belg.,' xix, part
2, p. 539. Molkenboer, 'Tijdschr. voor Natuurl. Geschied.,'
1843, p. 355, tabs. vi, vii. Marchand, 'Adansonia,' iv, p. 167
and p. 159. _Anagallis_, p. 171, _Lonicera_, p. 83, _Juncus_.
For other plants see Fresenius, 'Mus. Senk.,' 2, p. 35, &c.
Norman, 'Ann. Sc. Nat.,' ser. 4, 1858, vol. ix, p. 220. Christ,
'Flora' (B. Z.) 1867, p. 376, tabs. v, vi, _Stachys_. Cramer,
'Bildungsabweich.,' p. 26, &c. Baillon, 'Adansonia,' ii, p.
300. Moquin-Tandon, 'El. Ter. Veg.,' p. 230. Schauer's
translation, p. 220. Hallier, 'Phytopathologie,' p. 160.
FOOTNOTES:
[245] Engelmann makes use of the word frondescence in the same cases.
'De Anthol.,' p. 32, § 38, while Morren adopts the term Phyllomorphy,
'Lobelia,' p. 95.
[246] See Schlechtendal, 'Bot. Zeit.,' vol. xv, 1857, p. 873; also
Marchand, 'Adansonia,' iv, p. 156.
[247] For instances of similar changes in _Composites_, see De Candolle,
'Prod.,' t. vi, p. 571, _Centaurea Jacea phyllocephala_. Clos, 'Ann. Sc.
Nat.,' ser. iii, tom. xvi, 1851, p. 41. 'Science Gossip,' 1865, p. 104,
&c.
[248] Kickx, 'Bull. Acad. Belg.,' t. xviii, part 2, p. 288.
[249] Weber, 'Verhandl. Nat. Hist. Vereins. f. Preuss.,' &c., 1860, p.
381.
[250] Weber, loc. cit.
[251] Sauter, 'Flora v. Bot. Zeit.,' 1831, p. 11.
[252] 'Descr. et Icon. Plant.' tab. 20.
[253] For references see p. 115; see also to Eichler, 'Excurs.
Morpholog. de format. flor. Gymnosperm.,' in "Mart. Flor. Brasil,"
abstracted in English in 'Natural History Review,' April, 1864.
[254] "Calyx tunc plane non differt a foliis proxime ipsi
præcedentibus." Wolff, 'Theor. Gener.,' § 114. Linn., 'Proleps.,' § 6.
Goethe, 'Versuch.,' §§ 31-38.
[255] 'Bull. Soc. Bot. France,' vol. viii, 1861, p. 697.
[256] 'Organ. Véget.,' t. i, p. 492, pl. xxxii, f. 6.
[257] This distinction between laminar and vaginal venation is well seen
in cases like _Mussaenda_, _Calycophyllum_, or _Dipterocarpus_, where
the enlarged calycine segment has a strictly vaginal arrangement of its
veins, very different from that which occurs in the true leaf-blades.
These are cases, therefore, where the sheath of the leaf is unusually
enlarged, and are not to be referred, as is often done, to metamorphosis
of one or more sepals to perfect leaves. Prolified roses, cherries, &c.,
furnish frequently parallel cases. With reference to _Mussaenda_, C.
Morren held the view that the petal-like sepal was really a bract
adherent to the calyx, and incorporating with itself one of the calycine
lobes--"soudée au calice et ayant dévorée, en englobant dans sa propre
masse, un lobe calicinal." The Belgian _savant_ considers this somewhat
improbable explanation as supported by a case wherein there were five
calyx lobes of uniform size, and a detached feather-veined leaf
proceeding from the side of the ovary lower down ('Bull. Acad. Belg.,'
xvii, p. 17, _Fuchsia_, p. 169).
[258] In this order _Agrostemma Githago_ offers an illustration of a
normally leafy calyx.
[259] 'Bull. Bot.,' i, p. 6.
[260] Wolff's original opinion was that the stamens were equivalent to
so many buds placed in the axil of the petals or sepals (see 'Theoria
Generationis,' 1759, § 114)--an opinion which more recently has received
the support of Agardh and Endlicher. Wolff himself, however, seems to
have abandoned his original notion, for in his memoir, "De formatione
intestinorum præcipue tum et de amnio spurio aliisque partibus embryonis
gallinacei, nondum visis," &c., in 'Comm. Acad. Petrop.,' xii, p. 403,
anno 1766, he considers the stamens as essentially leaves. See also
Linn. 'Prolepsis,' § viii; Goethe, 'Metam.,' § 46.
[261] Müller (Argov.), in 'Mém. Soc. Phys. et d'Hist. Nat. Genev.,' t.
xvii.
[262] "If we keep in view the observations which have now been made, we
shall not fail to recognise the leaf in all seed-vessels,
notwithstanding their manifold forms, their variable structure, and
different combinations."--(Goethe, 'Metam.,' § 78.) Wolff, 'N. Comm.
Acad. Petrop.,' 1766, xii, p. 403, expresses precisely the same opinion
as to the nature of the seed-vessel.
[263] 'El. Terat. Veg.,' p. 205.
[264] 'Ann. Sc. Nat.,' 4th series, vol. ix, p. 209.
[265] 'Adansonia,' iv, p. 70. A similar deviation has been observed by
M. van Tieghem in the ovary of _Tropæolum majus_, 'Bull. Soc. Bot. Fr.,'
1865, p. 411.
[266] Planchon et Marès, 'Ann. Sc. Nat.,' ser. 5, vol. vi, 1866, p. 228,
tab. xii.
[267] 'Act. Acad. Nat. Cur.,' 22, 11. 1850, p. 543, t. v, vi.
[268] 'Neue Denkschrift der allg. Schweiz. Gesellsch.,' band v. p. 9,
tab. 3, 4.
[269] 'Ann. Sc. Nat.,' 2 ser., vol. i, p. 308, pl. ix, c.
[270] 'Adansonia,' vol. iv, pp. 159, 171.
[271] 'Bildungsabweichungen,' &c., tab. iv, figs. 1, 2, 21, 28, 29, &c.
[272] 'Bull. Soc. Bot. France,' viii, p. 395.
[273] 'Notulæ,' p. 125, atlas, pl. xxxv; and 'Journals of Travels,'
1847, p. 475, _Lonicera_.
[274] 'Ann. Science Nat.,' 3rd ser., vol. ix, p. 86, tabs. 5, 6.
[275] 'Comptes Rendus,' vol. xviii, March 25th, 1864, and 'Ann. Sc.
Nat.,' 3 ser., vol. ii, p. 32.
[276] 'Mém. Acad. Sc. Toulous.,' ser. 5, vol. iii.
[277] 'Bildungsabweich. Pflanz. Famil.,' p. 89, tab. xi.
[278] 'Bull. Soc. Bot. Fr.,' 1865, p. 411.
[279] Translated in 'Ann. Sc. Nat.,' 4th series, t. xiv, p. 24.
[280] The calyx is not unfrequently excepted.
[281] 'Bull. Bot.,' t. i, p. 6.
[282] Lindley, 'Theor. Horticult.,' ed. 2, p. 84, f. 17.
[283] Gris, 'Bull. Soc. Bot. Fr.,' 1858, vol. v, p. 261, and 'Ann. Sc.
Nat.,' ser. 4, vol. ix, p. 80. Planchon, 'Flore des Serres,' vol. i,
1856, p. 129.
[284] 'Flora,' 1856, p. 711.
[285] 'Theory of Horticult.,' ed. 2, p. 90, f. 25.
[286] As considerable interest attaches to the "Plymouth strawberry,"
and very little is known of it in this country, or on the continent, the
author gladly avails himself of this opportunity of inserting an account
of it, for which he is indebted to the kindness of Dr. Robert Hogg.--The
Plymouth Strawberry (_Fragaria vesca fructu hispido_) is a sort of
botanical Dodo upon which many have written, and which few have seen.
Many years have elapsed since it was first discovered; and although a
century and a half have passed since there was any evidence of its
existence, it serves still as an illustration for students in morphology
of one of those strange abnormal structures with which the vegetable
kingdom abounds.
It is to old John Tradescant we are indebted for the earliest record of
this plant. Johnson, in his edition of 'Gerard,' says; "Mr. John
Tradescant hath told me that he was the first that tooke notice of this
strawberry, and that in a woman's garden at Plimouth, whose daughter had
gathered and set the roots in her garden, in stead of the common
strawberry; but she, finding the fruit not to answer her expectation,
intended to throw it away; which labour he spared her in taking it and
bestowing it among the louers of such varieties, in whose garden it is
yet preserved." Doubtless one of those "lovers" was his friend John
Parkinson, who, in the year 1629, thus wrote concerning it: "One
strawberry more I promised to shew you, which, although it be a wilde
kinde, and of no vse for meate, yet I would not let this discourse passe
without giuing you the knowledge of it. It is in leafe much like vnto
the ordinary, but differeth in that the flower, if it haue any, is
greene, or rather it beareth a small head of greene leaues, many set
thicke together like vnto a double ruffe, in the midst whereof standeth
the fruit, which, when it is ripe, sheweth to be soft and somewhat
reddish, like vnto a strawberry, but with many small harmlesse prickles
on them which may be eaten and chewed in the mouth without any maner of
offence and is somewhat pleasant as a strawberry; it is no great bearer,
but those it doth beare, are set at the toppes of the stalks close
together, pleasant to behold, and fit for a gentlewoman to weare on her
arme, &c., as a rairitie in stead of a flower."
Merret, in his 'Pinax.' published in 1667, says he found it growing in
the woods of Hyde Park and Hampstead, and Zanoni was the first to figure
it (with the exception of Parkinson's rude woodcut) in his 'Istoria
Botanica,' published in 1675. It is mentioned by Morison and also by
Ray, the latter of whom inserts it in his Synopsis, but without any
habitat; though in his 'Historia Plantarum' he says: "Cantabrigiæ in
horto per aliquot annos colui." From this time henceforth the Plymouth
strawberry has become a botanical Dodo, nothing more having been seen or
heard of it except the mere record of the name. In 1766, M. Duchesne
informed the world of the generosity of "M. Monti, Docteur de
Philosophie et de Médecine à Boulogne en Italie," who divided with him a
dried specimen taken from his own herbarium, "Ce présent prétieux m'ôte
toute incertitude sur la nature de ce Fraisier et sur ses caractères
monstrueux. Il paroît ne pas avoir aujourd'hui plus d'existence."
[287] 'Bull. Soc. Bot. France,' 1856, vol. iii, p. 477.
[288] 'Ann. Sc. Nat.,' 3 ser., vol. ix, p. 86, tabs. v, vi.
[289] 'Bull. Soc. Bot. France,' vol. viii, 1861, p. 695.
[290] Ibid., vol. iii, 1856, p. 475.
[291] 'Flora,' 1856, p. 712.
[292] 'Trans. Linn. Soc.,' vol. xxvi, p. 37.
[293] 'Bull. Soc. Bot. France,' 1862, vol. ix, p. 36, tab. i, and also
p. 291.
[294] Ibid., 1857, vol. iv, p. 761.
CHAPTER II.
METAMORPHY OF THE FLORAL ORGANS.
One of the main arguments adduced by Goethe and others in support of the
now generally received doctrine of the essential morphological identity
of the various whorls of the flower is derived from the frequent
appearance of one organ in the guise of another. The several parts of
the flower become, as it is said, metamorphosed; sometimes the change
is complete, while at other times there may be every conceivable
intermediate condition between one form and another. The sense in which
the terms metamorphosis, substitution, transformation, and the like, are
herein used has already been explained. For the convenience of
arrangement, metamorphosis of the parts of the flower may be divided
into several subdivisions, according to the particular organ affected,
and according to the special kind or degree of change manifested, the
main subdivisions being here classed as Sepalody, Petalody, Staminody,
and Pistillody.
=Sepalody of the petals.=--This change, spoken of by most authors as
retrograde metamorphosis of the petals into sepals, or as a substitution
of sepals for petals, is obviously a condition that is in most cases
hardly distinguishable from virescence of the corolla, or from
multiplication of the sepals. Nor is this of much consequence unless
there are some special structural features which render the
discrimination a matter of importance, in which case the difficulty is
generally easily surmounted. The flower of the Saint-Valèry Apple may
perhaps be cited under this head. In the flower in question there are
neither stamens nor petals, unless the second or inner of sepals be
considered as sepaloid petals (fig. 152).
[Illustration: FIG. 152.--Flower of St. Valèry apple, with sepaloid
petals.]
M. Alph. de Candolle[295] describes an instance in _Primula Auricula_ in
which the corolla had assumed the appearance of the calyx, but neither
calyx nor corolla in this case possessed perfect stomata.
This malformation is much less common than the converse one of
calycanthemy. Many of the recorded instances of so-called metamorphosis
of the parts of the flower to sepals have occurred in monocotyledonous
plants, or others in which the calyx and corolla are of the same colour,
and constitute what is frequently termed the perianth; and as this is
usually brightly coloured (not green) it is more convenient to group the
metamorphoses in question under the general term Petalody, which thus
includes all those cases in which the organs of the flower appear in the
form of coloured petal-like organs, whether they be true petals or
segments of a coloured perianth. As the morphological difference between
the organs is one of position merely, there is little objection to be
raised to this course, the less so as the term petalody merely conveys
an idea of resemblance and not of absolute identity.
Petaloid coloration of the ordinary leaves, or of the bracts, is
mentioned under the chapter relating to colour.
=Petalody of the calyx--Calycanthemy.=--As with the bracts, so the calyx
in certain instances is naturally coloured, as in _Delphinium_,
_Tropæolum_, and others. In _Mussænda_, _Calycophyllum_, _Usteria_, &c.,
one or more of the calyx lobes become enlarged normally. Considered
teratologically, petaloid coloration of the sepals is either general or
partial; in the latter case the nerves retain their green colour
longest. There is in cultivation a variety of the primrose called
_Primula calycanthema_, in which the upper part of the calyx becomes
coloured, so that the flower seems to have two corollas placed one
within the other; a similar thing happens in _Mimulus_, in which plant,
as the calyx is permanent while the corolla is deciduous, the coloured
calyx is a great advantage in a horticultural point of view. Morren[296]
says that in order to produce the fine colour of the calyx of _Primula
officinalis_ (var. _smaragdina_) the Belgian gardeners cut away the
corolla in a very early stage, and that in consequence the colouring
matter proper to the corolla is developed in the tube of the calyx, the
edges of the limb remaining green, the middle of the limb being purple
(_Primula tricolor_).
[Illustration: FIG. 153.--Flower of _Mimulus_, with petaloid calyx.]
Under this head may be mentioned the occurrence of tubular sepals in
place of the ordinary flat ones in _Helleborus olympicus_; only two of
the sepals were thus affected in a specimen recently observed--a third
exhibited an intermediate condition.
The normal coloration of the calyx occurs most frequently in
polysepalous calyces; teratological coloration, on the other hand,
occurs especially in gamosepalous flowers. This assertion is borne out
by the frequency of the change in the plants already mentioned, and also
in the following:--_Campanula persicifolia_, _Anagallis arvensis_,
_Gloxinia_, _Syringa persica_,[297] _Calceolaria_, _&c. &c_. In the
last-named plant one or more of the lobes of the calyx may frequently be
seen replaced by a slipper-like petal.
Among polysepalous plants petaloid sepals have been observed in
_Ranunculus auricomus_, _Rubus cæsius_, _&c._ Fleischer also describes a
case of this kind in _Carum carui_.[298]
It will be seen from the above that in the majority of cases there is no
real metamorphosis or substitution of petal for calyx, but simply an
alteration in colour; nevertheless, a change in form may accompany a
change of colour: this happens especially if there has been any
displacement of organs. Thus, if, in an orchidaceous plant, a sepal be
displaced from any cause, or a petal be twisted out of its natural
position to occupy the place of an absent sepal, that petal will be
sepal-like in form, and _vice versâ_.
=Petalody of the stamens.=--A petaloid condition of the stamens is one
of the commonest of all malformations. A large number of so-called
double flowers (flores pleni)[299] owe their peculiar appearance to this
circumstance.
It is necessary to distinguish carefully this petaloid development of
the stamens from the corresponding condition of the pistils, and from
that kind of doubling which is a result of multiplication of the
corolla, as in _Datura_, _Campanula_, _Primula_, &c. (flores duplices,
triplices, &c.), or from that produced by true median prolification
(flores geminati, &c.).
In cases of true petaloid development of the stamens there are usually
numerous intermediate forms between that of the true petals and that of
the perfect stamens; indeed, in _Nymphæa_, _Canna_, and in some other
plants, such a transition occurs normally. Petalody of the stamens may
occur either without material change in the flower or it may exist in
combination or in conjunction with an increased development of parts
(Multiplication), or with a similar change in the carpels, and it is
either partial or complete.
Among the flowers in which petaloid development of the stamens happens
most frequently may be mentioned those in which the calyx is normally
coloured, as in _Nigella damascena_, _Aguilegia_, and _Delphinium_.
M. Alph. de Candolle, in the 'Neue Denkschriften,' 1841, described and
figured a singular form of _Viola odorata_, known under the name of
"Bruneau," in Switzerland, in which the stamens are absent, and their
place supplied by a second row of petals, within which is a third series
of petals, representing, says M. de Candolle, the inner row of stamens
that theory suggests should exist in the natural condition. Moreover,
the carpels in this variety are five in number instead of three. In
_Erica Tetralix_ the corolla may not unfrequently be found divided to
the base into its constituent petals, and the place of the stamens
occupied by a series of petal-like structures entirely destitute of
anther.
In monocotyledonous flowers, especially those with a coloured perianth,
the substitution of segments of the perianth for stamens occurs not
unfrequently. M. Seringe has observed this in the stamens of _Lilium
Martagon_, and there is in cultivation a variety of the white lily,
_Lilium candidum_, sometimes called the double white lily, in which the
segments of the perianth, in place of being arranged in two rows, are
greatly increased in number, and disposed in a spiral manner. In these
flowers, not only are the stamens and pistils thus modified, but also
the upper leaves of the stem. In so-called double tulips there is
likewise a replacement of stamens by coloured segments of the perianth,
but this happens generally in connection with an increase in the number
of organs. Moquin-Tandon remarks having seen in a garden in the environs
of Montpelier a tulip, the stamens of which showed all possible stages
of transition between the form proper to them and that of the perianth.
The pistil in this case was transformed into several small leaves.
Similar appearances have been observed in Iris, Hyacinths, Narcissus,
Colchicum, and Crocus. M. Fournier[300] describes a flower of _Narcissus
Tazetta_ from within the normal perianth of which sprang a second one,
equally provided with a cup and occupying the space usually filled by
the stamens. Flowers of _Narcissus poeticus_ may also be met with in
which the stamens are replaced by six distinct segments exactly
resembling those of the perianth in miniature.[301]
[Illustration: FIG. 154.--Double columbine, _Aquilegia_--petalody of the
filament.]
From an examination of these flowers it becomes evident that
petalification is brought about in different flowers in different ways;
sometimes it is the filament which becomes petaloid, sometimes the
anther-lobes, while at other times it is the connective which assumes
the appearance of petals.[302] For instance, in _Solanum tuberosum_,
_S. Dulcamara_, in _Anagallis_, in _Fuchsia_, and some other plants, the
anther-lobes themselves become petaloid, while the filament remains
unchanged.
In gardens two distinct varieties of Columbine are cultivated, the one
in which the filaments are dilated into the form of flat petals almost
entirely or quite destitute of anthers, while in the other the filament
is present in its usual form, but the anther is developed in the shape
of a tubular hood or spur.
De Candolle[303] observes that in the _Ranunculaceæ_ the species of
_Clematis_ become double by the expansion of the filament, those of
_Ranunculus_ by the dilatation of the anther, and those of _Helleborus_
by the petal-like development of both filament and anther. In some cases
even on the same plant all three modifications may be seen, as in
Camellias, some of which may be found with petaloid filaments with
anthers on the top, others with the filaments unchanged, but supporting
petaloid anthers, while in others it is the connective alone which is
petal-like. Where the flower naturally contains a large number of
stamens, as in Mallows, Roses, Magnolias, &c., petaloid expansion of the
filament is most common, though it is by no means confined to such
flowers, the change occurring in _Allamanda cathartica_, _Jasminum
grandiflorum_, and many other flowers with few stamens. A similar change
in the anther and connective takes place more frequently in flowers
where the number of stamens is smaller, but there are of course numerous
exceptions to this rule.
In those cases where there is more than one row of stamens, the
outermost are most liable to this change: thus in _Saxifraga decipiens_,
as shown by Ch. Morren,[304] the outer series of stamens--those opposite
to the sepals--become first affected, and, at a more advanced stage, the
inner row also; and this is the case in most flowers that have their
stamens in two rows. Occasionally it happens that an outer series of
stamens is abortive, or wholly suppressed, while the inner row becomes
petalodic; this was the case in some flowers of _Lilium auratum_ lately
exhibited by Messrs. Veitch.
Those flowers in which only a portion of the stamens undergo this change
are called semi-double, while in other cases that will be hereafter
mentioned, not only are the stamens thus rendered petaloid, but their
number is also augmented, as in most double roses, pinks, anemones,
poppies, &c.
In some double flowers, in which the stamens assume more or less
completely the appearance of petals, a singular appearance is afforded
by the presence of four wing-like processes emanating from the central
filaments, two on each side, so that the arrangement may be compared to
two sheets of paper folded in the centre and adherent in that situation,
though perfectly separate elsewhere, except sometimes at the top, where
they form a sort of hood. This change results from an imperfect petalody
of the anther; the two wings on each side of the central vascular cord
represent the front and back walls of an anther lobe, or rather of that
portion of the anther which, under ordinary circumstances, produces
pollen. In the malformed flowers no pollen is formed, at least in the
more complete states of the malformation, but the walls of the anther
lobe become preternaturally enlarged, and petaloid in texture and
appearance. This change occurs in some semi-double rhododendrons and
azaleas, in crocuses, and in a species of violet found at Mentone by Mr.
J. T. Moggridge.
There are numerous intermediate forms wherein the wing-like processes
may be traced all the way along the filament till they ultimately lose
themselves in the anther-lobes, with which they become continuous. In
some cases, as in _Crocus_ and _Rhododendron_, this is shown even more
clearly by the existence of two perfect pollen-sacs or quarter-anthers,
the remaining portions being petaloid and continuous with the dilated
filament. Not unfrequently these semi-petaloid stamens adhere to the
fronts of the petals, and then it appears, at a first glance, as if
three organs were stuck together, one in front of another, while in
reality there are but two.[305] (See _antè_, p. 35, fig. 12.)
[Illustration: FIG. 155.--Four-winged filaments of _Rhododendron_.]
The change in the anther, above alluded to, must not be mistaken for
that far more common one in which only a small portion of the anther
becomes petaloid, forming a sort of lateral wing or appendage to the
polliniferous portion, as happens normally in _Pterandra_, and is common
in some double fuchsias. In this latter instance there is but a single
wing, and the nature of the case is obvious.
Double flowers of _Orchidaceæ_ generally arise from petalification of
the filaments, with or without other coincident changes. What makes
double flowers in this order the more interesting is the development, in
a petaloid condition, of some or all of those stamens which under
ordinary circumstances are wholly suppressed, so that the morphological
structure of the flower, at first a matter of theory, becomes actually
realised. Fig. 156 is a diagram showing the presence of two additional
labella within the ordinary one in a species of _Catasetum_, and
representing two petaloid stamens, thus evidently completing the outer
staminal whorl, of which there is usually but a single representative
(see Peloria, Multiplication, Prolification). In some of these double
orchids it is, however, necessary not to confound a petaloid condition
of the existing column with the development of usually suppressed
stamens in a petaloid form. Thus, in _Lycaste Skinneri_ the column is
frequently provided with two petal-like wings, which might readily be
supposed to be two stamens of the inner whorl adherent to the column; a
little attention, however, to the relative position of these
adventitious wings is generally sufficient to enable the observer to
ascertain the true nature of the appearance.[306]
[Illustration: FIG. 156.--Diagram of flower of _Catasetum_, with two
labella.]
Some forms of duplicate or hose in hose corollas are apparently due, not
so much to the formation of a second corolla within the first, as to the
presence of an inner series of petal-like stamens, which, by their
cohesion, form a second pseudo-corolla within the first. The staminal
nature of this pseudo-corolla is inferred from the occasional presence
of anthers on it.[307] In _Datura fastuosa_, as well as in _Gloxinia_, a
pseudo-corolla of this kind sometimes occurs with the addition of a
series of petaloid stamens attached to its outer surface.[308]
When the petalody specially affects the anther-lobes, as in _Arbutus_,
_Petunia_, _Fuchsia_, _&c._, the venation of the petal-like portion is
very frequently laminar, thus tending to show that the anther is in
such cases really a modification of the blade of the leaf; but as, on
the other hand, we often find petal-like filaments bearing pollen-sacs
on their sides, it is clear that we must not attribute the formation of
pollen to the blade of the leaf only, but we must admit that it may be
formed in the filament as well.[309]
[Illustration: FIG. 158.--Portion of a double columbine (_Aquilegia_),
showing petalody of the connective.]
[Illustration: FIG. 159.--Petaloid stamens, _Hibiscus_.]
Petalody of the connective is of less frequent occurrence than the
corresponding change in the other portions of the stamen. It may be seen
in some forms of double columbine,[310] in which the connective forms a
tubular petal or nectary, and in double petunias and fuchsias. When it
occurs, the true anther-lobes are usually atrophied, and little or no
pollen is formed.
An occurrence of this nature in _Tacsonia pinnatistipula_, in
conjunction with the partial detachment of the stamens from the
gynophore, led Karsten to establish a genus which he called
_Poggendorffia_.[311]
From the subjoined list of genera in which petalody of the stamens, in
some form or other, has been observed, it will be seen that it happens
more often in plants with numerous distinct organs (Polypetalæ,
Polyandria, Polygynia, &c.) than in other plants with a smaller number
of parts, and which are more or less adherent one to the other. The
tendency to petalification is, moreover, greater among those plants
which have their floral elements arranged in spiral series, than among
those where the verticillate arrangement exists; and in any given
flower, if the stamens are spirally arranged while the carpels are
grouped in whorls, the former will be more liable to petalody than the
latter, and _vice versâ_. It has been before remarked, that this
condition is far more common in plants whose petals, &c., have straight
veins, like those in the sheath of a leaf, than in those the venation of
which is reticulate, as in the blade of the leaf. It must also be
remembered that in the same genus, even in the same species, different
kinds of doubling occur. Familiar illustrations of this are afforded in
the case of anemones, columbines, fuchsias, and other plants.
The existence of "compound stamens" in some flowers, as pointed out by
Payer, and others, and the researches of Dr. Alexander Dickson, confer
additional importance on the subject of petalody, and necessitate the
examination of double flowers with special reference to these compound
stamens, and to the order of their development.[312] The presence of
these compound stamens affords a satisfactory explanation of the
appearance in some double _Malvaceæ_, wherein the tufts of adventitious
petals are very liable to be mistaken for buds, produced by axillary
prolification in the axils of the petals, but which are in reality
compound and petaloid stamens. At other times, however, true axillary
prolification exists in these flowers; but then the supplemental florets
have always a calyx, which is wanting in the other instances.
Petalody of the stamens has been met with most frequently in the
following genera:
*Ranunculus!
*Anemone!
*Papaver!
*Clematis!
*Hepatica!
*Ficaria!
Thalictrum.
*Caltha!
*Trollius!
*Nigella!
*Aquilegia!
*Delphinium!
*Adonis!
*Pæonia!
*Nelumbium!
*Nymphæa!
*Berberis!
*Papaver!
*Chelidonium!
Sanguinaria.
Podophyllum.
*Mathiola!
*Cheiranthus!
*Iberis!
*Cardamine!
*Hesperis.
*Barbarea!
*Sinapis!
*Brassica!
*Helianthemum!
*Viola!
*Dianthus!
*Saponaria!
*Lychnis!
*Silene!
*Sagina!
*Hibiscus!
*Althæa!
*Malva!
Æsculus!
*Geranium!
*Pelargonium.
*Tropæolum!
Oxalis!
*Impatiens!
*Camellia!
Thea!
Trifolium!
Medicago!
*Ulex!
Spartianthus.
Clitoria.
Pisum!
Orobus!
Genista!
Spartium!
Cytisus!
Anthyllis.
Coronilla.
Lotus!
*Rosa!
*Kerria!
*Spiræa!
*Fragaria!
*Potentilla!
*Cratægus!
Cydonia.
*Pyrus!
Eriobotrya!
*Amygdalus!
*Prunus!
*Myrtus!
*Punica!
*Philadelphus!
*Deutzia!
*Fuchsia!
Godetia!
Clarkia!
Portulaca!
Ribes!
Saxifraga!
Daucus.
Ixora.
Serissa!
Gardenia!
Lonicera!
Sambucus.
Viburnum.
Scabiosa.
*Campanula!
Platycodon!
Calluna!
Azalea!
Rhododendron!
*Arbutus!
*Erica!
*Anagallis!
*Primula!
*Jasminum!
Syringa!
*Vinca!
*Nerium!
Allamanda!
Tabernæmontana.
*Calystegia!
Convolvulus!
Ipomoea.
*Datura!
*Petunia!
Solanum!
Orobanche.
Gentiana.
Mimulus.
*Antirrhinum!
Gratiola!
*Digitalis!
*Linaria!
Veronica!
Calceolaria!
Achimenes.
Gloxinia!
Clerodendron!
Bignonia.
Cyclamen!
Mirabilis.
Laurus!
Gladiolus!
Crocus!
Iris!
*Galanthus!
Leucojum!
Sternbergia!
Hippeastrum.
*Narcissus!
*Orchis!
Catasetum!
Hydrocharis.
Asphodelus.
*Tulipa!
Scilla.
*Convallaria!
Fritillaria!
*Lilium!
*Hyacinthus!
*Polianthes!
*Hemerocallis!
*Colchicum!
*Sagittaria!
*Tradescantia!
Commelyna!
Tofieldia.
=Petalody of the pistils.=--Taken by itself, this is much less common
than the corresponding change in the stamens. It generally affects the
style and stigma only, as happens normally in _Petalostylis_, _Iris_,
&c., but this is by no means always necessarily the case. In some of the
cultivated varieties of _Anemone_ and _Ranunculus_ all the parts of the
flower remain in their normal state, except the pistils, which latter
assume a petaloid appearance.
Many of the double flowers owe their peculiar appearance to the
combination of the following appearances--a petal-like form of the
stamens, increase in the number of these organs and similar changes
affecting the pistils, and is applied to several distinct conditions. If
in any given flower all the stamens and all the pistils become wholly
petaloid, no pollen is formed, and of course no seeds can be produced,
but this very rarely happens, as usually some pollen is produced, and
some ovules capable of being fertilised are developed.
In double flowers of _Primula sinensis_ it frequently happens that the
capsule is either partially leafy or partly petal-like; in either case
the fruit is open at the extremity, and often destitute of the style and
stigma. It is, however, doubtful if the ovules can be fertilised in
these flowers.
The following list comprises the names of those genera in which this
change has been most frequently observed, independently of corresponding
alterations in the stamens, but it is more usual for both sets of organs
to be similarly affected.
*Ranunculus!
*Anemone!
Nigella.
*Papaver!
*Dianthus!
Saponaria!
Viola!
Camellia!
Alcea.
Hibiscus!
Amygdalus!
Lonicera!
Scabiosa.
Æschynanthus!
Primula!
=Petalody of the ovules.=--The principal changes which occur in the
ovule have already been alluded to at pp. 262-272; it may here be
stated, however, that the ovules are occasionally represented by small
stalked petal-like structures. This happens with especial frequency
among _Cruciferæ_.[313]
=Petalody of the accessory organs.=--A petaloid condition of the disc,
of the scales, or other excrescences from the axis or from the lateral
portions of the flower, is of frequent occurrence, though it is but
rarely that the change is of any great importance in a morphological
point of view. C. Morren has given the name adenopetaly to a case
wherein one of the glands at the base of the petals in _Lopezia_ was
replaced by a petal.[314] A similar change may be seen in the double
Oleander.
=Staminody of the bracts.=--An instance of this has been already alluded
to in _Abies excelsa_, as observed by Prof. Dickson, and in which some
of the bracts were seen assuming the form and characteristic of the
stamens see _ante_: p. 192. Signor Licopoli met with a similar
substitution of anthers for bracts in _Melianthus major_.[315]
=Staminody of the sepals and petals.=--In the first named this is of
very rare occurrence. M. Gris has recorded an instance in _Philadelphus
speciosus_[316] which appears to be the only case on record. The
corresponding change in the case of the petals is far more common. De
Candolle cites in illustration of this occurrence flowers of the common
haricot, in which the alæ and carina of the corolla were thus
changed.[317] There is in cultivation a form of _Saxifraga granulata_
wherein the petals are replaced by stamens, so that there are fifteen
stamens. A similar change has been observed in _Capsella
bursa-pastoris_.
Cramer figures and describes a stamen occupying the place of a petal in
_Daucus Carota_.[318] Turpin[319] describes a similar occurrence in
_Monarda fistulosa_, in which the lower lip terminated in an anther, but
this may have been a case of adhesion. Moquin cites from Chamisso,
_Digitalis purpurea_, and from Jussieu, _Asphodelus ramosus_, as having
presented this change, and Wiegmann[320] has seen anthers developed on
the awns of _Avena chinensis_. In semi-double flowers of _Ophrys
aranifera_ and _Orchis mascula_, the lateral petals are occasionally
partially antheroid, and others occur in which two of the outer series
of stamens, which are ordinarily suppressed, are present, but in a
petaloid state. Reichenbach[321] figures an illustration of this change,
and also Moggridge.[322]
=Staminody of the pistils.=--The existence of this change has been
denied by several authors, nevertheless, it is of sufficiently common
occurrence. Alexander Braun notices the transformation of pistils into
stamens in Chives (_Allium Scorodoprasum_), and in which three stamens
appeared in the place of as many pistils, and had extrorse anthers,
while the six normal anthers are introrse. In the horse-radish
(_Armoracia rusticana_), two of the carpels are frequently converted
into stamens, while two other organs absent from the normal flower make
their appearance as carpels. Roeper has observed this phenomenon in
_Euphorbia palustris_,[323] and in _Gentiana campestris_.[324] In these
examples one of the carpels was apparently absent, and its place
supplied by an anther. Roeper has also mentioned a balsam with a
supernumerary stamen occupying exactly the position of a carpel.[325]
Agardh has observed a similar thing in a hyacinth, one half of the fruit
of which contained seeds, and the other half, anthers. B. Clarke
mentions an instance in _Mathiola incana_ in which the carpels were
disunited, and antheriferous at the margin.[326]
The passage of pistils to stamens in willows has been frequently
remarked, as in _Salix babylonica_, _silesiaca_, _cinerea_, _Caprea_ and
_nigricans_. One of the most curious illustrations of this
transformation in this genus is given by Henry and Macquart (Erst.
Jahrb. des bot. Vereines am m. et n. Rhein., 1837). In the flowers in
question the series of changes were as follows:--first, the ovary opened
by a slit, and then expanded into a cup; next, anther-cells were
developed on the margin of the cup, with stigmas alternating with them,
the ovules at the same time disappearing; lastly, the margin became
divided, and bore three perfect anthers, which in the more perfect
states were raised on three filaments.
_Campanula persicifolia_, _C. rapunculoides_, and _C. glomerata_ have
been observed to present an anther surmounting the pistil.[327] Double
tulips often present this change, and a like appearance has been
observed in _Galanthus nivalis_, and _Narcissus Tazetta_.
Moquin mentions the existence of this condition in a female plant of
maize, some of the pistils of which were wholly or partially converted
into anther-like organs. Mohl has recorded an analogous malformation in
_Chamærops humilis_, and in which the three carpels were normally
formed, and only differed from natural ovaries in this, that along the
two edges of the ventral suture there was a yellow thickening, which a
cross section of the ovary showed to be an anther-lobe filled with
pollen.[328]
In _Tofieldia calyculata_ a similar substitution of a stamen for a
carpel has been observed by Klotsch,[329] and Weber[330] gives other
instances in _Prunus_ and _Pæonia_. Corresponding alterations may be met
with in cultivated tulips, in the cowslip and other plants. In most of
the above cases the transmutation has been perfect, but in quite an
equal number of cases a portion only of the carpel is thus changed,
generally the style or the stigma; thus Baillon describes the stigmas of
_Ricinus communis_ as having been in one instance antheriferous.[331]
Moggridge figures a flower of _Ophrys insectifera_ in which the
rostellate process was replaced by an anther.[332]
Mohl remarks that the change of pistils into stamens is more common in
monocarpellary pistils than it is in those which are made up of several
carpels. It seems clear that in this transformation the lobes of the
anther and the development of pollen have no relation to the production
of ovules.
=Staminody of the accessory organs of the flower.=--The scales that are
met with in some plants, either as excrescences from the petals, or as
imperfect representatives of stamens or other organs, are occasionally
staminoid; thus the scales of _Saponaria officinalis_, of _Silene_,
_Nerium Oleander_, the rays of _Passiflora_, the corona of _Narcissus_,
have all been observed occasionally to bear anthers.[333] In the case of
_Narcissus_ the loose spongy tissue of the corona seems to have the
nearest analogy to the anther-lobes, while the prolonged connective is
more like the ordinary segments of the perianth in texture. The species
in which this change may most frequently be observed are, _N. poeticus_,
_N. incomparabilis_, and _N. montanus_.
M. Bureau found in some flowers of _Antirrhinum majus_ two petal-like
bodies standing up in front of, or opposite to the two petals of the
upper lip,[334] and similar developments in which each of the two
adventitious segments are surmounted by an anther may be met with
frequently. It does not follow because these organs bear anthers that
they are morphologically true stamens. They are really scales, &c.,
taking on themselves accidentally the characters proper to stamens.
=Pistillody of the perianth.=--The passage of the segments of the
perianth into carpels has been observed frequently in _Tulipa
Gesneriana_, the change in question being generally attended by a
partial virescence. M. Gay is said by Moquin to have observed a flower
of _Crocus nudiflorus_ in which the segments of the perianth were cleft
and fringed at the same time, so that they presented the appearance of
the stigmas.
[Illustration: FIG. 160.--Flower of tulip, allowing vertical attachment
of a leaf, and also the existence of ovules on the margins of the
segments of the perianth. Some of the parts are removed.]
=Pistillody of the sepals.=--In some double flowers of the garden pea
communicated by Mr. Laxton, among other peculiarities was a
supernumerary 5-6-leaved calyx, some of the segments of which were of a
carpellary nature, and bore imperfect ovules on their margins, while at
their extremities they were drawn out into styles.[335]
=Pistillody of the stamens.=--This change whereby the stamens assume more
or less the appearance of pistils is more commonly met with than is the
metamorphosis of the envelopes of the flower into carpels. In some cases
the whole of the stamen appears to be changed, while in others it is the
filament alone that is altered, the anther being deficient, or
rudimentary; while, in a third class of cases, the filament is
unaffected, and the anther undergoes the change in question. In those
instances in which the filament appears to be the portion most
implicated, it becomes dilated so as to resemble a leaf-sheath rather
than a leaf-stalk, as it does usually.
One of the most curious cases of this kind is that recorded in the
'Botanical Magazine,' (tab. 5160, f. 4) as having occurred in _Begonia
frigida_ already alluded to, and in which, in the centre of a male
flower, were four free ovoid ovaries alternating with as many stamens.
In the normal flowers of this plant, as is well known, the male flowers
have several stamens, while in the female flowers the ovary is strictly
inferior, so that, in the singular flower just described, the perianth
was inferior instead of being superior, as it is usually. It should be
added also that the perianth in these malformed flowers was precisely
like that which occurs ordinarily in the male flowers.
[Illustration: FIG. 161.--Supernumerary carpels in the orange, arising
from substitution of pistils for stamens.]
In some varieties of the orange, called by the French "bigarades
cornues," the thalamus of the flower, which is usually short, and
terminated by a glandular ring-like disc, is prolonged into a little
stalk or gynophore, bearing a ring of supernumerary carpels. These
carpels are isolated one from another, and are formed by the
transformation of the filaments of the stamens.[336]
The additional carpels in the case of the apple of St. Valéry, in which
the petals are of a green colour, like the sepals, are by some
attributed to the transformation of the stamens into carpels. These
adventitious carpels frequently contain imperfect ovules and form a
whorl above the normal ones. (See _Pyrus dioica_ of Willdenow.)[337] A
similar change occasionally happens in the stamens of _Magnolia
fuscata_, while in double tulips this phenomenon is very frequent, and
among them may be found all stages of transition between stamens and
pistils, and many of the parts combining the characters of both.[338]
Dunal and Campdera have described flowers of _Rumex crispus_, with seven
pistils, occupying the place of as many stamens.
[Illustration: FIG. 162.--Substitution of carpels for stamens in
_Papaver_.]
In _Papaver bracteatum_ a considerable number of the stamens sometimes
become developed into pistils, especially those which are nearest to
the centre of the flower, and in these flowers the filaments are said to
become the ovaries, while the anthers are curled so as to resemble
stigmas. A similar change is not infrequent _Papaver somniferum_.
Goeppert, who found numerous instances of the kind in a field near
Breslau, says the peculiarity was reproduced by seed for two years in
succession.[339] Wigand ('Flora,' 1856, p. 717) has noticed among other
changes the pistil of _Gentiana Amarella_ bearing two sessile anthers.
_Polemonium cæruleum_ is another plant very subject to this change.
Brongniart[340] describes a flower of this species in which the stamens
were represented by a circle of carpels united to each other so as to
form a sheath around the central ovary. By artificial fertilization M.
Brongniart obtained fertile seeds from the central normal ovary as well
as from the surrounding metamorphosed stamens.
_Cheiranthus Cheiri_ has long been known as one of the plants most
subject to this anomaly. De Candolle even mentions it in his 'Prodromus'
as a distinct variety, under the name of _gynantherus_. Brongniart (loc.
cit.) thus refers to the _Cheiranthus_:--"Sometimes these six carpellary
leaves are perfectly free, and in this case they spread open, presenting
two rows of ovules along their inner edges, or these edges maybe
soldered together, forming a kind of follicle like that of the
columbine; at other times, these staminal pistils are fused into two
lateral bundles of three in each bundle, or into a single cylinder which
encircles the true pistil. In a third set of cases these outer carpels
are only four in number, two lateral and two antero-posterior, all fused
in such a manner as to form around the normal pistil a prism-shaped
sheath, with four sides presenting four parietal placentæ, corresponding
to the lines of junction of the staminal carpels."
In the accompanying figures (fig. 163, _a-d_) the nature of this change
is illustrated. In some of the specimens it is easy to see that the two
shorter stamens undergo the change into carpels later and less perfectly
than the four longer ones, and not infrequently the outer pair are
altogether absent. In most of the flowers of this variety the petals are
smaller and less perfectly developed than usual.[341]
[Illustration: FIG. 163.--_Cheiranthus Cheiri_, var. _gynantherus_. _a._
Sepals and petals removed to show carpellodic stamens. _b._ The same
laid open. _c._ Transverse section. _d._ Plan of flower with four
carpel-like stamens, &c.]
In _Lilium tigrinum_, some specimens of which were gathered by Mr. J.
Salter, in addition to various degrees of synanthy and other changes,
some of the stamens were developed in the form of carpels, adherent by
their edges so as to form an imperfect tube or sheath around the normal
pistil. Fig. 164 shows one of the intermediate organs from these
flowers, in which half the structure seems devoted to the formation of
ovules, while the other half bears a one-celled anther. Lindley[342] has
also described a case of this kind in a species of _Amaryllis_.
[Illustration: FIG. 164.--Structure half anther, half carpel, _Lilium_.]
In _Saxifraga crassifolia_ it sometimes happens that mixed with the
stamens, and originating with them, are a number of distinct and
perfectly formed carpels, wholly separated from the normal carpels, in
the centre of the flower. In this particular instance there is usually
no intermediate condition between the stamen and the pistil.
Guillemin[343] also describes a transformation of the stamens into
carpels in _Euphorbia esula_.
When the anther is involved it may be only partially so, or almost the
whole organ may be transformed. As instances of very partial change may
be cited the passage of the connective into a stigma in _Thalictrum
minus_, or the passage of the points of the anthers into imperfect
styles in some species of bamboo.[344]
In _Rosa arvensis_ similar transformations have been observed of a
slightly more complex character than those just mentioned, and passing
into more important changes, especially to the formation of pollen
within ovules, formed on the edges of an open carpellodic anther (see p.
186).
Mr. Berkeley has recorded an analogous case in a gourd in which the
stamens bore numerous ovules (p. 200), and Baillon describes another
gourd in which certain fleshy appendages surrounding the androecium
were provided with ovules.[345]
Payer, in his 'Organogénie,' p. 38, mentions a stamen of _Dionæa_
bearing not only an anther, but likewise an ovule.
_Sempervivum tectorum_ and _S. montanum_, have long been noticed as
being very prone to present this change. Mohl[346] remarks that, in the
transformation of the stamens to the pistil in the common houseleek, the
filament of the stamen generally preserves its form, the anthers alone
undergoing change. At other times, however, the transformation takes
place at the same time, both in the filament and in the anther. When the
stamens are numerous some of them remain in their normal state, while
others, and especially the inner ones, undergo a change. Sometimes all
the stamens are changed simultaneously, while at other times some of
these organs may be found in which the anther is partially filled with
ovules, and partially with pollen.
In the accompanying figures (fig. 165, _a-h_) a series of intermediate
stages is shown between the ordinary stamen of _Sempervivum tectorum_
and the ordinary carpel, from which it will be seen that the filament is
little, if at all, affected, and that in those cases where there is a
combination of the attributes of the stamen and of the pistil in the
same organ the pollen is formed in the upper or inner surface of the
leaf-organ, while the ovules arise from the opposite surface from the
free edge, (_b_, _c_, _d_, _e_, _f_, _g_).
In a drawing made by the Rev. G. E. Smith of a malformed flower of
_Primula acaulis_, and which the writer has had the opportunity of
examining, the stamens are represented as detached from the corolla, and
their anthers replaced by open carpels, with ovules arising, not only
from their edges, but also from their surfaces, while the apex of the
carpellary leaf was drawn out into a long style, terminated by a
flattened spathulate stigma.
_Delphinium elatum_ is one of the plants in which this change has been
most frequently noticed.[347]
[Illustration: Fig. 165.--_Sempervivum tecotorum._ _a._ Normal stamen.
_h._ Normal carpel. _b_, _c_, _e_, _f_, _g_. Structure partly staminal,
partly carpellary. _d._ Transverse section through _c_, showing pollen
internally, ovules externally.]
In willows the change of pistils into staminal organs has been
frequently observed. In _Salix babylonica_ Prof. Schnizlein has
described various transition stages between the carpels and the stamens,
and in one instance, in addition to this change, a perfect cup-shaped
perianth was present, as happens normally in _Populus_[348]. Mr. Lowe
also records the conversion of stamens into ovaries in _Salix
Andersoniana_, and this by every conceivable intermediate
gradation.[349]
The following list will serve to show what plants are most subject to
this anomaly. It is difficult to draw any accurate inference from this
enumeration, but attention may be called to the frequency of this
occurrence in certain plants, such as the _Sempervivum_, the wallflower,
the poppy, and the heath. Why these plants should specially be subject
to these changes cannot be at present stated.
By the student of animal physiology such a change as above
described--equivalent to the substitution of an ovary or a uterus for a
testis--would be looked on as next to impossible; the simpler and less
specialised structure of plants renders such a change in them far more
easy of comprehension.
Thalictrum minus.
Delphinium elatum.
Magnolia fuscata.
Bocconia cordata.
*Papaver bracteatum!
* somniferum!
nudicaule.
Dionæa muscipula!
Barbarea vulgaris.
*Cheiranthus Cheiri!
Cochlearia Armoracia.
Tropæolum majus.
Citrus Aurantium.
*Sempervivum tectorum!
montanum.
Begonia frigida!
Cucumis, sp.
Cucurbita Pepo.
Pyrus Malus.
Rosa arvensis!
Saxifraga crassifolia!
Myrtus, sp.
Campanula rapunculoides.
Polemonium cæruleum.
Gentiana Amarella.
*Erica Tetralix.
Stachys germanica.
Primula acaulis.
Rumex crispus.
*Salix, sp. plur.!
Euphorbia esula.
Glochidion.
Asphodelus ramosus.
Amaryllis.
Lilium tigrinum!
longiflorum.
*Tulipa Gesneriana!
var. cult. plurim.!
Hemerocallis.
Zea Mays.
Bambusa, sp.
=Pistillody of the ovule.=--An instance of this extraordinary
transformation in the carnation, as observed by the Rev. Mr. Berkeley,
is given at p. 268.
FOOTNOTES:
[295] 'Neue Denkschrift. Schweiz. Gesellsch.,' band v, p. 9.
[296] 'Bull. Acad. Belg.,' xix, part 2, p. 93.
[297] Schlechtendal, 'Linnæa,' ix, p. 737.
[298] Misbilld., 'Cult. Gewachs.,' p. 32.
[299] Linn., 'Phil. Botan.,' § 120.
[300] 'Bull. Soc. Bot. France,' 1859, vol. vi, p. 199.
[301] Seemann's 'Journal of Botany,' vol. iii, p. 105; also Morren,
'Bull. Acad. Belg.,' vol. xx, part 2, p. 264.
[302] Morren, 'Bull. Belg.,' xviii, p. 503.
[303] 'Organ. Vég.,' t. i, p. 513.
[304] 'Bull. Acad. Roy. Belg.,' tome xvii; and Lobelia, p. 65.
[305] Masters, "On Double Flowers," 'Rep. Internat. Bot. Congress,'
London, 1866. p. 127.
[306] See also C. Morren, "Sur les vraies fleurs doubles chez les
Orchidées," 'Bull. Acad. Roy. Belg.,' vol. xix, part ii, 1852. p. 171.
[307] C. Morren, 'Bull. Acad. Belg.,' vol. xx, 1853, part ii, p. 284
(_Syringa_).
[308] 'Rep. Bot. Congress,' London, 1866, p. 135, t. vii, f. 14.
[309] Although it is generally admitted that the filament of the stamen
corresponds to the stalk of the leaf, and the anther to the leaf-blade,
yet there are some points on which uncertainty still rests. One of these
is as to the sutures of the anther. Do these chinks through which the
pollen escapes correspond (as would at first sight seem probable) to the
margins of the antheral leaf, or do they answer to the lines that
separate the two pollen-cavities on each half of the anther one from the
other? Professor Oliver, 'Trans. Linn. Soc.,' vol. xxiii, 1862, p. 423,
in alluding to the views held by others on this subject, concludes, from
an examination of some geranium flowers in which the stamens were more
or less petaloid, that Bischoff's notion as to the sutures of the anther
is correct, viz., that they are the equivalents of the septa of
untransformed tissue between the pollen-sacs. Some double fuchsias
('Gard. Chron.,' 1863, p. 989) add confirmation to this opinion. In
these flowers the petals were present as usual, but the stamens were
more or less petaloid, the filaments were unchanged, but the anthers
existed in the form of a petal-like cup from the centre of which
projected two imperfect pollen-lobes (the other two lobes being
petaloid). Now, in this case, the margins of the anther were coherent to
form the cup, and the pollen was emitted along a line separating the
polliniferous from the petaloid portion of the anther. This view is also
borne out by the double-flowered _Arbutus Unedo_, and also by what
occurs in some double violets, wherein the anther exists in the guise of
a broad lancet-shaped expansion, from the surface of which project four
plates (fig. 157), representing apparently the walls of the pollen-sacs,
but destitute of pollen; the chink left between these plates corresponds
thus to the suture of the normal anther.
[Illustration: FIG. 157.--Petaloid stamen of _Viola_, with four
projecting plates.]
The inner or upper portion of the anther-leaf is that which is most
intimately concerned in the formation of pollen; it comparatively rarely
(query ever) happens that the back or lower surface of the antheral leaf
is specially devoted to the formation of pollen. On the other hand, in
cases like those of the common houseleek, where we meet with petaloid
organs combining the attributes of anthers and of carpels, we find the
inner layers devoted to the production of pollen, the outer to the
formation of ovules.
That the pollen-lobes are not to be taken as halves of a staminal leaf,
but rather as specialised portions of it, not necessarily occupying half
its surface, is shown also in the case of double-flowered _Malvaceæ_, in
which the stamens are frequently partly petal-like, partly divided into
numerous separate filaments, each bearing a one-, or it may be even a
two-lobed anther. This circumstance is confirmatory of the opinion held
by Payer, Duchartre, Dickson, and other organogenists, as to the
compound nature of the stamens in these plants. The stamens are here
analogues not of a simple entire leaf, but of a lobed, digitate, or
compound leaf, each subdivision bearing its separate anther. On this
subject the reader may consult M. Müller's paper on the anther of
_Jatropha Pohliana_, _&c._, referred to at page 255.
[310] See C. Morren, "On Spur-shaped Nectarines," &c., 'Ann. Nat.
Hist.,' March, 1841, p. 1. tab. 11.
[311] Karsten, 'Flor. Columb. Spec.,' tab. xxix.
[312] See Dickson, "On Diplostemonous Flowers," 'Trans. Bot. Soc.
Edin.,' vol. viii, p. 100; and on the Androecium of _Mentzelia_,
_&c_., in Seemann's 'Journal of Botany,' vol. iii, p. 209, and vol. iv
(1866) p. 273 (_Potentilla_, _&c._).
[313] See Baillon, 'Adansonia,' iii, p. 351, tab. 12, _Sinapis_.
[314] 'Bull. Acad. Belg.,' xvii, part i, p. 516, c. tab., and
'_Lobelia_,' p. 83.
[315] Cited in 'Bull. Soc. Bot. France,' xiv, p. 253 ('Rev. Bibl.').
[316] 'Bull. Soc. Bot. Fr.,' 1858, p. 331.
[317] 'Mem. Legum.,' p. 44.
[318] 'Bildungsabweich, 'Pflanz. Fam.,' tab. 8, f. 12.
[319] 'Atlas de Göthe' p. 55, t. 4, f. 18.
[320] Wiegmann, 'Bot. Zeit.,' 1831, p. 5, tab. i.
[321] 'Ic. Flor. Germ.,' xiii, tab. 112, cccclxiv, f. 2.
[322] Seemann's 'Journal of Botany,' 1867, p. 317, t. 72, A (_Ophrys_).
[323] 'Enum. Euphorb.' p. 53.
[324] 'Linnæa.' i, p. 457.
[325] 'De Balsam,' p. 17.
[326] B. Clarke, 'Arrangement of Phænog. Plants,' p. 23.
[327] See 'Engelmann,' p. 26, tab. 3, f. 10, 11, 14.
[328] 'Ann. Sc. Nat.,' ser. 2, t. viii, 1837, p. 58.
[329] 'Bot. Zeit.,' 4, 1846, 889.
[330] 'Verhandl. Nat. Hist. Ver. Preuss. Rheinl. und Westph.,' 1858,
1860, p. 381. Cramer also, 'Bildungsabweich,' p. 90, cites a case in
_Pæonia_ where the carpel was open and petaloid, and bore an anther on
one margin, and four ovules on the other.
[331] 'Euphorbiaceæ,' p. 205.
[332] Seemann's 'Journ. Bot.,' iv, p. 168, tab. 47, f. 1.
[333] Moquin-Tandon, l. c., 220, _Passiflora_. Masters, 'Journ. Linn.
Soc.,' 1857, p. 159, _Saponaria_. Seemann's 'Journ. Botany,' vol. iii,
p. 107, _Narcissus_.
[334] 'Bull. Soc. Bot. Fr.,' 1857, p. 452.
[335] 'Gardeners' Chronicle,' 1866, p. 897.
[336] Maout, 'Leçons Element.,' vol. ii, p. 488.
[337] Poiteau and Turpin, 'Arb. Fruit,' t. 37, and Trécul, 'Bull Soc.
Bot. France,' vol. i. p. 307.
[338] Clos, 'Mem. Acad. Toulouse,' 5 ser., vol. iii.
[339] 'Bot. Zeit.,' 1850, t. viii, pp. 514, 664. 'Flora,' (B. Z.) 1832,
t. xv, p. 252; also cited in 'Ann. des Serres et des jardins,' vi, pp.
241-5. See also Schlechtendal, 'Bot. Zeit.,' 1845, t. 3, p. 6.
[340] 'Bull. Soc. Bot. France,' t. viii, p. 453.
[341] See also Allmann, 'Rep. Brit. Assoc.,' July, 1851.
[342] 'Theory of Horticulture,' ed. 2, p. 82.
[343] 'Mém. Soc. Hist. Nat. Paris.' i, 16.
[344] Gen. Munro, 'Trans. Linn. Soc.,' xxvii, p. 7.
[345] 'Bull. Soc. Bot. Fr.,' 1857, p. 21.
[346] 'Ann. Scienc. Nat.,' t. viii, 1837, p. 50, and 'Bot. Zeit.' (R.),
1836, t. xix, p. 513, &c. See also MM. Sourd Dussiples and G. Bergeron,
'Bull. Soc. Bot. France,' viii, p. 349; Von Schmidel, 'Icon. plant. et
Anal. part.' 1782, p. 210, fig. 54.
[347] Godron, 'Bull. Soc. Bot. Fr.,' xiii, p. 82, Rev. Bibl.
[348] Cited in Henfrey, 'Bot. Gazette,' iii, p. 12.
[349] 'Ann. Nat. Hist.,' September, 1856, p. 56. See also Kirschleger,
'Flora (Bot. Zeit.),' xxiv, 1841, p. 340, _Salix alba_. Henschel, 'Flora
(Bot. Zeit.),' 1832, t. xv, p. 253, _S. cinerea_. Hartmann, 'Flora (Bot.
Zeit.),' xxiv, p. 199, _S. nigricans_. Meyer, C. A., 'Bull. Phys.
Math.,' t. x, _S. alba_.
PART IV.
HETEROMORPHY.
There are certain malformations that have little in common beyond this,
that they cannot readily be allocated in either of the great groups
proposed by writers on teratology. There are also deformities which,
unlike the majority of deviations from the ordinary structure, are
absolute and not relative. While the latter are due to an exaggeration,
or to an imperfection of development, or, it may be, to a partial
perversion in organization, the former differ from the normal standard,
not merely in degree, but absolutely. This is often the case when
disease or injury affects the plant; for instance, in the case of galls
arising from insect-puncture the structure is rather a new growth
altogether, than dependent on mere hypertrophy of the original tissues.
These absolute deformities arising from the causes just mentioned belong
rather to pathology than to teratology strictly so called; but, under
the head of deformities, may be mentioned sundry deviations not
elsewhere alluded to.
CHAPTER I.
DEFORMITIES.
The special meaning here attached to the term deformity is sufficiently
explained in the preceding paragraph; it remains to give a few
illustrations, and to refer to other headings, such as Heterotaxy,
Hypertrophy, Atrophy, &c., for malformations capable of more rigid
classification than those here alluded to.
[Illustration: FIG. 166.--Portion of the under surface of a
cabbage-leaf, with horn-like excrescences projecting from it.]
=Formation of tubes.=--The production of ascidia or pitchers from the
cohesion of the margins of one or more leaves has been already alluded
to (see pp. 21, 30), but there is another class of cases in which the
tubular formation is due, not so much to the union of the margins of a
leaf as to the disproportionate growth of some portions as contrasted
with others, whence arises either a depressed cavity, as in the case of
a leaf, or an expanded and excavated structure, when the stem or some
portion of it is affected.
The fruit of the rose, the apple, the fig, and many others, is now
generally admitted to be composed externally of the dilated end of the
flower-stalk in which the true carpels become imbedded. Between such
cases and that of a peltate leaf with a depressed centre, such as often
occurs, to some extent, in _Nelumbium_, there is but little difference.
In cabbages and lettuces there not unfrequently occurs a production of
leaf-like processes projecting from the primary blade at a right angle
(see Enation). Sometimes these are developed in a tubular form, so as to
form a series of little horn-like tubes, or shallow troughs, as in
_Aristolochia sipho_. At other times the nerves or ribs of the leaf
project beyond the blade, and bear at their extremities structures
similar to those just described.
[Illustration: FIG. 167.--Lettuce leaf, bearing on the back a stalked
cup, arising from the dilatation of the stalk (?).]
In a variety of _Codiæum variegatum_ a similar formation may be seen to
a minor extent. Even the common _Scolopendrium vulgare_ occasionally
produces small pitchers of this character, as in the varieties named
_perafero-corautum_, Moore, and _peraferum_, Woll.[350]
In carnations leaves may sometimes be seen from both surfaces, from
which project long, sharp-pointed tubular spurs at irregular intervals.
A very singular illustration of this is figured by Trattinick,[351], in
which the leaves, epicalyx, sepals, and petals, were all provided with
tubular spurs.
In _Cephalotus follicularis_ rudimentary or imperfect pitchers may be
frequently met with, in which the stalk of the leaf is tubular and bears
at its extremity a very small rudimentary leaf-blade. It is not in all
cases easy to trace the origin and true nature of the ascidium, as the
venation is sometimes obscure. If there be a single well-marked midrib
the probability is that the case is one of cohesion of the margins of
the leaf; but if the veins are all of about equal size, and radiate from
a common stalk, the pouch-like formation is probably due to dilatation
and hollowing of the petiole. Again, when the result of a union of the
margins of the leaf, the pitcher is generally less regular than when
formed from the hollowed end of a leaf-stalk. Further information is
especially needed as to the mode of development and formation of these
tubular organs, so as to ascertain clearly when they are the result of a
true cupping process, and when of cohesion of the margins of one or more
leaves. (See Cohesion, p. 31. For bibliographical references consult
also A. Braun, 'Flora v. Bot. Zeit.,' 1835, t. xviii, p. 41,
_Aristolochia_.)
=Tubular formations in the flower.=--A similar formation of tubes
happens in some double flowers; for instance, it is not infrequent in
double flowers of _Primula sinensis_, in which tubular petal-like
structures are attached to the inner surface of the corolla; sometimes
these petaloid tubes replace the stamens, while at other times they
appear to have no relation to those organs. In the particular flowers
now alluded to the tubular form seems due to a dilatation, and not to a
cohesion of the margins. (See Cohesion, p. 23.) These tubular petals
resemble in form and colour almost precisely the normal corolla in
miniature, but are not surrounded by a calyx, nor do they contain
stamens, while the less perfect forms show clearly their origin from a
single tube-like organ.
[Illustration: FIG. 168.--Corolla of _Primula sinensis_ turned back to
show a tubular petal springing from it. One only is shown for the sake
of clearness; they are generally numerous.]
The formation of spurs or spur-like tubes in a quasi-regular manner has
been spoken of under the head of Irregular Peloria, p. 228, but we
occasionally meet with tubular processes which seem to occur in an
irregular manner, and to have no reference to the symmetrical plan of
the flower, and which are due probably to the same causes as those which
induce hypertrophy. Such spurs have frequently been seen on the corolla
of _Digitalis purpurea_, _Antirrhinum majus_,[352] _Tulipa Gesneriana_,
and occasionally on the sepals of _Fuchsia_. They are very frequent in
some seasons in the corolla of certain calceolarias (_C. floribunda_).
By Morren this production of adventitious spurs was called
"Ceratomanie."
[Illustration: FIG. 169.--Corolla of _Calceolaria_, showing irregular
tubular spurs projecting from the lower lip.]
Similar processes may sometimes be seen in the capsules of _Linaria
vulgaris_, as also in the fruits of some of the Solanums, quite without
reference to the arrangement of the carpels, so that their production
seems to be purely irregular.
Morren, as previously remarked, gave the name "Solenaidie" to tubular
deformities affecting the stamens, a term which has not been generally
adopted; the deformity in question is by no means of uncommon occurrence
in some double or partially pelorised flowers, as _Antirrhinum_,
_Linaria_, &c. A similar formation of conical out-growths may frequently
be met with in the fruits quite irrespectively of any disjunction of the
carpels.
=Contortion.=--An irregular twisting or bending of the stem or branches
is by no means of uncommon occurrence, the inducing causes being often
some restriction to growth in certain directions, or the undue or
disproportionate growth in one direction, as contrasted with that in
another. Hence it may arise from insect-puncture, parasitic growth, or
any obstacle to the natural development. Frequently it exists in
conjunction with fasciation, the ends of the branches being curved round
like a shepherd's crook, from the growth on one side being so much
greater than on the other. Sometimes it is a mere exaggeration of a
normal condition; thus, in what are termed flexuose stems the stem
twists alternately to one side or another, frequently in association
with an oblique form of the leaf. This state is sometimes present to an
extreme degree, as in some varieties of shrubs (_Cratægus_, _Robinia_,
&c.) cultivated for their singularly tortuous branches.
[Illustration: FIG. 170.--Portion of the culm of a _Juncus_, bent
irregularly.]
[Illustration: FIG. 171.--Portion of a branch of _Cratægus oxyacantha_,
var. _tortuosa_.]
Such cases as those just mentioned, however, are but slightly irregular
compared to others in which the deformity exists to such an extent that
the traces of the ordinary mode of growth are almost obliterated. M.
Moquin-Tandon[353] alludes to a case of this kind in a species of pine
(_Pinus_), in which a branch ended in four unequal divisions, which were
strongly curved from without inwards, then became united in pairs, these
latter in their turn blending into a single mass.
In the case of some beeches growing in the forest of Verzy, near Rheims,
the trunks of the trees are contorted in every direction, and, at a
height of from fifteen to twenty feet, a number of branches are also
given off, also much contorted, and occasionally intergrafted, so that
it seems as if a heavy weight had been placed on the trees and literally
flattened them. Similar malformations may occasionally be met with in
the branches of the oak, and commonly in the weeping ash.
M. Fournier[354] mentions the stems of _Ruscus aculeatus_ rolled in a
circle, others twisted spirally.
The phenomenon is not confined to woody plants, but has been met with in
chicory, in _Antirrhinum_, and other herbaceous species.
It is very difficult in some cases to separate these instances of
irregular torsion from those in which the twisting takes place in a more
or less regular spiral direction. In the former case the fibres of the
plant are only indirectly involved, but in the latter the fibres
themselves are coiled spirally from right to left, or _vice versâ_
(spiral torsion), while not unfrequently both conditions may be met with
at the same time.
The leaves also are subject to similar deformities, of which a notable
illustration has been recorded in the case of the date palm, _Phoenix
dactylifera_, originally observed by Goethe, and figured and described
by Jaeger;[355] the leaves are folded and twisted in every direction, in
consequence of the fibrous band or cord which surrounds the leaves, and
which generally breaks as the leaflets increase in size, remaining from
some cause or other unbroken, and thus serving to restrain the growth.
A similar irregularity of growth occurs, not unfrequently, in the case
of crocus leaves, when in the course of their growth, as they push their
way through the soil, their progress becomes checked either by a stone
or even by frost.
=Spiral torsion.=--Growth in a spiral direction, and the arrangement of
the various organs of the plant in a spiral manner, are among the most
common of natural phenomena in plants.[356] Fibres are coiled spirally
in the minute vessels of flowering plants, and are not wholly wanting
even among fungi. The leaf-organs are very generally spirally arranged;
the leaf-stalks are often so twisted as to bring leaves on one plane
which otherwise would occupy several. In the leaf itself we have a
spiral twist taking place constantly in _Alstroemeria_, in _Avena_, and
other plants. A similar tendency is manifested in the flower-stalks, as
in _Cyclamen_ and _Vallisneria_, and the whole inflorescence, as in
_Spiranthes_. Even the bark and wood of trees is often disposed
spirally. This is very noticeable in some firs, and in the bark of the
sweet chestnut (_Castanea_), of _Thuja occidentalis_, and other trees.
The knaurs or excrescences which are sometimes found on the roots or
stems of trees afford other illustrations of this universal tendency.
These bodies consist of a number of embryo buds, which, from some cause
or other, are incapable of lengthening. On examination every rudimentary
or undeveloped bud may be seen to be surrounded by densely crowded
fibres arranged spirally.
The axes of nearly all twining plants are themselves twisted, and
twisted in a direction corresponding to the spontaneous revolving
movement exhibited by these plants, as in the hop, the convolvulus,
passion flower, &c., the degree of twisting being dependent to a great
extent on the roughness of the surface around which the stem
twines[357].
Considered as an exceptional occurrence, it occurs frequently in certain
plants, and, when it affects the stem or branches, necessarily causes
some changes in the arrangement of the parts attached to them; thus,
spiral torsion of the axial organs is generally accompanied by
displacement of the leaves, whorled leaves becoming alternate, and
opposite or whorled leaves becoming arranged on one side of the stem
only. Frequently also this condition is associated with fasciation, or,
at least, with a distended or dilated state. An illustration of this in
_Asparagus_ has been figured at p. 14.
Very often the leaves are produced in a spiral line round the stem, as
in a specimen of _Dracocephalum speciosum_ described and figured by C.
Morren. The leaves of this plant are naturally rectiserial and
decussate, but, in the twisted stem the leaves were curviserial, and
arranged according to the 5/13 plan. Now, referring to the ordinary
notation of alternate leaves, we shall have the first leaf covered by
the fifth, with two turns of the spiral; since decussate leaves result
from two conjugate lines, the formula will be necessarily 2/5. The
fraction 5/13 hence comes regularly into the 2/5 series (2/5, 3/8,
5/13). Thus, the leaves in assuming a new phyllotaxy, take one quite
analogous to the normal one.
One of the most curious instances that have fallen under the writer's
own observation occurred in the stem of _Dipsacus fullonum_. (See
'Proceedings of the Linnean Society,' March 6, 1855, vol. ii, p. 370).
The stem was distended, and hollow, and twisted on itself; its fibres,
moreover, were arranged in an oblique or spiral direction; the branches
or leaf-stalks, which usually are arranged in an opposite and decussate
manner, were, in this case, disposed in a linear series, one over the
other, following the line of curvature of the stem. When the course of
the fibres was traced from the base of one of the stalks, upward around
the stem, a spiral was found to be completed at the base of the second
stalk, above that which was made the starting point. Now, if opposite
leaves depend on the shortened condition of the internode between the
two leaves, then, in the teazel-stem just described, each turn of the
spiral would represent a lengthened internode; and, if the fibres of
this specimen could be untwisted, and made to assume the vertical
direction, and, at the same time, the internodes were shortened, the
result would be the opposition of the branches and the decussation of
the pairs; this explanation is borne out by the similar twisting which
takes place so frequently in the species of _Galium_ and other
_Rubiaceæ_.
[Illustration: FIG. 172.--Twisted stem of _Dipsacus fullonum_.]
G. Franc[358] was one of the first to notice this twisting in _Galium_,
and M. Duchartre,[359] in mentioning a similar instance, gives the
following explanation of the appearance which will be found to apply to
most of these cases. In the normal stem of _Galium Mollugo_ the
branches are opposite in each verticil and crossed in the two
successive ones. The stem is four-angled, each angle having a nerve.
Each of these nerves, springing from the origin of a branch in one
whorl, terminates in the interval which separates the point of origin of
the two branches in the whorl next above it. In the deformed stem one of
the nerves corresponds to the insertion of a branch, its neighbour is in
the adjoining vacant space; hence it results that four nerves correspond
to two branches and to two consecutive interspaces, and hence the
analogy between a single normal internode provided with its two branches
and its four nerves. What confirms this inference is that the nerve,
which begins at the point of origin of a branch, after making one spiral
turn round the stem, terminates in the interval that separates the two
following branches, just as in a branch of the normal stem it ends in
the upper whorl between the two next branches. The torsion, then, in
this _Galium_ caused the separation of the two opposite branches of the
same verticil, and placed them one above another, and this being
reproduced in all the whorls, all the branches come to be arranged on
the same longitudinal line. The leaves are susceptible of the same
explanation; they are inserted in groups of three or four in one arc
round the origin of each branch. In the malformation each series or
group of four leaves, with its central branch, is equivalent to half a
whorl of the natural plant with its axillary branch. In other words, the
malformation consists in a torsion of the stem, which separates each
whorl into two distinct halves; these half-whorls, with their axillary
branches, are placed on a single longitudinal series one above another.
This case is quoted at some length, as it is an admirable example of a
very common form of malformation in these plants.
In some parts of Holland where madder is cultivated a similar
deformation is particularly frequent. The leaves, however, are not
always grouped in the way in which they were described by M. Duchartre,
but more commonly form a single continuous line; when arranged in
leaf-whorls it generally happens that some of the leaves are turned
downwards, while others are erect. It has been said that this condition
occurs particularly frequently in plants growing in damp places. It is
certainly true that spiral torsion of the stem is specially frequent in
the species of _Equisetum_, most of which grow in such spots. In these
plants either the whole of the upper part of the stem is thus twisted,
or a portion only: thus Reinsch[360] cites a case in _Equisetum
Telmateia_, where the upper and lower portions of the stem were normal,
while the intermediate portion was twisted spirally. In this instance
the whorl next beneath the spiral had twenty-eight branchlets, and that
immediately above it thirty. Along the course of the spire there were
two hundred and three; dividing this latter number by the mean of the
two preceding, it was seen that the spire included the constituents of
seven ordinary verticils.
[Illustration: FIG. 173.--Stem of _Galium_ spirally twisted. From a
specimen communicated by Mr. Darwin.]
Here also may be mentioned a curious bamboo, the stem of which is
preserved in the British Museum, and in which the internodes, on the
exterior, and the corresponding diaphragms and cavities within are
spiral or oblique in direction.
The root is also subject to the same malformation, the inducing cause
being usually some obstruction to downward growth, as when a plant has
been grown in a small pot, and becomes, as gardeners say, pot-bound.
[Illustration: FIG. 174.--Showing "pot-bound" root twisted spirally
(from the 'Gard. Chron.,' 1849).]
The axial portion of the flower, the thalamus, is also occasionally
twisted in a spiral direction, the lateral parts of the flower being in
consequence displaced. Morren spoke of this displacement of the floral
organs as "speiranthie."[361]
Morren draws a distinction between spiral-torsion or spiralism and the
less regular torsion spoken of in the preceding section; in the former
case not only is the axis twisted, but its constituent fibres also. The
condition in question in some cases seems to be inherited in the
seedling plants.
The following is a list of the plants in which spiral torsion of the
stem or branches has been most frequently observed. (See also under
Fasciation and Contortion.)
Hesperis matronalis.
Dianthus barbatus.
Pyrus Malus.
torminalis.
Cercis siliquastrum!
Punica Granatum.
Robinia pseudacacia!
Rubia tinctorum.
Dipsacus fullonum!
pilosus.
Gmelini.
Scabiosa arvensis.
*Valeriana officinalis!
dioica!
Galium aparine!
* Mollugo!
verum!
Hippuris vulgaris!
Veronica spicata.
longifolia.
Hyssopus officinalis.
Thymus Serpyllum.
Lamium purpureum!
Dracocephalum speciosum.
Mentha aquatica.
Mentha viridis.
Fraxinus vulgaris!
Sambucus nigra.
Zinnia.
Phylica.
Beta.
Rumex, sp.
Ulmus campestris.
Casuarina rigida.
Abies excelsa!
Lilium Martagon!
candidum.
*Asparagus officinalis!
Sagittaria sagittifolia.
Epipactis palustris.
Triticum repens!
Lolium perenne!
Phleum pratense.
Juncus conglomeratus!
Scirpus lacustris.
Equisetum Telmateia.
limosum.
fluviatile.
arvense!
Among the more important papers relating to this subject may be
mentioned:
Moquin-Tandon, 'El. Ter. Veg.,' p. 181. Kros, 'De Spira in
plantis conspicua.' Morren, 'Bull. Acad. Roy. Belg.,' 1851,
tom. xviii, part i, p. 27. Milde, 'Nov. Act. Acad. Leop. Carol.
Nat. Cur., 1839. Ibid., vol. xxvi, part ii, p. 429,
_Equisetum_. Irmisch, 'Flora,' 1858, t. ii, _Equisetum_.
Vrolik, 'Nouv. Mem. Instit. Amsterdam,' _Lilium_.
Schlechtendal, 'Bot. Zeit.,' xiv, p. 69, et v, p. 66. De
Candolle, 'Organ. Veget., t. i, p. 155, tab. xxxvi, _Mentha_,
_&c._ Alph. de Candolle, 'Neue Denkschr. Allg. Schweiz.
Gesellschft.,' band v, tab. vi, _Valeriana_. Duchartre, 'Ann.
Sc. Nat.,' ser. 3, vol. i, p. 292. 'Gardeners' Chronicle,' July
5, 1856, p. 452, _c. ic. xylogr._, spiral branches from
Guatemala--tree not known.
=Spiral twisting of the leaf= is scarcely of so common occurrence as the
corresponding condition in the stem. In _Alstroemeria_ it occurs
normally, as also in some grasses. In the variety _annularis_ of _Salix
babylonica_ the leaf is constantly coiled round spirally. A similar
contortion occurs in a variety of _Codiæum variegatum_ lately introduced
from the islands of the South Seas by Mr. J. G. Veitch.
Fern fronds are occasionally found twisted in the same manner, _e.g._
_Scolopendrium vulgare_ var. _spirale_.[362]
=Adventitious tendrils.=--Under ordinary circumstances tendrils may be
described as modifications of the leaf, the stipule, the branch, or of
the flower stalk, so that it is not a matter of surprise to find
tendrils occasionally springing from the sepals or petals, as indeed
happens normally in _Hodgsonia_, _Strophanthus_, _&c._
M. Decaisne[363] found a flower of the melon in which one of the
segments of the calyx was prolonged into a tendril, and Kirschleger
records a similar instance in the cucumber, while Mr. Holland ('Science
Gossip,' 1865, p. 105) mentions a case in which one of the prickles on
the fruit of a cucumber had grown out into a tendril.
In _Cobæa scandens_ the foliar nature of the tendril is shown by the
occasional presence of a small leaflet on one of the branches of the
tendril, and a similar appearance may frequently be seen in
_Eccremocarpus scaber_. On the other hand, in the vine, the axial nature
of the tendril is revealed by the not infrequent presence of flowers or
berries on them, as also in _Modecca_ and some _Passifloraceæ_.
Darwin, speaking of the tendrils of _Bignonia capreolata_, says it is a
highly remarkable fact that a leaf should be metamorphosed into a
branched organ, which turns from the light, and which can, by its
extremities, either crawl like a root into crevices, or seize hold of
minute projecting points, these extremities subsequently forming
cellular masses, which envelope by their growth the first fibres and
secrete an adhesive cement.
=Interrupted growth.=--This term is here used in the same sense as in
ordinary descriptive botany, as when an "interruptedly pinnate" leaf is
spoken of. A similar alternation may be observed occasionally as a
teratological occurrence, though it is not easy to account for it.
[Illustration: FIG. 175.--Interrupted growth of Radish (from the
'American Agriculturist.')]
[Illustration: FIG. 176.--Interrupted growth in Apple.]
Fig. 175 shows an instance of the kind in a radish, and fig. 176 a
similar deformity in the case of an apple, the dilatation of the
flower-stalk below the ordinary fruit producing an appearance as if
there were two fruits one above another.
In leaves this peculiar irregularity of development is more common.
In some varieties of _Codiæum variegatum_ the leaves resemble those of
_Nepenthes_, as the basal portion is broad, and terminates in a
projecting midrib destitute of cellular covering, and this again
terminates in a small pouch or pitcher. Somewhat similar variations may
be found in ferns, especially _Scolopendrium vulgare_.
Instead of the pouch there is formed sometimes in the plant last
mentioned a supplementary four-lobed lamina, the four lobes being in two
different planes, and diverging from the midrib, so that the section
would resemble [Symbol: Sideways X], the point of intersection of the x
representing the position of the midrib. This four-winged lamina is thus
very similar to the four-winged filaments described and figured at p.
289, and to the leaf-like anther of _Jatropha_ described by M. Müller,
p. 255.
=Cornute leaves= (_Folia cornuta_).--The condition to which this term
applies is that in which the midrib, after running for a certain
distance, generally nearly to the point of the leaf, suddenly projects,
often in a plane different from that of the leaf, and thus forms a small
spine-like out-growth. Should this happen to be terminated by a second
laminar portion, an interrupted leaf would be formed. In _Scolopendrium
vulgare_ and other ferns this condition has been noticed, as also in
some of the varieties of _Codiæum variegatum_ already referred to.
=Flattening.=--There are some plants whose stem or branches, instead of
assuming the ordinary cylindrical form, are compressed or flattened;
such are some species of _Epiphyllum_, _Coccoloba_, _Bauhinia_, &c. The
same thing occurs in the leaf-like branches of _Ruscus_, the
flower-stalks of _Xylophylla_, _Phyllanthus_, _Pterisanthes_. Martins
proposes to apply the word 'cladodium' to such expansions, just as the
term phyllodium is applied to the similar dilatation of the leaf-stalks.
If we exclude instances of fasciation, _i.e._ where several branches
are fused together and flattened, we must admit that this flattening
does not occur very often as a teratological appearance.
Mr. Rennie figures and describes a root of a tree which had become
greatly flattened in its passage between the stones at the bottom of a
stream, and had become, as it were, moulded to the stones with which it
came into contact.[364]
The spadix of _Arum_, as also of the cocoa-nut palm, has been observed
flattened out, apparently without increase in the number of organs.
When the blade of the leaf is suppressed it often happens that the stalk
of the leaf is flattened, as it were, by compensation, and the petiole
has then much the appearance of a flat ribbon (phyllode). This happens
constantly in certain species of _Acacia_, _Oxalis_, &c., and has been
attributed, but doubtless erroneously, to the fusion of the leaflets in
an early state of development and in the position of rest.[365]
In some water plants, as _Sagittaria_, _Alisma_, _Potamogeton_, &c., the
leaf-stalks are apt to get flattened out into ribbon-like bodies; and
Olivier has figured and described a _Cyclamen_, called by him _C.
linearifolium_, in which, owing to the suppression of the lamina, the
petiole had become dilated into a ribbon-like expansion--déformation
rubanée of Moquin.
FOOTNOTES:
[350] Moore, 'Nature Printed Ferns,' 8vo edition, vol. ii, p. 154, et p.
173.
[351] 'Flora (B. Z.),' 1821, vol. iv, p. 717, c. tab.
[352] Chavannes, 'Mon. Antirrh.'
[353] 'Bull. Soc. Bot. France,' t. vii, 1860, p. 877.
[354] Ibid., t. iv, 1857, p. 759.
[355] Jaeger, "De monstrosa folii _Phoenicis dactyliferæ_
conformatione a Goetheo olim observata," 'Act. Acad. Leop. Car. Nat.
Cur.,' vol. xvii, suppl., p. 293, c. tab. color. iv.
[356] See Goethe, 'Ueber die spiral Tendenz.'
[357] See Darwin "On Climbing Plants," 'Journ. Linn. Soc. Botany,' vol.
ix, p. 5.
[358] 'Ephem. Nat. Cur.,' dec. 2, ann. 1, 1683, p. 68, fig. 14.
[359] 'Ann. des Scienc. Nat.,' third series, vol. i, 1844, p. 292.
[360] 'Flora' Feb. 4, 1858, p. 69, tab. ii, f. 3, and also 'Flora,'
1860, p. 737, tab. vii, f. 9.
[361] 'Bull. Acad, Belg.,' t. xvii, p. 196, "Lobelia," p. 53, c. tab.
[362] Moore, 'Nature-printed Ferns,' 8vo edition, vol. ii, p. 183.
[363] 'Bull. Soc. Bot. Fr.,' 1860, vol. vii, p. 461. See also Naudin,
'Ann. Sc. Nat.,' 4 ser., t. iv, p. 5. Clos, 'Bull. Soc. Bot. Fr.,' t.
iii, p. 546.
[364] London's 'Magazine Nat. Hist.,' vol. ii, p. 463.
[365] C. Morren, 'Bull. Acad. Belg.,' 1852, t. xix, part iii, p. 444.
CHAPTER II.
POLYMORPHY.
Usually the several organs of the same individual plant do not differ to
any great extent one from another. One adult leaf has nearly the same
appearance and dimensions as another; one flower resembles very closely
another flower of the same age and so on. Nevertheless it occasionally
happens that there is a very considerable difference in form in the same
organs, not only at different times, but it may also be at the same
time. Descriptive botanists recognise this occurrence in the case of
leaves, and apply the epithet heterophyllous to plants possessed of
these variable foliar characters. In the case of the flower, where
similar diversity of form occasionally exists, the term dimorphism is
used.
As these phenomena appear constantly in particular plants, they are
hardly to be looked on, under such circumstances, as abnormal, but where
they occur in plants not usually polymorphic, they may be considered as
coming within the scope of teratology.
=Heterophylly.=--As a general rule, the leaves or leaf-organs in each
portion of a plant, from the rhizome or underground axis, where it
exists, to the carpellary leaf, have their own special configuration,
subject only to slight variations, dependent upon age, conditions of
growth, &c. The cotyledons are very uniform in shape in each plant, and
are scarcely ever subject to variation. The leaves near the base of the
stem, the root-leaves as they are not unfrequently called, sometimes
differ in form from the stem-leaves; these again differ from the bracts
or leaves in proximity to the flower. The floral envelopes themselves,
as well as the bud-scales, all have their own allotted form in
particular plants, a form by which they may, in most cases, be readily
recognised. Hence, then, in the majority of plants there is naturally
very considerable difference in the form of the leaf-organs, according
to the place they occupy and the functions they have to fulfil; but, in
addition to this, it not unfrequently happens that the leaf-organs in
the same portion of the stem are subject to great variation in form.
This is the condition to which the term heterophylly properly applies.
The variation in form is usually dependent on a greater or less degree
of lobing of the margin of the leaf; thus, in the yellow jasmine, almost
every intermediate stage may be traced from an ovate entire leaf to one
very deeply and irregularly stalked. _Broussonettia papyrifera_, and
_Laurus Sassafras_, and the species of _Panax_, may be mentioned as
presenting this condition. Sometimes in the last-named genus, as also in
_Pteridophyllum_, every gradation between simple and compound leaves may
be traced. The horse-radish (_Cochlearia Armoracia_) may also be
instanced as a common illustration of polymorphism in the leaves. In
ferns it is likewise of frequent occurrence, markedly so in
_Scolopendrium D'Urvillei_, in which plant every gradation from a simple
oblong frond to an exceedingly divided one may be found springing from
the same rhizome at the same time.
[Illustration: FIG. 177.--_Syringa persica laciniata_, showing
polymorphous leaves.]
A similar protean state, but little less remarkable, occurs in many of
our British ferns, notably in _Scolopendrium vulgare_, of which Mr.
Moore enumerates no fewer than 155 varieties,[366] many of the forms
occurring on the same plant at the same time. Cultivators have availed
themselves of this tendency to produce multiform foliage, not only for
the purposes of decoration or curiosity, as in the many cut-leaved or
crisped-leaved varieties, but also for more material uses, as, for
instance, the many varieties of cabbages, of lettuces, &c. Most of these
variations are mentioned under the head of the particular morphological
change of which they are illustrations.
The effect of a change in the conditions of growth in producing
diversity in the form of the leaf may be here alluded to. _Ficus
stipulata_, a plant used to cover the walls of plant-stoves in this
country, and growing naturally on walls in India, like ivy, produces
leaves of very different form, size, and texture, when grown as a
standard, from what it does when adhering to a wall. _Marcgraavia
umbellata_ furnishes another example of a similar nature, as indeed, to
a less extent, does the common ivy.
Allusion has been already made to the occasional persistence of forms in
adult life, which are commonly confined to a young state, as in the case
of some conifers which present on the same plant, at the same time, two
different forms of leaves. Mention has also been made of the presence of
adventitious buds on leaves and in other situations. The leaves that
spring from these buds are usually of the same form as the other leaves
of the plant, but now and then they differ. Of this a remarkable
illustration is afforded by a fern, _Pteris quadriaurita_, in which the
fronds emerging from an adventitious bud are very different from the
ordinary fronds.
[Illustration: FIG. 178.--Portion of a frond of _Pteris quadriaurita_,
with an adventitious bud, the form of the constituent foliage of which
is very different from that of the parent frond.]
=Dimorphism.=--This term, applied specially to the varied form which the
flowers or some of their constituent elements assume on the same plant,
is an analogous phenomenon to what has been above spoken of as
heterophylly, and, like it, it cannot, except under special
circumstances, be considered as of teratological importance. A few
illustrative cases, however, may here be cited.
Sir George Mackenzie describes a variety of the potato[367] (_Solanum
tuberosum_), which produces first double and sterile flowers, and
subsequently single fertile ones; the other portions of the plant do not
differ much.
_Stackhousia juncea_, according to Clarke, has mixed with its perfect
flowers a number of apetalous blossoms destitute of anthers.[368]
This peculiarity is well exemplified in the tribe _Gaudichaudieæ_ of the
order _Malpighiaceæ_. A. de Jussieu, in his monograph, speaks of these
flowers as being very small, green, destitute of petals, or nearly so,
with a single, generally imperfect anther; the carpels also are more or
less imperfect, but not sufficiently so to prevent some seeds from being
formed. A similar production of imperfect flowers has been noticed in
many other orders, _e.g._ _Violaceæ_, _Campanulaceæ_, &c. In some cases
these supplementary blossoms are more fertile and prolific in good seeds
than are the normally constructed flowers. M. Durieu de Maisonneuve
alludes to a case where flowers of this description are produced below
the surface of the ground. The plant in question is _Scrophularia
arguta_, and it appears that towards the end of the summer the lowest
branches springing from the stem bend downwards, and penetrate the soil;
the branches immediately above the lowest ones also bend downwards, but
do not always enter the earth. These branches bear fertile flowers:
those which are completely below the soil are completely destitute of
petals; those which are on the surface have a four-lobed corolla whose
divisions are nearly equal, like those of _Veronica_.[369]
To Sprengel, and specially to Darwin, physiologists are indebted for the
demonstration of the relation of di- and trimorphic flowers to
fertilisation. In certain genera of orchids, such as _Catasetum_, &c.,
flowers of such different form are produced that botanists, without
hesitation, considered them as belonging to different genera, until the
fact of their occasional production on the same plant showed that they
were not of even specific importance. It was reserved for Mr. Darwin to
show experimentally that these very different flowers are really sexual
forms of one and the same species, ordinarily occurring on different
plants, i.e. dioecious, but occasionally formed on the same spike. The
same excellent observer has demonstrated that the di- and trimorphic
forms of _Primula_, of _Linum_, _Lythrum_, and other plants--forms
differing mainly in the relative length of the stamens and styles, are
also connected with striking differences in the number of perfect seeds
produced. The most perfect degree of fertility is obtained when the
stigma of one form is fertilised by the pollen taken from stamens of a
corresponding height. On the other hand, when the union is, as Mr.
Darwin states, illegitimate, that is, when the pollen is taken from
stamens not corresponding in length to the style, more or less complete
sterility ensues in the progeny, sometimes even utter infertility, such
as happens when two distinct species are crossed, so that, in point of
fact, the offspring of these illegitimate unions correspond almost
precisely to hybrids.[370]
Mere variations of form arising from hybridisation or other causes
hardly fall within the limits of this work, though it is quite
impossible to say where variations end and malformations begin. There
are, however, two or three cases cited by Mr. Darwin[371] from Gallesio
and Risso to which it is desirable to allude. Gallesio impregnated an
orange with pollen from a lemon, and the fruit borne on the mother tree
had a raised stripe of peel like that of a lemon both in colour and
taste, but the pulp was like that of an orange, and included only
imperfect seeds. Risso describes a variety of the common orange which
produces "rounded-oval leaves, spotted with yellow, borne on petioles,
with heart-shaped wings; when these leaves fall off they are succeeded
by longer and narrower leaves, with undulated margins, of a pale green
colour, embroidered with yellow, borne on foot-stalks without wings.
The fruit whilst young is pear-shaped, yellow, longitudinally striated
and sweet; but, as it ripens, it becomes spherical, of a reddish-yellow,
and bitter."
=Sports or bud variations.=--These curious departures from the normal
form can only be mentioned incidentally in this place, as they pertain
more to variation than to malformation.
The occasional production of shoots bearing leaves, flowers, or fruits
of a different character from those found on the normal plant, is a fact
of which gardeners have largely availed themselves in the cultivation of
new varieties. The productions in question have been attributed to
various causes, such as cross-breeding, grafting, budding, dissociation
of hybrid characters, or reversion to some ancestral form, all of which
explanations may be true in certain cases, but none of them supply the
clue to the reason why one particular branch should be so affected, and
the rest not; or why the same plant, at the same time, as often happens
in Pelargoniums, should produce two, three, or more "sports" of a
different character.
These bud variations may be perpetuated by grafts or by cuttings,
sometimes even by seed. With reference to cuttings a curious
circumstance has been observed, viz., that if taken from the lower part
of the stem, near the root, the peculiarity is not transmitted, but the
young plant reverts to the characters of the typical form (Carrière).
This circumstance, however, is not of universal occurrence.
For further particulars on this interesting subject the reader is
referred to Darwin's 'Variation of Animals and Plants,' i, p. 373, where
numerous references are given, and wherein certain well-known and highly
remarkable instances, such as the _Cytisus Adami_, the trifacial orange,
&c., are discussed.
FOOTNOTES:
[366] 'Nature-printed Ferns,' 8vo edition, vol. ii, p. 197.
[367] 'Gard. Chron.,' 1845. p. 790.
[368] 'A New Arrangement of Phænog. Plants,' p. 36.
[369] 'Bull. Soc. Bot. France,' 1856, t. iii, p. 569.
[370] The reader will find an abstract of Mr. Darwin's views in his work
on the 'Variation of Animals and Plants,' vol. ii, p. 181.
[371] Loc. cit., i, 336.
CHAPTER III.
ALTERATIONS OF COLOUR.[372]
Changes in the colour of the several organs of plants are more often
either pathological or the result of variation than of malformation
properly so called.
Alterations in colour arise from a diminished or an increased amount of
colouring matter, or from an unusual distribution of the solid or fluid
matters on which the colour depends. The superposition of cells
containing colouring material of different tints produces naturally a
very different set of hues from those which are manifested when the
colours are not blended. Referring the reader to the ordinary text-books
on vegetable physiology and chemistry for details as to the nature and
disposition of colouring materials in plants under natural
circumstances, it will only be necessary to cite a few instances of
deviation from the general colour of plants or their organs.
=Albinism.=--This change is due to the deficient formation of green
colouring matter or chlorophyll, and is more a pathological condition
than a deformity.
It seems necessary to draw a distinction between this state and ordinary
blanching or etiolation. In the former case chlorophyll seems never to
be formed in the affected parts, even if they be exposed to light, while
an etiolated organ, when placed under favorable circumstances, speedily
assumes a green colour. In _Richardia æthiopica_ one or more leaves
become occasionally as white as the spathe is usually.
=Virescence.=--Engelmann[373] pointed out that, so far as flowers were
concerned, there are two ways in which they assume a green colour,
either by a simple development of chlorophyll in place of the colouring
matter proper to the flower, or by an actual development of leaf-like
organs in the room of the petals--frondescence. Morren[374] judiciously
proposed to keep these two conditions separate, calling the one
virescence, the other frondescence (see p. 241).
Many of the cases recorded as reversions of the parts of the flower to
leaves are simply instances of virescence; indeed, it is not in all
cases easy to distinguish between the two states. The examination of the
arrangement of the veins is often of assistance in determining this
point; for instance, if, under ordinary circumstances, the venation of
the petal be such as is characteristic of the sheath of the leaf, while
in the green-coloured flower of the same species the venation is more
like that which belongs to the blade of the leaf, the inference would,
of course, be that the green colour was due to frondescence or phyllody.
The persistence or duration of petals is often increased when they are
subject to this change; instead of falling off speedily they become
persistent when so affected.
Some flowers are more liable to virescence than others. The common
honeysuckle, _Lonicera Periclymenum_, is one of these, and it is
noticeable in this plant that the calyx remains unaffected--a
circumstance which Morren says shows the distinctness of virescence from
frondescence; for, in this instance, we have the most foliaceous portion
of the flower remaining unchanged, while the corolla and other organs,
usually less leaf-like in their nature, assume a green colour; but this
may rather be attributed to the axial nature of the so-called adherent
calyx. The stamens in these green-flowered honeysuckles are usually
green also, but with abortive anthers, and the pistil also is in a
rudimentary condition. _Umbelliferæ_ are not unfrequently subject to
this change, _e.g._, _Torilis Anthriscus_, _Daucus Carota_, _Heracleum
Sphondylium_, _Carum carui_, &c. _Primulaceæ_, again, are frequently
subject to virescence. Among _Compositæ_ the following species are
recorded as having had green flowers--_Cirsium tricephalodes_, _Senecio
vulgaris_, _Calendula officinalis_, _Pyrethrum Parthenium_, _Carduus
crispus_, _Hypochæris radicata_, _Hieracium prealtum_, _Cirsium
arvense_, _Coreopsis Drummondi_.[375] In _Ranunculaceæ_ virescence has
been observed in _Delphinium elatum_, _crassicaule_ and _Ajacis_,
_Anemone hortensis_ and _nemorosa_, _Aquilegia vulgaris_, _Ranunculus
Philonotis_.
Many of these cases, and others that might be cited, are probably
instances of frondescence or phyllody (see p. 241).
=Chromatism.=--This term is here intended to apply specially to those
cases in which any organ of a plant assumes a colour approximating to
that of the petals, or in which the normal green is replaced by tints of
some other colour. To a certain extent the change in question is the
same as that spoken of under the head of petalody (see p. 283), but
there are cases in which, while the ordinary situation and form are
those of leaves, the coloration is that of the petals. Such was the case
in the _Gesnera_ mentioned by Morren (see p. 88), and in which a leaf
occupied the position of an inflorescence, and became brightly coloured.
In tulips the presence of a highly coloured leaf on the flower-stalk,
below the flower, is not uncommon. So also the bracts or leaves below
the perianth in _Anemone coronaria_ and _hortensis_ not unfrequently
assume the coloration usually confined to the parts of the perianth. A
similar illustration has presented itself, as this sheet is passing
through the press, in which two of the leaflets of the compound leaf of
a rose were brightly coloured like the petals, the others being of
their ordinary green colour.
The occurrence of coloured bracts, as in _Poinsettia_, _Bougainvillea_,
&c., is very common under natural conditions, and need not here be
further alluded to.
Increased intensity of colour often accompanies teratological changes;
an instance has just been alluded to in the _Gesnera_; the feather
hyacinth, _Muscari comosum_, furnishes another illustration, the
adventitious pedicels being brightly coloured.
In fasciated stems, also, of herbaceous plants, it not unfrequently
happens that the upper portions of the stem are brightly coloured.
The occurrence of flowers or fruits of different colours on the same
plant, or even in the same cluster, is a phenomenon which does not come
within the scope of the present book; the reader may, however, be
referred to the excellent summary on this subject published by Mr.
Darwin in his work on the 'Variation of Animals and Plants under
Domestication.'
FOOTNOTES:
[372] These deviations are treated of under the head of alterations of
form, because they are not, in a teratological point of view, of
sufficient importance to demand a specific heading, while they appeal to
the sight in the same way as the deviations from the customary forms of
organs.
[373] 'De Antholys,' p. 32, § 38.
[374] 'Bull. Acad. Belg.,' xvii, part 2, p. 131, c. tab.
[375] See Cramer, 'Bildungsabweich,' pp. 17, 55, 82, 65. See also Lucas,
'Verhandl. des Bot. Vereins. Brandenb.,' heft 1, 2, _Anchusa_. Christ,
'Flora,' 1867. pp. 376, tab. 5, 6, _Stachys_.
BOOK III.
DEVIATIONS FROM THE ORDINARY NUMBER OF ORGANS.
To a certain extent the number of the organs of a plant is of even
greater consequence for purposes of classification than either their
form or their arrangement; for instance, the number of cotyledons in the
embryo is made the chief basis of separation between the two great
groups of flowering plants, the monocotyledons and the dicotyledons. In
the one group, moreover, the parts of the flower are arranged in groups
or whorls of five; in the other the arrangement is ternary. In mosses
the teeth of the peristome are arranged in fours, or in some multiple of
that number. So far as the larger groups are concerned, and also in
cases where the actual number of parts is small, the numerical relations
above described are very constant; on the other hand, in the minor
subdivisions, and especially where the absolute number of parts is
large, considerable variation may occur, so that descriptive botanists
frequently make use of the term indefinite, and apply it to cases where
the number of parts is large and variable, or, at any rate, not easy to
be estimated.
Considered teratologically, the changes, as regards the number of
organs, are readily grouped into those consequent on a decreased and
into those resulting from an increased development. The alteration may
be absolute or relative. There may be an actual deficiency in the number
of parts or an increase in their number, but in either case the change
may be simply a restoration of the primitive number, a species of
peloria, in fact. An increased number of parts, moreover, may depend not
so much on the formation of additional parts as on the subdivision of
one.
It seems also desirable to treat separately those cases in which there
is an increased number of buds either leaf-buds or flower-buds, as the
case may be, as happens in what is termed prolification. This formation
of buds occurring, as it does, often in unwonted situations is treated
of under the head of alterations of arrangement, the mere increase in
number being considered of subordinate importance as contrasted with the
altered disposition (see p. 100).
PART I.
INCREASED NUMBER OF ORGANS.
An augmentation in the number of parts may arise from several causes,
and may sometimes be more apparent than real. True multiplication exists
simply as a result of over-development; the affected organs are repeated
sometimes over and over again each in their proper relative position,
and without any transmutation of form.
Metamorphy, on the other hand, often gives rise to the impression that
parts are increased in number, when it may be that the stamens and
pistils, one or both, are not so much increased in number as altered in
appearance. The double anemones and ranunculus of gardens, amongst many
other analogous illustrations, may be mentioned. In these flowers, owing
to the petalody of the stamens and pistils, one or both, an impression
of exaggerated number is produced, which is by no means necessarily a
true one. Fission or lateral subdivision also gives rise to an apparent
increase in number; thus, some so-called double flowers, the elements of
which appeared to be increased in numbers, owe the appearance merely to
the laciniation or subdivision of their petals.
The French botanists, following Dunal and Moquin, attribute an increase
in the number of whorls in the corolla, and other parts of the flower,
to a process which they call chorisis, and they consider the
augmentation to be due to the splitting of one petal, for instance, into
several;--somewhat in the same manner as one may separate successive
layers of talc one from the other.
English botanists, on the other hand, have been slow to admit any such
process, because, in most instances, no alteration in the law of
alternation takes place in these double flowers, and in those few cases
where the law is apparently infringed, the deviation is explained by the
probable suppression of parts, which were they present would restore the
natural arrangement of the flower; and, that this is no imaginary or
purely theoretical explanation, is shown by some of the _Primulaceæ_,
wherein a second row of stamens is occasionally present in the adult
condition, and renders the floral symmetry perfect.
The double daffodil, where there are from forty to fifty petaloid organs
instead of fifteen, and wherein each piece exhibits a more or less
perfect coronal lobe at the junction of the claw and the limb, has been
cited as an objection to chorisis, though it is difficult to see on what
grounds.
In _Delphinium_, as shown by Braun,[376] the stamens and carpels are
members of a continuous spiral series, and in the double balsam an extra
corolline whorl is produced, without the suppression of the stamens, in
the following manner: the ordinary stamens are replaced by petals, the
carpels by stamens, while an additional whorl of carpels is produced at
the summit of the axis. In this instance, therefore, the doubling is
distinctly referrible to an absolute increase in the number of whorls,
and not to chorisis.[377]
On the other hand, it must be admitted that there are many cases which
are not to be explained in any other way than that suggested by the
French botanists before alluded to. Probably, the main difficulty in the
way of accepting the doctrine of chorisis is the unfortunate selection
of the word used to designate the process; this naturally suggests a
splitting of an organ already perfectly formed into two or more
portions, either in the same plane as the original organs, "parallel
chorisis;" or at right angles to it "collateral chorisis." Indeed,
before so much attention had been paid to the way in which the floral
organs are developed, it was thought that an actual splitting and
dilamination did really take place; Dunal and Moquin both assert as
much. The truth would rather seem to be that, in the so-called parallel
chorisis at least, the process is one of hypertrophy and
over-development rather than of splitting. The adventitious petal or
scale is an excrescence or an outgrowth from the primary organ, and
formed subsequently to it.
In the case of "compound stamens" the original stamens are first
developed each from its own cellular "mamelon," or growing point; and,
after a time, other secondary growing points emerge from the primary
one, and in this way the stamens are increased in number, without
reference, necessarily, to the so-called law of alternation. Outgrowths
from leaves, multiplying the laminar surface, are alluded to under the
head of hypertrophy, and it is probable that some of the cases of
duplication of the flower, or of the formation of adventitious segments
outside the ordinary corolla as alluded to in succeeding paragraphs (see
Pleiotaxy of the corolla), are due to a similar process.[378]
The formation of parts in unwonted numbers may be merely a reversion to
what is supposed to have been the original form, and in this way there
may be a restoration of parts that are usually undeveloped or
suppressed. There can be little or no doubt that there are in reality
six stamens in _Orchidaceæ_, of which one only, under ordinary
circumstances, is developed. When the numerical symmetry is restored, as
it sometimes is, it is obvious that the augmentation that occurs is of a
different character from that arising from a repetition or renewed
development of organs. When the increased number arises from
multiplication proper, or from repetition, the ordinary laws of
alternation are not interfered with, but if from chorisis or
"dédoublement," it may happen that the normal arrangement is disturbed.
Without studying the mode of development, it is not in all cases
possible to tell under which of the above categories any particular
instance should be placed; hence, in the following sections, except
where otherwise stated, the cases are grouped according to the
appearance presented in the adult condition, rather than to the way in
which the changes from the typical condition are brought about. With
reference to the foliar organs it is necessary to distinguish those
cases in which there is, from any cause, an augmentation in the number
of component parts of a whorl, from those in which the increase takes
place in the numbers of the whorls themselves.
FOOTNOTES:
[376] Braun, 'Pringsheim Jahrbuch f. Wiss. Bot.,' 1858, 1, p. 307, tab.
22, 23.
[377] Henfrey, 'Jour. Linn. Soc. Bot.,' vol. iii, p. 159.
[378] On the subject of chorisis or dédoublement the reader may
profitably consult Moquin-Tandon, 'Ess. sur les Dédoublements,' and the
same author in 'Ann. Sc. Nat.,' t. xxvii, p. 236. and 'El. Ter. Veget.,'
p. 337. Dunal, 'Consid. Org. Fleur.,' Montpell., 1829, p. 32, note 3. A.
de St. Hilaire in 'Ann. Sc. Nat.,' ser. 3, t. iii, p. 355, adnot.
Lindley, 'Elements of Botany,' p. 76. Asa Gray. 'Botanical Text Book.'
CHAPTER I.
MULTIPLICATION OF AXILE ORGANS, INFLORESCENCE, ETC.
By Linné an undue number of branches was designated as "plica," from the
analogy with the disease of the hair known as plica polonica: "_Plicata
dicitur planta, cum arbor vel ramus excrescit minimis intertextis
ramulis, tanquam plica polonica ex pilis, ceu instar nidi Picæ, quod
vulgo a genio ortum arbitratur; frequens apud nos in Betula, præsertim
Norlandiæ, in Carpino Scaniæ, nec infrequens in Pinu._"[379]
By some of the older authors this condition was called polyclady. In
some cases, it would seem to be due to fungi as in the witches' brooms
(hexenbesen) of the German forests; in other instances, it is a result
of mutilation as after the operation of pollarding.
Moquin-Tandon[380] mentions a case in a grafted ash in the botanic
garden of Toulouse, where below the graft there was a large swelling,
from which proceeded more than a thousand densely-packed, interlacing
branches.
This must have been similar to the condition so commonly met with in the
birch, and frequently in the hornbeam and the thorn, and which has
prompted so many a schoolboy to climb the tree in quest of the apparent
nest. It is probable that some of the large "gnaurs" or "burrs," met
with in elms, &c., also in certain varieties of apples, are clusters of
adventitious buds, some of which might, and sometimes do, lengthen out
into branches.
An increased number of branches also necessarily arises when the
flower-buds are replaced by leaf-buds.
[Illustration: FIG. 179.--Flower stalks of _Bellevalia comosa_, nat.
size, after Morren.]
Occasionally, a great increase in the number of pedicels, or
flower-stalks, may be met with in conjunction with a decreased number
of flowers, as in the wig-plant (_Rhus Cotinus_), or the
feather-hyacinth (_Bellevalia comosa_). In these cases the supernumerary
pedicels are often brightly coloured. To this condition Morren gave the
name mischomany, from [Greek: mischos], a pedicel, a term which has not
generally been adopted.[381]
[Illustration: FIG. 180.--Tuft of branches at the end of the
inflorescence of _Bellevalia comosa_, enlarged after Morren.]
M. Fournier[382] describes a case in the butcher's broom (_Ruscus
aculeatus_), wherein from the axil of the minute leaf subtending the
flower a secondary flattened branch proceeded.
Duchartre[383] cites the case of a hyacinth which, in addition to the
usual scape, had a second smaller one by its side terminated by a
solitary flower; indeed, such an occurrence is not uncommon.
Some tulips occasionally present three or four, or more, flowers on one
inflorescence, but whether from a branching of the primary scape, or
from the premature development of some of the axillary bulbils into
flowering stems which become adherent to the primary flower-stalk,
cannot, in all cases, be determined. Certainly, in some cases examined
by me the latter was the case.[384]
Under this head, too, may be included those cases wherein an ordinarily
spicate inflorescence becomes paniculate owing to the branching of the
axis and the formation of an unwonted number of secondary buds.
Instances of this kind may be met with in willows, hazels, alders, and
other amentaceous plants. In the case of the hazel the unusual
development of male catkins sometimes coincides with an alteration in
their position, instead of being placed near the axil of a leaf; they
become terminal. Jaeger figures and describes a bunch of _Pinus
sylvestris_ bearing in one case seventy minute cones, and in another
fifty-nine. These cones preserved the same spiral arrangement among
themselves which is proper to the leaves. These latter, indeed, replaced
the strobili above.[385]
[Illustration: FIG. 181.--Increased number of male catkins in the hazel
_Corylus avellana_.]
M. Reichardt describes an analogous case in the same species, and
attributes the inordinate number of cones to a fungus (_Peridermium
pini_). In this case there were no less than 227 cones, but each one
half the size of the ordinary cones.[386]
Of a similar character is the many-headed pineapple. Among grasses such
a branching of the inflorescence is exceedingly common,--which is the
more readily understood as the normal inflorescence is in so many cases
paniculate. Cultivators have, in some instances, availed themselves of
this peculiarity, as in the Egyptian wheat or corn of abundance
(_Triticum compositum_), certain varieties of Maize, etc. Similar
exuberant growths occur in _Orchidaceæ_, in _Cyperaceæ_, e.g. _Carex_,
in _Restiaceæ_, and indeed they may be found in any plant with a similar
form of inflorescence. In all these cases the branching begins at the
lower part of the spike, and extends from below upwards in an indefinite
manner, even although the primary inflorescence be definite.
Among the _Equisetaceæ_ a similar plurality of spikes occurs often as a
result of mutilation.[387] The deviation in question might in some
instances be turned to good account, as in the _Triticum_ before
mentioned or as in the broccoli shown at fig. 182, though it must be
added that the apparent advantages are often counterpoised by some
undesirable qualities or by some circumstance which prevents us availing
ourselves of the new condition.
=Multiplication of Bulbs.=--This occurrence has been briefly alluded to
previously (see p. 84). The most curious cases are those in which one
bulb is placed on the top of another as happened in some bulbs of
_Leucoium æstivum_ described by M. Gay.[388] Irmisch described a similar
phenomenon in _L. vernum_; and Mr. Moggridge has communicated drawings
of a similar formation in the same species grown in the neighbourhood of
Mentone.
From the instances cited it is clear that branching of the inflorescence
occurs most frequently in those plants naturally characterised by a
dense compact mode of growth, whether that be definite or indefinite, as
in spikes, umbels, capitula, &c.; so that compound spikes, umbels, &c.,
are formed in the place of simple ones (see also prolification of the
inflorescence, p. 102).
[Illustration: FIG. 182.--Broccoli, with six perfect heads on one stalk
('Gard. Chron.,' 1856, Oct. 25).]
=Increased number of florets= in the individual spikelets of grasses is
also met with under some circumstances. I have seen this in _Hordeum_
and _Lolium_, and an instance is figured in _Avena_ by Dr.
Wiegmann.[389] M. Duval Jouve[390] records a similar occurrence in
_Catabrosa aquatica_, the spikelets of which contained from two to seven
flowers.[391]
FOOTNOTES:
[379] 'Phil Bot.,' § 274.
[380] 'El. Ter. Veget.,' p. 392.
[381] 'Bull. Acad. Belg.,' xvii, part ii, p. 38.
[382] 'Bull. Soc. Bot. Fr.,' vol. iv, 1857. p. 760.
[383] Ibid., vol. viii, 1861, p. 159.
[384] See 'Gard. Chron.,' July, 1866, p. 656, and Clusius, 'Plant.
Rar.,' lib. 2, p. 143, _Tulipa serotina_ [Greek: polykladês], _minor_,
_&c._ Hort. Eysttett. Plant. Vern.,' fol. 12.
[385] 'Jaeger de Pini sylvestris monstrositate,' Stuttgardt, 1828.
[386] Cited in 'Bull. Soc. Bot. Fr.,' xiv, p. 265.
[387] Duval Jouve, 'Hist. Nat. Equiset. Fr.,' tab. 8, also Milde, 'Nov.
Act. Acad. Nat. Cur.,' t. xxvi, part 2. For branched inflorescence of
orchids, see 'Reichenbach Proc. Lond. Bot. Congress,' 1866, p. 121.
[388] 'Bull. Soc. Bot. Fr.,' vi, 266, vii, 457. Irmisch, 'Knollen und
Zwiebelgew.,' tab. 7, figs. 10, 11.
[389] 'Flora,' 1831, p. 5, tab. i; see also Hanstein, 'Flora,' 1857, p.
513. Schlechtendal, 'Bot. Zeit.,' xviii, p. 381.
[390] 'Bull. Soc. Bot. Fr.,' ix, p. 8.
[391] It will be seen, from what has been just said, that in some of the
cases where the axile organs, branches, &c., appear to be multiplied,
the increased number is due to subdivision rather than to renewed
formation (see Fission). Of this last description is an instance which
came under the writer's notice after the section relating to that
subject was in print, and which may therefore here be alluded to. The
instance is that of the subdivision of the leaf-like organs of
_Sciadopitys verticillata_. In one instance the pseudo leaf divided, and
from the division proceeded a little axis, bearing at its summit a
verticil of pseudo leaves. This division and formation of new axes and
verticils affords ample confirmation of the opinion thrown out by
Professor Alexander Dickson, that the apparent leaves of this plant were
really branches: see 'Revue Horticole,' 1867, and 'Report. Bot.
Congress,' London, 1866, p. 124.
CHAPTER II.
MULTIPLICATION OF FOLIAR ORGANS.
The cases referrible to this head may be ranged under two sections
according as the increase is due to plurality of ordinarily single
organs, or to an increase in the number of verticils or whorls.
When, in place of a single leaf organ two or more are really or in
appearance present the occurrence may be due to one of several causes;
among them may be mentioned an actual formation of parts in unwonted
number, hypertrophy or enation, chorisis or fission, disjunction,
adhesion of one leaf to another or to the stem, as in some of the leaves
called "geminate," wherein the two leaves, though apparently in
juxtaposition, yet originate from different parts of the stem, but by
coalescence or lack of separation produce the impression as if they
sprang from the same node. In the adult state it is not always possible
to ascertain with certainty to which of these causes the increase in the
number of leaves is due, though a clue to the real state of things may
be gained from attention to the distribution of the veins, to the
arrangement or phyllotaxy of the leaves, the size and position of the
supernumerary organs, &c.
The term "phyllomania," as ordinarily used, is applied to an unwonted
development of leafy tissue, as in some begonias where the scales or
ramenta are replaced by small leaflets, or as in some cabbage leaves,
from the surface of which project, at right angles to the primary
plane, other secondary leafy plates; but these are, strictly speaking,
cases of hypertrophy (see Hypertrophy).
Those instances in which the actual number of leaves is increased, so
that in place of one there are more leaflets, may be included under the
term "pleiophylly," which may serve to designate both the appearance of
two or more leaves in the place usually occupied by a single one, and
also those normally compound leaves in which the number of leaflets is
greater than usual.
The increased number of leaves in a whorl may well be designated as
"polyphylly," using the word in the same sense as in ordinary
descriptive botany, while "pleiotaxy" may be applied to those cases in
which the number of whorls is increased.
[Illustration: FIG. 183.--Supernumerary leaflet, _Ulmus campestris_.]
=Pleiophylly.=--As above stated, this term is proposed to designate
those cases in which there is an absolute increase in the number of
leaves starting from one particular point, as well as those in which the
number of leaflets in a compound leaf is preternaturally increased. The
simplest cases are such as are figured in the adjacent cuts, wherein, in
place of a single leaf, two are produced in the elm. In the one case the
new leaflet springs from the apex of the petiole and partially fills
the space consequent on the obliquity of the base of the leaf. In the
other it would seem as if two distinct leaves emerged from the stem in
juxtaposition. This is probably due to a lateral chorisis or subdivision
of the primitive tubercle or growing point, followed by a like
subdivision of the vascular bundle supplying it. There are certain
varieties of elm that very generally present this anomaly on their rank,
coarse, growing shoots. In these cases the new growths have the same
direction as the primary one, but in other cases the supplementary
production is exactly reversed in direction. Thus, in the common hazel
(_Corylus_) a second smaller leaf proceeding from the end of the
leaf-stalk at the base of the primary one may frequently be seen. M.
Germain de Saint Pierre records an instance in a mulberry leaf, from the
base of which proceeded a large leafy expansion divided into two
tubular, horn-like projections, and in the centre a thread-like process
representing the midrib and terminated by a small two-lipped limb.[392]
Dr. Ferdinand Müller speaks of a leaf of _Pomaderris elliptica_ as
bearing a secondary leaf on its under surface.[393]
[Illustration: FIG. 184.--Supernumerary leaf, _Ulmus montana_.]
[Illustration: FIG. 185.--Supernumerary leaf of hazel.]
The leaves of _Heterocentron macrodon_ have likewise been observed
occasionally to produce leaflets from their upper surface.
To this production of leaves from leaves the late Professor Morren
applied the term "autophyllogeny."[394] The Belgian botanist figures a
small perfect leaf springing from the nerves of the upper surface of the
primary leaf in a species of _Miconia_. As in the hazel, the direction
of the adventitious leaf is inversely that of the primary one, the upper
surface of the supernumerary leaflet being turned towards the
corresponding surface of the normal leaf. A similar occurrence took
place in _Gesnera zebrina_, but the new growth in this case sprang from
the lower face of the leaf. Morren explains the appearances in question
by supposing that the supplementary leaf is one of a pair belonging to a
bud borne on a slender stalk. This stalk and one of the bud-leaves are
supposed to be inseparably united with the primary leaf. But there is
no reason at all for supposing the existence of adhesion in these cases;
no trace of any such union is to be seen. A much more natural
explanation is that, from some cause or another, development at the apex
of the petiole or on the surface of the nerves, instead of taking place
in one plane only, as usual, takes place in more than one, thus showing
the close relationship, if not the intrinsic identity, between the
leaf-stalk and its continuation, the midrib, with the branch and its
subdivisions. The form of the leaf-stalk and the arrangement of the
vascular bundles in a circle in the case of the hazel, before alluded
to, bear out this notion. Such cases are significant in reference to the
notion propounded by M. Casimir de Candolle, that the leaf is the
equivalent of a branch in which the upper portion of the vascular circle
is abortive.[395]
Compound leaves, as has been stated, occasionally produce an extra
number of leaflets; one of the most familiar illustrations of this is in
the case of the four-leaved shamrock (_Trifolium repens_), which was
gathered at night-time during the full moon by sorceresses, who mixed it
with vervain and other ingredients, while young girls in search of a
token of perfect happiness made quest of the plant by day. Linné, who in
this matter, at any rate, had less than his usual feeling for romance,
says of the four-leaved trefoil that it differs no more from the
ordinary trefoil than a man with six fingers differs from one provided
with the ordinary number. It should be stated that five and six
adventitious leaflets are found almost as frequently as four.
Walpers describes a case where the leaf of _T. repens_ bore seven
leaflets. Schlechtendal alludes to a similar increase in number in
_Cytisus Laburnum_, and many other instances might be cited.
For figures or descriptions of four-leaved shamrocks the reader
is referred to Lobel, 'Stirp. Advers.,' Nov., p. 382.
Tabernæmontanus 'Krauterbuch,' S. 222. Schlechtendal, 'Bot.
Zeit.,' ix, p. 583, xiv, p. 71. Maugin, 'Bull. Soc Bot. Fr.,'
1866, t. xiii, p. 279. See also Cramer, 'Bildungsabweich,' p.
92. Walpers, 'Linnæa,' 1840, p. 362 (7-leaved). Schlechtendal,
'Bot. Zeit.,' 1844, p. 457, _Cytisus_. Wigand, 'Flora,' 1856,
p. 706.
Frondiferous leaves have much the appearance of branches provided with
leaves, and they may be compared with those instances in which an
adventitious bud is placed on the surface or edges of the leaves, as in
_Gesnera_, _Cardamine_, &c. In truth, the two conditions merge one into
the other, as in some begonias, where the ramenta often become leaf-like
and bear small bulbils in the axil.
When frondiferous leaves die the appendages die also, but when a true
bud has been formed on a leaf it does not of necessity die with the leaf
that bears it, but separates from it and continues to grow
independently.
=Increased number of stipules, spathes, &c.=--Seringe relates the
occasional presence of two or three additional stipules upon the
leaf-stalks of _Salix fragilis_, and even makes a variety (_Salix
pendula_, var. _multistipulata_).
An increase in the number of the spathes has been often noticed in
Arads[396]. Prof. Alex. Braun has studied this subject in some
detail[397]. In _Calla palustris_ the shoot which continues the growth
of the plant proceeds from the axil of the last leaf but one; the very
last leaf producing no bud, but if accidentally a shoot is developed in
this latter situation it produces flowers at once. No leaves are formed,
but, on the contrary, two or three spathes surround the spadix, so that
the presence of an increased number of spathes in this plant is
associated with the development of a side shoot from the axil of the
last leaf, the situation whence, under natural circumstances, no shoot
at all issues. The supernumerary spathes are not always on the same
level, but may be separated by a considerable interval. They vary very
much in size, and sometimes assume the form and appearance of leaves.
Similar anomalies occur in other Arads as _Arum maculatum_, _Richardia
æthiopica_, and _Anthurium Scherzerianum_, frequently combined with a
leaf-like appearance of the spathes and sometimes with a subdivision of
the spadix into two or three branches.
Engelmann relates the occurrence of an increased number of glumes in
_Bromus velutinus_ associated with suppression of the flowers.
=Polyphylly.=--As previously explained, this term is here applied to
those cases in which the members of any particular whorl are increased
in number, the whorls themselves not necessarily being augmented.
The simplest cases of this kind are those in which we meet with an
unusual number of leaves in a whorl.
=Increased number of leaves in a whorl.=--This may arise from actual
multiplication, or from lateral chorisis, or fission. The true nature of
the case may usually be ascertained by an examination of the
distribution of the veins of the leaves, or of the fibrous cords of the
stem, by the relative position of the supernumerary organs, &c.
Among plants with normally opposite leaves the following occasionally
produce them in whorls of three:--_Lonicera brachypoda_, _L. Xylosteum_,
_Weigela rosea_, _Cornus mas_, _Vinca minor_, &c.
_Paris quadrifolia_ may frequently be met with five leaves in its whorl,
or even six.[398]
=Increased number of bracts.=--This is not of infrequent occurrence; one
of the most curious instances is that recorded by Mr. Edwards[399] in
_Cerastium glomeratum_, where, in place of the usual pair of bracts at
the base of the head of flowers, there was a whorl of six or eight,
forming an involucre. The flowers in this case were apetalous and
imperfect.
=Polyphylly of the calyx.=--This may occur without any other
perceptible change, while at other times the number of the other parts
of the flower is proportionately increased. In a flower of a plum six
sepals in place of five sometimes exist; a precisely similar occurrence
in the flowers of the elder (_Sambucus_), the _Fuchsia_, and of
_OEnanthe crocata_, may occasionally be met with. In the latter case,
indeed, there are sometimes as many as ten segments to the calyx, and
this without the other parts of the flower being correspondingly
augmented. Among monocotyledons a similar increase is not uncommon, as
in _Tulipa_, _Allium_, _Iris_, _Narcissus_, &c.
In some plants there seems to exist normally much variation in the
number of parts; thus in some species of _Lacistema_ in adjacent flowers
the calyx may be found with four, five, or six segments.
Most of these cases of polyphylly affecting the calyx may be explained
by lateral chorisis or fission.
=Polyphylly of the corolla.=--This may happen in connection with similar
alterations in the calyx and stamens, or sometimes as an isolated
occurrence. In the latter case it may be due to lateral chorisis, to
substitution, or to the development of organs usually suppressed; thus,
when in aconites we meet with four or five horn-like nectaries (petals)
instead of two only, as usual, the supernumerary ones are accounted for
by the inordinate development of parts which ordinarily are in an
abortive or rudimentary state only. This is borne out by what happens in
_Balsamineæ_. In the common garden balsam the fifth petal is
occasionally present, while in _Hydrocera triflora_ this petal is always
present.
In a flower of a _Cyclamen_ recently examined there were ten petals in
one series, the additional five being evidently due to the subdivision
of the five primary ones; the natural circular plan of the flower was
here replaced by an elliptical one. A similar occurrence takes place in
the flowers of maples (_Acer_), which sometimes show an increased number
of parts in their floral whorls and an elliptical outline. Whether the
additional organs in this last case are the result of complete lateral
chorisis or of multiplication proper I do not know.
Orchids are very subject to an increase in the number of their labella.
As illustrations may be cited an instance recorded by Mr. J. T.
Moggridge in a flower of _Ophrys insectifera_, and in which there were
two labella without any other visible deviation from the ordinary
conformation.[400]
I am indebted to Mr. Hemsley for the communication of a similar specimen
in _O. apifera_, in which there were two divergent lips, each with the
same peculiar markings. One of the sepals in this flower was adherent to
one of the lateral petals. This augmentation of the labella depends
sometimes on the separation, one from the other, of the elements of
which the lip is composed, at other times on the development, in the
guise of lips, of stamens which are usually suppressed (see p. 380).
The following enumeration will suffice to show the genera in which an
increased number of petals or perianth-segments in any given whorl most
frequently occurs.
Anemone!
Ranunculus!
Aconitum!
Raphanus.
Bunias.
Saponaria.
Dianthus!
Pelargonium!
Hibiscus.
Fuchsia.
Sarothamnus!
Lotus!
Ulex!
Prunus!
Trifolium.
OEnanthe and Umbellif. pl.!
Sambucus!
Bryonia.
Campanula.
Solanum.
Veronica.
Cyclamen!
Primula!
Anagallis!
Plumbago.
Jasminum.
Syringa!
Tradescantia.
Iris.
Tigridia.
Narcissus.
Tulipa.
Convallaria!
Paris!
Hyacinthus!
Allium!
Ornithogalum.
Orchideæ, sp. pl.!
For other illustrations see multiplication of whorls, petalody;
see also Moquin, loc. cit., p. 350. Engelmann, loc. cit., p.
20, § 18. Cramer, loc. cit., p. 25.
=Polyphylly of the androecium.=--An increased number of stamens
frequently accompanies the corresponding alterations in other whorls,
and seems, if anything, to be more frequent among monocotyledonous
plants than among dicotyledonous ones; thus, we occasionally find
tetramerous flowers in _Crocus_, _Hyacinthus_, _Tulipa_, _Iris_,
_Tigridia_, &c., and more rarely in _Yucca_ (_Y. flexilis_[401]).
The increased number of stamens in a single whorl may result from a
development of organs usually suppressed, and constitute a form of
regular peloria as in _Linaria_, wherein a fifth stamen is occasionally
met with. Among normally didynamous plants such numerical restitution,
so to speak, is not unusual; thus, in _Veronica_ four and five stamens
occur. Fresenius has seen five stamens in _Lamium_, _Mentha_,
_Chelone_;[402] Bentham in _Melittis_, and other instances are cited
under the head of peloria. Chorisis may also serve to account for some
of these cases; thus, Eichler[403] figures a flower of _Matthiola annua_
with five long stamens instead of four; one of the long pairs of stamens
has here undergone a greater degree of repetition than usual. De
Candolle[404] cites and figures a curious form of _Capsella
Bursa-pastoris_ sent him by Jacquin, and which was to some extent
reproduced by seed. In the flowers of this variety there were no petals,
but ten stamens; hence De Candolle inferred that the petals were here
replaced by stamens, but Moquin[405] objects, and with justice, to this
view, as the ten stamens are all on the same line; he considers the
additional stamens to be the result of chorisis. Buchenau[406] mentions
the presence of seven stamens in another Crucifer, _Ionopsidium
acaule_. Here the supernumerary organ was placed between two of the long
stamens. The effect of chorisis in producing an augmentation of parts is
well seen in some plants that have some of their flowers provided with
staminodes or abortive stamens, and others with clusters or phalanges of
perfect stamens. Thus, in the female flowers of _Liquidambar_ there are
five small staminodes without anthers, whereas in the male flower the
stamens are numerous and grouped together in phalanges, so that the
relation of simple to compound stamens is in this case readily seen, as
also in many _Malvaceæ_, _Sterculiaceæ_, _Byttneriaceæ_, _Tiliaceæ_, and
_Myrtaceæ_. It is probably the idea of splitting or dilamination
involved in the word chorisis that has led many English botanists to
hesitate about accepting the notion. Had they looked upon the process as
identical with that by which a branched inflorescence replaces an
unbranched one, or a compound leaf takes the place of a simple one, the
objections would not have been raised with such force. The process
consists, in most cases, not so much in actual cleavage of a
pre-existing organ as in the development of new-growing points from the
old ones.
An illustration given by Moquin from Dunal[407] goes far to support the
notion here adopted. The majority of the stamens of laurels (_Laurus_)
have, says M. Dunal, on each side of the base of their filaments a small
glandular bifid appendage; these excrescences are liable to be changed
into small stamens. The male flowers have a four-leaved calyx, and
sometimes eight stamens, each with two glands, four in one row, opposite
to the sepals, four in a second series alternating with the first. More
generally two of the stamens are destitute of glands, but have in their
place a perfectly developed stamen, so that in these latter flowers
there are twelve stamens.
M. Clos[408] mentions a flower of rue (_Ruta_) wherein there were two
stamens joined together below and placed in front of a petal, as in
_Peganum_.
Buchenau[409] mentions a flower of _Lotus uliginosus_ in which there
were eleven stamens, namely, two free and nine monadelphous; and
Hildebrand describes an analogous increase in a flower of _Sarothamnus
scoparius_ in which, in conjunction with a seven-toothed calyx, there
were two carinas and fourteen stamens. It would seem probable in this
case that there was a coalescence of two flowers at an early date and
consequent suppression of some of the parts of the flower. Whether this
was the case or not in this particular illustration, it is nevertheless
certain that many of the recorded instances of increased number in the
organs of a flower are really the results of a fusion of two or more
flowers, though frequently in the adult state but few traces of the
coalescence are to be seen.
=Polyphylly of the gynoecium.=--Moquin[410] remarks that, as the
pistils are, generally speaking, more or less subject to pressure, owing
to their central position, and it may be added owing to their later
development, than the other parts of the flower, they are more subject
to suppression than to multiplication; nevertheless, augmentation in the
number of carpels does occasionally take place, especially when the
other parts of the flower are also augmented in number. Sometimes this
increase in the number of carpels is due to pure multiplication, without
any other change. At other times the increase is due to a substitution
of stamens or other organs for carpels (see Substitutions). In other
cases the augmentation seems to be due to the development of parts
usually suppressed; for instance, in _Antirrhinum_, where there are
usually only two carpels present, but where, under peculiar
circumstances, five may be found--thus rendering the symmetry
complete.[411] In _Papilionaceæ_, wherein usually only one carpel is
developed, we occasionally find two, or even more, as in _Wistaria_,
_Gleditschia_, _Trifolium_, &c. In _Prunus_ and _Amygdalus_ from two to
five carpels are occasionally to be found,[412] in _Mimosa_ five, in
_Umbelliferæ_ three to five; in some composites, _e.g._ _Spilanthes_,
five carpels have also been noticed; in _Cruciferæ_ three and four, in
grasses three.[413] The double cocoa-nut affords an illustration of the
development of two carpels out of three, one only generally arriving at
perfection. Triple nuts (_Corylus_) also owe their peculiarity to the
equal development of all three carpels which exist in the original
flower, but of which, under ordinary circumstances, two become abortive.
It is necessary, however, to distinguish these cases from those in which
two embryos are developed in one seed.
The following list may serve to show in what genera this change has been
most frequently noticed, and it may be said in general terms that
_Cruciferæ_, _Umbelliferæ_, and _Liliaceæ_, are the orders most
frequently affected. Cases of peloria are not included in the subjoined
list.
Nigella.
Aquilegia.
Pæonia!
Delphinium!
Iberis.
Diplotaxis.
Lunaria.
Ricotiana.
Octadenia.
Draba!
Lepidium.
*Cheiranthus!
Dianthus.
Brassica!
Parnassia.
*Acer!
Ptelea.
Citrus!
Philadelphus.
Prunus!
Amygdalus!
Cratægus!
Fuchsia!
Trapa!
Cassia.
Cercis.
Medicago.
*Phaseolus!
Wistaria.
Gleditschia.
Affonsea.
Trifolium!
Archidendron.
Mimosa.
Robinia.
Diphaca.
Coesalpinia.
Vicia.
Anthyllis.
Cucurbita.
Passiflora!
Sambucus!
*OEnanthe!
Daucus!
Angelica!
Heracleum!
Silaus.
Carum.
Thysselinum.
Campanula!
Spilanthes.
Chrysanthemum.
Anagallis.
Primula!
Fraxinus!
Lycium.
Cobæa.
Datura!
Solanum!
Sesamum.
Sideritis.
Coleus.
Veronica!
*Digitalis!
Antirrhinum!
Linaria.
Gloxinia!
Symphytum.
Anchusa.
Polygonum.
Euphorbia.
Cneorum.
Mercurialis!
Chenopodium.
Suæda.
Beta.
Corylus!
Lambertia.
Cocos!
Tigridia.
Tulipa!
Iris!
Narcissus!
Allium!
Ornithogalum.
Gagea!
Tradescantia!
Schoenodon.
Bambuseæ.
A few additional references may here be given to papers where
an increased number of carpels is described:--Engelmann, 'De
Antholys,' § 17, p. 19. Bernhardi, 'Flora,' 1838, p. 129.
Schkuhr., 'Bot. Handb.,' t. 179. Godron, 'Ann. Sc. Nat.,' ser.
5, vol. ii, p. 280, tab. xviii, _pluricarpellary Crucifers_.
Weber, 'Verhandl. Nat. Hist. Vereins. Rhein. Pruss.,' &c.,
1860, _Cerasus_, &c., &c. Baillon, 'Adansonia,' iv, p. 71,
_Trifolium_. Schlechtendal, 'Bot. Zeit.,' xv, p. 67, _Datura_,
three-celled fruit; 'Bot. Zeit.,' xiii, p. 823, _Phaseolus_,
double pistil--a common case. Cramer, 'Bildungsabweich,' p. 99,
reference to several leguminous plants with polycarpellary
pistils. Munro, Gen., 'Linn. Trans.,' vol. xxvi, p. 26,
_Bambuseæ_. Alph. de Candolle, 'Neue Denkschrift,'
_Cheiranthus_. Schimper, 'Flora,' 1829, ii, p. 433. Wigand,
'Bot. Untersuch.' Fleischer, 'Missbild. Cultur Pfl.' Cramer,
'Bildungsabweich,' p. 65, _Umbelliferæ_.
=Polyphylly of the flower in general.=--Although, for the sake of
convenience, multiplication has here been treated of as it affects the
members of individual whorls of the flower, yet it must be remembered
that, in general, the augmentation is not confined to one whorl, but
affects several; thus, if the sepals are increased, the petals are
likely to be so likewise, and so forth. One of the most curious
illustrations of this is that recorded by Mr. Berkeley[414] in a plum,
wherein there was an increased number of sepals, a corresponding
augmentation in the petals, while the pistil was composed of two and
sometimes three carpels distinct from the calyx and from each other. In
the flowers there did not appear to be any definite relation in the
position of the parts either with reference one to another or to the
axis.
[Illustration: FIG. 186.--Plum. Increased number of parts in the
calycine, corolline, and carpellary whorls respectively.]
In _Primulaceæ_ this general augmentation has been frequently
noticed.[415]
Among _Orchideæ_ the instance related by Dr. Seubert is worth alluding
to here. This botanist observed and figured a flower of _Orchis
palustris_ with tetramerous arrangement of parts, that is to say there
were four outer segments to the perianth, four petals, of which two
were lip-like, four stamens, three of which were rudimentary, and an
ovary with four parietal placentæ.[416]
The following list will serve to show in what plants this general
augmentation of parts has been observed most frequently:
Ranunculus.
Clematis!
Delphinium.
Brassica!
Ruta.
Acer!
Prunus!
Rosa!
Rubus.
Philadelphus!
Chrysosplenium.
Umbelliferæ, sp. pl.!
*Fuchsia!
OEnothera.
Adoxa.
Bryonia.
Cucumis!
Campanula!
Sambucus!
*Primula!
Anagallis!
Lycium.
Solanum.
Symphytum.
Syringa!
Linaria.
Chenopodium.
*Paris!
Convallaria!
Allium.
*Lilium!
*Tulipa!
Ornithogalum.
*Gagea!
Tradescantia!
Orchideæ, sp. pl.!
=Increased number of ovules or seeds.=--This appears not to be of very
frequent occurrence, at least in those plants where the number of these
organs is normally small; where, as in _Primula_, the ovules and seeds
are produced in large quantities, it is not practicable to ascertain
whether the number be augmented or not in any particular case. Very
probably, the attachment or source of origin of the ovules determines,
in some measure, their number. Thus, in the case of marginal
placentation the number must be limited by the narrow space from which
they proceed, whereas in parietal and free central placentation the
ovules are generally numerous. In the latter case, however, it will be
remembered that solitary ovules are not rare. An increased number of
ovules is generally remarked in conjunction with some other change, such
as a foliaceous condition of the carpel, in which the margins are
disunited. In such cases the ovules may occupy the margin or may be
placed a short distance within it, as in the case of some open carpels
of _Ranunculus Ficaria_,[417] and in which two ovules were borne in
shallow depressions on the upper or inner surface of the open carpel and
supplied with vascular cords from the central bundle or midrib. The
outer coating of the ovule here contained barred or spiral fusiform
vessels derived from the source just indicated.
In the very common cases where the pistil of _Trifolium repens_ becomes
foliaceous (see Frondescence), the outer ovules are generally two or
more instead of being solitary. So, also, in the Rose with polliniferous
ovules (see p. 274). Among _Umbelliferæ_ affected with frondescence of
the pistil a similar increase in the number of ovules takes place. It
will be borne in mind that in most, if not all, these cases the
structure of the ovule is itself imperfect.[418]
What are called in popular parlance double almonds or double nuts
(_Corylus_) are cases where two seeds are developed in place of one.
In the 'Revue Horticole,' 1867, p. 382, mention is made of a bush which
produces these double nuts each year--in fact, it never produces any
single-seeded fruit. The plant was a chance seedling, perhaps itself the
offspring of a double-seeded parent. It would be interesting to observe
if the character be retained by the original plant, and whether it can
be perpetuated by seed or by grafting.
It is necessary to distinguish in the case of the nut between additional
seeds or ovules, as just described, and the double, triple, or fourfold
nuts that are occasionally met with, and which are the result either of
actual multiplication of the carpels or of the continued development of
some of the carpels which, under ordinary circumstances cease to grow
(see _ante_, p. 364). In the case of a ripe nut with two seeds it might
be impossible to tell whether the adventitious seed were the product of
multiplication, or whether it belonged, in the first instance, to the
same carpel as that producing the fellow-seed, or to a different and now
obliterated ovary. In all probability, however, the second seed would be
accounted for by the development of two seeds in one carpellary cavity.
There is still another condition occasionally met with in the almond,
and which must be discriminated from the more common multiplication of
the seed, and which is the multiplication of the embryos within the
seed, and which furnishes the subject of the succeeding paragraph.
=Increased number of embryos.=--A ripe seed usually contains but a
single embryo, although in the ovular state preparation is commonly made
for more; and, indeed, in certain natural orders plurality of embryos in
the same seed does occur, as in _Cycadeæ_ and _Coniferæ_. In the seeds
of the orange (_Citrus_), in those of some _Euphorbiaceæ_, &c., there
are frequently two or more additional embryos. A similar occurrence has
been recorded in the mango, for a specimen of which I am indebted to the
Rev. Mr. Parish, of Moulmein.[419]
Plurality of embryos has also been observed in--
Raphanus sativus.
*Citrus Aurantium!
Diosma, sp.
Hypericum perforatum.
Triphasia aurantiaca.
*Æsculus Hippocastanum!
Euonymus latifolius.
*Mangifera indica!
Eugenia Jambos.
Amygdalus vulgaris!
Vicia, sp.
Cassia, sp.
*Viscum album!
Daucus Carota.
Ardisia serrulata!
Cynanchum nigrum.
fuscatum.
Euphorbia rosea.
Coelebogyne ilicifolia.
Allium fragrans.
Funckia, sp.
Carex maritima.
Zea Mays.
See Schauer's translation of Moquin-Tandon, 'El. Terat.
Veget.,' p. 245, adnot., and 'Al. Braun Polyembryonie.'
=Increased number of the cotyledons.=--Although the presence of one or
of two cotyledons in the embryo is generally accepted as a valuable
means of separating flowering plants into two primary groups, yet, like
all other means of discrimination, it occasionally fails, and, indeed,
almost always requires to be taken in conjunction with some other
character. There are cases among flowering plants where the embryo is
homogeneous in its structure, there are others in which the number of
the cotyledons is more than two. Thus, in some seeds of _Cola acuminata_
the cotyledons vary in number from two to five. I have not been able to
ascertain precisely whether this multiplication of the cotyledons is
characteristic of all the seeds of particular trees, or whether some
only are thus affected. Some fruits that I examined bore out the latter
view, as in the same pod were seeds with two, three, and four cotyledons
respectively.
I have also seen three cotyledons present in embryo-plants of _Correa_,
_Cratægus Oxyacantha_, _Dianthus sinensis_, _Daucus Carota_, _Cerasus
Lauro-cerasus_. De Candolle alludes to a case of the kind in the bean,
and figures a species of _Solanum_ with three cotyledons.[420] Jaeger
alludes to a similar instance in _Apium Petroselinum_;[421] Ehrenberg to
one in the marigold (_Calendula_);[422] Reinsch to an analogous
appearance in the beech (_Fagus_), associated with a union of the
margins of two out of the three cotyledons, and of those of two out of
the three leaves next adjacent.[423] This fusion seems frequently to
accompany increase in the number of cotyledons. It was so in the
_Correa_, and in the _Cratægus_ previously mentioned. Some of these
cases may be accounted for by chorisis or by a cleavage of the original
cotyledons, as happens, according to Duchartre,[424] in some Coniferæ,
which he considers to be improperly termed polycotyledonous. Whether
this holds good in the Loranths, where (_Nuytsia_, _Psittacanthus_) an
appearance of polycotyledony exists, is not stated. In the case of the
rue (_Ruta_) figured by M. A. de Jussieu[425] this splitting of one
cotyledon into two is sufficiently evident, as is also the case in the
sycamore (_Acer pseudo-platanus_), seedlings of which may often be met
with divided cotyledons.
In other instances a fusion of two embryo plants may give rise to a
similar appearance, as in the _Euphorbia_ and _Sinapis_ found by M.
Alph. de Candolle (see _ante_, p. 56).
=Pleiotaxy or multiplication of whorls.=--In the preceding section
notice has been taken of the increased number of parts in a single
whorl, but an augmentation of the number of distinct whorls is still
more frequently met with. Many of the so-called double flowers owe their
peculiarity to this condition. The distinction between the two modes in
which the parts of the flower are increased in number has been pointed
out by Engelmann, Moquin, and others, and the two seem to require
distinctive epithets; hence the application of the terms polyphylly and
pleiotaxy, as here proposed.
=Pleiotaxy in the bracts.=--An increase in the number of bracts has been
met with very constantly in a species of _Mæsa_, and in a peculiar
variety of carnation, called the wheat-ear carnation.[426] In some of
these cases the increase in the number of bracts is attended by a
corresponding suppression in the other parts of the flower. Such a
condition has been frequently met with in _Gentiana Amarella_, where the
bracts are increased in number, coloured purple, and destitute of any
true floral organs. A similar condition exists in some varieties of
_Plantago major_ (var. _paniculata_), as has been previously stated, p.
109.
[Illustration: FIG. 187.--Wheat-ear carnation. The appearance is due to
the multiplication of the bracts and the suppression of the other parts
of the flower.]
It has been noticed also in the common pea, _Pisum sativum_, and M.
Lortet[427] records a case of the kind in _Erica multiflora_, the
flowers of which, under ordinary circumstances, are arranged in
clusters, but in this case the pedicels were more closely crowded than
usual, and were covered for their whole length with small rose-coloured
bracts arranged in irregular whorls, the upper ones sometimes enclosing
imperfect flowers. In the 'Gardeners' Chronicle,' 1865, p. 769, is
figured a corresponding instance of _Delphinium Consolida_, in which the
bracts were greatly increased in number, petaloid, and, at the same
time, the central organs of the flower were wholly wanting.
[Illustration: FIG. 188.--_Delphinium Consolida_. Multiplication of
bracts at the expense of the other parts of the flower.]
[Illustration: FIG. 189.--Multiplication of bracts, &c., _Pelargonium_.]
In flowers of _Pelargonium_ may occasionally be seen a repetition of the
whorls of bracts, in conjunction with suppression and diminished size of
some of the other portions of the flower (fig. 189).
The common foxglove (_Digitalis purpurea_) has likewise occasionally
been observed subject to a similar malformation.
_Cornus mas_ and _C. suecica_ sometimes show a triple involucre.[428]
Irmish[429] records an analogous case in _Anemone Hepatica_, wherein the
involucre was doubled. Similar augmentation occurs in cultivated
Anemone. In addition to the plants already mentioned, Engelmann[430]
mentions as having produced bracts in unwonted numbers, _Lythrum
Salicaria_, _Plantago major_, _Veronica spicata_, _Echium vulgare_,
_Melilotus arvensis_, and _Rubus fruticosus_.
It must here be remarked that this great number of the bracts occurs
naturally in such plants as _Godoya_, in which the bracts, or, as some
consider them, the segments of the calyx, are very numerous, and
arranged in several overlapping segments.
In some of the cultivated double varieties of _Nigella_ the finely
divided involucral bracts are repeated over and over again, but on a
diminished scale, to the exclusion of all the other parts of the flower.
=Pleiotaxy or repetition of the calyx.=--The true calyx is very seldom
affected in this manner, unless such organs as the epicalyx of mallows,
_Potentilla_, &c., be considered as really parts of the calyx.
In _Linaria vulgaris_ Roeper observed a calyx consisting of a double
series, each of five sepals, in conjunction with other changes.[431] It
is also common in double columbines, delphiniums, nigellas, &c.
In the 'Revue Horticole,' 1867, p. 71, fig. 9, is described and figured
by M. B. Verlot a curious variety of vine grown for years in the Botanic
Garden at Grenoble, under the name of the double-flowered vine. The
place of the flower is occupied by a large number of successive whorls
of sepals disposed in regular order, and without any trace of the other
portions of the flower. It is, in fact, more like a leaf-bud than a
flower. The outermost whorls of this flower open at the time when the
ordinary flowers of vines do; the second series are gradually produced,
and expand about the time when the ovaries of the normal flowers begin
to swell; a third series then gradually forms, and so on, until frost
puts a stop to the growth. This malformation, it appears, is produced
annually in certain varieties of vine, and may be perpetuated by
cuttings.
The flower of the St. Valèry apple, already alluded to under the head of
sepalody, might equally well be placed here. It is not very material
whether the second whorl of organs be regarded as a repetition of the
calyx or as a row of petals in the guise of sepals.
Engelmann[432] cites the following plants as occasionally presenting a
repetition of the calyx, in most cases with a suppression of the other
floral whorls:--_Stachys lanata_, _Myosotis palustris_, _Veronica
media_, _Aquilegia vulgaris_, _Nigella damascena_, _Campanula
rapunculoides_.
=Pleiotaxy in the perianth.=--Increase in the number of whorls in the
perianth is common in lilies, narcissus, hyacinths, &c. It may be also
met with occasionally among orchids. The lily of the valley
(_Convallaria maialis_) seems also to be particularly subject to an
increase in the number of parts of which its perianth consists, the
augmentation being due partly to repetition or pleiotaxy, partly to the
substitution of petaloid segments for stamens and pistils.[433]
In this place may also be mentioned the curious deviation from the
ordinary structure occasionally met with in _Lilium candidum_, and known
in English gardens as the double white lily. In this case there are no
true flowers, but a large number of petal-like segments disposed in an
irregular spiral manner at the extremity of the stem, some of the
uppermost being occasionally verticillate.[434]
[Illustration: FIG. 190.--Double white lily. Multiplication of
perianth-segments and other changes.]
=Pleiotaxy of the corolla.=--With reference to double flowers, it was
remarked by Linné that polypetalous flowers were, as he said,
multiplied, while monopetalous flowers were duplicated, or triplicated,
as the case may be,[435] a statement that is true in the main, though
it requires modification. In the case of polypetalous, or rather
dialypetalous flowers, the petals may be very largely increased by
multiplication, as in roses, anemones, pinks, &c. In the last-named
genus the number is often so much increased that the calyx splits from
the tension exercised on it by the increasing mass within. This
multiplication may happen without any metamorphy or substitution of
petals for stamens, though, in the majority of cases, it is associated
with such a change. It is curious to observe in some of these flowers
that the total number of parts is not greatly increased; thus, in some
of the double-flowered _Leguminosæ_, such as _Ulex europæus_ and _Lotus
corniculatus_, the petals are repeated once or twice, the stamens are
petalodic, but reduced in number, while the carpels are usually entirely
wanting. Thus, owing to the diminished number of parts in the inner
whorls of the flower, these very double-looking blooms do not contain
any greatly increased number of parts.[436]
Flowers that, under ordinary circumstances, are gamopetalous, become, in
some instances, multiplied by the formation of additional segments, just
as in the case of polypetalous corollas; but in these cases the corollas
become polypetalous, their petals do not cohere one with another. Among
double flowers of this character may be mentioned _Campanula
rotundifolia_, _Gardenia_ sp., _Nerium Oleander_, _Serissa_ sp.,
_Arbutus Unedo_, &c. The change is associated with petalody of the
stamens and pistils.
A more frequent change among the monopetalous orders is the duplication
or triplication of the corolla, in consequence of which there appear to
be a series of corollas enclosed one within the other, the lobes of
which generally alternate with one another, but which sometimes are
superposed. This happens occasionally in the primrose (_Primula
acaulis_), and constitutes the variety called by the gardeners "hose in
hose."
The same condition occurs frequently in some species of _Datura_ and
_Campanula_.
[Illustration: FIG. 191.--_Campanula rotundifolia_. "Double flowers"
resulting from dialysis and multiplication of the petals.]
In _Antirrhinum majus_ double flowers of this character sometimes occur;
the outermost corolla is normal, the succeeding ones usually have their
petals separate one from the other; the stamens are sometimes present,
sometimes absent, and at other times petalodic. Similar occurrences may
be met with in labiates and jasmines, and in _Erica hyemalis_.
Mr. W. B. Hemsley has kindly furnished me with flowers of a similar kind
occurring in wild specimens of _Epacris impressa_,[437] and there are
analogous phenomena in the common honeysuckle (_Lonicera Periclymenum_),
in which three corollas and no stamens often occur.
This duplication may either be accounted for on the theory of chorisis
above alluded to, or by supposing that the extra corolline whorl is due
to a series of confluent petalodic stamens; that the latter is the true
explanation, in certain cases at least, is shown by some flowers of
_Datura fastuosa_, in which the second corolla was partially staminal in
its appearance, and bore nearly perfect anthers, in addition to the five
ordinary stamens, which were unaltered either in form or position. Some
partially virescent honeysuckle flowers have a similar structure.
There are other cases of apparent multiplication or duplication, due,
probably, rather to the formation of outgrowths from the petals than to
actual augmentation of their number. These excrescences occur sometimes
on the inner surface of the petals, or of the corolla; at other times on
the outer surface, as in some gloxinias, &c. This matter will be more
fully treated of under the head of hypertrophy and enation.
=Pleiotaxy of the androecium.=--An increase in the number of whorls in
the stamens is very common, especially in cases where the number of
circles of stamens is naturally large. The augmentation of the number of
stamens is still more frequent where these organs are arranged, not in
verticils, but in one continuous spiral line.
In _Cruciferæ_ there is always an indication of two whorls of stamens,
and this indication is rendered even more apparent in some varieties
accidentally met with. So in _Saponaria_, in _Dianthus_, and other
_Caryophylleæ_, three and four verticils of stamens have been met with.
In _Lonicera Periclymenum_ a second whorl of stamens more or less
petalodic sometimes occurs.
Moquin mentions a variety of _Rubus fruticosus_ in which nearly 900
petaloid organs existed in the place of the twenty-five or thirty
stamens natural to the plant, the other organs of the flower being in
their ordinary condition, with the exception of the pistil, which did
not attain its full size. Baillon records the occasional existence of
two rows of stamens in _Ditaxis lancifolia_.
=Increased number of stamens in orchids, &c.=--Various deviations from
the ordinary type of orchid structure have been already alluded to under
the head of displacement, fusion, peloria, substitution, &c., but the
alterations presented by the androecium in this family are so
important in reference to what is considered its natural conformation,
that it seems desirable, in this place, to enter upon the teratological
appearances presented by the androecium in this order, in somewhat
greater detail than usual. The ordinary structure of the flower with its
three sepals, two petals, labellum, column; and inferior ovary, is well
known. Such a conformation would be wholly anomalous and inexplicable
were it not that the real number and arrangement of parts have been
revealed by various workers labouring to the same end in different
fields. Thus, Robert Brown, Link, Bauer, Darwin, and others, paid
special attention to the minute anatomy and mode of distribution of the
vessels; Irmisch, Crueger, Payer, and others, to the evolution of the
flower; Lindley, St. Hilaire, and Reichenbach, to the comparison of the
completed structures in the various genera and species; while the
teratological observers have been numerous, as will be seen from the
selected references cited at the end of this paragraph and in other
places. The result of this manifold study has been a pretty general
agreement that the structure of the order (omitting minor details) is as
follows:--A six-parted perianth in two rows, the outer three (sepals)
generally regular and equal in shape; of the inner three (petals or
tepals) two are regular, and one, the labellum very irregular,
consisting not only of a petal, but of two abortive stamens incorporated
with it. The column is considered to be made up of one perfect and three
abortive stamens, in inseparable connection with three styles. By some,
however, it is supposed that all the stamens are confluent with the
column and none with the lip.
[Illustration: FIG. 192.--Diagram showing the arrangement of parts in an
orchid flower. According to Crüger, the stamens A 2, A 3, should be
distinct from the lip. The uppermost figure 2 should have been 1. (See
text.)]
In either case it is admitted that there are six stamens in two rows.
The first row consists of one posterior stamen, which is generally
perfect, and two abortive stamens incorporated with the labellum. The
second row also consists of three stamens, all of which are usually
abortive and inseparable from the column. Traces of them may
occasionally be met with in the form of tubercles or wing-like processes
from the column. In _Cypripedium_, while the ordinary stamen of the
outer row is deficient, two of the inner series are present. The
diagram, fig. 192, will serve to show the arrangement of the parts as
above described. + represents the situation of the stem or axis; on the
opposite side is the bract; between these are placed the sepals, one
posterior or next the axis (incorrectly numbered 2 in the plan), two
lateral 1, 1; next in order follow the petals, 2, 2, 2, two lateral and
somewhat posterior, one larger (the lip), anterior; the outer series of
stamens are represented by A 1, A 2, A 3, the two latter being fused
with the labellum; _a_ 1, _a_ 2, _a_ 3 represent the position of the
inner verticil of stamens, while s, s, s denote the three carpels. It is
foreign to the purpose of this book to detail the varied evidence in
support of this explanation of the homologies of orchid flowers.[438]
All that can be done in these pages is to set forth the evidence
furnished by teratology as to this matter--evidence for the most part
accumulated and recorded without any special reference to any theory of
orchid structure.
The following details all refer to flowers in which the number of
stamens in orchidaceous plants was increased beyond what is necessary.
They are arranged with reference to the number of adventitious organs,
beginning with those in which the number was smallest, and proceeding
thence to those in which it was greatest. In some cases it has not been
possible to ascertain whether the adventitious organs were really
restorations of the numerical symmetry, substitutions of one part for
another, stamen for petal, &c., or wholly adventitious productions.
Unless otherwise stated, the interpretation put upon the facts thus
recorded is that of the present writer, and not necessarily that of the
original observer.
Mr. J. T. Moggridge has described and figured a flower of
_Ophrys insectifera_ in which there was a vestige of a second
stamen present, probably one of the inner series fig. 192
(_a_^2).[439] The same observer also records the presence of a
second anther between the lobes of the normal one. This can
hardly be referred to either of the typical stamens, but would
seem to be a perverted development of the rostellum.[440]
Roeper is stated by Cramer[441] to have seen a specimen of
_Orchis morio_ with two stamens.
In a flower of _Habenaria chlorantha_, described by the late
Professor Henslow,[442] the outer three stamens are suppressed,
while two of the inner group are present, as happens normally
in _Cypripedium_.
A flower of _Cattleya violacea_ afforded a similar
illustration; but in this case only one of the inner stamens
was developed, and this in the form of a small petal, partly
adherent to the column.
In _Dendrobium normale_, Falconer, not only is the perianth
regular, but the column is triandrous,[443] the three stamens
(according to the diagram of its structure given by Lindley)
pertaining to the outer row.
In a specimen of _Dendrobium hoemoglossum_ kindly forwarded
from Ceylon by Mr. Thwaites there were three stamens present,
of which one posterior belonged to the outer series A 1, and
two lateral to the inner _a_ 1, _a_ 2, fig. 192.
M. His observed, several years in succession, some flowers of a
species of _Ophrys_ with three sepals, no lateral petals, one
lip, and three perfect stamens. In this case probably the two
supernumerary stamens were petals which had assumed an
anther-like character.
Wydler describes a flower of _Ophrys aranifera_ in which one
outer and two inner stamens were present.[444] I have myself
met with three such flowers in the same species. The stamens
present were A 1, _a_ 1, _a_ 2.
Dr. J. E. Gray exhibited at the Botanical Society of London, in
August, 1843, a specimen of _Ophrys apifera_ with a triandrous
column, the supernumerary anthers belonging, apparently, to the
inner whorl.
In his 'Catalogue of the Plants of South Kent,' p. 56, tab. iv,
f. 16, the Rev. G. E. Smith describes and figures a flower of
_O. aranifera_ with a triandrous column, seemingly of the same
kind as that spoken of by Dr. Gray.
Mr. Moggridge met with a triandrous flower in the same species,
and refers the appearance to "a fusion of two flowers,
accompanied by suppression and modification."[445] As, however,
no details are given in support of this opinion, it may be
conjectured that the two additional stamens were members of the
inner whorl _a_ 1, _a_ 2, and thus the conformation would be
the same as in the flowers just mentioned. The figures given by
Mr. Moggridge bear out this latter view, while they lend no
support to the hypothesis advanced by him. Nevertheless, no
decided opinion can be pronounced by those who have not had the
opportunity of examining the flowers in question.
Alphonse de Candolle[446] figures a flower of _Maxillaria_ in
exactly the same condition, so far as the stamens are
concerned, as in the Ophrys flowers just mentioned. It is
curious to observe that in many of these cases the two lateral
petals are suppressed.
Von Martius mentions the occurrence of three anthers
(_naturaliter conformatæ_) in _Orchis morio_.[447] Richard,
as cited by Moquin-Tandon, Lindley, and others, describes and
figures a peloria of _Orchis latifolia_ with regular triandrous
flowers.[448]
The writer has examined, in the Royal Gardens at Kew, a flower
of _Cattleya crispa_ in which were three stamens, the central
one normal; the two lateral ones, belonging probably to the
inner whorl, were in appearance like the lateral petals, and
one of them was adherent to the central perfect column.
Duchartre[449] mentions a flower of _Cattleya Forbesii_ in
which there were two labella in addition to the ordinary one,
the column being in its normal condition. From the analogy of
other cases it would appear as if the additional labella in
this instance were the representatives of two stamens of the
outer whorl. Beer likewise has put on record the existence of a
triandrous _Cattleya_.[450]
A specimen of _Catasetum eburneum_ forwarded by Mr. Wilson
Saunders was normal so far as the sepals and two lateral petals
were concerned, but the anterior petal or labellum was flat and
in form quite like the two lateral ones; the column was normal
and in the situation of the two anterior stamens of the outer
series A 2, A 3, were two labella of the usual form (fig. 156,
p. 291). Perhaps the _Oncidium_ represented at p. 68, fig. 29,
may also be explained on the supposition that the two lateral
lobes of the labellum in this flower were the representatives
of stamens.
In Fig. 193 is shown the arrangement of parts in a flower of
_Ophrys aranifera_. Here there were three sepals, two lateral
petals, one of which was adherent to the side of the column;
the central labellum was seemingly deficient, but there were
two pseudo-labella placed laterally in the position of the two
antero-lateral stamens of the outer series (A 2, A 3). Within
these was another perfect stamen occupying the position of the
anterior stamen of the inner series (_a_ 3). In another flower
of the same species, gathered at the same time (fig. 194),
there were three sepals not at all different from those of the
normal flower. The three petals next in succession were also,
in form and position, in their ordinary state. In colour,
however, the two upper lateral petals differed from what is
customary, in having the same purplish-brown tint which
characterises the lip. Within these petals, at the upper part
of the flower, there was the ordinary column, and at the
opposite side, alternating with the petals before mentioned,
two additional lip-like petals, one provided with a half-anther
containing a single perfectly formed pollen-mass (A 2, A 3). It
is, perhaps, worthy of notice that the arrangement of the
coloured spots on the true labellum, and that on the
adventitious lips, replacing the two lower of the outer
stamens, were not of a similar character. The supernumerary
lips had the [Greek: pi]-shaped marking which is so common in
this species, while the true lip was, as to its spots, much
more like _O. apifera_. Alternating with this last whorl were
three columns, all apparently perfectly formed and differing
only from the ordinary one in their smaller size and
corresponding to _a_ 1, _a_ 2, _a_ 3. The ovary in this flower
was two-celled, with four parietal placentas, thus giving an
appearance as though there had been a fusion of two or more
flowers associated with suppression and other changes. The
position of the supernumerary organs and the absence of any
positive sign of fusion in the bracts or other part of the
flower, seemed, however, to negative the idea of fusion.[451]
[Illustration: FIG. 193.--Diagram showing the arrangement of
parts in a malformed flower of _Ophrys aranifera_ (see p.
384).]
[Illustration: FIG. 194.--Malformed flower of _Ophrys
aranifera_ with two supernumerary lips and three additional
stamens.]
A similar illustration, for a knowledge of which the writer is
indebted to the kindness of Professor Asa Gray and Mr. Darwin,
occurred in some specimens of _Pogonia ophioglossoides_
collected by Dr. J. H. Paine in a bog near Utica, New York. It
will be seen from the following description that these flowers
presented an almost precisely similar condition to those of the
_Ophrys aranifera_ just mentioned. "The peculiarities of these
flowers," writes Professor Gray, "are that they have three
labella, and that the column is resolved into small petaloid
organs. The blossom is normal as to the proper perianth, except
that the labellum is unusually papillose, bearded almost to the
base. The points of interest are, first, that the two accessory
labella are just in the position of the two suppressed stamens
of the outer series, viz. of A2 and A3, as represented in the
diagram, fig. 192; and there is a small petaloid body on the
other side of the flower, answering to the other stamen, A1.
Secondly, in one of the blossoms, and less distinctly in
another, two lateral stamens of the inner series (_a_1 and
_a_2) are represented each by a slender naked filament. There
are remaining petaloid bodies enough to answer for the third
stamen of the inner series and for the stigmas, but their order
is not well to be made out in the dried specimens." It may here
be mentioned that _Isochilus_ is normally triandrous.
A tetrandrous flower of _Cypripedium_ has also been recorded.
In _Isochilus_, according to Cruger, there are often five
stamens, and there are several, besides those already
mentioned, in which six more or less perfect stamens have been
seen--of these the following may be taken as illustrations. A
hexandrous flower of _Orchis militaris_ has been recorded by
Kirschleger,[452] and in the accompanying diagram (fig. 195),
from Cramer,[453] of a monstrous flower of _Orchis mascula_,
there is one perfect stamen of the outer row and two lip-like
stamens of the same series, while the inner verticil comprises
one perfect and two abortive stamens.
[Illustration: FIG. 195.--Diagram of flower of _Orchis mascula_
with two additional lips, two perfect and two imperfect stamens
(after Cramer).]
Morren[454] describes some flowers of _Orchis morio_ in which
there were three sepals, three petals, and within the latter
two other ternary series of petals; this would seem to be a
case of petalody of all six stamens. Morren, however, seems to
have considered the additional segments as repetitions of the
corolline whorl, though he describes a central mass as the
column bearing a "_souvenir_ of the anther." Nevertheless,
there is no decisive evidence either in his figure or his
description in support of his opinion as to the nature of the
central mass, which might be a distorted condition of the
styles, or, as is more probable, a rudimentary and irregular
flower. Morren also describes another flower of the same plant
in which there were three sepals, two lateral petals partially
lip-like in aspect, a third labellum normal, two additional
labella representing the two anterior stamens of the outer
whorl, while more or less developed rudiments of the remaining
four stamens also exist.
While, in most cases, the supernumerary stamens can, by reason
of their relative position, their complete or partial
antheriferous nature, be safely referred to one or other of the
six stamens, making up a typical orchid flower, there are other
specimens in which the additional stamens are altogether
adventitious, and do not admit of reference to the homologue.
Thus it was in a specimen of _Odontoglossum Alexandræ_ examined
by the writer, and in which, within a normally constructed
perianth, there were six columns, all polliniferous, but
arranged in so confused and complicated a manner that it was
impossible to make out any definite relation in their position.
There was nothing to indicate a fusion of flowers, but rather
an extension of the centre of the flower, and consequent
displacement of the stamens, &c. Again, the existence of
adventitious stamens does not necessarily imply the development
of organs usually suppressed, inasmuch as they may result from
the assumption by the lateral petals of staminal
characteristics.
Nevertheless, as far as teratology is concerned, specimens may
be found in which some or all of the usually suppressed stamens
of _Orchidaceæ_ may be found. These stamens may be all perfect
(polliniferous), or, as is more frequently the case, more or
less petal-like. Moreover, when the stamens are petalodic, the
form assumed is usually that of the labellum.
The presence of stamens in undue numbers in orchids is very
generally, but not always, attended by some coincident
malformation, of which the most frequent is cohesion of two or
more sepals, and consequent displacement or adhesion of one
petal to the side of the column. Petalody of the styles and
median prolification are also sometimes found in association
with an augmented number of stamens.
[Illustration: FIG. 196.--Increased number of carpels, tulip.]
[Illustration: FIG. 197.--Fruit of St. Valery apple cut lengthwise.]
=Pleiotaxy of the gynoecium.=--An increase in the number of whorls of
which the pistil consists is not of very frequent occurrence. Generally
after the formation of the whorl of carpels, the energy of the growing
point ceases, or if by chance it be continued, the result is more
generally the production of a new flower-bud (median prolification) than
the repetition of the carpellary series. It is necessary also to
distinguish between the veritable augmentation of the pistil and the
semblance of it, brought about by the substitution of carpels for some
other organs, as pistillody of the stamens, and even of the segments of
the perianth, is not very unfrequent, as has already been stated under
the head of substitution. Again, the increased number of carpels which
is sometimes met with in such flowers, as _Magnolia_ or _Delphinium_,
where the ovaries are arranged in spiral series, is not strictly
referable to the present category.
The orange is one of the plants most frequently subject to an
augmentation in the number of carpellary whorls; sometimes this is due
to the stamens assuming the guise of carpels, but at other times the
increase occurs without any alteration in the stamens or other organs.
If the adventitious carpels be exposed, they are covered with yellow
rind, while those portions that are covered by the primary carpels are
destitute of rind. Some varieties of the double tulip are very subject
to a similar change, but, in this case, the petals and the stamens very
frequently become more or less carpellary in their nature. Fig. 196
represents an increased number of whorls of carpels in the variety
called "rex rubrorum," the segments of the perianth having been removed.
In the St. Valery apple, already referred to, there is a second whorl of
carpels above the first, a fact which has been made use of to explain
the similar structure of the pomegranate.
The tomato (_Lycopersicum esculentum_) is another plant in which an
adventitious series is frequently produced, and generally in combination
with the primary series.
In the Chinese primrose (_Primula sinensis_) a supernumerary whorl is
frequently met with, generally associated with other changes in the
construction and arrangement of the parts of the flower.
M. de Candolle[455] mentions a flower of _Gentiana purpurea_ with four
carpels in one series, and five others in the circle immediately above
them. Wigand[456] alludes to an instance wherein there was a second pair
of carpels above the first in _Vinca herbacea_. Dr. Sankey has forwarded
flowers of a _Pelargonium_ having a double series of carpels, eight in
the outer row, five in the inner, and this condition is stated to exist
in the flowers of the same plant for two years consecutively. In
_Aquilegia_ I have met with a similar increase in the whorls of
carpels.[457] Meissner records a similar augmentation in _Polygonum
orientale_.[458]
Wigand[459] describes and figures a flower of _Vinca minor_, in which
there were two carpels intervening between the ordinary pair, and a
similar illustration has been observed by the writer in _Allamanda
cathartica_. Eichler[460] has put on record a similar case in a
capparid.
Marchand[461] mentions a polycarpellary berberid (_Epimedium
Musschianum_). The supernumerary carpels in this flower were placed on a
short axis, which originated in the axils of the stamens, and as these
latter organs were present in their usual number and position, the
adventitious carpels could not be considered as resulting from a
transformation, or substitution of carpels for stamens.
Lastly, the instance cited by Dr. Allman[462] in _Saxifraga Geum_ may be
alluded to. Here there was a row of adventitious carpels between the
stamens and pistils, the backs of the carpels being turned towards the
axis of the flowers. Dr. Allman explains the presence of the
supernumerary parts by the supposed production of a whorl of secondary
axes between the stamens and the centre of the flower. These axes are
further supposed to bear imperfect flowers, of which the additional
carpels are the only traces, but this explanation seems forced.
In addition to the references already cited the following may be given:
Duchartre, 'Ann. Sc. Nat.,' 4 ser., vii, p. 23 (Tulip).
Ferrari, 'Hesperides,' pp. 271, 395, 405. Duchartre, 'Ann. Sc.
Nat.,' 4 ser., 1844, vol. i, p. 294. Maout, 'Leçons Elément.,'
vol. ii, pp. 488-9. Clos, 'Ann. Sc. Nat.,' 1865, p. 317
(_Citrus Aurantium_).
Clos, 'Bull. Soc. Bot. Fr.,' vol. xiii; 'Rev. Bibl.,' p. 75.
Pasquale, 'Reddicont Accad. Sc. Fis. e Math. Napoli.' Octr.
1866 (_Solanum Lycopersicum_).
On the general subject of multiplication, in addition to previous
citations, the reader may be referred to A. P. de Candolle, 'Théorie
Elément. Bot.,' ed. 3, p. 89.
=Increased number of flowers in an inflorescence.=--This happens
generally as a result of over luxuriant growth, and scarcely demands
notice here, being rather referable to variation than to malformation.
The increased number of florets in the spikelets of some grasses has
already been alluded to (p. 351). Thus spikelets of wheat occasionally
produce more than the three florets which are proper to them.[463] It
will be remembered that in this as in many other grasses there are
rudimentary florets, and it is no matter for surprise that these florets
should occasionally be fully developed.
FOOTNOTES:
[392] 'Bull. Soc. Bot. Fr.,' vol. vii, 1860, p. 587.
[393] 'Fragment. Phyt. Austral.,' part xx, p. 270.
[394] 'Bull. Acad. Belg.,' xvi, pt. i, p. 60, "Fuchsia," p. 125, c. ic.
[395] "Théorie de la feuille," 'Arch. des Sciences Bibl. Univers.,'
1868.
[396] See Engelmann, 'De Antholysi,' p. 16, section 12.
[397] Verhandl. des Botanisch. Vereins Brandenburg,' 1859, 1 heft.
[398] See Henslow. 'Mag. Nat, Hist.' 1832, vol. v, p. 429.
[399] 'Phytologist,' September, 1857.
[400] Seemann's 'Journal of Botany,' iv, p. 168, t. 47, f. 3.
[401] 'Illust. Hortic.,' 1866, misc., p. 97.
[402] See Fresenius, 'Mus. Senkenb.,' bd. 2, p. 43. Schlechtendal, 'Bot.
Zeit.,' iv, pp. 403, 492, _Veronica tetrandra_.
[403] 'Flora,' 1865, tab. 6, fig. 8.
[404] 'Org. Veget.,' t. i, p. 497, pl. 42, f. 3.
[405] 'El. Ter. Veg.,' p. 354.
[406] Cited in "Rev. Bibl." of 'Bull. Soc. Bot. Fr.,' 1866, p. 171.
[407] Loc. cit., 351.
[408] 'Mém. Acad. Toulous.,' vi, 1862, ex 'Bull. Soc. Bot. Fr.,' "Rev.
Bibl.," vol. ix, 1862. p. 127.
[409] 'Flora.' 1857. p. 289.
[410] L. c., p. 354.
[411] Giraud, 'Ed. Phil. Mag.,' Dec., 1839.
[412] See _Cerasus Caproniana_, D. C. 'Plant. Rar. Hort. Genev.,' tab.
18.
[413] Nees, 'Linnæa,' v, p. 679, tab. 11 (_Schoenodorus_).
[414] 'Gard. Chron.,' 1852, p. 452.
[415] See Cramer, 'Bildungsabweich.' pp. 16, 24.
[416] 'Linnæa,' 1842, p. 389, c. ic.
[417] Seemann's 'Journal of Botany,' 1867, vol. v, p. 158.
[418] Cramer, 'Bildungsabweich,' p. 66, _Astrantia major_, _Eryngium_,
to which may be added _Daucus_, _Heracleum_, &c.
[419] See also Reinwardt, 'Nov. Act. Acad. Nat. Cur.,' 12, 1, 37; and
Masters, 'Journ. Linn. Soc.,' vi, p. 24.
[420] 'Organog. Veget.,' tab. 53.
[421] 'Missbild.,' p. 206.
[422] Ehrenberg, 'Flora,' 1846, p. 704.
[423] 'Flora,' 1860, tab. 7.
[424] 'Ann. Sc. Nat.,' 3 ser., t. x, p. 207.
[425] 'Mem. Mus.,' xii. t. 17.
[426] 'Nov. Act. Acad. Nat. Cur.,' xv, tab. xxviii, f. 3; 'Bot. Mag.,'
t. 1622. "Caryophyllus spicam frumenti referens." A similar malformation
in _Dianthus barbatus_ is not uncommon. It has lately been introduced
into gardens under the name of _Dianthus_ "_mousseux_," but is not
likely to find favour with gardeners.
[427] 'Bull. Soc. Bot. France,' t. vi, 1859. p. 268.
[428] Weber, 'Verhandl. Nat. Hist. Vereins. Rhein. Pruss.,' 1860.
[429] 'Bot. Zeit.,' 1848, p. 217.
[430] 'De Anthol.,' p. 17, § 12.
[431] 'Linnæa,' vol. ii, 1827, p. 85.
[432] 'De Antholysi,' p. 17, tab. iii, f. 15, 16; Weinmann, 'Phytanth.
iconogr.,' nro. 292.
[433] See Hildebrand, 'Bot. Zeit.,' 1862, p. 209, tab. viii; Cramer,
'Bildungsabweich.,' p. 7, tab. xiii; Engelmann, 'De Antholysi,' p. 18,
&c. For similar changes in _Gagea arvensis_ see Wirtgen, 'Flora,' 1838,
t. xxi. p. 350, and 'Flora.' 1846, p. 353. Some of these are cases of
synanthy.
[434] Schlechtendal, 'Bot. Zeit.,' xx, 1862, p. 301.
[435] 'Phil. Bot.,' § 126.
[436] C. Morren, 'Bull. Acad. Belg.,' xix, part ii, p. 17.
[437] 'Seemann's Journal of Botany,' iii, p. 354.
[438] On this point the reader will find an excellent summary in
Lindley's 'Vegetable Kingdom,' cd. iii, p. 183_a_, and in Darwin,
'Fertilisation of Orchids,' p. 292. See also Crüger,'Journ. Linn. Soc.,'
t. viii, p. 134.
[439] 'Seemann's Journal of Botany,' vol. iv, p. 168, tab. 47.
[440] Ibid., t. iv. 1866, p. 168, t. xlvii, f. 1.
[441] 'Bildungsabweich,' p. 8; see also 'Bot. Zeit.,' 1852, p. 425.
[442] 'Journ. Linn. Soc.,' t. ii, p. 104. tab. 1, fig. B.
[443] Lindl., "Orchid. Ind.," 'Jour. Linn. Soc.,' iii, p. 9.
[444] 'Arch. Bot.,' ii, p. 300, tab. xvi, f. 11.
[445] 'Seemann's Journal of Botany,' v, p. 318, tab. lxxii, figs. A 4, 4
_a_.
[446] "Monstr. Veg.," in 'Neue Denkschrift,' p. 17, tab. vii.
[447] 'Flora,' t. viii, 1825, p. 736.
[448] 'Mem. Soc. d'Hist. Nat.,' ii, 1, p. 212, tab. iii.
[449] 'Bull. Soc. Bot. Fr.,' t. vii, 1860, p. 26.
[450] 'Beitr. Morphol. und Biol. Orchid.,' quoted by Cramer;
'Bildungsabweich,' p. 9.
[451] Masters, 'Journ. Linn. Soc.,' viii, p. 207. See also Rodigas,
'Bull. Soc. Bot. Belg.,' iv, p. 266, for similar changes in _Cypripedium
Hookeræ_.
[452] Kirschleger, 'Flora,' 1844, p. 131.
[453] 'Bildungsabweich,' p. 11, tab. xiv, f. 3.
[454] 'Bull. Acad. Roy. Belg.,' t. xix, part 2, p. 171.
[455] 'Organogr. Végét.,' t. i, p. 509, tab. 40, figs. 6, 7.
[456] 'Flora,' 1856, p. 715.
[457] 'Linn. Trans.,' t. xxiii, p. 364, tab. 34, fig. 5.
[458] 'Monog. Polygon,' pl. 3, K. f. 12.
[459] 'Flora,' 1856, tab. viii.
[460] Ibid., 1865, tab. ix, f. 6.
[461] 'Adansonia,' vol. iv, 1864, p. 127.
[462] 'Ann. Nat. Hist.,' 1845, vol. xvi, p. 126.
[463] See Schlechtendal, 'Bot. Zeit.,' t. xviii, p. 381 (_Triticum_);
also 'Flora,' t. xiv, 1831, p. 5 (_Avena_).
PART II.
DIMINISHED NUMBER OF ORGANS.
A diminution in the number of parts is generally due to suppression,
using that word as the equivalent of non-development. It corresponds
thus in meaning with the _Fehlschlagen_ of the Germans, the _avortement
complète_ of Moquin and other French writers. It differs from atrophy,
or partial abortion, inasmuch as the latter terms apply to instances
wherein there has been a partial development, and in which evolution has
gone on to a certain extent, but has, from some cause or other, been
checked. These cases will be found under the head of diminished size of
organs. As the word abortion is used by different authors in different
ways, it is the more necessary to be as precise as possible in the
application of the term. In the present work abortion is used to apply
to cases wherein parts have been formed, but wherein growth has been
arrested at a certain stage, and which, therefore, have either remained
_in statu quo_, while the surrounding parts have increased, or have,
from pressure or other causes, actually diminished in size.
In practice, however, it is not always possible to discriminate between
those instances in which there has been a true suppression, an absolute
non-development of any particular organ, and those in which it has been
formed, and has grown for a time, but has afterwards ceased to do so,
and has been gradually obliterated by the pressure exercised by the
constantly increasing bulk of adjacent parts, or possibly has become
incorporated with them. In the adult flower the appearances are the
same, though the causes may have been different.
CHAPTER I.
SUPPRESSION OF AXILE ORGANS.
Absolute suppression of the main axis is tantamount to the non-existence
of the plant, so that the terms "acaulescent," "acaulosia," etc, must be
considered relatively only, and must be taken to signify an atrophied or
diminished size of the stem, arising from the non-development of the
internodes.
The absence of lateral branches or divisions of the axis is of frequent
occurrence, and is dependent on such causes as the following:--deficient
supply of nutriment, position against a wall or other obstacle, close
crowding of individual plants, too great or too little light, too rich
or too poor a soil, &c.
Probably the absence of the swollen portion below the flower in the case
of many proliferous roses, double-flowered apples, as already referred
to, may be dependent on the non-development of the extremity of the
peduncle or flower-stalk. Thus, in a double-flowered apple recently
examined, there was a sort of involucel of five perfect leaves, then
five sepals surrounding an equal number of petals, numerous stamens, and
five styles, but not a trace of an expanded axis, nor of any portion of
the carpels, except the styles. The views taken as to the nature of this
and similar malformations must depend on the opinion held as to the
nature of inferior pistils, and on the share, if any, that the expanded
axis takes in their production. As elsewhere said, the evidence
furnished by teratology is conflicting, but there seems little or
nothing to invalidate the notion that the end of the flower-stalk and
the base of the calyx may, to a varying extent, in different cases,
jointly be concerned in the formation of the so-called calyx-tube and of
the inferior ovary. Obviously it is not proper to apply to all cases
where there is an inferior ovary the same explanation as to how it is
brought about.
As these pages are passing through the press, M. Casimir de Candolle has
published a different explanation as to the nature of the hip of the
rose, having been led to his opinion by the conclusion that he has
arrived at, that the leaf is to be considered in the light of a
flattened branch, whose upper or posterior surface is more or less
completely atrophied.
According to M. de Candolle, the calyx-tube, in the case of the rose, is
neither a whorl of leaves, nor a concave axis in the ordinary sense in
which those terms are used, but is rather to be considered as a
ring-like projection from an axis arrested in its ulterior development.
The secondary projections from the original one correspond to an equal
number of vascular bundles, and develope into the sepals, petals,
stamens, and ovaries. If these organs remained in a rudimentary
condition, the tube of the calyx would be reduced to the condition of a
sheathing leaf. The rose flower, then, according to M. de Candolle, may
be considered as a sheathing leaf, whose fibro-vascular system is
complete, and from which all possible primary projections are
developed.[464]
If, as M. de Candolle considers, the leaf and the branch differ merely
in the fact that the vascular system is complete in the latter, and
partly atrophied in the former, it would surely be better to consider
the "calyx-tube" of the rose as a concave axis rather than as a leaf,
seeing that he admits the fibro-vascular system to be complete in the
case of the rose.
With reference to this point the reader is referred to Mr. Bentham's
account of the morphology and homologies of the _Myrtaceæ_ in the
'Journal of the Linnean Society,' vol. x, p. 105. See also _ante_, pp.
71, 77.
Some doubts also exist as to the nature of the beak or columella of such
fruits as those of _Geraniaceæ_, _Malvaceæ_, _Umbelliferæ_,
_Euphorbiaceæ_, &c. The nature of the organ in question may probably be
different in the several orders named; at any rate the subject cannot be
discussed in this place, and it is mentioned here because, now and then,
it happens that the organ in question is completely wanting, and hence
affords an illustration of suppression.
FOOTNOTES:
[464] 'Théorie de la feuille.' p. 24.
CHAPTER II.
SUPPRESSION OF FOLIAR ORGANS.
This subject may be considered, according as the separate leaves of the
stem or of the flower are affected, and according as either the number
of members of distinct whorls, or that of the whorls themselves, is
diminished.
The terms aphylly, meiophylly, and meiotaxy may be employed, according
as the individual leaves are altogether wanting, or with reference to
the diminished number of parts in a whorl, or a decrease in the
verticils.
=Aphylly.=--Entire suppression of the leaves is a rare phenomenon. Under
ordinary circumstances it occurs in most _Cactaceæ_, in some of the
succulent Euphorbias, and other similar plants, where the epidermal
layers of the stem fulfil the functions of leaves. But even in these
plants leaf-like organs are present in some stage or another of the
plant's life.
Partial suppression of the leaf occurs sometimes in compound leaves,
some or other of the leaflets of which are occasionally suppressed.
Sometimes, as Moquin remarks, it is the terminal leaflet which is
wanting, when the appearance is that of _Cliffortia_, at other times the
lateral leaflets are deficient, as in _Citrus_ or _Phyllarthron_.
_Ononis monophylla_ and _Fragaria monophylla_ may be cited as instances
of the suppression of the lateral leaflets. If the blade of the leaf
disappears entirely, we have then an analogous condition to that of the
phyllodineous acacias.
With reference to the strawberry just mentioned, Duchesne, 'Hist. Nat.
Frais.,' p. 133, says that this was a seedling raised from the _fraisier
des bois_, and the characters of which were reproduced by seed, and have
now become fixed. The monophyllous condition has been considered to be
the result of fusion of two or more leaflets, but however true this may
be in some cases, it is not the case with this strawberry. M. Paillot
states that he has found the variety in a wild state.[465]
In like manner varieties of the following plants occur with simple
leaves, _Rosa berberifolia_ (_Lowea_), _Rubus Idæus_, _Robinia
pseudacacia_, _Fraxinus excelsior_, _Sambucus nigra_, _Juglans nigra_,
&c.
In one instance seen by the writer every portion of the leaf of a rose
was deficient, except the stipules and a small portion of the petiole.
(See abortion.)
=Meiophylly.=--A diminished number of leaves in a whorl occasionally
takes place; thus, in some of the _Stellatæ_, and frequently in _Paris
quadrifolia_, the number of leaves in the verticil is reduced. Care must
be exercised in such instances that an apparent diminution arising from
a fusion of two or more leaves be not confounded with suppression.
=Meiophylly of the calyx or perianth.=--A lessened number of sepals is
not a very common occurrence among dicotyledonous plants. Seringe
figures a proliferous flower of _Arabis alpina_ with two sepals only,
and a similar occurrence has been noticed in _Diplotaxis tenuifolia_.
In _Cattleya violacea_ the writer has met with a flower in which the
uppermost sepal was entirely wanting, while two of the lateral petals
were fused together. Moquin records that in some of the flowers of
_Chenopodiaceæ_, in which the inflorescence is dense, a suppression of
two or three sepals sometimes occurs. The species mentioned are _Ambrina
ambrosioides_, _Chenopodium glaucum_, and _Blitum polymorphum_.
=Meiophylly of the corolla.=--Suppression of one or more petals is of
more frequent occurrence than the corresponding deficiency in the case
of the sepals. Among _Caryophyllaceæ_ imperfection as regards the
numerical symmetry of the flower is not uncommon, as in species of
_Cerastium_, _Sagina_, _Dianthus_, &c. In _Ranunculaceæ_ the petals are
likewise not unfrequently partially or wholly suppressed. A familiar
illustration of this is afforded by _Ranunculus auricomus_, in which it
is the exception to find the corolla perfect.[466] Some varieties of
_Corchorus acutangulus_ in west tropical Africa are likewise subject to
the same peculiarity. Amongst _Papilionaceæ_ absence of the carina or of
the alæ is not uncommon, as in _Trifolium repens_, _Faba vulgaris_, &c.
Moquin relates a case of the kind in the haricot bean, in which the
carina was entirely absent, and another in the pea, where both carina
and alæ were missing, thus reducing the flower to the condition that is
normal in _Amorpha_ and _Afzelia_. Suppression of the upper lip in such
flowers as _Calceolaria_ has been termed by Morren "apilary."
In _Orchidaceæ_ entire absence of the labellum, frequently without any
other perceptible change, is of common occurrence. The writer has seen
numerous specimens of the kind in _Ophrys apifera_ and _O. aranifera_;
also in _Dendrobium nobile_, _Ærides odoratum_, _Cypripedium villosum_,
_Listera ovata_, &c. Morren[467] mentions analogous deficiencies in
_Zygopetalum maxillare_, _Calanthe_ sp., and _Cattleya Forbesii_. In
most of these there was also a fusion of the two lower sepals, which
were so twisted out of place as to occupy the situation usually held by
the labellum. At the same time the column was partially atrophied. To
this deficiency of the lip the author just quoted proposed to apply the
term acheilary, [Greek: a-cheilarion]. Mr. Moggridge has communicated to
the author an account of certain flowers of _Ophrys aranifera_, in which
the petals were deficient, sometimes completely, at other times one or
two only were present.
=Meiophylly of the androecium.=--Suppression of one or more stamens,
independently of like defects in other whorls, is not uncommon, even as
a normal occurrence, _e.g._ in _Carlemannia_, where the flower, though
regular, has only two stamens, and other similar deficiencies are common
in Dilleniads.
Seringe relates the occurrence of suppression of some of the stamens in
_Diplotaxis tenuifolia_,[468] St. Hilaire in _Cardamine hirsuta_, others
in _C. sylvatica_.
In _Caryophyllaceæ_ suppression of one or more stamens has been observed
in _Mollugo cerviana_, _Arenaria tetraquetra_, _Cerastium_, &c.[469]
Among violets the writer has observed numerous flowers in which two or
three stamens were suppressed. Chatin[470] alludes to a similar
reduction in _Tropæolum_, while in flowers that are usually didynamous
absence of two or more of the stamens is not unfrequent, _e.g._ in
_Antirrhinum_, _Digitalis_, while in a flower of _Catalpa_ a solitary
perfect stamen, and a complete absence of the sterile ones usually
present, have been observed. This might have been anticipated from the
frequent deficiencies in the staminal whorl in these plants under what
are considered to be normal conditions. Reduction of the staminal whorl
is also not unfrequent in _Trifolium repens_ and _T. hybridum_, and has
been seen in _Delphinium_, &c.[471]
=Meiophylly of the gynoecium.=--Numerical inequality in the case of
the pistil, as compared with the other whorls of the flower, is of such
common occurrence, under ordinary circumstances, that in some text-books
it is looked on as the normal condition, and a flower which is isomerous
in the outer whorls is by some writers not considered numerically
irregular if the number of the carpels does not coincide with that of
the other organs.
But in this place it is only necessary to allude to deviations from the
number of carpels that are ordinarily found in the particular species
under observation. As illustrations the following may be
cited:--_Arenaria tetraqueta_, which has normally three styles, and a
six-valved capsule, has been seen with two styles, and a four or
five-valved capsule. Moquin relates an instance in _Polygala vulgaris_
where there was but a single carpel, a condition analogous to that which
occurs normally in the allied genus _Mozinna_. _Reseda luteola_
occasionally occurs with two carpels only, while Aconites, Delphiniums,
Nigellas, and Pæonies frequently experience a like diminution in their
pistil.
In a flower of _Papaver Rhæas_ the writer has recently met with an ovary
with four stigmas and four parietal placentæ only, and to Mr.
Worthington Smith he is indebted for sketches of crocus blooms with two,
and in one instance only a solitary carpel.
Moquin cites the fruit of a wild bramble (_Rubus_) in which all the
little drupes which go to make up the ordinary fruit were absent, except
one, which thus resembled a small cherry. In _Cratægus_ the pistil is
similarly reduced to a single carpel, as in _C. monogyna_.
The writer has on more than one occasion met with walnuts (_Juglans_)
with a single valve and a single suture.[472] If the ovary of _Juglans_
normally consisted of two valvate carpels, the instances just alluded to
might possibly be explained by the suppression of one carpel, but the
ovary in _Juglans_ is at first one-celled according to M. Casimir de
Candolle.
Among monocotyledons _Convallaria majalis_ may be mentioned as very
liable to suffer diminution in the number of its carpels, either
separately or in association with other changes.[473]
=Meiophylly of the flower as a whole.=--In the preceding sections a
reduction in the parts of each individual whorl has been considered
without reference to similar diminution in neighbouring verticils. It
more commonly happens, nevertheless, that a defect in one series is
attended by a corresponding imperfection in adjoining ones. Thus
trimerous fuchsias and tetramerous jasmines may frequently be met with,
and Turpin describes a tetramerous flower of _Cobæa scandens_. Perhaps
monocotyledonous plants are more subject to this numerical reduction of
the parts of several verticils than are other flowering plants. Thus, in
both _Lilium lancifolium_ and _L. auratum_ the writer has frequently met
with pentamerous flowers. In _Convallaria maialis_ a like deviation not
unfrequently occurs.[474] M. Delavaud has recorded a similar occurrence
in a tulip.[475]
Dimerous crocuses may also sometimes be met with. In one flower of this
nature the segments of the perianth were arranged in decussating pairs,
and the four stamens were united by their filaments so as to form two
pairs.
M. Fournier mentions something of the same kind in the flower of an
_Iris_.[476]
Orchids seem peculiarly liable to the decrease in the number of their
floral organs. Prillieux[477] mentions a flower of _Cattleya
amethystina_ wherein each whorl of the perianth consisted of two
opposite segments.
The same observer has put on record instances of a similar kind in
_Epidendrum Stamfordianum_. In one flower of the last-named species the
perianth consisted of one sepal only, and one lip-like petal placed
opposite to it.[478] Morren[479] describes a flower of _Cypripedium
insigne_, in which there were two sepals and two petals. Of a similar
character was the flower found by Mr. J. A. Paine, and described in the
following terms by Professor Asa Gray in the 'American Journal of
Science,' July, 1866:--"The plant" (_Cypripedium candidum_) "bears two
flowers: the axillary one is normal; the terminal one exhibits the
following peculiarities. The lower part of the bract forms a sheath
which encloses the ovary. The labellum is wanting; and there are two
sterile stamens, the supernumerary one being opposite the other, _i.e._
on the side of the style where the labellum belongs. Accordingly the
first impression would be that the labellum is here transformed into a
sterile stamen. The latter, however, agrees with the normal sterile
stamen in its insertion as well as in shape, being equally adnate to the
base of the style. Moreover, the anteposed sepal is exactly like the
other, has a good midrib and an entire point. As the two sterile stamens
are anteposed to the two sepals, so are the two fertile stamens to the
two petals, and the latter are adnate to the style a little higher than
the former. The style is longer than usual, is straight and erect; the
broad, disciform stigma therefore faces upwards; it is oval and
symmetrical, and a light groove across its middle shows it to be
dimerous. The placentæ, accordingly, are only two. The groove on the
stigma and the placentæ are in line with the fertile stamens.
Here, therefore, is a symmetrical and complete, regular, but dimerous
orchideous flower, the first verticil of stamens not antheriferous, the
second antheriferous, the carpels alternate with these; and here we have
clear (and perhaps the first direct) demonstration that the orchideous
type of flower has two stamineal verticils, as Brown always insisted."
[Illustration: FIG. 198.--Regular dimerous flower of _Calanthe
vestita_.]
[Illustration: FIG. 199.--Regular dimerous flower of _Odontoglossum
Alexandræ_.]
Dr. Moore, of Glasnevin, kindly forwarded to the writer a flower of
_Calanthe vestita_ (fig. 198), in which there were two sepals only,
anterior and posterior, and two petals at right angles to the two
sepals. The lip was entirely wanting, but the column and ovary were in
their usual condition. In _Odontoglossum Alexandræ_ a similar reduction
of parts has been observed by the author (fig. 199).
It is curious to observe in these flowers how precisely one sepal
occupies the position of the labellum, and how the lateral petals are
displaced from the position they usually occupy, so as to form a regular
flower, the segments of which decussate, thus giving rise to a species
of regular peloria.
The genus _Mælenia_ was established on a malformed flower of _Orchis_ of
similar character to those above mentioned.
=Meiotaxy of the calyx.=--As already mentioned, this term is here
employed to denote those illustrations in which entire whorls are
suppressed. Complete deficiency of the calyx in a dichlamydeous flower
seems seldom or ever to occur; the nearest approach to it would be in
those cases where the calyx is, as it is termed, "obsolete," but here it
is chiefly the limb of the calyx which is atrophied, the lower portion
being more or less adherent to the ovary. In what are termed
monochlamydeous flowers both calyx and corolla are wanting, as in
_Salicineæ_ and many other orders.
=Meiotaxy of the corolla.=--Deficiency of the entire corolla occurs in
conjunction with similar reductions in other organs, or as an isolated
phenomenon in the many apetalous varieties of plants recorded in books.
Deficiency of the corolla was observed in _Campanula perfoliata_ and
_Ruellia clandestina_ by Linné, who calls such blooms _flores
mutilati_.[480] Drs. Hooker and Thomson relate a similar occurrence in
_Campanula canescens_ and _C. colorata_. Some plants seem as a normal
occurrence to produce flowers of different construction, and are hence
termed dimorphic, as in many _Malpighiaceæ_, _Violaceæ_, _Oxalidaceæ_,
in some of the flowers of which the petals are altogether wanting, while
in others the corolla is developed as usual. This deficiency of the
corolla is frequently, but not invariably, associated with an increased
fertility. Thus, in some violets the flowers produced in summer, and in
which the petals are either entirely suppressed or are more or less
atrophied, are always fertile, while the blossoms developed in spring,
and in which the petals are always present, are much less fertile. In
_Oxalis Acetosella_ there are two forms of flower, the one with, the
other without, petals, but both seem equally fertile. Linné remarks that
many plants which, in warm latitudes, produce a corolla, do not do so
when grown in colder climates. Thus, certain species of _Helianthemum_
are apetalous in Lapland. In the Pyrenees, according to Bentham, the
flowers of _Ajuga iva_ are constantly deprived of their corolla.[481]
Apetalous flowers have been noted most frequently in the following
plants:
Aconitum, sp. pl.!
Cardamine impatiens.
Cheiranthus Cheiri!
Viola odorata!
Cerastium vulgatum!
Alsine media.
Stellaria.
Lychnis dioica!
Dianthus barbatus, and other Caryophylleæ.
Helianthemum, sp.!
Oxalis Acetosella.
Balsamineæ.
Malpighiaceæ.
Rosa centifolia.
arvensis!
Cratægus!
Medicago lupulina.
Melilotus officinalis.
Ononis minutissima.
Saxifraga longifolia.
Verbascum Thapsus.
Ajuga iva.
Teucrium Botrys.
Lamium purpureum!
amplexicaule.
Polemonium cæruleum.
Campanula, sp. pl.!
Ruellia clandestina.
Lonicera Periclymenum!
Tradescantia, sp.!
Hymenocallis.
The following references apply some to apetalous and others to
dimorphic flowers, but it must be remembered that the latter
plants are not necessarily wanting in petals or stamens, &c.,
though the functional activity of the parts may be impaired:
A. de Jussien, 'Monogr. Malpigh.,' pp. 82, 334. Torrey, 'Fl.
New York,' i, p. 428. Hooker and Thomson, 'Journ. Linn. Soc.,'
ii, p. 7, Guillemin, 'Archiv. de Botan.,' i, p. 412. Michalet,
'Bull. Soc. Bot. Fr.,' vii. p. 465. Müller, 'Bot. Zeit.,' 1857,
p. 729. 'Natural History Review,' July, 1862, p. 235.
=Meiotaxy of the androecium.=--Complete suppression of the stamens
occurs normally in the female flowers of unisexual plants, and, as an
accidental occurrence, is not very uncommon. _Erica Tetralix_ is one of
the plants in which this is said to happen. The variety _anandra_ is
said to have been known in France since 1635. Cornuti speaks of it in
his 'Enchiridion.' In 1860 M. du Parquet discovered it in peaty woods
near Nangis (Seine et Marne).
Many _Umbelliferæ_, such as _Trinia vulgaris_, present a like
deficiency, while it is of common occurrence among _Rosaceæ_ and
_Pomaceæ_. In the latter group the St. Valery apple, so often referred
to, is an illustration. To obtain fruits from this variety it is
necessary to apply pollen from another flower, a proceeding made the
occasion of festivity and rejoicing by the villagers in some parts of
France. In some of the _Artemisias_, especially in _Artemisia
Tournefortiana_, all the florets have been noticed to be female, owing
to the suppression of the stamens, and this suppression is associated
with a change in the form of florets.[482] Mr. Moggridge has
communicated to the author flowers of _Thymus Serpyllum_ from a plant in
which all the stamens were deficient, the flower being otherwise normal.
M. Dupont has given a list of nineteen species of _Chenopodiaceæ_ in
which female flowers are occasionally produced, owing to the entire
suppression of the staminal whorl.[483]
Flowers the subjects either of regular or irregular peloria, _q. v._,
are often destitute of some or all their stamens, _e.g._ _Calceolaria_,
_Linaria_, _Viola_, &c., while in cases of synanthy suppression of some
of the parts of the flower, and specially of the stamens, is of very
common occurrence.
Suppression of the androecium as a teratological occurrence has been
most frequently noticed in the following plants, omitting members of
those families whose floral construction is normally incomplete in the
majority of instances, and exclusive also of cases of substitution. See
also under Heterogamy.
Ranunculus Ficaria!
auricomus!
bulbosus!
Cruciferæ, sp. pl.
Violaceæ, sp. pl.
Honckenya peploides.
Stellaria.
Caryophyllaceæ, sp. pl.
Malpighiaceæ, sp. pl.
Tropæolum majus!
Fragaria vesca!
Rubus, sp.
Pyrus Malus.
Agrimonia vulgaris.
Rosaceæ, sp. pl.
Trifolium hybridum.
repens.
Umbelliferæ, sp. pl.
Onagraceæ, sp. pl.
Hippuris vulgaris.
Callitriche vernalis.
autumnalis.
Lonicera Periclymenum.
Erica Tetralix.
Thymus Serpyllum.
Calceolaria.
Compositæ, sp. pl.
Chenopodiaceæ, sp. pl.
Stratiotes aloides.
=Meiotaxy of the gynoecium.=--Complete suppression of the pistil is of
more frequent occurrence than that of the stamens, hence more flowers
become accidentally unisexual by suppression of the pistil than by
deficiency of the stamens.
In many _Umbelliferæ_, e.g. _Torilis Anthriscus_, _Cicuta virosa_, the
central flowers are often male, owing to the suppression of the pistil.
In many double flowers, owing to the excessive multiplication of
petaloid stamens, the pistil is suppressed, in which cases it often
happens that the flower is depressed in the centre, as in some garden
varieties of _Ranunculus_. Schlechtendal, in describing a flower of
_Colchicum autumnale_, in which the perianth was virescent, says that,
although the stamens were present, the pistil was absent.
In proliferous flowers the pistil is often completely defective, its
place being occupied by the adventitious bud or axis.
As in other cases of like nature, suppression of the pistil is very
frequently consequent on fusion of flowers or other changes. Thus Morren
relates an instance of synanthy in the flowers of _Torenia scabra_,
accompanied by resorption or disappearance of some parts and spiral
torsion of others. The pistil was entirely absent in this instance.[484]
M. Gaetano Licopoli places on record an instance where the petals and
carpels of _Melianthus major_ were suppressed.[485]
On the whole, the pistil seems less subject to changes of this character
than the androecium.
Suppression of the pistil has been most frequently recorded in flowers
(normally bisexual) of--
Ranunculus!
Aconitium!
Delphinium!
Pæonia.
Caryophylleæ!
Umbelliferæ.
Trifolium repens.
hybridum.
Compositæ, sp. pl.
Datura.
Torenia asiatica.
Colchicum autumnale.
=Suppression of ovules,--abortion of seeds.=--The two cases are taken
together, as the effects are similar, though it must be remembered that
in the one case the ovules at any rate have been formed, but their
development has been arrested, while in the other they have never
existed. The precise cause that has determined the absence of seed
cannot in all cases be ascertained in the adult condition, hence it is
convenient to treat the two phenomena under one head.
Many plants in other than their native climates either produce no fruit
at all, or the fruits that are produced are destitute of seed, _e.g._
_Musa_, _Artocarpus_, &c. Some of the cultivated varieties of the grape
and of the berberry produce no seeds.
Suppression or abortion of the seed is frequently associated with the
excessive development either in size or number of other portions of the
plant, or with an altered condition, as when carpels become foliaceous
and their margins detached. Hybridisation and cross fertilisation are
also well-known agents in diminishing the number and size of seeds.
=Meiotaxy of the parts of the flower in general.=--In the preceding
sections suppression has been considered as it affected individual
members of a whorl or separate whorls. It rarely happens, however, that
the suppression is limited in this way. More generally several of the
parts of the flower are simultaneously affected in the same manner.
A few illustrations are all that is necessary to give as to this point.
One of the most familiar instances is that of the cauliflower or
broccoli, where the common flower-stalk is inordinately thickened and
fleshy, while the corolla and inner parts of the flower are usually
entirely suppressed; the four sepals can, however, generally be
detected.
Maximowicz describes a _Stellaria_ (_Kraschenikovia_) in which the upper
flowers are male only, while the lower ones, which ultimately become
buried in the soil, have neither petals, stamens, nor styles, but the
walls of the capsule are fleshy, and enclose numerous seeds.[486]
Kirschleger[487] mentions a variety of _Lonicera Caprifolium_, which was
not only destitute of petals but of stamens also.
In some species of _Muscari_ and _Bellevalia_ the uppermost flowers of
the raceme show more or less complete suppression of almost all the part
of which the flower normally consists. In those cases where an imperfect
perianth exists, but in which the stamens and pistils are entirely
suppressed, Morren applies the term Cenanthy, [Greek: kenos], empty.
=Complete suppression of the flower.=--It is not necessary in this place
to allude to that deficient production of flowers characteristic of what
is termed by gardeners a "sky bloomer." In such plants often the
requisite conditions are not complied with, and the skill of the
gardener is shown in his attempt to discover and allow the plant to
avail itself of the necessary requirements. We need here only allude to
those instances in which provision is made for the production of
flowers, and yet they are not produced. A good illustration of this is
afforded by the feather-hyacinth, _Hyacinthus comosus_, in which the
flowers are almost entirely suppressed, while the pedicels are
inordinately increased in number, and their colour heightened. Something
similar occurs in several allied species, and in _Bowiea volubilis_. The
wig plant (_Rhus Cotinus_) affords another illustration of the same
thing. Some tendrils also owe their appearance to the absence of
flowers, being modified peduncles; proofs of this may frequently be met
with in the case of the vine.
In _Lamium album_ I have seen one of the verticillasters on one side of
the stem completely wanting, the adjacent leaf being, however, as fully
formed as usual.
=General remarks on suppression.=--On comparing together the various
whorls of the flower in reference to suppression, and, it may be added,
to atrophy, we find that these phenomena occur most rarely in the calyx,
more frequently in the corolla, and very often in the sexual
organs and seeds; hence it would seem as if the uppermost and most
central organs, those most subject to pressure and latest in date of
development--formed, that is, when the formative energies of the plant
are most liable to be exhausted--are the most prone to be suppressed or
arrested in their development. When the plants in which these
occurrences happen most frequently are compared together, it may be seen
that partial or entire suppression of the floral envelopes, calyx, and
corolla, is far more commonly met with in the polypetalous and
hypogynous groups than in the gamopetalous or epigynous series.
The orders in which suppression (speaking generally) occurs most often
as a teratological occurrence are the following:--_Ranunculaceæ_,
_Cruciferæ_, _Caryophyllaceæ_, _Violaceæ_, _Leguminosæ_, _Onagraceæ_,
_Jasminaceæ_, _Orchidaceæ_. It will be observed that these are all
orders wherein suppression of the whole or part of the outer floral
whorls takes place in certain genera as a constant occurrence.
Again, it may be remarked that many of these orders show a tendency
towards a regular diminution of the assumed normal number of their
parts; thus, among _Onagraceæ_, _Circeia_ and _Lopezia_ may be referred
to, the former normally dimerous, the latter having only one perfect
petal. So in fuchsias, a very common deviation consists in a trimerous
and rarely a dimerous symmetry of the flower.
Although, if the absolute number of genera or orders be counted, there
appears to be little difference in the frequency of the occurrence of
suppression in irregular flowers as contrasted with regular flowers, yet
if the individual instances could be counted in the two groups
respectively it would be found that suppression is more common among
irregular than in regular flowers. Thus, the number of individual
instances of flowers in which the perianth is defective is comparatively
large among _Violaceæ_, _Leguminosæ_, and _Orchidaceæ_. This statement
hardly admits of precise statistical proof; still, it is believed that
any observer who pays attention to the subject must come to the same
conclusion. This is but another illustration of the fact that conditions
which are abnormal in one plant constitute the natural arrangement in
others.
As to the suppressions that occur in the case of the sexual organs, and
the relations they bear to dimorphism, diclinism, &c., but little stress
has been laid on them in this place, because their chief interest is in
a physiological point of view, and is treated of in the writings of
Mohl, Sprengel, Darwin, Hildebrand, and others. All that need be said
here is, that teratology affords very numerous illustrations of those
intermediate conditions which are also found, under natural
circumstances, between the absolutely unisexual flowers, male or female,
and the structurally hermaphrodite ones. Rudimentary stamens or pistils
are of very common occurrence in monstrous flowers. See Chapter on
Heterogamy, &c.
FOOTNOTES:
[465] 'Rev. Hortic.,' 1866, p. 467.
[466] De Rochebrune, 'Bull. Soc. Bot. Fr.,' ix, p. 281. The author
points out seven grades between complete absence of petals and their
presence in the normal number in this plant. See also Gaudin, in 'Koch.
Fl. Helv.;' Koch. 'Synops. Fl. Germ.;' Cramer, 'Bildungsabweich,' p. 85.
[467] 'Bull. Acad. Belg.,' t. xix, part 1, p. 255.
[468] 'Bull. Bot.,' i, p. 7, tab. i, f. 7.
[469] See Gay, 'Ann. Sc. Nat.,' iii, p. 27.
[470] 'Ann. Sc. Nat.,' 4 ser., v, p. 305.
[471] Cramer, 'Bildungsabweich,' p. 90.
[472] See also Clos, 'Bull. Soc. Bot. Fr.,' xiii, p. 96, adnot.
[473] See Cramer, 'Bildungsabweich,' p. 7. Hildebrand, 'Bot. Zeit.,' xx,
1862, p. 209.
[474] See Hildebrand, 'Bot. Zeit.,' xx, 1862, p. 209.
[475] 'Bull. Soc. Bot. Fr.,' viii, p. 287.
[476] 'Bull. Soc. Bot. Fr.,' vol. viii, 1861, p. 152.
[477] Ibid., ix, p. 275.
[478] Ibid., 1861, vol. viii, p. 149.
[479] 'Lobelia,' p. 55.
[480] 'Phil. Bot.,' p. 119.
[481] 'Cat. Plant. Pyr,' p. 58.
[482] Moquin-Tandon, loc. cit., p. 328.
[483] For other instances see Chatin in 'Ann. Sc. Nat.,' 4 ser., vol. v,
p. 305.
[484] See also Morren. 'Bull. Acad. Belg.,' xv, Fuchsia, p. 67.
[485] Cited in 'Bull. Soc. Bot., France,' t. xiv ("Rev. Bibl."), p. 253.
[486] 'Primit. Flor. Amurens.' p. 57.
[487] 'Flora.' 1848. p. 484.
BOOK IV.
DEVIATIONS FROM THE ORDINARY SIZE AND CONSISTENCE OF ORGANS.
In the animal kingdom the entire adult organism, as well as each of its
separate parts, has certain dimensions, beyond which, under ordinary
circumstances, it does not pass, either in the one direction or the
other. It may not be easy or possible to state what the limits are, but,
practically, this inability to frame a precise limitation is productive
of no inconvenience. It is universally admitted that a certain animal
attains such and such dimensions, and that one organ has a certain
proportionate size as contrasted with another. The same rules hold good
in the case of plants, though in them it is vastly more difficult to
ascertain what may be called the normal dimensions or proportions.
Nevertheless observation and experience soon show what may be termed the
average size of each plant, and any disproportion between the several
organs is speedily detected.
When there is a general reduction in size throughout all the organs of a
plant, or throughout all the nutritive organs, stem, leaves, &c., and
the several portions participate in this diminished size, we have what
are generally termed "dwarf varieties," dwarf in comparison, that is,
with the ordinary condition of the plants; on the other hand, if the
entire plant, or, at least, if the whole of one set of organs be
increased in size beyond the recognised average, we have large
varieties, often qualified by such terms as _macrophylla_, _longifolia_,
_macrantha_, &c. &c. In all these cases either the entire plant or whole
series of organs are alike increased or diminished beyond average
limits; and such variations are often very constant, and are transmitted
by hereditary transmission. It may be supposed that such deviations may
have originated, in the first instance, either from excessive use, or
from disuse, or from the agency of certain conditions promoting or
checking growth, as the case may be; but whether or no, it is certain
that these variations often persist under different conditions, and that
they often retain their distinctive characters side by side with plants
presenting the normal average dimensions. In other cases the variations
in size are of a less general character, and affect certain organs of a
whorl in a relative manner, as, for instance, in the case of didynamous
or tetradynamous stamens, where two or four stamens are longer than
their fellows, the long or short stamens and styles of di- and
tri-morphic flowers, &c. These differences are sometimes connected with
the development of parts in succession, and not simultaneously.
Teratological deviations of size differ from those of which mention has
just been made chiefly in this, that they are more limited in their
manifestations. It is not, as a rule, the whole plant, or the whole
series of nutritive or of reproductive organs, that are affected, but it
is certain parts only; the alteration in size is more a relative change
than an absolute one.
For convenience sake the teratological alterations of size may be
divided into those which are the result of increased growth and those
which arise from diminished action. It will be seen, therefore, that in
these instances it is the bulk of the organs that is increased, not
their number; moreover, their development or metamorphosis is not
necessarily altered. In connection with increased size an alteration of
consistence is so frequent that the two phenomena are here taken
together. It will be borne in mind that the changes of consistence from
membranous to succulent or woody are very frequent in the ordinary
course of development. They may also occur as accidental phenomena, or
the normal conditions of any particular flower or fruit may be exactly
reversed, the usually succulent fruit becoming dry and capsular, and so
forth.
PART I.
HYPERTROPHY.
The term hypertrophy may serve as a general one to comprise all the
instances of excessive growth and increased size of organs, whether the
increase be general or in one direction merely. General hypertrophy is
more a variation than a deformity, unless indeed it be caused by insect
puncture or the presence of a fungus, in which case the excessive size
results from a diseased condition. For our present purpose hypertrophy
may be considered as it affects the axile or the foliar organs, and also
according to the way in which the increased size is manifested, as by
increased thickness or swelling--intumescence, or by augmented
length-elongation, by expansion or flattening, or, lastly, by the
formation of excrescences or outgrowths, which may be classed under the
head of luxuriance or enation.
As size must be considered in this place relatively, it is not possible
to lay down any precise line separating what are considered to be the
normal dimensions from those which are abnormal.
In practice no inconvenience will be found to accrue from this inability
to establish a fixed rule, and we may say that an hypertrophied organ is
one which, from some cause or other, attains dimensions which are not
habitual to the plant in its usual, healthy, well-formed state.
It will be seen that under this general head of hypertrophy, increase of
size, however brought about, is included; thus, not only increase in
length, but also in thickness; alterations of substance or consistence,
no less than of dimensions, are here grouped together. The alterations
of consistence resulting from an inordinate development of cellular,
fibrous, or ligneous tissue, are, of course, strictly homologous with
the similar changes which occur, under ordinary circumstances, during
the ripening of fruits or otherwise.
Hypertrophy, whatever form it may assume, may be so slight as not
perceptibly to interfere with the functions of the part affected, or it
may exist to such an extent as to impair the due exercise of its office.
It may affect any or all parts of the plant, and is generally coexistent
with, if not actually dependent on, some other malformation. Thus, the
inordinate growth of some parts is most generally attended by deficiency
in the size and number of others, as in the peripheral florets of
_Viburnum_ or _Hydrangea_, where the corollas are relatively very large,
and the stamens and pistils abortive.
CHAPTER I.
ENLARGEMENT.
A swollen or thickened condition (_renflement_) is usually the result of
a disproportionate formation of the cellular tissue as contrasted with
the woody framework of the plant. We see marked instances of it in
cultivated carrots and turnips, the normal condition of the roots or
root-stocks in these plants being one of considerable hardness and
toughness, and their form slender, tapering, and more or less branched.
The disproportionate development of cellular tissue is also seen in
tubers and bulbs, and in the swollen stems of such plants as
_Echinocactus_, _Adenium obesum_, some species of _Vitis_, &c. So, too,
the upper portion of the flower-stalk occasionally becomes much
dilated, so as ultimately to form a portion of the fruit. But it is not
necessary to give farther illustrations of this common tendency in some
organs to become hypertrophied. As a result of injury from insects or
fungi, galls and excrescences of various kinds are very common, but
their consideration lies beyond the scope of the present work.
[Illustration: FIG. 200.--_Pelargonium_, one branch of which was
hypertrophied.]
=Enlargement of axile organs.=--All the species of _Pelargonium_,
_Geranium_, _Mirabilis,_ as well as those of _Caryophylleæ_ and other
orders, have tumid nodes as a normal occurrence. In the genus
_Pelargonium_ this swelling is sometimes not confined to the nodes, but
extends to the interspaces between them, _e.g._ _P. spinosum_. This
condition, which happens as a natural feature in the species just named,
may also occur as an exceptional thing in others. The author is indebted
to Dr. Sankey for a branch of _Pelargonium_ which was thus thickened,
the remaining branches not being in any way affected. The leaves on the
swollen branch were smaller than the others, and their stalks more
flattened. There was, in this instance, no trace of fungus or insect to
account for the swelling of a single branch, which might, therefore, be
due to bud-variation, perhaps to reversion to some ancestral form. The
repeated cross fertilisations to which Pelargoniums have been subjected
render this hypothesis not an improbable one.
As an accompaniment to a spiral torsion of the woody fibres, this
distension of the stem is frequently met with, as in _Valeriana_,
_Dipsacus,_ &c. (See Spiral Torsion.)
=Knaurs.=--On certain trees, such as the oak, the hornbeam, some species
of _Cratægus_, &c., hard woody lumps may occasionally be seen
projecting, varying greatly in size, from that of a pea to that of a
cocoa-nut. They are covered with bark, and consist in the interior of
very hard layers of wood disposed irregularly, so as to form objects of
beauty for cabinet-makers' purposes. From the frequent presence of small
atrophied leaf-buds on their surface, it would seem as if the structures
in question were shortened branches, in which the woody layers had
become inordinately developed, as if by compensation for the curtailment
in length.[488] The cause of their formation is not known, but it has
been ascertained that they are not due to insect agency. Knaurs may
occasionally be used for purposes of propagation, as in the case of the
"uovoli of the olive" and the "burrs" that are formed on some varieties
of apple, from which both roots and leaf-shoots are produced in
abundance.
A distinction must be drawn between those instances in which the
swelling is solid throughout from the excessive formation of cellular
tissue, and those wherein it is hollow from the more rapid growth of the
outer as contrasted with the inner portions. These latter cases might be
classed under the head of distension.
[Illustration: FIG. 201.--Formation of tubers or hypertrophied buds in
the axils of leaves in the potato.]
=Enlargement of the buds= may be seen in the case of bulbs and tubers.
Occasionally these organs are developed in the axils of leaves, when
their nature becomes apparent. A swollen bud or bulbil in this
situation is not uncommon in some cultivated tulips and lilies. The
presence of small tubers in the axils of the leaves in the potato, as
shown in fig. 201, is also not unfrequent.
[Illustration: FIG. 202.--Inflorescence of ash (_Fraxinus_), with
hypertrophied pedicels, flowers absent.]
=Enlargement of the flower-stalk.=--The cauliflower and broccoli afford
familiar illustrations of hypertrophy of the flower-stalk, accompanied
by a corresponding defective development of the flowers. In the case of
the ash the terminal pedicels occasionally become swollen and distorted,
while the flowers are completely deficient, as shown in the adjacent cut
(fig. 202).
In grapes a similar condition may occasionally be met with in which the
terminal pedicels become greatly swollen and fused into a solid mass. It
would seem probable that this change is due to insect puncture, or to
the effect of fungus growth at an early stage of development, but as to
this point there is at present no evidence.[489]
[Illustration: FIG. 203.--Monstrous pear, showing extension and
ramification of the succulent floral axis. The bases of the sepals are
also succulent.]
In the apple a dilatation of the flower-stalk below the ordinary fruit
may occasionally be observed, thus giving rise to the appearance of two
fruits superposed and separated one from the other by a constriction.
(See fig. 176, p. 327.) The lower swelling is entirely axial in these
cases, as no trace of carpels is to be seen. M. Carrière[490] mentions
an instance wherein from the base of one apple projected a second
smaller one, destitute of carpels, but surmounted by calyx-lobes as
usual. The direction of this supernumerary apple was the exact opposite
of that of the primary fruit.
[Illustration: FIG. 204.--Monstrous pear, showing extension and swelling
of axis, &c.]
In pears, quinces, and apples, a not uncommon deviation is one in which
the axis is prolonged beyond the ordinary fruit, like which it is much
swollen. Occasionally the axis is not only prolonged, but even ramifies,
the branches partaking of the succulent character of the ordinary pome.
Such instances are frequently classed under the head of prolification,
but they have in general no claim to be considered in this light, for
the reasons already given in the chapter relating to that subject. (See
p. 135.)[491]
A very curious illustration of hypertrophy of the flower-stalk is
recorded and figured by M. Carrière[492] in the cherry. The calyx in
these fruits was completely superior, the succulent portion of the fruit
being made up of the dilated extremity of the peduncle, and possibly in
part of the base of the calyx. The general appearance was thus that of a
crab-apple. There was no stone in the interior, but simply a rudimentary
kernel or seed.[493]
Moquin-Tandon records an instance in which the stamens of each
individual flower in the inflorescence of a vine were hypertrophied, the
sepals, petals, and other organs of the flower, being proportionately
diminished.[494]
In this place may also be mentioned the hypertrophied condition of the
placenta observed by Alphonse de Candolle in a species of _Solanum_, and
also in a species of _Melastoma_. Not only was the placenta unusually
large in these flowers, but it also protruded beyond the ovary.[495] A
similar state of things in _Lobelia_ and _Cuphea_ has already been
alluded to under the head of Alterations of Direction (p. 210).
The following singular growth in a tomato is described by the Rev. M.
J. Berkeley in the 'Gardeners' Chronicle' for 1866, p. 1217, and appears
to have been an extension of the placenta:--"On the first glance it
seemed as if an unusually large grape-stone had accidentally fallen on
the upper surface of the fruit, and was attached by the narrow base. The
process was, however, five lines long, and much narrowed below, besides
which, though it was pale green above, the base was coral-red, like the
tomato itself. It grew on a narrow and shallow crack on the surface of
the fruit, and was found below to communicate directly with a
fibro-vascular bundle, which entered into the composition of a portion
of the placenta. On making a vertical section, instead of being
succulent, as I expected, it was white and spongy within, with several
lacunae, and one or two irregular fibro-vascular bundles, with highly
developed spiral vessels threading the centre. These vessels, moreover,
were tinged with brown, as in many cases of diseased tissues. There was
not the slightest appearance of placentæ or anything indicating an
abortive fruit. On closer examination the cuticle was found to consist
of thick-walled cells, exactly like those of the tomato, while the
spongy mass consisted of a similar tissue to the fleshy portion of the
fruit, but with far less wrinkled walls, and more indistinct
intercellular spaces. The most striking point, however, was the immense
quantity of very irregular and unequal starch-grains with which they
were gorged, which gave a peculiar sparkling appearance to them when
seen _en masse_. I am inclined to regard the body rather as an abortive
axis than an undeveloped fruit. In almost all, if not all, these cases
of abnormal growth, whether from leaves, petioles, fruit, or other
portions of the plant, we find an immediate connection with one or more
spiral vessels, which if not existent at first are developed sooner or
later. In the present case the connection of the fibro-vascular tissue
of the fruit and abnormal growth was plain enough, but whether it
existed when the body was first given off I am unable to say, as it was
fully developed when the fruit was brought to me."
=Enlargement of the leaves.=--Increase in the size or substance of
leaves takes places in several ways, and affects the whole or only
certain portions of them. The simplest form of this malformation is met
with in our cabbages, which, by the art of the gardener, have been made
to produce leaves of greater size and thickness than those which are
developed in the wild form. In such instances the whole substance of the
leaf is increased in bulk, and the increase affects the fibrous
framework of the leaves as well as the cellular portions, though the
exaggerated development of the latter is out of proportion to that of
the former.
In some species of _Podocarpus_ there may occasionally be seen at the
base of the branchlets a dozen or more fleshy scales, of a rose colour,
passing gradually into the ordinary leaves of the plant, and evidently
analogous to the three fleshy confluent bracts which surround the ripe
fruit.
In other instances, while the fibrous framework of the leaf retains its
usual degree of development, the cellular parenchyma is developed in
excess, and, if the increase is so arranged that the number of
superposed layers of the cellular tissue is not increased, or their
thickness exaggerated, then we get such leaves as those of the "kail,"
or of the "Savoys" leaves, which are technically called by descriptive
botanists "folia bullata." In such leaves the disc of the leaf, rather
than the margin, is increased and its surface is thrown up into little
conical projections, which are hollow on the under side.
But leaves may increase beyond their usual size without such grave
alterations of form as those to which allusion has just been made. It is
well known that if a tree be cut down and new shoots be sent out from
the stump, the leaves formed on these shoots very often greatly exceed
the ordinary ones in dimensions. Such cases as this hardly come under
the head of malformations. But where one part only of the leaf is
excessively developed, the other portion remaining in its ordinary
condition, there can be no hesitation in ranking the phenomenon as
teratological.
Thus, Moquin says that the median nerve may be prolonged beyond the
blade of the leaf in the form of a short strap or ribbon-like
excrescence, while, at other times, the lateral parts of the leaf are
subjected to undue development. He refers to a case cited by
Schlotterbec[496] in which each side of the leaves of a yellow "violier"
(wallflower) was dilated into a kind of projecting lobe on either side
of the true apex of the leaf, thus rendering it in appearance
three-lobed. M. Delavaud[497] puts on record a case of hypertrophy in
the leaves of the common elm, resulting in the formation of an
additional lobe and a return to the tricostate type. A leaf so affected
is stated to have presented the appearance of a fusion of two leaves.
(See also Multiplication of leaves, p. 353.)
The hypertrophied and coloured leaf of _Gesnera_ occupying the place of
the absent inflorescence has been previously alluded to under the head
of displacement (p. 88).
In some instances hypertrophy is the opposite of suppression; as in the
case previously mentioned, where the stipule in the inflorescence of a
pea, which is usually undeveloped and rudimentary, was developed in the
form of a leafy cup or pitcher.
Another instance of the development of parts usually suppressed, is
afforded by the bud-scales of _Magnolia fuscata_, which may sometimes be
found with small but perfect leaves projecting from them, the leaf in
this case being the lamina which is ordinarily abortive, while the
scales are the representatives of the stipules. This condition is said
by Hooker and Thomson ('Flora Indica,' p. 73) to be constant in
_Magnolia Campbelli_.
=Enlargement of the perianth, &c.=--One or all the segments of the
perianth may be subjected to hypertrophy; thus, the utricle of _Carex
vulpina_ may frequently be observed to attain four or five times its
usual size, the contained ovary remaining unaffected. This condition is
generally the result of insect puncture. The growth of parasitic fungi
will produce a similar result, as is often seen in the common shepherd's
purse, _Thlaspi bursa pastoris_, and other _Cruciferæ_. The perianth of
_Rumex aquaticus_ has been also observed to be occasionally
hypertrophied in conjunction with a similar condition of the pistil and
with atrophy of the ovules.
Moquin relates having found flowers of _Salsola Kali_ and of
_Chenopodium murale_ in which some of the segments of the perianth were
five or six times larger than they should be.
[Illustration: FIG. 205.--Hypertrophy of the perianth in _Cocos
nucifera_.]
The adjoining woodcut represents a singular condition of some cocoa-nuts
in the Kew Museum, the appearance of which is due apparently to an
hypertrophied condition of the segments of the perianth, which have not
only increased in length as the central nut has ripened, but have
developed in their tissues that fibrous tissue which ordinarily is found
in the pericarp only. This view of the structure of these nuts is borne
out by the fact that, under normal circumstances, the base of the
perianth contains a considerable amount of fibrous material. In the
present case this has increased to such an extent that the fruit appears
surrounded by a double husk, by an inner one as usual, and by an outer
six-parted one.
It will be remembered that in some of the _Cinchonaceæ_, e.g.
_Mussænda_, _Pinckneya_, _Calycophyllum_, one or more of the calycine
lobes are normally dilated and petaloid, the others remaining small and
comparatively inconspicuous. Inequality in size is, indeed, a common
occurrence in the sepals of many natural orders--_Polygalaceæ_,
_Leguminosæ_, _Labiatæ_, &c. The flowers of a rose are mentioned by
Moquin as having presented an enlargement of the calyx without any other
alterations in form. Schlechtendal has noticed the same thing in
_Papaver Rhoeas_, Reichenbach in _Campanula persicifolia_, and A. de
Candolle in _C. Rapunculus_. M. Brongniart also has recorded[498] a
remarkable variety of _Primula sinensis_ cultivated in the Jardin des
Plantes at Paris, wherein the calyx is enormously developed. MM.
Fournier and Bonnet have described flowers of _Rubus_ with hypertrophied
calyx in conjunction with atrophy and virescence of the petals and other
changes.[499]
The corolla may be hypertrophied in some cases, though the change is
more rare than in most other organs. Moquin-Tandon mentions as subject
to this anomaly species of _Galeopsis_, _Prunella_, _Scabiosa_, and
_Dipsacus_, and also mentions a remarkable variety of _Viola odorata_
cultivated in the neighbourhood of Toulouse. The same learned author
also alludes to the so-called double Composites, viz. those in which the
usually tubular florets of the disc assume the form and proportions of
those of the ray, but these are hardly cases of hypertrophy.
=Enlargement of the androecium.=--Dunal[500] alludes to a curious
instance in a species of _Verbascum_, the lower flowers of which had
hairy stamens as usual, but the filaments of the topmost flower were
quite destitute of hairs, and dilated like a flat ribbon.
Moquin relates having found in the neighbourhood of Toulouse a plant of
_Solanum Dulcamara_ in which all the upper flowers had two or three
stamens of larger dimensions than the others. This happens habitually in
_Solanum tridynamum_ and _S. Amazonicum_, and to a less extent in _S.
vespertilio_ and _S. cornutum_; also in some species of _Hyoscyamus_.
These cases show the close affinity between the _Solanaceæ_ and the
_Scrophulariaceæ_.
=Enlargement of the gynoecium.=--In some flowers which have become
accidentally female the pistil becomes unusually large, and even to such
an extent as to prevent the passage of the pollen. Moquin remarks having
seen this enlargement in the pistils of _Suæda fruticosa_ and _Kochia
scoparia_. The flowers of these Chenopods, under these circumstances,
resemble the female flowers of some nettles. The styles of _Anemone_ are
also much enlarged as the result of cultivation, and from their petaloid
appearance resemble those of the _Iris_ (Goethe). MM. Seringe and
Heyland[501] have figured some anomalous flowers of _Diplotaxis
tenuifolia_ in which the pistil, more or less distended and deformed,
was considerably elongated below, so that it seemed to be borne upon a
long stalk, analogous to that of fruits of Capparids. Dr. Klinsman[502]
mentions an instance of a similar kind combined with hypertrophy of the
sepals and pistils; indeed, the alteration is not uncommon among
Crucifers. _Pyrethrum inodorum_ is very subject to hypertrophy. The
styles of its radial florets become elongated without any other
alteration; at the same time the small corollas become green, and show a
tendency to assume a foliaceous condition. Sometimes the hypertrophy
affects also the styles of the central florets, and these also become
enlarged to double or treble their usual dimensions.
Linné has remarked that the ovary of _Tragopogon_ sometimes assumes very
large dimensions, as also does the pappus. He mentions a double-flowered
variety, the ovaries of which become ten or twelve times larger than
ordinary. M. Clos[503] records an instance in _Rumex scutatus_ wherein
the pistil was hypertrophied or club-shaped, and open at the top, or in
other cases funnel-shaped, three-lobed at the summit, each lobe
terminated by a style. One of the most frequent causes tending to the
hypertrophy of the pistil is attributable to the puncture of insects;
thus, when the ovary of _Juncus articulatus_ is thus punctured, it
acquires a size two or three times larger than ordinary, becoming at the
same time sterile.[504]
Occasionally the enlargement may be due to a fusion or incorporation of
other elements; thus, M. Lemaire describes an instance in which the
style of _Sinningia purpurea_ was much larger than ordinary, tubular,
bearing three small lobes, and altogether bearing much resemblance to
the column or "gynosteme" of Orchids. This appearance was due to the
cohesion and intimate union of the styles with three abortive
stamens.[505]
=Enlargement of the fruit.=--Most cultivated fruits are in a state of
true hypertrophy. Girod de Chantrans, after many trials, succeeded in
producing a peculiar variety of pea with pods double the ordinary
size.[506] M. Clos[507] mentions a case wherein the carpels of
_Delphinium dictyocarpum_ were hypertrophied. The change in size may or
may not be attended by a difference in form; thus, in certain
_Leguminosæ_, as _Medicago lupulina_, _Melilotus leucantha_, the carpels
are sometimes hypertrophied and elongated, so as to resemble a claw or
hook.[508]
The fruit of the common groundsel (_Senecio vulgaris_) is in its normal
condition two or three times shorter than the involucre, and cylindrical
for its whole length, but it frequently happens that the fruits become
as long as the involucre itself, and taper from the base upwards, so as
to become beaked. Under this head may also be mentioned the fleshy
bulbils that are found in the capsules of _Crinum_, _Amaryllis_, and
_Agave_. These are true seeds enormously dilated.[509] In these seeds
the outer coating becomes very thick and fleshy, and is traversed by
spiral vessels.
It is obvious that very important results in a practical point of view
may be and have been arrived at by cultivators availing themselves of
this tendency of plants to increase in dimensions under certain
circumstances. It is needless to do more than refer to the many fruits,
vegetables, and cereals, which have thus become enlarged and improved by
careful selection and rearing.
=Alterations of consistence= often accompany changes in size. The change
may be one whereby the tissues become unusually hardened, by the
excessive formation of secondary woody deposits, or softer and more
succulent than ordinary, from the formation of an inordinate amount of
loose cellular tissue. Generally speaking, the appearances presented in
such cases are not sufficiently striking to demand notice other than as
regards their size. One illustration, however, may be cited from its
singularity. This was the case of a dahlia, in which the centre of the
flower was occupied by a projecting knob as large as a walnut, brown in
colour, and very hard in texture. This knob was nothing but the enlarged
and indurated extremity of the common receptacle, destitute of the
scales and florets which usually spring from it. No insect-puncture
could be detected, and no other reason for this peculiarity could be
ascertained.
FOOTNOTES:
[488] On the subject of knaurs, the reader is referred to Trécul, 'Ann.
Sc. Nat.,' 3 ser., vol. xx, p. 65; Lindley, 'Theory of Horticulture;'
Rev. M. J. Berkeley, 'Gardeners' Chronicle,' 1855, p. 756.
[489] Jaeger, 'Flora.' 1860. p. 49, tab. i.
[490] 'Revue Horticole,' 1868, p. 110, figs. 12, 13.
[491] The reader may also refer for further information on the subject
of malformed pears to Irmisch. 'Flora,' 1858, p. 38, tab. i; Lindley,
'Theory of Horticulture'; Caspary, 'Bull. Soc. Bot. France,' vol. vi,
1859 (Rev. Bibl.), p. 235; Duhamel, 'Phys. Arbr.,' liv. iii, cap. 3. p.
393, fig. 308; Bonnet, 'Recherch. Us. feuilles,' tab. xxvi, fig. 2;
Moquin-Tandon, 'El. Ter. Veg.,' p. 384, &c. Some of the cases recorded
are, however, instances of true prolification.
[492] 'Revue Horticole' 1868, p. 310.
[493] The interest of this accident is great, as showing how an
habitually superior ovary may become inferior--a change so rare in its
occurrence that its existence has been denied, and thus forming a marked
contrast with the frequency with which the converse change of an
inferior ovary to a superior one, from want of union with the calyx or
from imperfect development of the peduncle, may be observed. It is also
interesting as showing how the peduncle may become swollen, and at the
same time how the woody deposit of the endocarp may, as if by
compensation, be deficient. And, again, the malformation is not without
significance in regard to the relationship between the drupaceous and
the pomaceous subdivisions of _Rosaceæ_. The case would fitly be
included under alterations of position, but the sheets relating to that
subject were printed off before the publication of M. Carrière's notice.
[494] 'Bull. Soc. Bot. France,' 1860, vol. vii, p. 881.
[495] "Monstr. Veget.," in 'Neue Denkschrift.'
[496] "Sched. de Monst. Plant." in 'Act. Helvet.,' t. ii, pl. ii, f. 14.
[497] 'Bull. Soc. Bot. France,' vol. viii, 1861, p. 144.
[498] 'Ann. Sc. Nat.,' sér. 2, t. i, p. 308, pl. ix _c_, fig. 1.
[499] 'Bull. Soc. Bot. France,' 1862, t. ix, p. 37.
[500] 'Consid. org. Fleur.,' Montpell., 1829, 25, 26, pl. ii, f. 18 and
19.
[501] 'Bull. Bot.,' t. i, p. 7, tab. 1.
[502] 'Linnæa,' vol. x, p. 604, tab. 5.
[503] 'Mém. Acad. Sc. Toulouse,' 5 ser., vol. iii.
[504] 'Ré. nosol. Végét.,' pp. 342.
[505] 'Illustr. Hortic.,' 1868, Misc., p. 62.
[506] 'Ann. Soc. Linn.,' Paris, t. i, p. 139.
[507] 'Mém. Acad. Toulouse,' t. 6, 1862.
[508] 'D. C. Prod.,' ii, pp. 172, 187.
[509] Richard, "Obs. sur les bulbilles des Crinum;" 'Ann. Sc. Nat.,' t.
ii, p. 12. pl. i, fig. 1, 2. See also A. Braun, "Mémoire sur les graines
charnues des Amaryllidèes," &c.; 'Ann. Sc. Nat.,' 1860, vol. xiv, p. 1,
tab. 1.
CHAPTER II.
ELONGATION.
The class of cases coming under this head are sufficiently indicated by
the name. There are many instances of this phenomenon occurring under
different conditions, which, though unusual, can hardly be called
abnormal, such, for instance, as the great lengthening of roots in their
search for water, the excessive elongation that takes place in plants
when grown at a distance from the light, in their endeavour to attain to
which they become, as gardeners phrase it, "drawn." A similar result is
brought about in forests or plantations, where long spars are required,
by allowing the trees to grow very close to each other, so as to prevent
the lateral extension of the branches. When plants grow in running
water their roots, stems, and sometimes their leaves, become excessively
elongated, as in _Ranunculus fluitans_, the flower-stalks of _Valisneria
spiralis_, &c. These are cases of variation rather than of malformation,
but are none the less curious, or sometimes perplexing; thus, Lapeyrouse
described, in his 'Supplement à la flore des Pyrenées,' p. 27, under
the name _Potamogeton bifolium_, a plant which Mr. Bentham subsequently
discovered to be nothing but a flowerless variety of _Vicia Faba_
distorted by its growth in water.[510]
=Elongation of the root.=--This, as already remarked, is more often a
variation than a malformation, and is usually due to the presence of
water at a distance necessitating growth at the extremities of the root,
or to the presence of some obstacle, such as a stone, to avoid which the
root elongates till it has passed the obstruction. Occasionally in
Crocus corms some of the fibrils may be met with much lengthened and
thickened, and invested with a fleshy sheath. It is not certain,
however, that these structures are roots; possibly, nay probably, they
may be processes from the stem thrust downwards into the soil, similar
to the formations already described in the tulip (p. 85, fig. 39).
=Elongation of the inflorescence.=--Under this heading it is necessary
to consider lengthening of the common rachis in the case of an aggregate
inflorescence, and lengthening of the individual flower-stalks, whether
they be solitary or portions of a multiple inflorescence. The two
phenomena may occur together, but they are quite as often independent
one of the other. Thus, among _Umbelliferæ_ the umbels are occasionally
met with supported on unusually long stalks, while the pedicels of the
individual flowers may or not be increased in length; so also with some
of the Composites, or the heads of flowers of some _Leguminosæ_,
_Trifolium repens_, &c. &c.
Another illustration of the sort is that recorded by M. Fournier,
wherein the usually umbellate inflorescence of _Pelargonium_ was,
through the lengthening of the main stalk, transformed into a raceme.
Among Composites a similar change may sometimes be met with.
MM. Clos and De Schönefeld have recorded the existence of a variety of
the sweet chestnut (_Castanea_)in which the female catkins were as long,
and bore nearly as many flowers, as the male spikes. This is stated to
be of constant occurrence in some localities, and to be accompanied by a
diminished size of the fruits. A similar elongation has been observed in
the case of the walnut, catkins of which have been seen bearing thirty
to thirty-five large nuts.[511]
In the strobile of the hop, _Humulus Lupulus_, a like elongation may
sometimes be met with, generally in association with a more or less
leafy condition of some of the scales.
Of a similar character, but complicated with extrusion or eversion of an
ordinarily concave axis, is the fig described by Zuccarini,[512] and
from the appearances presented by which that author draws the inference
that the peculiar appearance of the fig is due to the formation of a
large number of small bracts blended together for the greater part of
their length, and accompanied by the suppression of the internodes, and
consequent shortening of the axis. In the monstrous fruit the axis is
prolonged, and forms a kind of raceme or catkin, surrounded at the base
by numerous bracts, as in many _Amentaceæ_. (See p. 204, figs. 105,
106.)
A lengthening of the axis of the female strobiles of _Coniferæ_ is not
of infrequent occurrence in _Cryptomeria japonica_, _Larie europæa_,
&c., and this is usually associated, as has been before stated, with a
leaf-like condition of the bracts, and sometimes even with the
development of leaf-bearing shoots in place of the scales. (See under
Prolification of Inflorescence and Phyllomorphy, and for references, p.
115.)
=Elongation of the secondary flower-stalks.=--In the previous section
the effect of elongation of the main rachis has been considered. A
corresponding deviation occurs in the peduncles or pedicels, and
sometimes alters the general character of the inflorescence very
considerably, converting a spike into a raceme, a raceme into a corymb,
a capitulum into an umbel, and so forth. A few such cases may here be
alluded to. Fig. 206 represents a specimen of _Ranunculus acris_, in
which the lower and lateral flower-stalks were not only increased in
number, but so much lengthened as to form a flat-topped inflorescence--a
corymbose cyme. In many leguminous plants, as in _Trifolium repens_,
_Lotus corniculatus_, &c., what is usually a compact spike, or head of
flowers, becomes a raceme from the elongation of the pedicels. In
_Umbelliferæ_ a similar change occurs, by virtue of which sometimes the
umbels themselves, and at other times the florets, are raised on
unusually long stalks, as in _Angelica Razoulzii_, _Carum Carui_,
_Thysselinum palustre_.[513] In _Compositæ_, when affected by an
analogous change, the capitulum assumes the appearance of a simple
umbel, as in _Hypochæris radicata_, _Senecio vulgaris_, and other
plants.
[Illustration: FIG. 206.--Inflorescence of _Ranunculus acris_, with
secondary peduncles lengthened.]
In some of the double-flowered apples which have been previously alluded
to, the flower-stalk is inordinately long when compared with the
adjacent ones. Possibly in some of these cases the absence of the usual
swelling of the upper part of the peduncle may be connected with its
increased length. One of the most striking instances of lengthened
flower-stalk occurred in an apple flower, wherein there was no swelling
beneath the calyx, while the latter was represented by five perfect
stalked leaves.
=Elongation of the leaves.=--In the case of water plants this change
keeps pace with the corresponding growth of the stem, _e.g._
_Ranunculus fluitans_, and in terrestrial plants there are varieties
termed longifoliar, from the unusual length of the leaves. A similar
lengthening occurs in the involucral leaves of _Umbelliferæ_ and
_Compositæ_, changing very materially the general aspect of the
inflorescence. Occasionally, also, the leaf-lobes of parsley (_Apium
Petroselinum_) and other crested-leaved plants may be observed to lose
their ordinary wavy form, and to be lengthened into flat riband-like
segments, as shown in fig. 207.
The only further illustrations that it is requisite to give of such
changes in this place are those occurring in lobed or compounded leaves,
which, from a lengthening of the midrib or central stalk, convert a
digitate or palmate leaf into a pinnate one. In these instances the
lobes or leaflets become separated one from another by a kind of
apostasis. This change may be frequently seen in the horse-chestnut,
particularly in the young shoots formed after the trees have been pruned
or pollarded. In the adjoining cut the intermediate stages between a
palmate or digitate leaf to a pinnate one may be seen. The specimens
from which the drawing was made were taken from the same tree at the
same time.
[Illustration: FIG. 207.--Portion of leaf of parsley, showing the change
from short wavy to long flat leaf-lobes.]
In the white clover, _Trifolium repens_, a similar transition may often
be observed, as also in some species of _Potentilla_.[514]
=Elongation of the parts of the flower.=--The only circumstance that
needs especial mention under this section is the great lengthening that
sometimes takes place in the carpels, sometimes as a result of injury
from insects or fungus, at other times without assignable cause.
[Illustration: FIG. 208.--Leaves of horse-chestnut, _Æsculus_, showing
passage from digitate to pinnate leaves.]
In the case of inferior ovaries this lengthening is, perhaps, even more
common, as in _Umbelliferæ_, _Compositæ_, &c. The common groundsel
(_Senecio vulgaris_) is especially liable to this form of enlargement of
the pistil, either in association with a leafy condition of the pappus
or without any such change.
=Elongation of the thalamus, placenta, &c.=--In some plants, as in
_Magnolia_ or _Myosurus_, the thalamus becomes much elongated, and bears
the carpels disposed spirally around it. A similar lengthening occurs in
malformed flowers, usually in association with a similar change in the
lower or outer part of the flower, by virtue of which the whorls become
separated from each other (Apostasis). Elongation and protrusion of the
placenta have been already alluded to at p. 119, and also at p. 125. In
some of these cases the elongated placenta has taken the form of a
leaf-bearing shoot.[515]
=Apostasis.=--Engelmann made use of this term to express the separation
of parts one from another by the unusual elongation of the
internodes.[516] He drew a distinction between the separation of
individual organs one from the other, and the corresponding displacement
of whorls. The subject has already been, to a considerable degree,
treated of in these pages under the head of dialysis, displacement, and
prolification, and but little need here be added. With reference to the
distance between one whorl and another, it will be remembered that,
although in the majority of cases the floral whorls are packed closely
together, yet in other instances the floral axis becomes elongated, and
thus separates the whorls one from another, by structures such as the
gynophores, androphores, &c., of _Passifloreæ_, _Caryophylleæ_,
_Capparideæ_, &c. &c.
A similar elongation of the thalamus, bringing about the separation of
the floral whorls, or of their constituent parts, is very commonly met
with in association with median prolification. Where the individual
floral elements are thus thrown out of their usual verticillate
arrangement, they naturally assume a spiral disposition, and are, in
some cases, united by their margins, so that a spiral sheet or tube is
formed, surrounding the axis. This frequently occurs in double flowers
of the Chinese primrose, _Primula sinensis_.
Engelmann[517] figures a case wherein the calyx of _Anagallis
phoenicea_ was separated by a rather long internode from the corolla,
and a like illustration in _Torilis Anthriscus_.
[Illustration: FIG. 209.--Flower of _Delphinium_, showing apostasis of
carpels, from lengthening of the thalamus, &c. (Cramer.)]
A frequent change in Crucifers is due to the formation of a long stalk
bearing the pod, and thus giving rise to the appearance met as a
constant occurrence in Capparids.
In _Tropæolum majus_ a similar elevation of the pistil may occasionally
be seen.
The adjacent figure of a monstrous _Delphinium_ taken from Cramer
illustrates well the elongation of the floral axis and the apostasis of
the carpels. In this instance the axis is terminated by a second flower
(median prolification).
One of the best-marked illustrations of these changes occurs in a
permanent malformation of _Epilobium hirsutum_, specimens of which were
originally obtained from the late Professor Henslow. The several floral
parts are here, some virescent, others truly foliaceous, and each whorl
is separated from its neighbour by a rather long internode. In _Fuchsia_
and _Campanula_ a like change may occasionally be observed.
Engelmann, in addition to those previously mentioned, cites the
following plants as having manifested this change:
_*Convallaria majalis!_, _*Tulipa Gesneriana!_, _Veronica Chamædrys_,
_Orobanche gracilis_, _Solanum Lycopersicum_, _Gentiana campestris_,
_Hypericum_, _Helleborus fetidus_, _Caltha palustris_, _Brassica
oleracea!_ and many _Rosaceæ_, _Caryophylleæ_, _Cruciferæ_, and
_Ranunculaceæ_. (See Dialysis, Median Prolification, &c.)
Apostasis of the sub-floral or involucral leaves is not of infrequent
occurrence in malformations affecting _Compositæ_ and _Umbelliferæ_. In
the following genera it has been observed with especial
frequency:--_Torilis Anthriscus_, _Eryngium_, _Athamanta Cervaria_,
_Leontodon_, _Tragopogon pratense!_, _Wedelia perfoliata!_ In garden
anemones, also, it is a common deviation.
FOOTNOTES:
[510] 'Cat. Plant.,' Lang., p. 113.
[511] 'Bull. Soc. Bot. France,' t. i, 1854, p. 173, and t. xiii, p. 96.
[512] 'Abhandl. Math. Phys. Class.,' Band. iv, Abhandl. i, tab. i.
[513] See Cramer, 'Bildungsabweich,' pp. 62-79, and Fleischer,
'Missbild, der Culturpflanzen.'
[514] Schlechtendal, 'Bot. Zeit.,' 1844, p. 457; 'Linnæa,' xi, p. 301,
xiv, p. 363; 'Bot. Zeit.,' 1856, p. 72; Masters, 'Rep. Brit. Assoc.,'
Manchester, 1861; Coultas, 'What may be learnt from a tree,' p. 118.
[515] For further details refer to the chapter on Displacements, p. 86.
[516] 'De Antholysi,' p. 42, § 49.
[517] Loc. cit., tab. 2, f. 6.
CHAPTER III.
ENATION.
Under the above heading are included certain forms arising from excess
not of growth, but of development, and consisting in the formation of
supplementary lobes or excrescences from various organs.
The new formations are not due either to a repetition or to a partition
of any organ, but are out-growths from others previously formed.
In prolification and in multiplication the adventitious structures are
of independent origin. In fission the new developments grow
simultaneously with the older ones, of which, indeed, they are mere
repetitions. Moreover, in fission the supplementary lobes do not, in
general, project a plan different from that of the original structure,
at least in the first instance, though their direction may ultimately
become changed.
In enation the new growth projects from a previously formed organ after
it has attained to considerable size, or even after its ordinary
proportions have been attained, and it sprouts out from the beginning in
a plane which is at a considerable angle to that of the parent organ,
and it is sometimes of a different structure from it, and has different
functions to fulfil.
Many of the instances that occur of scales projecting from petals, as in
_Caryophylleæ_, _Sapindaceæ_, &c., the coronal filaments of
passion-flowers, the cup of _Narcissus_, the appendages that beset the
segments of the perianth in _Lilium lancifolium_, and other similar
growths, may be referred to a like process. In many cases this has been
proved by a study of the development of the flower, from which it
appears that the growths in question are developed subsequently to the
formation of the ordinary floral whorls. It is requisite, however, to be
cautious in pronouncing upon the exact nature of these bodies, in the
absence of a knowledge of their period and mode of formation. They may
be mere outgrowths from one or other of the customary whorls, or they
may represent abortive stamens or petals, &c. Where circumstances
prevent the course of development from being traced, something may be
inferred as to their real nature from their position in regard to the
other parts of the flower, from their anatomical structure, and from
analogy or comparison with like organs in other plants. The period of
their formation is, perhaps, of less importance than was at one time
supposed, since it is well ascertained that, in some cases, the
formation of the parts of the flower, _e.g._ the stamens of mallows,
follows a centrifugal rather than a centripetal order.
In the case of monstrous developments of this nature too much care can
hardly be exercised, and the observer should rarely venture on an
explanation of the nature of the case from the evidence afforded by the
monstrous growth apart from that to be derived from the study of the
development and organization of the normal flower and from analogous
formations in allied plants.
=Excrescences from axile organs--Warts.=--In a preceding paragraph the
formation of gnaurs has been alluded to. There are other outgrowths,
called warts, occasionally met with in trees, and which are more closely
connected with the central tissues of the stem, while at the same time
they are not provided with buds, in which two particulars warts differ
from gnaurs.
Excrescences of this kind often attain a very large size, and may be
seen on old elms and other trees, but, as their formation is probably
more pathological than teratological, no further notice of these
structures need here be given. No special notice need here be taken of
the tubercles on the roots of so many _Leguminosæ_, nor of the peculiar
excrescences on the roots of _Taxodium distichum_, as these appear to be
normal formations. But it may be well to mention in this place an
anomalous development which occurs occasionally in _Ruscus aculeatus_,
and in which, from the upper surface of the ordinary flattened leaf-like
branch, projects at right angles a second similar branch, so that in
section the appearance would be like that of the inverted letter t;
thus, [Symbol: Inverted upper-case T].
=Enation from foliar organs--Leaves.=--The development of adventitious
lobes from leaves may take place either from their surfaces or their
margins. A few illustrations may be given of each. In cabbage leaves a
formation of adventitious laminæ projecting at right angles from the
primary one may frequently be observed. In the instance figured (fig.
210) the new growths proceeded almost exclusively from the thick midrib,
which, in the figure, is shown cut through just above the base. Not only
is the ordinary semilunar band of vascular tissue to be here seen, but a
similar broken line of vessels exists on the upper side of the
leaf-stalk; thus the whole structure resembles that of a stem or a
branch as much as that of a true leaf.
[Illustration: FIG. 210.--Section through base of midrib of cabbage
leaf, showing supplementary laminæ, &c.]
The development of secondary leaves from the surfaces of primary ones
(phyllomania, autophyllogeny) has already been alluded to at p. 355.
Some of the cases wherein a leaf seems to have a double lamina may be
alluded to here, though possibly they would more properly be referred to
fission. The appearance presented is as if four wings projected from the
midrib, so that a cross section would be nearly in the form of
[Symbol: )O( turned 90 degrees.]. In an orange leaf presenting this
appearance the lower surface of one lamina was, as usual, dull in
colour, while the upper surface of the subjacent lamina was likewise
dull; hence the impression might arise that this was an instance of the
adhesion of two leaves back to back, but the petioles were not twisted,
as they must have been had two leaves thus been united, and neither in
the petiole nor in the midrib was there the slightest indication of
fusion, the vascular bundles being arranged in a circular manner, not in
a horseshoe-like arrangement, as would have been the case had adhesion
taken place.[518] (See p. 33.)
Such leaves as those of the hedgehog holly, _Ilex Aquifolium_, var.
_feroæ_, and, to a less extent, bullate leaves, may also be mentioned
here as illustrations of hypertrophy or enation.
[Illustration: FIG. 211.--_Nephrodium molle_. Ordinary frond and forked
and crested varieties of the same, the crest arising from the inordinate
development of the margins of the pinnules.]
When the increased development occurs at the margin of the leaves,
especially, the result is a wavy or crisped appearance, "folia undulata,
_vel_ crispa."[519] These conditions occur normally in such leaves as
those of _Rumex crispus_, _Malva crispa_, &c., and are developed to an
extreme degree in garden varieties of parsley, some kails, &c., as well
as in many ferns, but these are probably cases rather of fission than
enation as here understood.[520]
=Enation from the sepals.=--The basal lobes of the calyx in _Campanula
Medium_, under normal circumstances, may be referred to in illustration
of this occurrence, while the adventitious spurs on the calyx of some
monstrous flowers seem due also to a like cause. These have already been
alluded to at p. 315.
=Enation from the corolla.=--The instances of this are more frequent
than in the case of the calyx, and admit of classification according as
they occur in polypetalous or gamopetalous flowers, on the outer or
inner surface of the petals, &c. Under natural circumstances the
formation of scales, lobes, &c., from the petals, as in some
_Caryophylleæ_, _Sapindaceæ_, &c. &c., may be explained, as already
remarked, by this process, rather than by fission, chorisis, or by
substitution of petals for stamens, &c. Each case must, however, be
examined on its own merits, as it is not safe to decide upon the
arrangement of parts in one flower by simply referring to the analogy of
others. In the following illustrations the course of development has
not, in all cases, been observed, and hence the explanation here given
must be taken with some reserve; for should it prove that the
adventitious lobes, &c., are formed simultaneously with the ordinary
petals, the case will be one of chorisis rather than of enation, as here
understood. Again, it may be that the supernumerary organs really
represent petals or stamens in disguise, though this hypothesis demands
the further assumption (in order to account for the interference with
the law of alternation) that suppression of certain organs has taken
place.
Taking first those instances in which the supplementary petals appear on
the inner surface of the corolla, as being at once the most frequent,
and as presenting the closest analogy, with similar conformations, under
natural circumstances, certain double-flowered varieties of the Chinese
primrose, _Primula sinensis_, may be mentioned. In these flowers the
calyx is normal, the tube of the corolla is traversed by ten vascular
bundles, and the limb is divided into ten fimbriated lobes. About
halfway up the tube, on the inner surface, are given off five
supernumerary petals, opposite to as many lobes of the corolla. Some of
the supplementary petals have a stamen in front of them, in the same
relative position as in the normal flower. In some cases the back or
outer surface of the supplementary petal is turned towards the inner or
upper surface of the primary corolla, thus [Symbol: ((turned 90 degrees
cw]; while, in other instances, the front of the adventitious lobe is
directed towards the corresponding surface of the original petal, thus
[Symbol: () turned 90 degrees]. Whether these supernumerary petals are
formed by chorisis or by enation cannot, with certainty, be determined
without examining the early stages of development.
[Illustration: FIG. 212.--_Datura fastuosa._ True corolla turned back to
show the supernumerary corolla with the petal-like segments attached to
its outer surface (reduced).]
Of more interest are those instances where the adventitious growth is on
the outside of the corolla; thus in a garden azalea there was
intermediate between the calyx and the corolla, both of which were
normal, a series of five petalodes, alternating with the sepals, and,
therefore, opposite to the lobes of the corolla, and adherent with them
at the very base, though elsewhere detached. These petalodes were
concave on the surface looking towards the calyx, and were there
brightly coloured, while the tint of the opposite surface looking
towards the corolla was of a duller hue, corresponding with that of the
outside of the corolla-tube. This arrangement of the colour was thus
precisely similar to that which occurred in the four-winged leaves
already referred to at p. 446. In some flowers of _Datura fastuosa_ a
similar series of excrescences was observed; the calyx and the corolla
were normal within the latter, intervening between it and the stamens
was a second corolla produced by duplication, and adherent to the inner
surface of this latter were five stamens. So far there was nothing very
peculiar; it remains to say, however, that on the outer surface of the
second corolla were five petal-like lobes closely adherent to it below,
but partially detached above. The colour of the adventitious segments
was paler on the outside than on the inner surface, as in the corolla
itself. The position of the several parts was such that they were
opposite one to the other; hence, while the lobes of the inner corolla
were opposite to those of the outer one, the intermediate petalodes were
opposite to both; thus:
S S S S S
--------------------------
P P P P P
X X X X X
--------------------------
P P P P P
st st st st st
The X indicating the position of the petalodes.
[Illustration: FIG. 213.--Gloxinia, with supernumerary segments on the
outside of the true corolla.]
A still more singular case is that of a variety of the Gloxinia,
described originally by Professor Edouard Morren,[521] but which is now
becoming common in English gardens. When first observed these flowers
were observed to produce petaloid segments outside the ordinary corolla,
and partially adherent to (or rather, not completely separated from it)
much as in the azalea before mentioned, the outer surface being brightly
coloured, like the inner surface of the corolla in ordinary gloxinias.
Being encouraged and tended by gardeners, in course of time, instead of
a series of petalodes, more or less distinct from one another, a second
corolla or "catacorolla" was formed outside the primary one, so that a
hose in hose flower was produced, but, in this case, the supplementary
flower was formed on the outside and not within the ordinary corolla.
Moreover, the disposition of the colour was reversed, for in the
outermost corolla the richest hues were on the outer surface, while in
the inner or true corolla they were on the inside.
Professor Morren considers the adventitious petalodes as rudiments of so
many supplementary flowers, axillary to the calyx, and adnate to the
corolla; each lobe then would, in this view, represent an imperfect
flower, and the completed catacorolla would be formed of a series of
confluent flowers of this description. But this view involves the
assumption of the suppression of all the parts of the flower, except the
lobes in question.
[Illustration: FIG. 214.--"Catacorolla" of _Gloxinia_, formed from the
union of adventitious petalodes on the outside of the true corolla
(after Morren).]
The view here propounded that the lobes in question are enations from
the true petals, which become confluent, so as to form the catacorolla,
is surely more simple, involves no assumptions of suppression of parts;
and moreover, is borne out by the examination of some flowers, where the
production of these adventitious lobes from the outside of the minute
partially developed petals could be distinctly seen.
=Enation from the stamens.=--An illustration of this process occurred in
some double-flowered rhododendrons, which presented the following
arrangement of parts:--calyx and corolla normal; within the latter eight
petal-like stamens, forming a pseudo-corolla. The appearance presented
by the petaloid filaments and anthers was as if they were adnate to the
centre of the petals, but, on closer examination, it appeared that the
petaloid expansion to which the dilated filament was apparently
attached, was equally a part of the stamens; in other words, that the
filament was provided with four petal-like wings, two on each side
[Symbol: 00 topped by (turned cw 90°, an o above and another ( turned cw
above that]. This disposition was well seen in the anther, half of which
was, in some cases, petaloid like the filament; in fact, the inner wing
of the latter was directly continuous with the petal-like expansion from
the anther. A section through the latter showed, going from within
outwards, the cut edges of two perfect polliniferous lobes in the
centre; and on either side the petaloid wing representing the remaining
anther-lobe; outside these were the edges of the remaining wings, one on
each side. (See p. 290, fig. 155.)
=Enation from the carpels.=--The only instances of this that need be
referred to are such cases as those in which spur-like projections,
horns, tubercles, or winged expansions, are formed from the surface of
the ovary during the course of its development. The extraordinary
cornute oranges described and figured by Ferrari, Gallesio, and other
writers on the genus _Citrus_, may be mentioned under this head. A
similar formation occurs in the fruit of some species of _Solanum_. (See
p. 316.)
FOOTNOTES:
[518] It is desirable in this place to allude to a singular case of
fissiparous division of a leaf of _Prunus Laurocerasus_ described by
Prof. Alexander Dickson ('Seemann's Journ. Botany,' vol. v, 1867, p.
323), and which did not come under the writer's notice till after the
sheet relating to fission, p. 61, had been sent to press. Dr. Dickson
thus speaks of this abnormal leaf:--"The petiole (unchanged) supported
two laminæ, placed back to back, and united by their midribs (_i.e._ not
separated) to within about an inch from their extremities, which were
perfectly free from each other. These laminæ stood vertically, their
edges being directed towards and away from the axis; and as they were
placed back to back, the shining surfaces, corresponding in structure to
the normal upper leaf-surface, were directed laterally outwards. In the
axil of this abnormal leaf were two axillary buds. The existence of two
leaf-apices and two axillary buds shows that this was not due to an
accidental exuberance of development, but to fissiparous division,
which, had it been complete, would have resulted in the replacement of a
single leaf by two leaves. The arrangement in Prof. Dickson's leaf may
be thus represented: [Symbol: )OO( with X above]. The nature of the case
may be even better seen by comparison with the normal arrangement, which
would be [Symbol: (OX turned 90 degrees ccw], while in those cases where
the fission of the leaf occurs in the same plane as that of the primary
lamina, as where a leaf splits into two lobes at the apex, with a midrib
to each, the arrangement is as follows: [Symbol: OX turned 90 degrees
ccw, with 2 arcs below forming a half circle], the X in all cases
representing the position of the axis, the O that of the axillary bud,
and the [Symbol: ( turned 90 degrees ccw] that of the laminæ."
[519] Linn., 'Phil. Bot.,' § 274. The term "_crispa_" is surely
preferable to that of Ré, "phyllorhyseme."
[520] See C. Morren, "Consid. sur les déformations," &c., in 'Bull.
Acad. Belg.,' 1852, tom, xix, part 3, p. 444; and as to ferns, see
Moore, 'Nature-Printed British Ferns,' 8vo ed., where numerous
illustrations are given.
[521] 'Bull. Acad. Belg.,' t. xix, p. 224, tab. i; and 'Gardeners'
Chronicle,' 1865, p. 865.
PART II.
ATROPHY.
Under the head of atrophy are included those cases wherein the organs
affected are actually present, but in a dwarfed and stunted condition as
compared with surrounding parts.
The diminished size is, in such instances, obviously due to a partial
development and to an arrest of growth at a certain stage, from the
operation of various causes, either external or inherent to the
organization itself. It may affect any part of the plant, and exists, in
very varying degree, in different instances, being sometimes so slight
in amount as not to preclude the exercise of the functions of the part;
while in others, the structure is so incomplete that the office cannot
be performed. These differences depend, of course, upon the stage of
development which the organ had reached when its growth was checked. For
practical purposes atrophy may be distinguished from suppression by the
fact that in the latter case a certain element of the flower or plant
which, under ordinary circumstances, is present, is entirely wanting,
while, in the former class, it exists but in a rudimentary condition.
Again, atrophy is to be separated from that general diminution in the
size of the whole plant or of distinct parts of that plant which is
comprised under the term "nanism." Thus the several dwarf varieties of
plants (var. _nanæ_), or those in which the leaves or flowers are
smaller than usual (var. _parvifoliæ_, v. _parvifloræ_), are truly
regarded as variations, and not as malformations properly so called.
Atrophy is partial and special in its operation, nanism is general.
Under ordinary circumstances atrophy is exemplified by the presence of
rudimentary or imperfect organs, as, for instance, in _Pentstemon_,
_Scrophularia_, &c., where one stamen is atrophied.
For convenience sake atrophy may be divided into abortion and
degeneration, the first including cases where, from arrest of
development occurring at an early stage, organs are present; but in a
much smaller and more rudimentary condition than usual, their form and
general appearance, except so far as regards their dimensions, not being
materially altered. On the other hand, in cases of degeneration,
development is not entirely checked, but rather perverted, so that not
only the dimensions are lessened, but the form is altered.
CHAPTER I.
ABORTION.
The sense in which this term is here understood has been explained in
the preceding paragraph. It is only necessary to say further, that cases
of abortion are to be distinguished from those of suppression, on the
one hand, and those of degeneration on the other. In suppression there
is from the first an absolute deficiency of a particular organ. In
degeneration the part is present, but in a diminished and perverted
condition. In abortion it exists, but in a stunted and dwarfed, but not
otherwise permuted state.
=Abortion of axile organs.=--When the main stem is arrested in its
growth, the habit and general appearance of the plant are materially
altered, as in the so-called stemless plants, _plantæ acaules_. In these
the internodes are so slightly developed that the leaves are closely
crowded in tufts or rosettes. When this shortening of the stem
(acaulosia) occurs, without other considerable change in other organs,
the deviation is classed under the head of variation rather than of
monstrosity; and, indeed, in very many plants, this arrested growth of
the axis is the rule rather than the exception. When occurring in an
abnormal manner, atrophy of the stem is most frequently attended by
other more or less grave alterations in other structures; thus
Moquin-Tandon[522] cites an instance of _Camphorosma monspeliaca_,
wherein the stems presented the form of very short, hard, woody
tubercles, thickly clothed with deformed leaves, and invested by a vast
number of hairs, longer and more dense than usual. A similar deformity
sometimes occurs in an Indian species of _Artabotrys_; in these
specimens the branchlets are contracted in length, and bear numerous
closely packed scaly leaves, densely hairy, and much smaller than
ordinary.
Spines and thorns may he looked on as atrophied branches, and seem to
result from poorness of soil, as the same plants, which, in hungry land,
produce spines, develop their branches to the full extent when grown
under more favorable conditions.[523]
In the birch an arrest of development in some of the branches is of
common occurrence. The branch suddenly ceases to grow in length; at the
same time it thickens at the end into a large bulbous knob, from which
are developed a profusion of small twigs, whose direction is sometimes
exactly the reverse of that of the main branch. (See p. 347.)
The branches of the common spruce fir, especially the lateral ones, when
attacked by a particular species of aphis, are very apt to be developed
into a cone-like excrescence.[524]
A shortened condition of the flower-stalks occurs occasionally, greatly
altering the general character of the inflorescence. This has been
observed in pelargoniums and in the Chinese primrose, in both of which
the effect was to replace the umbellate form of inflorescence by a
capitate one.
=Abortion of the receptacle.=--Here may be mentioned those cases of
flowers with habitually inferior ovary (real or apparent), in which the
receptacle fails, from some cause or other, to dilate as usual. This has
already been alluded to under the head of Prolification, Displacements,
&c. (pp. 78, 130, &c., figs. 35-37, 64, &c.), and hence requires only
incidental comment in this place. There are, however, certain other
cases of a similar nature which may here be referred to; such as the
abortive condition of the inferior ovary, or rather of the receptacle,
that usually encircles the ovary in _Compositæ_ and _Umbelliferæ_. In
the former natural order the following plants have been met with in this
condition:--_*Tragopogon pratense!_, *_Cirsium arvense_, _Hypochæris
radicata_, _Senecio vulgaris!_, _Coreopsis Drummondi_. In the latter
order, _Daucus Carota!_ _OEnanthe crocata!_ and _Thysselinum
palustre_, seem most frequently to have been observed in this
state.[525] In some gourds the receptacle may be seen partially
developed only, and forming a kind of cup, from which the true carpels
protrude.
=Abortion of the leaves.=--Arrest of growth in the leaves occurs in
different ways; sometimes the whole leaf is smaller than usual; at other
times certain parts only are reduced in size; while, in a third class of
cases, portions of the leaf are entirely suppressed.
Moquin[526] mentions having seen the leaves of _Chenopodium vulvaria_,
and of _Diplotaxis muralis_ reduced to a fourth of their natural size;
and he alludes to other cases of the same nature, seen by other
observers, in _Hypericum perforatum_ and _Blitum polymorphum_.
_Nicandra physaloides_[527] has also been met with in a similar
condition, which, indeed, is a common result of insect-puncture, and of
fungous growth in plants. Those instances in which the leaf is
diminished in size, without any attendant malformation in other organs,
may be regarded rather as variations than as monstrosities, as in the
case of the entire-leaved varieties of those plants which ordinarily
have cut or divided leaves, _e.g._ _Plantago Coronopus_, var.
_integrifolia_, _Papaver Rhoeas integrifolia_, &c. &c. The same remark
may be made of those specimens in which one part of the leaf is
developed to a less extent than another, as happens in the submerged
leaves of such plants as _Ranunculus aquatilis_, _Cabomba aquatica_, the
spiney leaves of _Berberis_, the fenestrated leaves of _Ouvirandra_, &c.
In the illustrations last cited the relative deficiency of one portion,
as contrasted with another, takes place as a constant occurrence, and is
uniform and regular throughout the whole leaf. When, on the other hand,
the deficiency in question happens accidentally and irregularly, the
change may be considered as a malformation. One side of the blade of the
leaf is frequently affected in this manner, the other portions remaining
unaffected. It would appear as if any plant might be thus altered, but
the following species appear to be particularly subject to this change:
_Æesculus Hippocastanum_, _Digitalis purpurea_, _Morus alba_, _Fagus
silvatica contracta_ (hort.), _Codiæum variegatum_ var. _erosum_
(hort.), _Broussonettia papyrifera_, _Scolopendrium vulgare_, &c.
Frequently this irregular diminution in proportion is coexistent with an
unusual degree of cleavage or laciniation of the margin, as in _Acer
platanoides laciniatum_, _Tilia asplenifolia_, _Alnus imperialis_
(hort.), _Fagus silvatica_ var. (hort.), &c.
In the case of what are sometimes termed interrupted leaves, the laminar
portions of the leaf are here and there deficient on both sides of the
midrib, leaving small portions of the latter, as it were, denuded and
connecting the segments of the laminæ one with the other. This has been
observed amongst other plants in _Veronica latifolia_, _Broussonettia
papyrifer_, _Codiæum variegatum_ var. _interruptum_ (hort.),
_Scolopendrium vulgare_, &c.[528] (See p. 328.)
In some of the leaves which have been already referred to in
illustration of the inordinate growth of the cellular portions, the
increased development of parenchyma is associated with a contracted
state of the midrib and its branches, producing a puckered appearance of
the leaf, an exaggerated degree of that change which produces what are
termed "folia bullata." In illustration may be cited various species of
_Mentha_, _Perilla_, _Coleus_, _Fagus silvatica crispa_, _Cytisus_,
_Laburnum_ var., and other forms, cultivated in gardens for their
singularity.
Entire absence of the stalk of the leaf occurs normally in sessile
leaves; on the other hand the blade of the leaf is only occasionally
developed in the phyllodineous Acacias, in some species of _Oxalis_,
_Indigofera_, _Lebeckia_, _Ranunculus_, _Bupleurum_, &c.
De Candolle,[529] from a consideration of _Strelitzia juncea_, in which
the petiole alone is developed, was led to the inference that in many
monocotyledonous plants the blade of the leaf was never developed, the
portion present being the sheath or stalk, unprovided with limb. The
correctness of this inference is shown, amongst other things, by the
occasional presence of a leaf-blade in _Strelitzia juncea_ itself.
Occasionally the laminar portions of the leaf are completely wanting,
leaving only the main ribs, as in the case of _Berberis_, while the
adjoining figure (fig. 215) represents an instance of a cabbage wherein
the innermost leaves are represented by thick fleshy cylindrical bodies
corresponding to the midribs of the ordinary leaves. There is in
cultivation a variety of the cabbage which constantly presents this
peculiarity.
[Illustration: FIG. 215.--Inner leaves of cabbage reduced to their
midribs.]
The suppression of one or more leaflets of a compound leaf has already
been referred to at p. 396.
=Abortion of the perianth, calyx, and corolla.=--Illustrations of
partial development in these organs are not rare, under ordinary
circumstances, as for instance the "obsolete" calyx of Umbellifers. In
the cauliflower the branches of the inflorescence are contracted in
length, while their succulence is much increased; at their extremities
they bear crowds of imperfect flowers, in which the calyx only is
visible, and that only in a rudimentary and partially developed
condition. Imperfect development of the whole or of some of the
constituent parts is more common in the case of the corolla than in that
of the calyx. In _Arenaria serpyllifolia_ the petals, especially in
autumn, are only one fourth the length of the sepals. _Anagallis
phoenicea_, _Honckenya peploides_, _Arabis alpina_, _Ranunculus
auricomus_, _Rubus fruticosus_, and _Geranium columbinum_, also
frequently afford illustrations of this circumstance.
[Illustration: FIG. 216.--Abortion of four out of five petals, _Viola
tricolor_, side and front views.]
At fig. 216 is represented a pansy in which four of the five petals were
very small and colourless, while the lower spurred petal was of the
usual size and colour. In this flower the stamens and pistils were
wholly suppressed, and the flower-stalk, instead of being bent near the
flower, retained its primary straight direction. Similar atrophic
conditions of the corolla occur habitually among _Violaceæ_.
The diminished size of the petals sometimes coexists with an increase in
their number, as in a flower of _Streptocarpus Rexii_, mentioned by
Bureau.[530]
Among monocotyledons this partial development seems to be even more
frequent than in dicotyledons. In addition to the well-known cases of
certain species of _Bellevalia_ and _Muscari_, wherein the uppermost
flowers of the raceme are more or less atrophied (see p. 347, fig.
179), a few less common illustrations may be cited. In crocuses it is
not a very uncommon circumstance to find the three inner segments of the
perianth smaller than natural, and generally unequal in size. This
occurs without any other perceptible change in the flower.
Schlechtendal[531] mentions a flower of _Fritillaria imperialis_ in
which the perianthial leaves were relatively very small, and destitute
of the usual nectary, while the stamens, on the other hand, were of
their natural size and appearance. Fresenius[532] records a similar
occurrence in the same plant.
Morren[533] gives details of like appearances in _Hymenocallis
americana_, and Delavaud[534] in _Tigridia pavonia_.
In certain orchids an arrested development of the perianth is habitual,
as in _Oncidium abortivum_ (fig. 217), where, on a large branching
panicle, numerous abortive, but few perfect, flowers are produced.
In a similar way the petals and labellum of _Odontoglossum
Uro-Skinneri_ have been found reduced to filamentous processes.
[Illustration: FIG. 217.--Flower of _Oncidium abortivum_, magnified.]
=Abortion of the stamens.=--Atrophy of one or more stamens is of very
common occurrence, as a general rule, in many genera of plants, _e.g._
_Scrophularia_, _Erodium_, many _Restiaceæ_, &c. &c. As a strictly
teratological condition atrophy of the stamens is more rare than
complete suppression. It has been noticed in _Arabis alpina_, _Cerastium
glomeratum_, _C. tetrandrum_, _Rhamnus catharticus_, _Anemone_,
_Hepatica_, &c. It happens frequently among Orchids both wild and
cultivated. In the _Hymenocallis_ flowers described by the elder Morren,
four out of five stamens were atrophied. In other flowers, otherwise
perfectly formed, one abortive stamen was found bearing a spherical
indehiscent anther. All these atrophied anthers of _Hymenocallis_ were
found to contain pollen, differing at first sight but little from what
is usual, but presenting this important peculiarity, that while the
normal pollen does not burst until it comes into contact with the
stigma, in the abnormal flowers the outer coat of the pollen-grains
split while still within the anther, from which latter, indeed, they
could not escape, owing to the indehiscent nature of the latter. Again,
the pollen-tube of the abnormal grains cracked, in its turn, on mere
exposure to the air, and liberated the fovilla, so that the pollen of
these atrophied anthers was necessarily impotent, because it opened
before it could be applied to the stigma, even had that been rendered
possible by the opening of the anther.
An abortive condition of the stamens and of the pollen, is of very
common occurrence among hybridised plants. Gaertner and other writers
have spoken of this defective condition as contabescence.[535] It forms
one reason for the sterility so frequently observed in the case of true
hybrids. In some hybrid passion-flowers, while all other parts of the
flower were apparently perfect, even to the ovules, the stamens were
atrophied, and distorted, and contained little or no pollen; the few
grains of the latter being smaller than usual. (See under Heterogamy,
pp. 193-196, and p. 398.)
=Abortion of the pistil, fruit, &c.=--Traces of the carpels occur in
many male flowers of unisexual plants, _e.g._ _Sterculiaceæ_,
_Euphorbiaceæ_, _Restiaceæ_, &c. &c., and in some natural orders there
appears to be a tendency towards a dioecious condition, _e.g._
_Caryophylleæ_, as in _Lychnis dioica_, _Silene otites_, _Arenaria
tetraquetra_, &c. The last-named plant is stated to have, in some cases,
imperfect pistils; in others, rudimentary stamens; while a third set of
flowers are hermaphrodite.[536] The ovary of aconites, according to
Moquin, is very subject to atrophy.
[Illustration: FIG. 218.--Bladder plum.]
During the maturation of the pistil, and its passage to the fruit, great
changes of consistence frequently take place, owing to the development
of cellular tissue, or of woody matter, according as the fruit is
succulent or woody. It sometimes happens that, owing to some disturbing
causes, the changes that usually occur fail to do so; thus, the stone of
plums is occasionally deficient, as in what are termed bladder-plums
(fig. 218); some of these, consisting merely of a thin bladder, are
curiously like the pods of _Colutea_.[537]
MM. Fournier and Bonnet[538] describe a fruit of a _Rubus_, with
perfectly dry fruits, like those of a _Geum_, and this form was
considered by Steudel to form a distinct species. It is, however, merely
a variety in which the fruits have not become succulent.[539]
Schlechtendal describes[540] the ordinarily baccate fruit of a vine as
becoming dry, and even dehiscing by valves like a capsule.
In maize it occasionally happens that one or two of the longitudinal
series of fruits become abortive, leaving a smooth furrow, at first of a
greenish colour, but ultimately of a reddish yellow. Often a second row
of fruits, opposite to the first, is also atrophied, so that the whole
spike changes its cylindrical form for a flattened one.[541] See also
under Heterogamy, Meiophylly, &c.
=Abortion of the ovules.=--In the case of a pluri-ovulate ovary it
rarely happens that all the ovules attain to maturity, some never get
fertilised, others, pressed on by their neighbours on either side,
become impeded in their development, and finally disappear, or remain as
rudiments.[542] This is the case, under ordinary circumstances, and
still more so in the case of hybrid plants, or of monsters. Where the
outer coats of the ovule become more or less leafy in appearance (see p.
262), the inner investments become more or less atrophied, or are even
more frequently entirely suppressed, as is also the nucleus.
In other cases, a simple arrest of development takes place; the ovule,
for instance, which should be anatropal, remains straight, while the
integuments, checked in their development, form imperfect sheaths from
which the shrivelled nucleus protrudes.
=Depauperated Ferns.=--The preceding illustrations have been taken from
flowering plants chiefly, but a similar defective development is
manifested in cryptogamous plants. The contraction and imperfect
development of the fronds of some varieties of ferns, hence called
depauperated, may receive passing notice, as also the cases in which the
sori or clusters of spore cases are denuded of their usual covering,
owing to the abortion or imperfect development of the indusium, as in
what are termed exindusiate varieties.[543]
=General remarks on abortion, coincident changes, &c.=--Reference has
already been made, while treating of hypertrophy, suppression, &c., to
certain other changes affecting the flower at the same time. Atrophy of
one organ or set of organs, for instance, is frequently accompanied by a
compensating hypertrophy or by an increased number of other parts. In
the feather-hyacinth, _Muscari comosum_, var., _monstrosum_, the absence
of flowers is compensated for by the inordinate formation of brightly
coloured threads which appear to be modified pedicels (see pp. 347,
348); so also in the wig plant, _Rhus Cotinus_. So the atrophy of the
stamens, in some flowers, is coincident with the hypertrophy of the
pistil. Thus, Unger, 'Denkschr. d. Kais. Acad. der Wissensch. Math. Nat.
Classe,' Mai 25, 1848, p. 103, tab. ix, describes a case wherein the
corolla and stamens of _Desmodium marylandicum_ were atrophied, while
the calyx and legume, on the other hand, were hypertrophied.
Fusion of the members of one whorl with one another, or with the
components of an adjacent series, often entails atrophy or suppression,
either in the united organs themselves, or in adjacent ones. A
foliaceous condition of the outer portions of a flower is very generally
attended by atrophy or complete suppression of the inner portions.
From this point of view the observations of Morren[544] on the different
degrees of atrophy up to complete suppression, observable in the flowers
of _Bellevalia comosa_, are of importance. According to this observer,
the most highly differentiated parts, such as the stigmas, the ovules,
and the anthers, are the first to disappear, the filaments often being
developed without anthers. Ultimately a deformed and empty perianth
alone remains. In the ordinary course of things the mouth of the
perianth is open, but in some of these malformations it is closed, and
when that happens, the effects of atrophy are the more observable in the
stamens and pistils.
The impotence of the pollen in certain atrophied flowers, as noticed by
the same observer, is of much interest, especially in reference to the
sexual relationship between the different forms in polymorphic flowers
as studied by Mr. Darwin.
A change in direction may also be noted as a common accompaniment of
atrophy or suppression; thus, in a capsule of _Veronica Beccabunga_,
which was one-celled by the abortion of one carpel, the style was
lateral instead of terminal.
As to the causes of these structural deviations but little is known;
certain of them have been already alluded to. In some cases atrophy and
suppression maybe regarded as permanent states of a condition usually
transitory, but this is clearly not always the case. Among external
causes anything bringing about an enfeebled condition might be supposed
to lead to atrophy, or suppression of some parts.
Gaertner[545] attributes the arrested development and fall of flowers to
some among the following causes:--1. non-application of the pollen of
the same variety, and consequent imperfect fertilisation; 2. any
considerable injury to the calyx, &c.; 3. destruction of the style or
stigma before the fertilisation of the ovary; 4. application to the
stigma of imperfect or heterogeneous pollen or indifferent pulverulent
matter; 5. defective conceptive power in the ovary.
Abortion of the ovules is considered by the same authority to be due
to--1. deficiency of heat; 2. excess of moisture; 3. peculiar formation
of the ovary; 4. over-luxuriant development of roots or buds; 5.
peculiar conditions of cultivation; thus, cuttings and layers produce
sterile and abortive seeds much more frequently than plants of the same
species raised from seed; 6. abortion of the seed is often combined with
luxuriant development of the walls of the fruit.
Temperature and climatal changes in general seem not to be without
effect, as has been already mentioned in the case of _Arenaria
tetraquetra_, which is polygamous when growing in mountain districts.
Other illustrations of a similar character are mentioned under the head
of Heterogamy (p. 196).
Pressure has been already alluded to as one of the most obvious of the
inducing causes of atrophy and suppression.
In the case of _Ranunculus auricomus_ before cited, in which the petals
are rarely perfect, M. de Rochebrune considers that the deficiencies in
question depend, in great measure, on the amount of moisture in the
localities where the plant grows. In most places the flowers and carpels
are apt to become more or less abortive, while the leaves are luxuriant;
while, in dry places, the foliage is small, but the flowers are more
perfect. This is quite consonant with other facts relating to the
development of flowers or of leaves in general.
But while external agencies undoubtedly play some part in bringing about
these changes, it is almost certain that internal causes inherent to the
organization of the plant are more important. Mr. Darwin[546] accounts
for the existence of rudimentary organs by the operation of the general
rule of inheritance, and explains their stunted condition as the effect
of disuse, not so much, of course, in the particular flower as in its
predecessors. This disuse may be the result of the superior efficacy of
foreign pollen as contrasted with that formed in the individual flower
itself. In this way many hermaphrodite flowers tend to become
dioecious, as in _Caryophyllaceæ_, _Orchidaceæ_, _Plantaginaceæ_,
_Primulaceæ_ and other orders.
Although many of the circumstances above mentioned apply to plants whose
structure is habitually rudimentary, there is no reason why they may
not, under due restrictions, be applied to plants whose organs are only
occasionally defective.
For further remarks on the subject of Abortion, the reader is
referred to the sections relating to suppression, etc., also to
Moquin-Tandon, 'El. Terat. Veget.,' p. 120; C. Morren, "De
l'atrophie en général," in 'Bull. Acad. Belg.,' t. xviii, 1851,
part i, p. 275.
FOOTNOTES:
[522] 'El. Ter. Veg.,' p. 132.
[523] _Spinosæ arbores cultura sæpius deponunt spinas in hortis_, 'Linn.
Phil. Bot.,' § 272.
[524] Mr. Selby, in his 'History of British Forest Trees,' p. 465, gives
the following account of the formation of this peculiar growth:--"In the
autumn the parent aphis deposits her eggs at the base of the embryo
leaves, within the bud destined to produce the shoots of the following
year. When these begin to burst and expand in spring, the leaves, at
whose bases the eggs have been deposited, instead of increasing in
length, enlarge at the base, and form a cell or cyst whose mouth is at
first closed by a red velvety-looking substance. If opened in this state
a nest of small greenish aphides is distinctly visible, and at a certain
period, or when they have acquired maturity, which is towards the end of
the summer, the mouth of the cell opens and the insects fly off to
inflict a similar injury upon the nascent buds of the year. In some
instances the leaves of only a portion of the circumference of a shoot
are affected, in which case, though a slight distortion may take place,
the branch is not prevented from elongating; but in others, where the
whole of the leaves around the shoot are converted into nidi, elongation
is prevented and distortion to a great extent takes place."
[525] See Cramer, 'Bildungsabweich.,' pp. 53, 64, for further
references.
[526] 'El. Ter. Veg.,' p. 124.
[527] Schlechtendal, 'Bot. Zeit.,' 1857, vol. xv, p. 67.
[528] On the subject of this paragraph the reader may consult A. Braun,
"Ueber abnorme Blattbildung," &c., in 'Verhandl.,' d. 35,
'Naturforscherversammlung;' Jaeger, 'Flora,' 1850. p. 481, tab. 4,
_Digitalis_.
[529] 'Org. Veget.,' i. p. 286.
[530] 'Bull. Soc. Bot. France, vol. viii, 1861, p. 710.
[531] 'Linnæa,' 1830, vol. v, p. 492.
[532] 'Mus. Senkenb.,' ii. p. 45.
[533] 'Bull. Acad. Roy. Belg.,' 1851, t. xviii. part i, p. 275.
[534] 'Bull. Soc. Bot. France,' vol. viii, 1861, p. 147.
[535] See Darwin, 'Variation of Domest. Anim. and Plants,' ii, 165.
[536] Gay, 'Ann. Sc. Nat.,' ser. i, 1824, t. iii, p. 44.
[537] See De Candolle, 'Mem. Legum.,' tab. 3, f. 1; Wyville Thomson,
'Trans. Bot. Soc. Edinb.,' 1851, July 10th; Berkeley, 'Gardeners'
Chronicle,' June 22nd, 1867, p. 654. A similar case is described by Dr.
Robb, in Sir W. Hooker's 'Journal of Botany,' 1841, vol. iii, p. 99,
with illustrative figures. The specimens there described were produced
at New Brunswick, where plum trees flower very freely, but seldom
produce ripe fruit. Dr. Robb's account is as follows:--"In the summer of
1839 I had an opportunity of watching the process of destruction among
the plums, and it was as follows--Before or soon after the segments of
the corolla had fallen off, the ovarium had become greenish yellow,
soft, and flabby. As the fruit continued to increase in magnitude, its
colour grew darker and of a more ruddy yellow, and at the end of a
fortnight or three weeks the size of the abortive fruit rather exceeded
that of a ripe walnut. In fact, an observer might imagine himself to be
walking amongst trees laden with ripe apricots, but, like the fabled
fruit on the banks of the Dead Sea, these plums, though tempting to the
eye, when examined, were found to be hollow, containing air, and
consisting only of a distended skin, insipid, and tasteless. By-and-bye
a greenish mould is developed on the surface of the blighted fruit; then
the surface becomes black and shrivelled, and at the expiration of a
month from the time of flowering the whole are rotten and decomposed.
The flower appears about the beginning of June, and before August there
is hardly a plum to be seen. It is curious that where two flower-stalks
arise from one point of the branch, one will often go on to ripen in the
normal way, while the other will become abortive, as above described."
In a specimen described by Mr. Berkeley there were two distinct ovules
of equal size close to the apex of the fruit, connected with the base by
vessels running down the walls. It should be observed that there is a
worthless variety of plum, Kirke's stoneless, or Sans Noyau, in which
the kernel is not surrounded by any bony deposit.
[538] 'Bull. Soc. Bot. Fr.,' 1862, vol. ix, pp. 37 et 291.
[539] Carl Schimp, 'Fl. Friburg,' vii, p. 745; Hook, fil., 'Journ. Linn.
Soc.,' vi, p. 9.
[540] 'Linnæa,' vol. v, 1830, p. 493.
[541] Moquin-Tandon, 'El. Ter. Veg.,' p. 325.
[542] Alph. De Candolle states that the position of the abortive ovules
affords a good character for discriminating between certain species of
_Quercus_, 'Bibl. Univ. Genev.,' 1862, t. xv, p. 929.
[543] See Moore, 'Nature-Printed Ferns,' 8vo, for numerous illustrations
both of depauperate and exindusiate ferns. _Scolopendrium vulgare_ seems
to be one of the ferns most commonly affected in this way. Moore, loc.
cit., vol. ii, pp. 135, 147, 159, 165, &c.
[544] 'Bull. Acad. Belg.,' t. xvii, p. 38, t. 1; Lobelia, p. 85.
[545] Cited in 'Henfrey's Botanical Gazette,' i, p. 179.
[546] 'Origin of Species,' p. 450.
CHAPTER II.
DEGENERATION.
While the terms atrophy and abortion apply in the main to a mere
diminution of size, as contrasted with the ordinary standard,
degeneration may be understood to apply to those cases in which not only
is the absolute bulk diminished, but the whole form is altered and
depauperated. Degeneration, thus, is the result not so much of a
deficiency in growth as of a perversion of development.
Under natural, _i.e._ habitual circumstances, the formation of pappus
in place of a leafy calyx may be considered as an illustration of
degeneration. It is evident, however, that no very decided line of
demarcation can be drawn between cases of perversion and of arrest of
development.
=Formation of scales.=--These may be mere epidermal excrescences, or
they may be the abortive rudiments of leaves. Of this latter nature are
the "cataphyllary" leaves which invest the root stocks of so many
perennial plants, the perulæ of leaf-buds, or the paleæ on the common
receptacle of composite flowers. Other illustrations of a like character
are to be met with in the membranous scales that represent leaves in
_Ruscus_, _Asparagus_, _Pinus_, &c. Similar productions are met with
within the flower, where they may occur as the representatives of
sepals, petals, stamens, or pistils, or as mere excrescences. (See
Enation.) Whole families of plants, _e.g._ _Sapindaceæ_, are
characterised by the presence of these organs, which are often of great
interest to the morphologist as indicating the true symmetry of the
flower, while they have acquired fresh importance since the publication
of Mr. Darwin's work on the 'Origin of Species,' wherein we are taught
to regard these rudiments as, in many cases, vestiges of organs that
were more completely developed in the progenitors of the present race of
plants, and the exercise of whose functions, from some cause or other,
having been rendered impossible, the structures become, in process of
time, proportionately stunted.
Thus, in dioecious plants we frequently find traces of stamens in the
female flowers, and rudiments of the pistil in the male flower,
indicating, according to the Darwinian hypothesis, that the ancestors of
these plants were hermaphrodite (see Heterogamy).
Mr. Darwin has also shown that, in some cases, the utmost degree of
fertility is attained, not from the action of the pollen on the stigma
of the same flower, but on the influence of the male element of one
blossom upon the female organs of another flower on another individual
plant.
Hence, in such plants there is a tendency to a separation of the sexes,
while, from what has been before stated, it might be expected that
rudiments of the male or female organs would be found, and also as a
result of the operation of the law of inheritance. On the same
principles it is easy to understand the occasional presence of the
perfect in place of the rudimentary organs, as in _Dianthus_.
In some instances the assumption of a scale-like form by any organ is
attended by a change in texture, the organs becoming dry and scarious,
or fleshy. Moquin cites in illustration of the first phenomenon the
flower of a _Vicia_, in which the petals were thick and fleshy, like the
scales of a bulb; and of the second the leaves of a _Chrysanthemum_,
which were replaced by small, glossy scales, like those which invest
ordinary leaf-buds. Sometimes the entire flower is replaced by
accumulations of small, acute, green scales. Cases of this kind, wherein
the flowers of a pea and of the foxglove were replaced by collections of
small ovate green scales packed one over the other till they resembled
the strobile of a hop, have been already alluded to. Most of these
scales are represented as having had other accumulations of scales in
their axils.
Similar collections of scales may frequently be met with in the birch
and in the oak, and probably represent abortive leaf-buds. Other cases
of a like kind in _Gentiana Amarella_, where the scales are coloured,
are mentioned elsewhere.
In some kinds of _Campanula_ a similar change is not uncommon.
=Formation of hairs, spines, &c.=--The adventitious production of hairs
is likewise frequently due to an arrested growth, in some cases arising
from pressure impeding the proper development of the organ. In other
cases the formation of hair seems to accompany the diminished
development of some organ, as on the barren pedicels of the wig plant,
_Rhus Cotinus_. A similar production of hair may be noticed in many
cases where the development of a branch or of a flower is arrested, and
this occurs with especial frequency where the arrest in growth is due to
the puncture of an insect, or to the formation of a gall. In such cases
the hairs are mere excrescences from the epidermis.
Prickles differ but little from hairs save in their more woody texture,
but true spines or thorns are modifications either of a leaf or of a
branch. Their presence seems often dependent on the soil in which the
plants grow, or on other external circumstances.
They occur normally in the sepals of _Paronychia serpyllifolia_ and
other plants.
=Formation of glands.=--Under this name are associated a number of
(generally) rudimentary organs very different in their morphological
nature and significance, and also in their functions. Some are truly
glandular or secreting organs, while others have no visible office.
Anything like a complete account of these structures would be out of
place, and reference is only made to them here on account of the
occasional existence of intermediate forms, which throw light on the
morphological significance of these structures. Thus, in _Passiflora_
and _Viburnum Opulus_, the so-called glands on the sides of the petiole
appear to represent leaflets, and are not unfrequently developed as
such.
M. Dunal observed a flower of _Cistus vaginatus_ in which some of the
stamens were replaced by an hypogynous disc.[547] Moquin has seen
similar instances in the flowers of a Rose, _Hypericum_, and Poppy.
M. Planchon[548] gives an account of some very curious malformations in
_Drosera intermedia_, which go to show that the ovules are homologous
with the glandular hairs on the margins of the leaves of these plants,
an opinion corroborated by the researches of MM. Grönland and
Trécul.[549]
Dr. Hooker shows that the pitcher of _Nepenthes_ is due to a
modification of a gland placed at the extremity of the midrib.[550]
=Formation of tendrils.=--These are of very varied morphological import;
sometimes they are degenerated peduncles, as in passion-flowers, or
vines; at other times they are of foliar origin; or, again, they may
proceed from the segments of the perianth, as in _Hodgsonia_ and some
other cucurbitaceous plants. From their very different origin in
different plants it is necessary to study the development in each case,
and not apply to the generality what may be peculiar to one. In any case
this formation in question generally belongs more to general morphology
than to teratology.[551]
Kirschleger, however, has recorded the existence of a cirrhose sepal in
_Cucurbita Pepo_.[552]
FOOTNOTES:
[547] 'Consid. Org. Fleur.,' p. 44, pl. ii, fig. 23.
[548] 'Ann. Sc. Nat.,' 3 ser., Bot. ix, pl. 6, ff. 1, 2.
[549] 'Ann. Sc. Nat.,' 3 ser., Bot. 1855, pp. 297, et 303.
[550] 'Trans. Linn. Soc.,' xxii, p. 415.
[551] See Darwin, "On Climbing Plants," 'Journal of Linnean Society,'
vol. ix, p. 1.
[552] 'Flora,' 1845, p. 615.
GENERAL CONCLUSIONS.
At the end of many of the preceding sections, and whenever the
requirements of the case demanded it, a brief summary of the main facts
and of the inferences to be derived from them has been given. It may be
useful to give in conclusion a few general remarks on the whole subject.
It will be seen from the numerous facts herein cited, that the so-called
monstrous formations (excluding morbid growths the result of disease or
injury) present no peculiarities absolutely foreign to the normal
organisation of plants. The difference between the natural and monstrous
development is one of degree and frequency of occurrence, not of kind.
Deviations from the customary form have been shown to arise from
excessive or diminished growth, or from arrested or exalted development.
Even in those instances where, for convenience' sake, the term perverted
development has been used, it must be understood as applying only to the
particular plant or organ under consideration, as the form assumed is
perfectly in accordance with the ordinary conformation of some other
plant or group of plants.
The period at which malformations occur is a matter of some importance;
this is, indeed, implied in the term arrest of development; evolution
goes on with growth up to a certain point and is then stopped, and thus
changes are brought about in the part affected of a different nature
from those dependent on non-development or suppression.
Some malformations are congenital, therefore, while others are
acquired--in the former instance the disturbance is coeval in origin,
and contemporaneous in its growth and development, with those of the
affected part; in the latter case the organ may have attained its
ordinary degree of perfection, or at least may have advanced some way
towards it, before any deviation shows itself. True chorisis or fission,
for instance, is usually a congenital affection, arising at a very early
period of development, while enation takes place from structures which
are all but complete as to their organisation, even though they may not
have attained their full dimensions. The date of appearance is also of
consequence in determining the true nature of some changes; it does not
always follow, for instance, that because one organ occupies the
position of another, it is of the same nature as the one whose place it
fills. The presence of anthers on petals or on such organs as the corona
of _Narcissus_ does not necessarily constitute those parts actual
stamens, but rather staminodes. The true stamens are either wanting, or
if present, they are in advance of their imitators as regards their
development.
=General morphology of the leaf and axis. Homology.= Since the time when
Goethe's generalisations were adopted by A. P. De Caudolle, special
attention has been given to the form and mode of development of the
leaf-organ; for as it was well said by Wolff, if once the course of
evolution and the structure of the leaf were known, those of the parts
of the flower would follow as a matter of course.
It is not necessary, in this place, to pursue the subject of the
development and construction of the leaf further than they are
illustrated by ordinary teratological phenomena.
From this point of view perhaps the most interesting circumstance is the
part that the sheath of the leaf plays.[553] In many cases of so-called
metamorphosis, it is the sheath of the leaf that is represented and not
the blade. In normal anatomy the sepals, petals, carpels, and even the
stamens, as a general rule, correspond to the sheath rather than to the
blade of the leaf, as may be seen by the arrangement of the veins. The
blade of the leaf seems to be set apart for special respiratory and
absorbent offices, while the sheath is in structure, if not in office,
more akin to the stem. It would not be easy apart from their position to
distinguish between a tubular sheathing leaf and a hollow stem. The
development of adventitious growths by chorisis or enation has been
frequently alluded to in the foregoing pages, and many illustrations
have been given of the power that leaves have of branching in more than
one plane, owing to the projection of secondary growing-points from the
primary organ. These new centres of development are closely connected
with the fibro-vascular system of the leaf, so that no sooner does a new
growing point originate, than vessels are formed to connect the new
growth with the general fibrous cord, see pp. 355, 445. This leads M.
Casimir De Candollo to consider the entire leaf as a composite
structure. The morphological unit, says he, is the cellular protrusion
or growing point (_saillie_) and its corresponding fibro-vascular
bundle.[554]
The identity, in a morphological point of view, of the leaves and the
lateral parts of the flower is so thoroughly recognised that little
need be said on that score, save to repeat that the homology of the
floral organs is usually not so much with the entire leaf as with its
sheath.
The most singular instances of morphological identity are those relating
to the sexual organs. We have seen the gradual transition of stamens to
pistils, and of pistils to stamens, the development of ovules on the
edges of the anther, the co-existence of pollen with ovules on an
antheroid body, and, stranger still, the actual development of pollen
within the tissues of the ovule itself! From such facts, in addition to
what we know of the relative position, internal structure, and mode of
development of the organs, it is impossible to avoid coming to the
conclusion that, however distinctly these parts may, under ordinary
circumstances, be set apart for the performance of distinct functions,
morphologically they are homologous.
These ideas may be carried yet farther--the same sort of evidence, which
is adduced in support of the morphological identity of leaves with the
parts of the flower, may be advanced in confirmation of the opinion,
that, morphologically, there is no distinction between axis and leaf.
The leaf, according to this view, is a specialised portion of the axis
set apart to do certain work, just as the petals, stamens, &c., are
leaves told off for distinct uses. It is unnecessary to refer to the
intermediate productions linking the leaf-form to that of the axis, all
that is requisite here is to point out the facts that teratology lends
in support of these views. These may be summed up by the statement that
almost all those attributes which morphologists recognise as peculiar to
one or the other organ respectively, may be and are manifested by both.
We have the stem acquiring the characters of the leaf, and the leaf
those of the stem. Thus we have seen leaves, leaf-buds, branches, and
flower-buds springing from leaves or leaf-organs;[555] see pp. 174, 177,
445, &c. The structure that we are apt to associate exclusively with
one is found to pertain to the other. The arrangement of the vascular
cords in the leaf-organ finds its counterpart in the axis, generally, it
is true, modified to suit altered circumstances or diverse purposes. In
some cases the disposition is absolutely indistinguishable in the two
organs. It may then be said that the distinctions usually drawn between
axis and leaf are not absolute, and that, however necessary such a
separation may be for descriptive or physiological purposes,
morphologically the two organs are identical. Again, it may be said that
leaf and axis are two phases of the same organ,--an organ capable of
existing in its undifferentiated state in the form of a thallus among
Cryptogams, but which in the higher groups of plants becomes marked out
into separate portions, each portion having its own distinct functions
to fulfil for the common benefit of the whole organisation.[556]
=Special morphology.=--Under this heading brief reference may be made to
some of the organs whose morphological nature has been, and still is,
much contested. It is clear that for the due elucidation of these
matters, development and the comparative investigation of similar
structures in different plants must be studied. Teratological data by
themselves can no more be trusted to give a correct solution of any
particular question, than the evidence furnished by other departments of
botanical science taken separately. With this statement by way of
caution, allusion may be made to some of the organs whose morphological
construction is illustrated by the facts recorded in the present
volume.
=Calyx-tube.=--In descriptive botany it is the common practice to speak
of a calyx-tube, by which is meant a tubular or sheathing portion at the
base of the flower, below the sepals or calyx-lobes, and distinct or
inseparable from the ovary. The question morphology has to solve is
whether this tubular structure is to be considered as a portion of the
axis, or whether it is to be regarded as composed of the confluent bases
of the sepals.
Mr. Bentham, who has recently reviewed the evidence as to the nature of
the calyx-tube in his paper on _Myrtaceæ_,[557] still holds to the
notion that the "calyx-tube" or "hypanthium" is formed from the
concretion of the basal portions of the sepals. He founds his
conclusions upon such facts as the following: the circumstance that the
point of origin of the leaf is not always the same as the point of
disarticulation or separation from the axis, inasmuch as the basal
portion of the leaf is often adherent to the stem for some distance,
though still recognisable as foliar not axial in its nature. In the same
manner, the corolla and androecium may be concrete at the base, so
that the stamens are for convenience' sake described as inserted into
the tube of the corolla, though it is generally admitted that both
stamens and petals are really hypogynous, and it is not usual to
consider the corolla-tube up to the divergence of the stamens as part of
the receptacle. A similar remark applies to the carpels and placentas.
Mr. Bentham further considers that the gradual disconnection of the
various whorls, that may be traced in many plants, is a further proof of
concretion, rather than of expansion of the axis, but this argument may
fairly be met by the consideration that the several whorls emerge at
different heights.[558]
Organs originally free and distinct become ultimately combined at the
base by the gradual protrusion from the receptacle of a ring or tube
under them, as in the stamens of _Leguminosæ_; yet, says Mr. Bentham, no
one would propose to describe the staminal tube of monadelphous
_Leguminosæ_ as part of the receptacle and not of the stamens. Perhaps
not, for descriptive purposes, but morphologically it would not be easy
to separate such a tube from the receptacle. The principal kinds of
malformation which have a bearing on this subject are mentioned at pp.
77-81 and 247, from which it may be seen that the evidence furnished by
teratology is conflicting. It would seem, indeed, that while in some
families of plants there may be a real calyx-tube, in others the tubular
portion is a sheath-like prolongation of the axis. In _Primula_ or
_Pedicularis_, where the venation is clearly laminar, the tubular
portion is distinctly calycine. In other cases the so-called calyx-tube
seems as certainly to be an expansion of the receptacle, as in
_Rosaceæ_, _Myrtaceæ_, _Melastomaceæ_, _Passiflora_,[559] &c.
Where the petals and stamens are described as being inserted into the
throat of the calyx, or are perigynous, it may be assumed as a general
rule, subject to but few exceptions, that the so-called calyx-tube is
really a portion of the receptacle.[560] After all, this is very much a
question of words, and for the following reasons,--very often the base
of the calyx does evidently form a tube, and no one can say where the
calyx ends and the receptacle begins. Again, many leaves are known to
originate in the form of a ring-like protrusion from the axis, and from
this primary ring originate secondary developments. Thus the asserted
difference between a leaf, with such a history of development, and an
axial structure becomes obliterated. From this point of view, peltate
leaves like those of _Tropæolum_ or _Nelumbium_ become very significant.
In both the leaf-stalk is cylindrical and traversed, as in the case of
all cylindrical leaf-stalks, by a circle of fibro-vascular cords, as in
a branch, and which radiate in all directions in the blade of the leaf.
Now, if (as often happens to a slight extent) the central portion of the
leaf were much depressed, owing to the disproportionate growth of the
peripheral, as contrasted with the central portions, we should have a
funnel-like or tubular formation, precisely similar to many of the
so-called calyx-tubes. And, if we further suppose new growths to
originate from the sides of this funnel or tube, by chorisis or enation,
we should have the homologue of a tubular calyx, to the inner surface of
which are attached petals, stamens, &c. From the consideration of
circumstances such as these just detailed, together with that of the
arrangement of the vascular cords, M. Casimir De Candolle arrives at the
conclusion that the calyx-tube is a ring-like projection from an axis
whose further direct development is arrested. The secondary projections
or growing-points correspond to the several fibro-vascular cords of the
primary ring, and are ultimately developed into sepals, petals, stamens
and ovaries (see pp. 394, 509).
=Androecium.=--The main points of morphological interest relating to
the androecium, referred to in this volume, are those concerning the
structure of the anther (see p. 292), the compound nature of the stamens
in some orders (see pp. 294, 345), and the nature of the androecium in
orchids (see p. 380).
=Inferior ovary.=--Is the pistil always foliar in its morphological
nature, or is it, in some cases, as Schleiden taught, formed from the
axis alone? To a great extent the reply to this question is dependent on
the conclusions that may be arrived at as to the true nature of the
calyx-tube. Considered from a teratological point of view, there is no
reason for considering the inferior ovary to be purely axial. On the
contrary, the evidence derived from this source supports the ordinary
opinion that the carpels are invaginated within the expanded top of the
flower-stalk and more or less adherent to it. Some of the gourds afford
good illustrations of this, the upper part of the carpels in these
fruits projecting beyond the axial portion. But this matter loses much
of its importance if the morphological identity of axis and leaf-organ
be conceded. The carpels in inferior ovaries seldom or never correspond
to the lamina of the leaf, and between the vaginal portion of the
carpellary leaf, and the axis who shall draw the distinction?
=Placentation.=--Some botanists have considered the placentas to be
portions of the carpel, and have compared the production of ovules on
them to the formation of buds on the leaf of _Bryophyllum_. Others have
been led to see in each placenta, even when it is, to all outward
appearance, a portion of the carpellary leaf, a direct prolongation from
the axis, adherent to the leaf. Teratology shows that ovules may be
formed indifferently on leaf-organs or on stem-organs. Sutural,
parietal, axile, free-central placentation, and, if there be more forms,
all may be met with even in the same ovary (see pp. 96, 508). Now, if
there were such special tendencies in the axis, as contrasted with the
leaf, to produce ovules, it is hardly likely that such anomalous
arrangements as those just mentioned would be as frequent as they are.
But as leaves produce other leaves, from their edges or their surfaces,
and as they form buds in the same situations, just as axial organs
do,[561] there is surely little ground for considering the placentas, or
ovuliferous portions of the plant, to be of necessity axial. Here again,
much of the difficulty vanishes if the morphological identity of the
leaf-form and of the stem-form be admitted.
=Structure of the ovule.=--The nature of the ovule and of its coverings
has been a fertile source of controversy. The teratological data bearing
on this subject have been given at pp. 262-272. These data strongly
support the notion of the foliar nature of the coatings, and of the
axial nature of the nucleus, taking leaf and axis either in the ordinary
sense, or as modifications one of the other. It has been shown that the
ovular coats may themselves become carpels, and that ovules may be
developed upon ovules, p. 268. Whether the intra-carpellary siliques of
_Cheiranthus_, not uncommonly met with (p. 182), are instances of ovular
transmutation may be open to doubt.
The axial nature of the nucleus has been inferred from its position,
mode of growth, and from its occasionally lengthening into a leafy or
even a floriferous shoot. Probably it may occasionally be invested by
sheathing coats, more analogous to tubular processes from the
receptacle, than to foliar organs, as is the case in _Welwitschia_. The
discussion of this matter, however, pertains rather to normal morphology
than to teratology.
=Morphology of conifers.=--The nature of the pseudo-leaves of
_Sciadopitys_, and probably of other Conifers, is illustrated by
teratology, as also is the true constitution of the scale of the cone
(see pp. 192, 245, 352), though it must be admitted that little or no
light is thrown on that much-contested point--the true nature of the
ovule of Gymnosperms.
=Relative position of organs.=--When organs are considered, not
separately, but in their relations to each other, the appearances
presented are referable to similar causes. Thus, the separation of parts
usually united has been shown to depend on an excess of development,
the persistent union of parts, usually separate in the adult state, has
been traced to an arrest of the process of development, by no means
necessarily coexistent with diminished growth. The diminished or
increased number of parts is, in like manner, attributable to analogous
causes, as also are the variations in arrangement and form, spoken of
under the heads of Displacement, Peloria, Substitution, &c.
In the instance of displacements, it has been shown how slight a change
is required to transform the so-called inferior ovary into a superior
one. A defective development of the top of the flower-stalk in some
cases, in others a lack of union between the tube of the receptacle or
of the calyx (comprising in those terms not only the apex of the
receptacle, but the base of the sepals) and the carpels, suffice to
bring about this change in a character which for systematic purposes is
of great value.
=Law of alternation.=--The circumstances that interfere with the law of
alternation may be briefly alluded to. The deviations from the customary
arrangement have been very generally attributed to suppression, or to
chorisis. It is unquestionable that either of these affords an efficient
explanation of the arrangement in question, as also does that
modification of chorisis, as it may be considered, which has been
treated of under the head of Enation. Spiral torsion of the axis would
likewise bring about analogous results. Still, it is quite conceivable
that opposition or superposition of organs may occur without the
intervention of any such operations. This will be the more readily
conceded when it is remembered that the phyllotaxis of leaves not
unfrequently varies on different branches of the same individual tree,
and that a similar variation in the flower would at once disturb the
customary alternate arrangement. Coalescence of the vascular bundles in
an unusual manner, and an irregular disposition of these cords have
also been considered to bring about deviations from the rule of
alternation, but in general the formation of the cords is subsequent to
that of the growing points or mamelons.
Adhesions, accompanied by displacements, occasionally produce similar
deviations, the nature of which is usually easily detected.
=Co-relation.=--The importance of this subject first prominently brought
into notice by Geoffroy St. Hilaire gains in force daily. Rarely is a
malformation an isolated phenomenon, almost always it is associated,
from the operations of cause or effect, with some others. Instances of
this co-relation have been cited in the preceding pages, and many more
might have been mentioned, had the consideration of the relationship
between form and function formed part of the plan of this volume. A
change in itself slight, often acquires importance from its association
with other alterations. This is particularly well seen in the case of
the receptacle. Let an ordinarily concave thalamus remain, from
defective development, flat, and how great the change in the appearance
of the flower. Let the usually contracted receptacle be lengthened, and
the whole aspect of the flowers so affected is altered to such an extent
that, were their history not known, botanists would have no hesitation
in assigning them to widely separate groups in their schemes of
classification. Peloria, too, of either form, affords excellent
illustrations of the co-existence of one changed condition with another.
Not only is the form of one set of organs altered, but the number, the
relative proportion, and the direction of the other organs of the flower
are altered likewise.[562] Not only is the whole symmetry changed, but
the physiological operations carried on in the flower undergo
corresponding alterations.
There are certain co-relations which do not appear to have hitherto
attracted the attention they merit; such, for instance, is that which
exists between the particular period at which an organ is developed and
its position and form. In normal morphology this has, to some extent,
been worked out, as in the case of definite and indefinite, centrifugal
and centripetal inflorescences, and in the definite or indefinite
formation of shoots, &c.
Other instances may be cited in the frequent co-existence of regular
flowers and definite inflorescence, the terminal position of many
peloriated flowers, the relationship between indefinite inflorescence
and prolongation of the axis, &c.
Again, the simultaneous evolution of the parts of the flower and their
consequent verticillate arrangement, are often associated with the
production of different forms from those characteristic of organs
developed in succession, and, in consequence, arranged spirally. In the
case of simultaneous development we meet with a repetition of whorls,
as in what are termed hose-in-hose flowers (flores duplicati,
triplicati, &c.), and also with cases of peloria. In instances where the
organs are formed successively in spiral order, we meet with such
changes as median prolification, petalody, and phyllody. All these are
alterations which we might anticipate from the activity of the growing
point being checked at a certain stage in the one case, while it is
continuous in the other. This relationship between the definite and
indefinite modes of growth and the form of the several organs of the
flower, is more constant in reality than it may appear to be from a
perusal of the lists of genera in the foregoing pages, in which it was
not possible to show sufficiently well the comparative frequency of any
given changes in individual plants. Had it been possible to give
statistics setting forth the frequency of certain deviations in plants
or groups having a particular organisation, as compared with the rarity
of their occurrence in other plants of a different conformation, these
co-relationships would have been rendered much more evident. A hundred
different plants, for instance, may be named in any particular list, of
which fifty shall be of one type of structure, and the remainder of
another. And the co-relative changes in each fifty may appear to be
evenly balanced, but so far is this from being the case, that the
frequency of the occurrence of a particular change, in one species in
the list, may be so great as far to exceed the instances of its
manifestation in all the rest put together. This difficulty is only very
partially obviated by the addition of the * to signify especial
frequency of occurrence of any given malformation in the plants to whose
names it is affixed.
=Compensation.=--But little further need be said on this head. An
atrophied condition of one part is generally associated with an
hypertrophied condition of another, and scarcely a change takes place in
one direction, but it is associated with an inverse alteration in some
other. This principle is not universal, and its application must not be
unduly strained. It requires specially to be considered in reference to
differences in the degree or kind of functional activity exercised by
the organs implicated--points beyond the scope of the present volume.
=Teratology and classification.=--Lastly, there remain to be mentioned
the bearings of teratology on systematic botany. There are those who
would entirely exclude teratology from such matters. It may be expedient
to do so when the object sought is one of convenience and facility of
determination only, but when broader considerations are concerned,
teratology must no more be banished than variation. In most instances
the one differs but in degree from the other. If variation affords aid
in our speculations as to the affinities and genealogical descent of
species and other groups, so does teratology, and in a far higher
degree.
Take the characters of exogens as distinct from endogens; even under
ordinary circumstances, no absolute distinction can be drawn between
them. There are plants normally of an intermediate character, while, to
take exceptional instances, there are exogens with the leaves and
flowers of endogens, and endogens whose outward organisation, at any
rate, assimilates them to exogens. Diclinous or monochlamydeous plants
owe their imperfect conformation to suppression, and may become
structurally complete by a species of peloria. Structurally
hermaphrodite flowers become unisexual by suppression, or are rendered
incomplete by the non-development of one or more of their floral whorls.
Hypogynous flowers become perigynous by adhesion, or by lack of
separation; perigynous ones become hypogynous by an early detachment
from the receptacle that bears them, or by the arrested development of
an ordinarily cup-like receptacle.
How the relative position of the carpels and the calyx may be altered
has already been alluded to, as has also the circumstance that while it
is common to find an habitually inferior or adherent ovary becoming
superior or free, it is much more rare to find the superior ovary
adherent to the receptacle or to the calyx.[563] Regular and irregular
peloria, too, serve to show how slight are the boundaries, not only
between different genera, but also between different families.
While, therefore, teratology may be an unsafe guide in strictly
artificial schemes, it is obvious that its teachings should have great
weight in all philosophical systems of classification.
The questions will constantly arise, does such and such a form represent
the ancestral condition of certain plants? Is it a reversion to that
form? or is it, on the other hand, the starting point of new forms?
Such questions cannot receive at present any satisfactory answer, but
the evidence we have seems to indicate that pre-existing forms were
simpler, and less specialised in structure than those now existing, and
hence if we meet with malformations of a simple kind, we may consider
them as possible reversions; while, if they present features of
increased complexity, and more sharply defined differentiation, we may
assume them to be evidences of a progressive rather than of a
retrogressive tendency.
That monstrosities so called may become the starting points of new forms
is proved by circumstance that, in many cases, the peculiarities are
inherited so that a new "race" is produced and perpetuated: and if a new
race, why not a new species? The difference is one of degree only.
FOOTNOTES:
[553] See Clos., 'Bull. Soc. Bot. Fr.,' 1856, vol. iii, p. 679.
[554] 'Théorie de la Feuille,' p. 26.
[555] An additional illustration of this may be cited, which has been
brought under the notice of the writer by Dr. Welwitsch recently, and in
which some of the leaflets of the pinnate leaf of a species of
_Macrolobium_ were absent, and their place supplied by flowers arranged
in cymes.
[556] The presence of a bud at the extremity once considered to be an
absolute distinction between branch and leaf, which latter never forms a
bud exactly at the apex--is invalidated by the case of the Nepaul
barley, p. 174.
[557] 'Journ. Linn. Soc.,' vol. x, p. 103 _et seq._
[558] See also the receptacular tube (ovary?) of _Bæckea_ bearing
stamens, see p. 183. It would be natural to see stamens springing from
the receptacle but not from the ovary.
[559] In _Passiflora_ the organogeny of the flower clearly shows the
truth of this assertion, as was indeed shown by Payer and Schleiden.
[560] See Payer, 'Organ. Veget.'
[561] It must, however, be borne in mind that no true leaf-organ has yet
been seen with a bud at its exact apex (unless it be the nepaul barley),
while in the case of an axial organ such a position of the bud is
constant. The nearest approach is in the case of impari-pinnate leaves
in which the terminal leaflet is jointed to the common rachis, and in
the leaves of some _Meliaceæ_ which continue to push forth new leaflets
even after the leaf has attained maturity.
[562] A singular instance of co-relation was shown by Mr. Saunders at
the Scientific Committee of the Royal Horticultural Society, February
16th, 1868, in a hyacinth with perfectly green, long, tubular, erect,
not horizontally spreading flowers.
[563] An illustration of this latter nature in the case of a cherry,
which was surmounted by the calyx lobes, precisely as in the case of a
pomaceous fruit, has been given at p. 424, _adnot._
APPENDIX
DOUBLE FLOWERS.[564]
In ordinary language, the epithet double flowers is applied to flowers
of very varied structural conformation. The most common conditions
rendering a flower double, in the popular acceptation of the term, are
substitutions of petals or petal-like bodies for stamens and pistils,
one or both. (See Petalody, p. 283.) Another very common mode of
doubling is brought about by a real or apparent augmentation in the
number of petals, as by multiplication, fission, or chorisis. (See pp.
66, 343, 371, 376.) Sometimes even the receptacle of the flower within
the outer corolla, divides, each subdivision becoming the centre of a
new series of petals, as in some very luxuriant camellias and anemones.
The isolation of organs which, under ordinary circumstances, are united
together, is another circumstance, giving rise, in popular parlance, to
the use of the term double flower. (See Adesmy, Solution, pp. 58, 76,
82.) Prolification is another very frequent occurrence in the case of
these flowers, while still other forms arise from laciniation of the
petals, or from the formation of excrescences from the petals or
stamens, in the form of supplementary petal-like lobes. (See Enation, p.
443.)
As these matters are all treated of under their respective headings, it
is not necessary to allude to them again in detail. It may be well,
however, to allude, in general terms, to the causes which have been
assigned by various writers for their formation, and to the means which
have been adopted by practical experimenters to secure the production of
the flowers often so much esteemed by the florist. It must be admitted
that, in spite of all that has been written on the subject, but very
little is known about these matters. In the case of the stock the
following means have been adopted by cultivators in order to obtain
plants bearing double instead of single flowers. There is first the
crossing of single flowers with double ones, effected by planting a
double-flowered plant in proximity to a single-flowered one; but this,
it is obvious, could lead to no important results, since the double
flowers, having no pollen, could not possibly influence the seed, which
is borne only by the single-flowered plants. Another plan is the
degustation of the buds, that is to say, the chewing of the well-formed
buds; it is held that the single plants can be recognised by their
sweeter taste and greater consistence, and may thus be weeded out; but
there is at least the disadvantage attending this method, that the
plants, single as well as double, must all be grown up to the period
when these buds are tolerably well advanced. A third method which has
been adopted is, that of sowing the seeds at a particular lunar epoch,
great confidence being placed in the plan of planting them during the
last quarter of the moon, but such confidence is found to be misplaced.
The plan of removing the stamens has had its supporters, but as this
must be done at an early stage of development, and could only influence
the result by diverting the vital force which would be expended in the
maturation of the pollen, to the perfecting of the seeds, it is obvious
that the plan is impracticable for all ordinary purposes, even if in any
degree efficient, which from the plasticity of vegetable development,
and the faculty of doubling which is inherent in the stock family, is
not at all improbable. Still another mark, the presence of a fifth petal
in the single or seed-bearing flower, has been held to indicate the
assurance of obtaining a crop of double-flowered plants from seeds saved
from flowers possessing this peculiarity. To a certain extent,
doubtless, this expectation would be realised, owing to the plasticity
and inherent quality just alluded to, but the proportion would be too
small for any useful practical purpose.
"The gardeners of Erfurt," observes M. Chaté, who has written a
book[565] on the subject, in which he makes known a means of obtaining
double-flowered stocks founded on more than fifty years' practice in his
family, "have, for a long time, to a certain extent monopolised the sale
of seeds of these plants. To obtain these seeds, the Erfurt gardeners
cultivate the flowers in pots, and place them on shelves in large
greenhouses, giving them only sufficient water to prevent them from
dying. So cultivated the plants become weakened, the pods shortened, and
the seeds less numerous, and better ripened; and these seeds give from
60 to 70 per cent. of double flowers.
"The seeds from these plants are said to be mostly of an abnormal shape,
which is so striking that experienced cultivators are able to separate
those which would furnish double flowers from those which would produce
single ones."
M. Chaté's method, which he calls the French one, gives still greater
results, viz.: 80 per cent. of double flowers, and these produced by
very simple means. "When my seeds," he observes, "have been chosen with
care, I plant them, in the month of April, in good dry mould, in a
position exposed to the morning sun, this position being the most
favourable. At the time of flowering I nip off some of the flowering
branches, and leave only ten or twelve pods on the secondary branches,
taking care to remove all the small weak branches which shoot at this
time. I leave none but the principal and the secondary branches to bear
the pods. All the sap is employed in nourishing the seeds thus borne,
which give a result of 80 per cent. of double flowers. The pods under
this management are thicker, and their maturation is more perfect. At
the time of extracting the seeds the upper portion of the pod is
separated and placed aside, because it has been ascertained that the
plants coming from the seeds situated in this portion of the pod, give
80 per cent. of single flowers. They yield, however, greater variety
than the others. This plan of suppressing that part of the pod which
yields single flowers in the largest proportion, greatly facilitates the
recognition of the single-flowered plants, because there remains to be
eliminated from among the seedlings only from 10 to 15 per cent.
This separation of the single from the double-flowered plants, M. Chaté
tells us is not so difficult as might be supposed. The single stocks, he
explains, have deep green leaves (glabrous in certain species), rounded
at the top, the heart being in the form of a shuttlecock, and the plant
stout and thickset in its general aspect, while the plants yielding
double flowers have very long leaves of a light green colour, hairy, and
curled at the edges, the heart consisting of whitish leaves, curved so
that they enclose it completely. Such is the substance of M. Chaté's
method of securing so large a proportion of double-flowered plants, and
then of separating them from the remaining single ones--a method which
commends itself to the good sense of the intelligent cultivator."[566]
Signor Rigamonti, a great cultivator of pinks, asserted that he was able
to distinguish double from single-flowered pinks, in the seedling state.
According to this gentleman, those seedlings which produce three
cotyledons in a whorl in place of two, form double flowers. In the case
of _Primula sinensis_ the same results occurred. Some had three leaves
in a ring, others two; most had the leaves standing one over the other
as usual. These were divided into three sets, and when they flowered,
the first lot were all double, the second semi-double, the third single.
But these statements have not been confirmed by other observers; and the
writer can safely assert that seedling pinks occasionally produce three
cotyledons, and subsequently single flowers. He has never observed a
double flower under these circumstances, though it is true his
experience in this matter has been but small.
A writer in Otto's 'Gartenzeitung,' considers that double flowers are a
consequence of dryness of soil and atmosphere, and not of a luxurious
soil, rich in nutritious matter, having arrived at this conclusion from
an observation of the following circumstances:
"Fifty years ago we saw _Kerria japonica_ in a hothouse with single
flowers. Twenty years later we met with it in several gardens, in the
open air, but always with double flowers. At this time we were assured
that single-flowered plants were no more to be found in the whole of
Europe, and botanists forming herbaria offered considerable sums for a
branch of _K. japonica_ with single flowers. We were requested to take
the plant in hand for the purpose of inducing it to produce single
flowers. We were advised to plant it out in a rich soil, which was done,
but, by chance, the situation was sloping, consequently it did not
retain moisture, and all the flowers produced for several years in
succession were double. Shortly after, the captain of an English ship
again brought plants bearing normal flowers from Japan, which were soon
spread over the continent, and of which we received one plant. After
three years all the young plants raised from cuttings were
double-flowered.
"In the year 1820 we several times visited a garden in the neighbourhood
of Vienna, well known on account of its plant culture. The gardener
there possessed an immense plant of _Camellia japonica_ with single
flowers, and some small plants raised from this by cuttings, but no
other variety of camellia. He fertilised the flowers with their own
pollen, harvested seeds, which he sowed, and the plants raised from them
were placed in an extremely dry, lofty conservatory, where, after some
years, instead of producing single flowers, they all produced double
ones. The seedlings and mother plant were planted in one and the same
kind of earth, and some of the flowers on the old plant also showed an
inclination to become double.
"This, at that time, to us, enigmatical phenomenon, was kept in mind
until we had an opportunity of instituting comparisons between the
climate of Japan and China and our own, and we then concluded that in
the case of a plant imported from thence, and exposed to such different
climatical influences, the origin of the greater or less imperfection of
its sexual organs was probably owing to this change, as we had
experienced in _Kerria_ and _Camellia_; and that the sterility of many
other exotic plants might be attributed to the same cause. The
difference in the climatical relations of Japan and Europe is very
considerable. In Japan, previous to the new growth of _Kerria_ and
_Camellia_, a rainy season of three months' duration prevails; in
Europe, on the contrary, dry winds prevail especially in the eastern
part, where our plains are often transformed into deserts. Is it,
therefore, remarkable that a plant introduced from Japan into Europe,
exposed to the influences of this great diversity of climate, should
produce imperfect sexual organs incapable of further propagating the
plant from seeds? A rich soil, with the necessary amount of moisture,
will never engender double flowers."[567]
Mr. Darwin[568] describes a peculiar form of _Gentiana Amarella_, in
which the parts of the flower were more or less replaced by compact
aggregations of purple scales in great numbers. A similar condition is,
indeed, not uncommon in this plant, and, as Mr. Darwin also remarked, on
hard, dry, bare, chalky banks, thus bearing out the views expressed by
the writer in the 'Gartenzeitung' just cited. Some double flowers of
_Potentilla reptans_ found growing wild near York, and transmitted to
the writer by a correspondent, were observed growing along a high wall,
in a dry border, close to a beaten path, bordering on a gravel pit,
others were found on a raised bank, which, from its elevation and
exposure to the sun, was particularly dry.
On the other hand, the double-flowered _Cardamine pratensis_, which is
occasionally found in a wild state, always grows in very wet places.
Of late years a remarkable double-flowered race of _Primula sinensis_
has been obtained. In particular, Messrs. Windebank and Kingsbury, of
Southampton, have succeeded in raising a set of plants in which the
flowers are very double and very attractive in a florist's point of
view. The corollas in these flowers are not merely duplicated, but from
their inner surface spring, in some cases, funnel-shaped or tubular
petals (p. 315), so regular in form as quite to resemble a perfect
corolla. These tubes are attached to the inner side of the tube of the
corolla, in the same way as are the stamens, these latter organs being,
it appears, absent. The carpels are present, but open at the top, and
bear numerous ovules, hence it was at first surmised that these plants
were obtained and perpetuated, by the application of pollen from single
flowers to these double-flowered varieties.
The raisers of this fine race however assert that "the double kinds are
all raised from the seed obtained from _single_ flowers; the double
blooms do not produce seed, as a rule, and even if they did yield seed,
and it were to germinate, the plants so raised would simply produce
single flowers." Semi-double flowers will produce seed, but it is
necessary that they should be fertilised with the pollen from the single
blooms. They rarely, however, if ever, produce really double flowers
when so fertilised, and the number of semi-double flowers, even, is
always small, the remainder, and, consequently, the larger part, proving
single. To obtain double varieties, the raiser fertilises certain fine
and striking single flowers, with the pollen of other equally fine
single blooms, and the desired result is obtained. This is Messrs.
Windebank and Kingsbury's _modus operandi_, the exact process or mode of
accomplishment being, however, a professional secret.[569]
From what has been said, as well as from other evidence which it is not
necessary to detail in this place, it may be seen that the causes
assigned by physiologists, and the plans proposed by cultivators for the
production of double flowers, are reducible to three heads, which may be
classed under Plethora, Starvation, and Sterility. These three seem
inconsistent one with the other, but are not so much so as they at first
sight appear to be.
Tho advocates of the plethora theory have much in their favour: for
instance, the greater frequency of double flowers among cultivated
plants than among wild ones. The great preponderance of double flowers
in plants derived from the northern hemisphere, when contrasted with
those procured from the southern, as alluded to by Dr. Seemann, seems
also to point to the effect of cultivation in producing these flowers.
Now, although this is, to a large extent, due to the selection that has
been for so long a period practised by gardeners, still that process
will not account for the appearance of double flowers where no such
selection has been exercised; as in the case of wild plants. Some double
peas, observed by Mr. Laxton, appeared suddenly; they had not been
selected or sought for, but they were produced, as it would appear, as a
result of high cultivation, and during the period when the plant was in
greatest vigour; and as the energies of the plant failed, so the
tendency to produce double flowers ceased. Indeed, in reference to this
subject, it is always important to bear in mind the time at which double
flowers are produced; thus, an annual plant subjected to cultivation,
will, it may be, produce single flowers for the firet year or two, then
a few partially double flowers are formed, and from these, by careful
selection and breeding, a double-flowered race may be secured.
Sometimes, as in the peas before alluded to, in the same season the
earlier blossoms are single, while later in the year double blossoms are
produced. This happens, not only in annuals, but also in perennials, and
is not infrequent in the apple; an illustration of this occurrence in
this tree is given in the 'Gardeners' Chronicle' for 1865, p. 554.[570]
Sometimes the flowers on a particular branch are double, while those on
the rest of the plant are single.[571] On these points, the evidence
furnished by a double white hawthorn in the Royal Botanic Gardens at
Edinburgh is important. Professor Balfour kindly wrote as follows in
reply to an inquiry respecting this plant:--"A double white hawthorn in
the Royal Botanic Gardens produced double flowers in spring. It retained
its leaves during autumn and winter, until the following spring. It then
flowered in the second spring, but produced weak single flowers only,
and has continued to do so ever since. The flowering has been always
weak, since this change of flowers from double to single. Mr. M'Nab
attributes the change in the duration of the leaves to the filling up of
the ground round the tree, to the height of a foot and a half on the
stem. He is now trying the effect of extra manure in giving extra vigour
to the plant." Here, at least, the production of single flowers would
seem to be the result of debilitating causes, connected with the unusual
persistence of the leaves, &c., for while the tree was healthy, double
flowers were produced.
A similar illustration came under the writer's own notice. Some seedling
balsams, of a strain which from long selection and hereditary tendency
produces, year after year, double flowers were, in the spring (of 1866),
allowed to remain in the seed-pans for many weeks after they were ready
to be potted off; they were hence partly starved, and when they bloomed,
they produced single flowers only. But these same plants, when more
liberally treated, produced an abundance of double flowers. Moreover,
other seedlings of the same batch, but sown later, and potted off at the
usual time, produced double flowers as usual. Of a like character is the
fact that the double _Ranunculus asiaticus_ loses its doubleness if the
roots are planted in a poor soil.
On the other hand, the way in which double stocks are stated to be
produced at Erfurt, viz.: by giving the plants a minimum supply of
water, and the other circumstances alluded to as showing the connection
between the production of double flowers, and a deficiency of water, as
well as the experiments of Mr. Monro, go to show that, so far from
plethora, the inducing cause must be more nearly allied to inanition,
though the impoverishing process is, to a certain extent, counteracted
by only allowing a few of the seed-pods to ripen, and thus concentrating
in a small number of flowers the nutriment intended for many.
Professor Edward Morren ('Bull. Acad. Roy. Belg.,' 2me ser., vol. xix,
p. 224) considers the existence of true variegation in leaves, and the
production of double flowers, as antagonistic one to the other; the
former is a sign of weakness, the latter of strength. But it would seem
that the exceptions are so numerous--so many cases of the co-existence
of variegated leaves, and double flowers are known, at least in
individual plants if not in species--that no safe inferences can be
drawn as to this point. Since the above remarks were printed, Professor
Morren has published a second paper on the subject, upholding his former
views as to the incompatibility of variegated foliage (not mere
colouration) and double flowers. In this paper he criticises the
objections raised by the present writer and others, and examines some
of the alleged exceptions. Some of these the Belgian savant finds to
prove his rule, inasmuch as although there is a co-existence of
variegated foliage and double flowers in these illustrations, yet the
plants are weakly, the flowers ill formed, or fall off before expansion.
Admitting all this, there still remain cases in which double flowers and
variegated foliage do exist in conjunction, and where the plants are
vigorous and the flowers well developed. Instances of this are known to
cultivators in species of _Dianthus_, _Hemerocallis_, _Althæa_,
_Pæonia_, _Rosa_, _Ranunculus_, _Serissa_, _Saponaria_, etc., and
probably the art of the cultivator would speedily be successful in
raising other examples, were it a matter of importance or interest to
them to do so. At any rate, the existence of a few unimpeachable
illustrations is sufficient to support the opinion of the present
writer, and objected to so strongly by M. Morren that, in the present
state of our knowledge, "no safe inferences can be drawn" from the facts
alluded to by the Belgian professor.[572]
Mr. Darwin[573] has thrown out the suggestion that the cause for the
appearance of double flowers may be sought for in some previous state of
things, bringing about sterility or imperfect formation, or functional
activity of the genitalia of the flower, and consequent compensatory
increase of the petaline element, either in the form of an increased
number of bracts, petals, &c., or in the substitution of petals for
stamens and pistils, &c.
In considering these points the question arises whether they can be
reconciled one with another. And there is little doubt but that they may
be. The production of a flower is preceded by an arrest of vegetation;
this is obvious: the current of the plant's life becomes changed, the
growth of the leaves is checked, the lengthening of the branches is
arrested as the flower-bud forms; moreover, there is a close
relationship in a large majority of flowers between the outer envelopes
of the flower and the scales of a leaf-bud; this is especially so in
regard to the venation, and is admitted by all morphologists. So far,
then, it may be said that the production of a flower, like that of a
bud, is due to a diminution of vegetative action; and as in double
flowers we have, for the most part, merely a repetition and exuberant
formation of floral envelopes, so we may attribute their formation to a
continuance of the same feeble vegetative action as that which produced
the first or normal series. How, then, can a copious supply of rich
food, such as is provided by cultivation, produce double flowers? To
this question, according to our theory, the reply would be that the
quantity of food is excessive, more than the plant can properly digest;
and hence vegetative action is stopped, at least partially--pretty much
as it would be if the plant were placed in the opposite condition of
starvation. The effect of supplying a plant (or an animal) with an
excessive supply of food, which it cannot assimilate, is in many
respects similar to that which results from partially cutting off the
supplies. And the same reasoning applies to sterility. If by high
culture, or the supply of an undue quantity of nourishment, the
constitution of the plant be impaired, or if the plant be pampered, it
is no wonderful thing that sterility should ensue. Hence, then, may it
not be asserted as a general principle that in the production of double
flowers a partial arrest of development, if not of growth, however
produced, is an essential preliminary? All the attendant phenomena, such
as the obliteration of the stamens, the augmentation in the number of
floral whorls, the occurrence of prolification, are consistent with the
supposition of a primary arrest of development, more or less complete,
as the case may be: at one time permanent, at another time relaxed and
intermittent, or in a third set of cases the vegetative activity or
power of growth may be restored, and from the centre of the flower may
spring a perfect branch with perfect leaves, the production of sheaths
only being superseded by the development of leaves, in which all the
parts--sheath, stalk, and blade--are present.
When once the disposition to form double flowers is established, that
tendency becomes hereditary: there are races of single Stocks in which,
out of hundreds of plants, scarcely one double-flowered form is met
with; but when the tendency to produce double blooms is set up, single
flowers become the exception: thus, in the Balsams, before mentioned,
not one in fifty now produces single flowers, and the seeds of these
double Balsams produce double-flowered seedlings, with scarcely a
"rogue" among them.
The following list of plants producing double flowers of any kind is
taken from that given in 'Seemann's Journal of Botany,' vol. ii, p. 177,
and to which some additions have been made. Miscalled double flowers,
such as those of the _Compositæ_, _Viburnum Hydrangea_, &c., are
excluded.
RANUNCULACEÆ.
Clematis Viticella, _Linn._, S. Europe.
florida, _Thunb._, Japan.
Fortunei, _Moore_, Japan.
patens, _Desne_, Japan.
Anemone japonica, _Sieb. et Zucc._, Japan.
coronaria, _Linn._, S. Europe, Asia Minor.
hortensis, var. _Linn._, S. Europe.
palmata, _Linn._, N. Africa, Spain, Portugal.
nemorosa, _Linn._, Europe, N. America, Siberia.
sylvestris, _Linn._, S. Europe, Siberia.
Hepatica triloba, _Chaix._, Europe.
Ranunculus bulbosus, _Linn._, Europe, N. Amer.
repens, _Linn._, Europe, Siberia, N. Amer.
acris, _Linn._, Europe, Siberia.
aconitifolius, _Linn._, Europe.
gramineus, _Linn._, Italy, France, Portugal, Switzerland.
bullatus, _Linn._, S. Europe.
asiaticus, _Linn._, The East.
Ficaria ranunculoides, _Moench._, Europe.
Thalictrum anemoides, _Michæ._, N. America.
Caltha palustris, _Linn._, Europe, Asia, N. America.
Trollius europæus, _Linn._, Europe.
nepalensis, Himalaya.
Nigella damascena, _Linn._, Mediterranean.
Aquilegia vulgaris, _Linn._, Europe.
canadensis, _Linn._, N. America.
Delphinium Ajacis, _Linn._, S. Europe.
grandiflorum, _Linn._, Siberia, N. America.
Consolida, _Linn._, Europe, N. America.
cheilanthum, _Fisch._, Siberia.
elegans, _D. C._, North America.
Adonis autumnalis, _Linn._, Europe.
vernalis, _Linn._, Europe, Asia.
Pæonia Moutan, _Sims_, China, Japan.
officinalis, _Retz._, Europe.
tenuifolia, _Linn._, Tauria.
albiflora, _Pall._, Siberia.
paradoxa, _Andr._, S. Europe.
NYMPHÆACEÆ.
Nelumbium speciosum, _Willd._, Africa, Asia.
BERBERIDACEÆ.
Berberis, _sp. cult._
PAPAVERACEÆ.
Papaver Rhoeas, _Linn._, Europe.
bracteatum, _Lindl._, Russia.
somniferum, _Linn._, S. Europe, Asia Minor, Egypt.
Chelidonium majus, _Linn._, Europe, Asia.
Sanguinaria canadensis, _Linn._, N. America.
Podophyllum peltatum, _Linn._, N. America.
CRUCIFERÆ.
Mathiola incana, _R. Br._, Mediterranean.
glabrata, _D. C._
annua, _Sweet._, South Europe, Syria.
Cheiranthus Cheiri, _Linn._, Europe.
Iberis umbellata, _Linn._, Europe.
amara, _Linn._, Europe.
Cardamine pratensis, _Linn._, Europe, Asia, Africa, America.
Hesperis matronalis, _Linn._, Europe, Siberia.
Barbarea vulgaris, _R. Br._, Europe.
Sinapis arvensis, _Linn._, Europe.
Brassica oleracea. _Linn._, Europe.
CISTACEÆ.
Helianthemum vulgare, _Spach._, Europe, N. Africa.
VIOLACEÆ.
Viola odorata, _Linn._, Europe, Siberia.
grandiflora, _Linn._, Europe,
tricolor, _Linn._, Europe.
CARYOPHYLLEÆ.
Dianthus barbatus, _Linn._, France, Germany.
chinensis, _D. C._, China.
Poiretianus, _Seringe_, ?
Caryophyllus, _Linn._, France, Italy.
arboreus, _Linn._, Crete.
hybridus (_gardens_).
corymbosus, _Sibth._, Asia Minor.
plumarius, _Linn._, Europe, Siberia, N. America.
deltoides, _Linn._, Europe.
Saponaria officinalis, _Linn._, Europe.
Lychnis sylvestris, _Schkr._, Europe.
vespertina, _Linn._, Europe.
flos cuculi, _Linn._, Europe.
Viscaria, _Linn._, Europe.
chalcedonica, _Linn._, Japan, Asia Minor.
Silene inflata, _Sm._; _var._ maritima, _D. C._, Europe.
ALSINEÆ.
Sagina procumbens, _Linn._, Europe.
MALVACEÆ.
Hibiscus Rosa sinensis, _Linn._, E. Indies.
flavescens, _Cav._, China.
alba, _Hook._, China.
syriacus, _Linn._, Syria, Carniola.
Althæa rosea, _Cav._, Caucasus, &c.
Malva rotundifolia, _Linn._, Europe.
moschata, _D. C._, Europe.
HIPPOCASTANEÆ.
Æsculus Hippocastanum, _Linn._, Europe, N. America.
GERANIACEÆ.
Geranium pratense, _Linn._, Europe, Siberia.
sylvaticum. _Linn._, Europe.
Pelargonium zonale, _Willd._, S. Africa.
Tropæolum majus, _Linn._, Peru.
minus, _Linn._, Peru.
Oxalis cernua, _Thunb._, S. Africa.
Impatiens Balsamina, _Linn._, E. Ind.
TERNSTRÖMIACEÆ.
Camellia reticulata, _Lindl._, China.
Sasanqua, _Thunb._, China.
japonica, _Linn._, Japan.
Thea maliflora, _Seem._, Japan.
AURANTIACEÆ.
Citrus Aurantium, _Linn._, Asia, South Europe.
PAPILIONACEÆ.
Trifolium repens, _Linn._, Europe, S. America.
Medicago sp., ?., Europe.
Ulex europæus, _Link._, Europe.
Spartianthus junceus, _Linn._, S. Europe.
Clitoria Ternatea, _Linn._, E. India.
Orobus viscoides, _D. C._, Croatia, &c.
vernus, _Linn._, Europe.
Genista tinctoria, _Linn._, Europe.
sibirica, _Linn._, Siberia.
scoparia, _Lam._, Europe.
Cytisus albus, _Link._, Portugal.
Anthyllis Vulneraria, _Linn._, Europe.
Coronilla Emerus, _D. C._, Europe.
Lotus corniculatus, _Linn._, Europe.
ROSACEÆ.
Rosa lutea, _Mill._, Europe.
cinnamomea, _Linn._, Europe, N. America.
spinosissima, _Linn._, Central Asia.
Carolina, _Linn._, N. America.
villosa, _Linn._, Europe, Central Asia.
centifolia, _Linn._
damascena, _Linn._, Syria.
rubiginosa, _Linn._, Europe, Asia, N. America.
moschata, _Ait._, Madeira, N. Africa.
canina, _Linn._, Europe.
alba, _Linn._, Europe, Caucasus.
indica, _Linn._, China.
nivea, _D. C._, China.
Eglanteria, _Linn._, Europe.
gallica, _Linn._, Europe, Caucasus.
pimpinellifolia, _Linn._, Europe, Central Asia.
Banksiæ, _R. Br._, China.
sulphurea, _Ait._, East.
Rubus fruticosus, _Linn._, Europe.
rosifolius, _Linn._, Mauritius, E. India.
corylifolius, _Smith_, Europe.
cæsius, _Linn._, Europe.
Kerria japonica, _D. C._, Japan.
Spiræa Filipendula, _Linn._, Europe.
Ulmaria, _Linn._, Europe.
prunifolia, _Sieb. et Zucc._, Japan.
Reevesii, _Lindl._, China.
strobilacea, _Sieb. et Zucc._, Japan.
Fragaria vesca, _Linn._, Europe, N. America.
Potentilla alpestris, _Hall. f._, Europe.
reptans, _Linn._, Europe, Asia.
Tormentilla, _Schrank_, Europe, Asia.
anserina, _Linn._, Europe.
Geum rivale, _Linn._, Europe.
POMACEÆ.
Cratægus Oxyacantha, _Linn._, Europe.
Crus galli, _Linn._, N. America.
Cydonia japonica, _Pers._, Japan.
Pyrus communis, _Linn._, Europe.
Malus, _Linn._, Europe.
Eriobotrya japonica, _Lindl._, Japan.
AMYGDALEÆ.
Amygdalus Persica, _Linn._, Persia.
communis, _Linn._, Mauritania.
Prunus domestica, _Linn._, Europe.
spinosa, _Linn._, Europe, N. America.
avium, _Linn._, Europe.
Cerasus, _Linn._, Europe.
Kerii, _Steud._, Japan.
japonica, _Thunb._, China, Japan.
insititia, _Linn._, Europe.
triloba, _Lindl._, China.
MYRTACEÆ.
Myrtus communis, _Linn._, S. Europe.
Punica Granatum, _Linn._, S. Europe, Marocco.
PHILADELPHACEÆ.
Philadelphus Coronarius, _linn._, S. Europe.
Deutzia Crenata, _sieb. Et Zucc._, Japan.
ONAGRACEÆ.
Fuchsia globosa, _Lindl._ (and var. hort. pl.), Mexico.
Epilobium tetragonum, _D.C._, Europe.
Clarkia pulchella, _Pursh._, California.
elegans, _Douglas_, N. America.
PORTULACACEÆ.
Portulaca grandiflora, _Hook_, Chili.
GROSSULARIACEÆ.
Ribes sanguineum, _Pursh._, N. America.
SAXIFRAGACEÆ.
Saxifraga granulata, _Linn._, Europe.
UMBELLIFERÆ.
Daucus Carota, _Linn._, Europe.
RUBIACEÆ.
Ixora grandiflora, _De Cand._, E. India.
Serissa foetida, _Comm._, China, Japan.
Gardenia Fortuniana, _Hook._, China.
florida, _Linn._, China, E. India.
radicans, _Thunb._, Japan.
CAPRIFOLIACEÆ.
Lonicera Periclymenum, _Linn._, Europe.
Sambucus nigra, _Linn._, Europe.
CAMPANULACEÆ.
Campanula latifolia, _Linn._, Europe, Asia.
Tenorei, _Morett_, Naples.
Trachelium, _Linn._, Europe.
Vidallii, _H. C. Wats._, Europe.
pyramidalis, _Linn._, S. Europe.
rotundifolia, _Linn._, Europe, N. America.
persicifolia, _Linn._, Europe.
glomerata, _Linn._, Europe, Asia.
Medium, _Linn._, Europe.
rhomboidea, _Linn._, Europe.
Platycodon grandiflorum, _D. C._, Siberia.
ERICACEÆ.
Calluna vulgaris, _Linn._, Europe, N. America.
Rhododendron indicum, _Sweet._, E. India.
ponticum, _Linn._, Asia Minor.
Azalea nudiflora, _Linn._, N. America.
glauca, _Lam._, N. America.
Arbutus Unedo, _Linn._, S. Europe.
Erica Tetralix, _Linn._, Europe.
cinerea, _Linn._, Europe.
hyemalis, gardens.
EPACRIDACEÆ.
Epacris impressa, _R. Br._, Australia.
PRIMULACEÆ.
Primula villosa, _Jacq._, Europe.
Auricula, _Linn._, Europe.
denticulata, _Smith_, E. India.
acaulis, _Jacq._, Europe.
clatior, _Jacq._, Europe.
prænitens, _Ker._ = sinensis, _Lindl._, China.
Lysimachia Nummularia, _Roem et Schult._, Europe.
Anagallis tenella, _Linn._, Europe.
JASMINACEÆ.
Jasminum officinale, _Linn._, S. Europe.
Sambac., _Ait._, E. India.
hirsutum, _Hook._, China.
grandiflorum, _Lindl._, S. Europe.
OLEACEÆ.
Syringa persica, _Linn._, Persia.
vulgaris, _Linn._, Europe, Persia.
APOCYNEÆ.
Vinca minor, _Linn._, Europe.
major, _Linn._, Europe.
Nerium odorum, _Ait._, E. India.
Oleander, _Linn._, S. Europe.
Tabernæmontana coronaria, _Willd._, E. India.
Allamanda cathartica, _Aubl._, S. America.
CONVOLVULACEÆ.
Calystegia sepium, _R. Br._, Europe, America, Asia.
pubescens, _Lindl._, China.
Convolvulus tricolor, _Linn._, S. Europe.
Ipomoea pandurata, _Meyer_, S. America.
SOLANACEÆ.
Datura cornigera, _Hook._, Peru.
fastuosa, _Linn._, S. America, Egypt.
arborea, _Linn._, S. America.
chlorantha, _Hook._
humilis, _Desf._
Petunia nyctaginiflora, _Juss._, S. America.
violacea, _Hook_, S. America.
Solanum Dulcamara, _Linn._, Europe.
GENTIANACEÆ.
Gentiana Amarella, _Linn._, Europe.
OROBANCHACEÆ.
Orobanche sp.
SCROPHULARIACEÆ.
Mimulus luteus, _Linn._, Chili.
Antirrhinum majus, _Linn._, S. Europe.
Digitalis purpurea, _Linn._, Europe.
Linaria vulgaris, _Mill._, Europe, N. America.
Veronica, sp.
Calceolaria, var. cult.
GESNERACEÆ.
Achimenes longiflora, _D. C._, Mexico.
Gloxinia var. hort.
VERBENACEÆ.
Clerodendron fragrans, _Willd._, Japan.
Verbena var. hort.
NYCTAGINEÆ.
Mirabilis Jalapa, _Linn._, Trop. America.
LAURINEÆ.
Laurus nobilis, _Linn._, S. Europe.
Sassafras, _Linn._, N. America.
IRIDACEÆ.
Gladiolus tristis, _Linn._, Cape of Good Hope.
Crocus aureus, _Sibth_, Europe, Asia Minor.
Susianus, _Curt._, Asia Minor.
pusillus, _Tenore_, Italy.
vernus, _Smith_, S. Europe.
Iris sibirica, _Linn._, Europe.
Iris Kæmpferi, _Siebold_, Japan.
AMARYLLIDACEÆ.
Galanthus nivalis, _Linn._, Europe.
Leucoium vernum, _Linn._, Europe.
Sternbergia lutea, _Gawl._, Europe, Asia Minor.
Hippeastrum equestre, _Herb._, S. America.
Narcissus cernuus, _Salisb._, S. Europe.
Telamonius, _Schult._, Europe.
lobularis, _Schult._
concolor, _Schult._, Portugal.
biflorus, _Curt._, Europe.
italicus, _Ker._, Italy.
incomparabilis, _Curt._, Italy.
Cypri, _Haw._, Cyprus.
Pseudo-Narcissus, _Linn._, Europe.
poeticus, _Linn._, Europe.
Jonquilla, _Linn._, S. Europe, East.
Tazetta, _Linn._, S. Europe.
poculiformis, _Salisb._, S. Europe.
ORCHIDACEÆ.
Orchis Morio, _Linn._, Europe.
mascula, _Linn._, Europe.
pyramidalis, _Linn._, Europe.
Ophrys fucifera, _Linn._, Europe.
See also pp. 380, 509.
HYDROCHARIDACEÆ.
Hydrocharis Morsus ranæ, _Linn._, Europe.
ASPHODELEÆ.
Asphodelus luteus, _Linn._, S. Europe.
LILIACEÆ.
Tulipa Gesneriana, _Linn._, Asia Minor.
sylvestris, _Linn._, S. Europe.
Scilla autumnalis, _Linn._, Europe.
nutans, _Smith_, S. Europe.
Convallaria majalis, _Linn._, Europe, America.
Polygonatum, _Linn._, Europe.
Trillium grandiflorum, _Spreng._, America.
Fritillaria Meleagris, _Linn._, Europe.
imperialis, _Linn._, Persia.
Lilium Martagon, _Linn._, Europe.
candidum, _Linn._, Syria, Persia.
Hyacinthus orientalis, _Linn._, East.
Polianthes tuberosa, _Linn._, E. India.
Hemerocallis disticha, _Don._, Nepal.
Kwanso, gardens.
fulva, _Linn._, S. Europe.
COLCHICACEÆ.
Colchicum autumnale, _Linn._, Europe.
Tofieldia calyculata, _Wahl._, Europe.
BUTOMACEÆ.
Sagittaria latifolia, _Willd._, N. America.
sagittifolia, _Linn._, Europe, Asia, America.
COMMELYNACEÆ.
Tradescantia virginica, _Linn._, N. America.
alba, gardens.
FOOTNOTES:
[564] This appendix forms a portion of a paper published in the
'Proceedings of the International Botanical Congress,' London, 1886, p.
127, and which it has been deemed advisable to reproduce with sundry
additions and modifications.
[565] 'Traité des Giroflées,' per E. Chaté.
[566] Leading Article in the 'Gardeners' Chronicle,' p. 74, 1866.
[567] Otto's 'Gartenzeitung,' 1866.
[568] 'Gard. Chron.,' 1843, p. 628.
[569] 'Gard. Chron.,' 1867, p. 381.--Art. "Chinese primroses."
[570] See also p. 79, fig. 36. A similar flower is figured in 'Hort.
Eystett. Ic. Arb. Vern.,' fol. 5. "Fructus nondum observatus est
fortassis alimento uberius in flores refuso, nullus sperari possit."
[571] See De Candolle, 'Plant. Rar. Genev.,' 1829, p. 91; and Alph. de
Candolle.' Géog. Bot.,' p. 1080.
[572] See 'Gardeners' Chronicle,' 1868, p. 1113.
[573] Ibid., 1843, p. 628.
NOTE.
During the progress of the foregoing pages through the press, several
additional illustrations of particular malformations have come under
notice. Some of the more important of these may here be recorded.
_Fasciation_ (see p. 11).--The following plants may be added to the
list:--_Acer eriocarpum_, _Arabis albida_, _Brassica oleracea_, var.,
_Guarea_, sp., _Artabotrys_ sp. In all, with the exception of the
first-named, the fasciation occurred in the inflorescence. In some
species of _Artabotrys_, indeed, fasciation and curvation of the
inflorescence are common.
_Synanthy_ (p. 39).--Several additional instances of adhesion of two or
more flowers in _Calanthe vestita_, _C. Veitchii_, and other forms of
this genus may be cited. These furnish further illustrations of the much
greater liability of some plants to particular changes as compared with
others. _Scilla bifolia_, _Gagea arvensis_, and _Viola odorata_ may be
added to the list of synanthic plants.
_Alterations of placentation, &c._ (see pp. 98, 483).--M. Casimir De
Candolle, in a letter to the author, dated March 8th, 1869, thus writes
of the existence of a double row of carpels in _Pyrus spectabilis_ and
_Cratægus Oxyacantha_, "a longitudinal section of a double flower of
_Pyrus spectabilis_ shows two rows of carpels, placed one above another.
The arrangement of the vascular bundles shows that the upper row is
external in relation to the lower series. The carpels of the latter are
wholly coalescent as in a pear, while those of the upper verticil are
only partially coherent or sometimes quite distinct. The placentation is
constantly axile in the inferior row and parietal in the upper one. The
number of ovules in each carpel of the superior row varies greatly, and
they are often, but not always, inserted in two longitudinal ranks, as
is constantly the case in the lower carpels. Double flowers of _Cratægus
Oxyacantha_ present the same anomalies." For analogous instances in
_Digitalis_, see p. 98. See also p. 380, _Saxifraga_.
_Prolification_, p. 120.--A. P. De Candolle, "Organographie Végétale,"
tab. 40, figures an instance of suppression of one lobe of the ovary in
_Iris chinensis_, and of the presence at the base of the flower of an
adventitious and imperfect flower-bud, as in the _Phlomis_, mentioned at
p. 119.
_Monoecious Misleto_, p. 193.--In this specimen, exhibited at one of the
meetings of the Scientific Committee of the Royal Horticultural Society
in 1869, there were both male and female flowers on the same bush. The
plant was of the male sex, with numerous long slender whip-like,
somewhat pendulous, branches bearing comparatively large broad yellowish
leaves, and fully developed male flowers at the end. From the side of
one of these male branches, near the base, protruded a tuft of short,
stiff branches, bearing small, narrow, dark green leaves, ripe berries
and immature female flowers. There was no evidence of grafting or
parasitism, of the female branch on the male, the bark and the wood
being perfectly continuous so that the only tenable supposition is that
this was a case of dimorphism.
_Adventitious leaflet and pitcher_, see pp. 30 and 355. In a species of
_Picrasma_, in which the leaves are impari-pinnate and spread
horizontally, an adventitious leaflet was observed to project at right
angles to the plane of the primary leaf. It emerged at a point nearly
corresponding to that at which the normal pinnæ were given off. The
appearance presented was thus like that of a whorl of three leaves,
except that the shining surface of the adventitious leaflet,
corresponding to the upper face of the normal leaflets, was directed
towards the axis, _i.e._, away from the corresponding portion of the
neighbouring pinnæ, while the dull surface, corresponding to the lower
part of an ordinary leaflet, looked towards the apex of the main leaf,
or away from the axis. In one instance, a stalked pitcher was given off
from the same point as that from which the supernumerary leaflet
emerged, the pitcher being apparently formed from the cohesion
(congenital) of the margins of a leaflet.
In the normal leaf of this plant there is between the bases of the
pinnæ, a small reddish gland or stipel? attached to, or projecting from,
the upper surface of the rachis. It appeared from some transitional
forms that the adventitious leaflet, just mentioned, was due to the
exaggerated development of this gland, but no clue was afforded as to
the origin of the ascidium. It was not practicable to examine the
arrangement of the vascular bundles in the rachis.
_Additional labella in Phaius._--A flower of _Phaius grandiflorus_ was
found in the same condition as the _Catasetum_, mentioned at pp. 291 and
382.
_Tubular stem._--A species of _Sempervivum_, exhibited by Mr. Salter, of
Hammersmith, at one of the summer exhibitions of flowers at the Royal
Horticultural Society in 1868, under the name of _S. Bollei_, deserves
notice from its bearing on the question of such structures as the
calyx-tubes, the hip of the rose and such like, see pp. 394, 482. In
this plant the leaves appeared to be arranged some on the outside,
others on the inside, of an erect hollow cylinder, some six inches in
height. The oldest leaves were outside, the youngest within, so that the
appearance presented was as if the summit of the axis had been pushed or
drawn in, much as the finger of a tight glove might be invaginated in
withdrawing it from the hand.
The plant in question thus furnishes an actual illustration of the
supposititious case mentioned at p. 482.
_Double flowers_, see pp. 499, et seq.--The following species may be
added to those already recorded: _Lychnis coronaria_, _Hibiscus
mutabilis_, _Lotus major_, _Pisum sativum_, _Godetia_ sp., _Ipomoea
purpurea_, _Convolvulus minor_, _Heliotropium peruvianum_, _Trillium
grandiflorum_, and _Phaius grandiflorus_.
INDEX TO SUBJECTS.
A.
Abortion, 455, 467
of axile organs, 455
calyx, 460
corolla, 460
indusium, 467
leaves, 458
ovules, 466
perianth, 460
pistil, 464
receptacle, 457
stamens, 463
Acaulescence, 393
Acaulosia, 393, 456
Acheilary, 398
Adesiny, 58, 76
Adhesion, 32
of axes, 50, 55
embryos, 56
leaves, 33
parts of flower, 34
roots, 53
Adventitious buds, 156, 176
flowers, 174, 176, 180
gemmæ, 173
leaves, 162
roots, 156
shoots, 161
Albinism, 337
Alternation, 3, 485
Androecium, enlargement of, 430
meiophylly of, 398
meiotaxy of, 405
of orchids, 380
pleiotaxy of, 379
polyphylly of, 361
Androgynism, 193
Anther (see connective), contabescence of, 463
morphology of, 291
ovuliferous, 200
petalody of, 291
sutures of, 291
Apilary, 397
Apostasis, 440
Aphylly, 395
Arrangement, 1
Ascidia, 30, 313
bibliography, 30
plants with, 30
Atrophy, 454 (see abortion)
Antophyllogeny, 355
Avalidouires (vines), 211
Axes, abortion of, 455
adhesion of, 50, 55
cohesion of, 9
enation from, 444
enlargement of, 418
fission of, 60
suppression of, 398
Axile organs, see Axes
B.
Barley, Nepaul, 174
Bigarades cornues, 303
Bladder-plums, 465
Bracts, multiplication of, 358
staminody of, 298
phyllody of, 242
Buds, adventitious on fruits, 178
on leaves, 170, 174
in ovary, 180
on petals, 177
in pith, 171
on roots, 160 (see flower-buds, prolification)
variations of, 336
Bulbs, displacement of, 84
multiplication of, 172, 350
Burrs, 347, 420
C.
Catacorolla, 450
Calycanthemy, 283
Calyphyomy, 34
Calyx, abortion of, 461
dialysis of, 70
meiophylly of, 396
meiotaxy of, 403
obsolete, 460
petalody of, 283
pleiotaxy of, 374
polyphylly of, 359
solution of from ovary, 77
Calyx-tube, 394, 480, 509
Carnation wheat-ear, 371
Carpels (see Pistil, Fruit, Ovary), adventitious, 182
dialysis of, 73
enation from, 453
fission of, 68
in ovary, 182
Cauliflower, 421
Cenanthy, 408
Chloranthy, 273, 279
bibliography, 280
remarks on, 279
plants subject to, 280
Chorisis, 59, 343
parallel, 344
collateral, 344
Chromatism, 339
Cladodes, 328
Classification, teratology in relation to, 488
Cohesion of leaves, 21, 25
of petals, 28
pistils, 29
sepals, 27
stamens, 29
stems, 9
Colour, alterations of, 337
Columella, 395
Coniferæ, leaves of, 217, 352, 484
inflorescence of, 245
scales of, 192, 245, 484
Compensation, 488
Connective, petalody of, 293
Consistence, alterations of, 432
Contabescence, 463
Contortion, 317
Co-relation, 486
Cornute leaves, 328
Corolla, abortion of, 461
dialysis of, 71
duplicate, 376
hose in hose, 377
meiophylly of, 397
meiotaxy of, 403
pleiotaxy of, 374
polyphylly of, 359
virescence of, 338
Cotyledons, increased number of, 370
shoots, below, 161
Cuttings, formation of, 159
D.
Dédoublement, 59 (see Chorisis)
Deflexion, 209
Deformities, 311
Degeneration, 470
Depauperate ferns, 466
Diadelphia, 29
Dialysis, 58, 69
of calyx, 71
carpels, 73
corolla, 72
plants subject to, 72
of leaves--margins of, 70
stamens, 73
Diaphysis, 103
Dioecious plants, 192, 193
Dimorphism, 333
Dimorphic flowers, 403
Direction, changes of, 201
Diremption, 87
Disjunction, see Dialysis, Fission, Solution
Displacement, 84
of bulbs, 84
carpels, 96
flower-parts of, 91
inflorescence, 85
leaves, 87
ovules, 96
placentas, 96
Distension, 419
E.
Ecblastesis, 107, 138
Elongation, 433
of parts of flower, 438
flower-stalks, 435
inflorescence, 434
leaves, 437
nucleus of ovule, 269
placenta, 440
receptacle, 440
root, 434
thalamus, 440
Embryos, adhesion of, 56
increased number of, 369
Enation, 443
from axile organs, 444
carpels, 453
corolla, 449
foliar organs, 445
sepals, 448
stamens, 453
Enlargement, 417
of androecium, 430
axile organs, 418
buds, 420
flower stalk, 421
fruit, 431
gynoecium, 430
perianth, 428
placenta, 425
Epanody, 226
Epistrophy, 226
Etiolation, 337
Eversion, 204
Excrescences, 444 (see Enation)
F.
Fasciation, 11
plants affected with, 20, 508
Fastigiation, 202
Ferns, crested, 63, 447
depauperated, 466
exindusiate, 467
supra-soriferous, 189
Filaments, see Stamens
petaloid, 290
4-winged, 290
Finger and toe, 69
Fission, 59
of carpels, 68
leaf-organs, 61, 66
plants, subject to, 66
of petals, 66
stem-organs, 60
stamens, 68
Flattening, 328
Floral organs, displacement of, 91
elongation of, 439
metamorphy of, 281
Florets, increased number of, 351, 390
Flowers, adventitious, 174
on fruits, 177
on leaves, 174
in ovary, 180
on petals, 177
on spines, 177
apetalous, 404
double, 490, 510
hermaphrodite, 196
homomorphic, 188
increased number of, 390
mutilated, 403
unisexual, 193
Flower-stalk, enlargement of, 421
Flower-bud (see Prolification), replaced by leaves or scales, 164
in place of leaf-buds, 176
Foliar organs (see leaves), adhesion of, 32
Foliar organs, cohesion of, 21, 25
enation from, 445
fission of, 61
suppression of, 396
Form, alterations of, 213
juvenile, persistence of, 217
Frondescence, 241, 279, see Phyllody, Virescence
Fruit, adhesion of, 44
enlargement of, 431
G.
Gemmæ, formation of, 173
Glands, formation of, 473
Gnaurs, 158, 347, 417, 419
Grafting, 53, 56
Greffe des Charlatans, 56
Growth interrupted, 327
irregular, 228
Gymnaxony, 211
Gynantherus, 305
Gynoecium (see pistils)
enlargement of, 430
meiophylly of, 399
meiotaxy of, 406
pleiotaxy of, 388
polyphylly of, 363
suppression of, 406
H.
Hairs, formation of, 472
Hermaphroditism, 197
Heterogamy, 190
Heteromorphy, 311
Heterophylly, 330
Heterotaxy, 156
Homology, 476
Homomorphy, 188
Hose in hose corollas, 291, 377
Hypertrophy, 415, see Enlargement
I.
Independence, 58
Indusium, abortion of, 467
Inflorescence, displacement of, 84
elongation of, 434
prolification of, 102, 115
Interrupted growth, 327
Inversion of organs, 206
Irregularity, 213
Irregular growth, 228
K.
Knaurs, (see gnaurs)
Kail, 426
L.
Laciniation, see fission
Layering, 156
Leaders, formation of, 203
Leaf-sheath, 477
Leaves, see foliar organs
abortion of, 458
adhesion of,
by surfaces, 33
to stem, 34
adventitious, 162-165, 509
cornute, 328
displacement of, 86
elongation of, 437
enlargement of, 421
frondiferous, 355
geminate, 352
multiplication of, 358
nature of, 477
palmate-passage of to pinnate, 439
spiral torsion of, 326
supernumerary, 353
Lily, double white, 375
M.
Meiotaxy of androecium, 405
of calyx, 403
corolla, 403
gynoecium, 405
Meiophylly of androecium, 398
of calyx, 397
corolla, 397
gynoecium, 399
perianth, 397
Mellarose, 134
Metaphery, 91
Metamorphy, 239, 281
calycanthemy, 283
chloranthy, 273
petalody, 283
phyllody, 241
pistillody, 302
sepalody, 282
staminody, 298
Mischomany, 348
Monadelphia, 29
Monoecious, 192, 193, 509
Monosy, 58
Morphology, 479
Multiplication, see pleiotaxy, pleiophylly
of bracts, 358, 371
bulbs, 350
cotyledons, 370
embryos, 369
florets, 351
foliar organs, 352
whorls, 371
N.
Nepaul Barley, 174
Number, alterations of, 341
increased, 343, 353
diminished, 392
O.
Orchids, androecium of, 380
prolification in, 153
Organs, rudimentary, see Atrophy
Ovary, inferior, nature of, 394, 482
solution from calyx, 77
stamens in, 184
Ovules, abortion of, 466
increase of, 367
in place of pollen, 200
polliniferous, 183
petalody of, 297
phyllody of, 262
pistillody of, 310
suppression of, 407
malformations of, 262
bibliography of, 272
P.
Parasitical plants, 55
Peduncles, elongation of, 435
Peloria, 207, 228
bibliography of, 227, 239
regular, 219
plants subject to, 226
irregular, 229
plants, subject to, 239
Perianth, abortion of, 460
enlargement of, 428
meiophylly of, 396
pistillody of, 303
pleiotaxy of, 375
Persistence, xxxvi _adnot._, 217
Petalody, 283
of accessory organs, 297
anther, 291
calyx, 283
connective, 292
ovules, 297
pistils, 297
stamens, 284
plants, subject to, 295
Petals, cohesion of, 28
enation from, 448
fission of, 66
phyllody of, 251
staminody of, 298
tubular, 23, 314
Phyllode, 328
Phyllody, 240 (see Virescence, Chloranthy)
of accessory organs, 272
bracts, 242
calyx, 244
plants subject to, 250
in Conifers, 245
of corolla, 251
plants subject to, 252
of ovules, 262
plants subject to, 271
pistils, 256
plants subject to, 261
stamens, 253
plants subject to, 256
Phyllomania, 352
Phyllomorphy, see Phyllody
Phyllotaxy, 1, 320
Pistil, abortion of, 464
cohesion of, 29
petalody of, 296
staminody of, 298
Pistillody, 302
of ovules, 268, 310
perianth, 302
sepals, 302
stamens, 303
plants subject to, 310
Pitchers, 30, 313, 509, see Ascidia
Placentation, changes in, 96, 508
bibliography, 100
nature of, 483
Placenta, elongation of, 439
enlargement of, 421
Pleiomorphy, 228
Pleiophylly, 353
Pleiotaxy, 371
of androecium, 375
bracts, 371
calyx, 374
corolla, 376
gynoecium, 388
perianth, 375
Plien, 346
Plymouth Strawberry, 275
Polyadelphia, 29
Pollen in ovules, 183
abortion of, 463
replaced by ovules, 200
Polyclady, 346
Polycotyledony, 370
Polyembryony, 369
Polymorphy, 328
Polyphylly of androecium, 361
of calyx, 350
corolla, 359
plants subject to, 360
of flower, 363
gynoecium, 363
Polyphylly, bibliography, 364
plants subject to, 364
Position, changes of, 83
relative, 485
Prolification, 100
axillary, 138
foliar, 141
floral, 142
plants affected with, 148
bibliography of, 154
complicated, 151
of embryo, 155
of flower, 115
coincident changes, 128
median foliar, 116
median floral, 119, 508
plants affected with, 137
of fruit, 134
inflorescence, 102
bibliography, 115
median foliar, 103
median floral, 105
lateral floral, 107
lateral foliar, 106
R.
Receptacle, abortion of, 457
elongation of, 116, 440
spiral torsion of, 325
Reflexion, 209
Regularity, 213
Rhizotaxy, 1
Rose Willow, 166, 168
Roots, adventitious, 156
elongation of, 434
Rudimentary organs, 469
S.
Saint Valery Apple, 135, 282, 304, 375, 388
Savoys, 426
Scales, formation of, 164, 448, 470
Scape, leaves on, 163
Seeds, abortion of, 407
union of, 50
Sepals, adhesion of, to petals, 34
cohesion of, 27
enation from, 448
phyllody of, 243
pistillody of, 303
staminody of, 298
Sepalody, 282
Separation, 58
Sex, changes of, 190, 509
Shamrock, four-leaved, 356
Shoots below cotyledons, 167; _see_ Leaders
Size, alterations in, 411
Solenaidie, 21, 316
Solution, 59, 76
bibliography, 82
of calyx, 77
plants subject to, 82
of stamens, 82
Spathes, increased number of, 357
Speiranthy, 91, 325
Spiral torsion, 319
plants subject to, 325
of leaf, 326
of receptacle, 324
Spines, 456
Sports, 336
Spurs, formation of, 228, 315
Stamens, see Androecium
abortion of, 463
adhesion of, 34, 35
cohesion of, 29
compound, 294, 345
dialysis, 73
enation from, 453
fission of, 68
in ovary, 183
petalody of, 283
phyllody of, 253
pistillody of, 303
tubular, 316
Staminody, of accessory organs, 301
of bracts, 298
petals, 298
pistils, 299
sepals, 298
Stasimorphy, 216
Stem, see axes
Stipules, increased number of, 357
Strawberry, Plymouth, 275
blind, 195
Suppression, 393
of androecium, 405
flower, 408
foliar organs, 395
Suppression of ovules, 407
remarks on, 409
of seeds, 407
Symmetry, 213
Synanthy, 37
bibliography, 45
plants subject to, 44, 508
Syncarpy, 45
Syngenesia, 29
Synophty, 57
Synspermy, 50
T.
Tendrils, adventitious, 326
formation of, 473
Thalamus, see Receptacle
Thorns, 456
Torsion spiral, 319
Tubers, 421
in axils of leaves, 142
Tubes, formation of, 312, 509 (see Ascidia, Solenaidy, Spurs)
Tubular petals, 314
stamens, 316
U.
Union, 8
Unisexuality, 195
Uovoli, 420
V.
Varieties, dwarf, 411
Venation, 338
Virescence, 338
Viviparous plants, 106, 168
W.
Warts, 444
Wheat-ear carnation, 371
INDEX OF NAMES OF PLANTS.
[In the following Index the names of the orders that are incidentally
mentioned are printed in small capitals, those of the genera and species
in ordinary type. The names are inserted as found in the several
records, &c., without in general any attempt having been made to
determine their accuracy. For this reason the authority for the specific
name is rarely given, such citations being here unnecessary if not
impracticable. It may, however, be assumed that the names made use of
are those generally adopted by naturalists.
This index will be found useful for statistical purposes. It will show
at a glance, at least approximately, how often certain genera and
species are affected with malformation, as contrasted with others. The
nature of the malformation may of course be ascertained by referring to
the particular page indicated by the number. The proportion of wild to
cultivated plants may also be approximately ascertained, and the effects
of cultivation estimated. The disproportionate frequency with which some
species are affected, e.g., _Trifolium repens_, &c., as contrasted with
other closely allied, and perhaps equally common species, under
apparently identical conditions, is also made manifest.]
A.
Abies Brunoniana, 245
excelsa, 21, 61, 192, 298, 325, 456,
Larix, 90
pectinata, 52
Acacia, 329
Aceras anthropophora, 238
Acer, 359, 364, 367, 508
platanoides, 66, 459
pseudo-platanus, 20, 371
Aceranthus, 225, 226
Achimenes, 106, 114, 296
longiflora, 506
Aconitum, 148, 231, 359, 360, 399, 404,
407, 464
Napellus, 39, 44, 238
Acorus, 225
Actæa spicata, 251, 252
Adenium obesum, 417
Adenorophium luxurians, 254
Adonis, 262, 295
autumnalis, 500
vernalis, 500
Adoxa, 367
Ærides odoratum, 398
Æschynanthus, 44, 297
Æsculus Hippocastanum, 50, 66, 295,
369, 438, 459, 501
Affonsea, 364
Afzelia, 397
Agaricus, xxiii, 54
Agave, 177, 432
Americana, 33, 45
Angelica, 365
Agrimonia, 137, 406
Agrostemma, 148
Githago, 271
Agrostis alba, 169
Ailanthus glandulosa, 21
Aira alpina, 169
cæspitosa, 169
Ajuga Iva, 404
pyramidalis, 20
reptans, 243
Alcea, 149, 297
Alchemilla minima, 171
Aldrovanda vesiculosa, 86
Alisma, 115, 329
natans, 107
parnassifolia, 167
ALISMACEÆ, 115
Allamanda, 296
cathartica, 288, 390, 505
Allium, 106, 114, 170, 299, 360, 365, 367
fragrans, 369
vineale, 150
Alliaria officinalis, 269, 271
Almond, see _Amygdalus_.
Alnus, 349
fruticosa, 192
imperialis, 459
incana, 21
glutinosa, 66, 244, 349
laciniata, 65
Alopecurus pratensis, 169
Alsine media, 67, 252, 404
Alstroemeria, 319, 326
Althæa, 295
rosea, 20, 501
Alyssum, 137
incanum, 252
AMARYLLIDACEÆ, 115, 138, 150
Amaryllis, 307, 310, 432
Ambrina ambrosioides, 397
AMENTACEÆ, 114, 435
Amorpha, 21, 397
fruticosa, 23, 30, 243
AMYGDALEÆ, 500; see _Rosaceæ_
Amygdalus, 122, 137, 155, 295, 297, 364
communis, 250, 252, 369, 503
Persica, 74, 176, 503
Anagallis, 73, 138, 141, 150, 288, 296, 360, 365, 367
arvensis, 117, 161, 256, 263, 271, 278, 281, 284
collina, 44,
phoenicea, 141, 253, 271, 441, 461
tenella, 505
Webbiana, 281
Anomodon alternatus, 49
Ananassa, 350
Anchusa, 132, 138, 339, 365
ochroleuca, 125, 259, 262, 281
paniculata, 262
Androsace maxima, 16, 20
Anemiopsis californica, 63, 66
Anemone, 113, 121, 136, 140, 142, 148, 258, 289, 295, 296, 297, 360,
374, 430, 463, 491, (see _Hepatica_)
coronaria, 107, 250, 256, 339, 499
hortensis, 107, 250, 339, 499
japonica, 161, 499
nemorosa, 250, 256, 339, 499
palmata, 499
Anemone pavonina, 499
Pulsatilla, 250
rivularis, 165
sylvestris, 250, 499
Angelica, 114, 137, 143, 150
Razoulzii, 244, 437
Anthemis arvensis, 20
nobilis, 20
retusa, 44
Anthoxanthum, 61
odoratum, 61
Anthriscus, 442
Anthurium Scherzerianum, 358
Anthyllis, 295
Antirrhinum majus, 20, 22, 24, 31, 44, 57, 73, 82, 104, 114, 121, 131,
225, 226, 227, 230, 233, 235, 238, 253, 272, 296, 301, 315, 316,
318, 363, 365, 378, 398, 505
Apargia, 114
autumnalis, 20
Apium, 82, 113, 150
graveolens, 66, 158
Petroselinum, 370, 437
APOCYNACEÆ, 137
Apple, St. Valery, 135, 282, 304, 375, 388
Aquilegia canadensis, 500
Skinneri, 266, 271
vulgaris, 24, 70, 127, 136, 220, 226, 252, 257, 260, 261, 271, 280,
286, 287, 288, 293, 295, 74, 390, 500
Arabis, 148, 508
alpina, 397, 461, 463
pumila, 170
sagittata, 44
Araucaria, 245
Arbutus Unedo, 291, 292, 296, 377, 504
Archidendron, 365
Ardisia serrulata, 369
Arenaria serpyllifolia, 461
tetraquetra, 398, 399, 464, 469
Armeria, 114
Aristolochia Clematitis, 38, 45, 314
caudata, 231, 238
sipho, 23
Armoracia rusticana, 64, 299
Arnoseris, 114
Artabotrys, 456, 508
Artemisia, 405
Artocarpus, 407
Arum, 329
maculatum, 66, 225, 227, 245, 358
Asparagus officinalis, 12, 19, 21, 320, 325, 471
Asphodelus, 138, 296
Asphodelus luteus, 506
ramosus, 298, 310
Asplenium Trichomanes, 190
Astrantia, 114
major, 368
Athamanta, 82, 137, 149
Cervaria, 250, 442
Atriplex, 227
hortensis, 224
Atropa Belladonna, 44
Aucuba, 21
japonica, 21, 197
AURANTIACEÆ, 137, 149, 502
Avena, 319, 351, 391
chinensis, 298
Azalea, 35, 114
glauca, 504
indica, 44, 73, 166, 209, 289, 296
nudiflora, 504
B.
Babingtonia, 185
Bæckea diosmifolia, 183
BALSAMINEÆ, 359, 404, 501
Balsam, see _Impatiens_
Bamboo, see _Bambusa_
Bambusa, 307, 310, 324, 365
Barbarea, 295
vulgaris, 310, 500
Barkhausia, taraxacifolia, 20
Barley, Nepaul, 174
Bauhinia, 328
BEGONIACEÆ, 114
Begonia, 31, 81, 106, 114, 162, 170, 352
frigida, 199, 303, 310
fuchsioides, 281
phyllomaniaca, 170
Bellevalia, 408, 461, 467
comosa, 348
Bellis perennis, 17, 20, 31, 106, 114, 164, 244
Berberis, 272, 295, 458, 460, 500
vulgaris, 20
Beta, 19, 325, 365
vulgaris, 20
Betonica Alopecuros, 42, 44, 226
Betula alba, 66, 346, 456, 472
populifolia, 66
Bidens, 114, 165, 223
BIGNONIACEÆ, 222
Bignonia, 272, 296, 327
Bikkhia, 80
Blitum, 45
polymorphum, 397, 458
Bocconia, 224
cordata, 310
Bowiea volubilis, 409
BORAGINACEÆ, 132, 138
Bouchea hyderabadensis, 166
Bougainvillea, 339
Brachythecium plumosum, 49
Brassica, 20, 136, 139, 295, 364, 367
Napus, 27, 205
oleracea, 30, 33, 66, 67, 106, 113, 136, 141, 142, 148, 250, 252,
264, 271, 280, 351, 408, 421, 426, 442, 445, 501, 508
Rapa, 181
Breynia, 198
Bromelia, 103
Bromus velutinus, 358
Broussonettia papyrifera, 331, 459
Bruniaceæ, 80, 81
Brunia microphylla, 81
Bryonia, 360, 367
Bryophyllum calycinum, 158, 171, 483
proliferum, 166
Bryum cæspititium, 49
Bunias, 97, 136, 280, 360
Bunium creticum, 159
flexuosum, 20
Bupleurum, 149, 459
falcatum, 15, 20
BUTOMACEÆ, 507
Buxbaumia indusiata, 49
Byrsonima, 137
BYTTNERIACEÆ, 362
C.
Cabomba aquatica, 458
CACTACEÆ, 81, 113, 149, 395
Cactus, 160
Cachrys taurica, 197
Cæsalpinia, 365
digyna, 48
Cakile maritima, 246, 250
Calanthe, 227, 398, 402, 508
vestita, 39, 45, 227, 402, 508
Calceolaria, 41, 44, 230, 233, 284, 296, 397, 405, 406, 505
crenatifolia, 238
floribunda, 316
rugosa, 238
Calendula, 114, 138, 339, 370
officinalis, 252, 280, 339
Calla palustris, 357
Callitriche, 196
autumnalis, 406
vernalis, 406
Caltha, 136, 148, 295
palustris, 141, 250, 442, 500
Calluna, 296, 504
Calycophyllum, 249, 283, 429
Calystegia, 114, 296
Calystegia Sepium, 505
pubescens, 505
Camellia japonica, 288, 295, 297, 491, 494, 502
reticulata, 502
Sasanqua, 502
CAMPANULACEÆ, 80, 114, 127, 131, 138, 139, 150, 334
Campanula, 71, 72, 73, 82, 138, 150, 250, 285, 296, 365, 367, 404,
442, 472
canescens, 403
colorata, 403
glomerata, 242, 300, 504
latifolia, 504
Medium, 20, 37, 44, 61, 251, 448, 504
persicifolia, 44, 284, 300, 429, 504
pyramidalis, 281, 504
Rapunculus, 429
rapunculoides, 20, 252, 300, 310, 375
rhomboidea, 504
rotundifolia, 377, 378, 504
Tenorei, 504
thyrsoidea, 20
Trachelium, 504
Vidallii, 504
Campanumæa, 80, 81
Camphorosma monspeliaca, 456
Canna, 285
Cannabis, 82, 194, 197
sativa, 81
Cannamois virgata, 197
CAPPARIDACEÆ, 148, 390
CAPRIFOLIACEÆ, 45
Capsella bursa pastoris, 298, 361
Cardamine, 295, 357
hirsuta, 398
Impatiens, 404
pratensis, 65, 170, 181, 495, 500
sylvatica, 398
Carduus arvensis, 20
crispus, 166, 339
heterophyllus, 260, 262, 250
tataricus, 250, 260, 262
Carex, 115, 138, 150, 191, 194, 350
acuta, 143, 198
cæspitosa, 199
glauca, 143, 199
maritima, 369
paludosa, 199
vulpina, 428
Carica Papaya, 199
Carlemannia, 398
Carlina, 114
vulgaris, 20
Carpinus, 346
Betulus, 66
Carthamus, 138
Carum, 82, 114, 365
Bulbocastanum, 159
Carui, 244, 271, 285, 339, 437
CARYOPHYLLACEÆ, 99, 113, 120, 137, 139, 140, 148, 250, 379, 397, 398,
404, 406, 407, 410, 418, 442, 443, 448
Casuarina rigida, 325
Cassia, 364, 369
marylandica, 30
Castanea vesca, 11, 66, 104, 114, 319, 435
Catabrosa aquatica, 351
Catalpa, 399
Catasetum, 291, 296, 334
eburneum, 384
Cattleya amethystina, 401
Forbesii, 34, 384, 398
marginata, 223, 227
Mossiæ, 224, 227, 238
violacea, 383, 397
Caucalis leptophylla, 33
Caulophyllum, 75, 125
Caylussa, 137
Cedrus Libani, 61
CELASTRACEÆ, 149
Celastrus, 149
Celosia, 19, 20
Centaurea, 37, 114
collina, 34
Jacea, 43, 243
Scabiosa, 20
moschata, 44
Centranthus, 247
macrosiphon, 250
ruber, 42, 44
Cephalotus follicularis, 314
Cerastium, 62, 97, 262, 397, 398
glomeratum, 280, 358, 463
tetandrum, 463
triviale, 252, 280
vulgatum, 252, 404
Cerasus, 74, 117, 149, 250, 260, 424, 489
avium, 262
caproniana, 364
Lauro-cerasus, 64, 66, 370
vulgaris, 252, 262
Ceratonia Siliqua, 30
Cercis, 364
siliquastrum, 325
Chamærops humilis, 300
Chærophyllum, 113
Cheiranthus, 121, 131, 136, 148, 295, 364
Cheiri, 20, 33, 35, 36, 250, 252, 271, 404, 427, 500
var. gynantherus, 305, 310
Cheiranthus incanus, 250
Chelone, 361
barbata, 238
Chelidonium majus, 66, 170, 280, 295, 500
CHENOPODIACEÆ, 397, 405, 406
Chenopodium, 45, 365, 367
glaucum, 397
murale, 428
Quinoa, 62, 66
Vulvaria, 458
Chirita sinensis, 170
Chlorophytum Sternbergianum, 107
Chorozema ilicifolium, 21
Chrysanthemum, 16, 72, 365
indicum, 20, 188, 472
Leucanthemum, 20
Chrysosplenium, 367
Cichorium Intybus, 20, 44
Cicuta virosa, 406
CINCHONACEÆ, 429
Cionidium Moorei, 190
Cirsium, 114, 138
arvense, 250, 457
lanceolatum, 20
tricephalodes, 252, 339
Cissus, 211
CISTACEÆ, 137
Cistus vaginatus, 473
Citrus, 137, 149, 364, 453
Aurantium, 33, 35, 44, 56, 75, 134, 303, 310, 335, 369, 388, 389,
391, 502
Clarkia, 24, 295
elegans, 177, 503
pulchella, 503
Cleistanthus polystachyus, 198
Clematis, 136, 148, 288, 295, 367
florida, 499
Fortunei, 499
patens, 499
Viticella, 28, 499
Cleome, 137, 148
Cleonia lusitanica, 238
Clerodendron fragrans, 506
Cliffortia, 396
Clinacium dendroides, 49
Clitoria Ternatea, 231, 238, 295, 502
Clusia rosea, 11
Cluytia semperflorens, 198
Cneorum, 365
Cnicus palustris, 20
Cnidium, 113
Cobæa scandens, 73, 82, 272, 326, 365
Coccoloba platycladon, 328
Cochlearia Armoracia, 64, 299, 310, 331
Cocos, 115, 365
nucifera, 429
Codiæum variegatum, 31, 314, 326, 328, 459
Coelebogyne ilicifolia, 369
Cola acuminata, 370
Colchicum autumnale, 45, 67, 73, 250, 287, 296, 406, 407, 507
Coleus, 365, 459
Columnea Schiedeana, 226
Columbine, see _Aquilegia_
Colutea, 465
Commelyna, 73, 296, 507
COMMELYNACEÆ, 245, 507
COMPOSITÆ, 72, 73, 86, 107, 114, 127, 131, 138, 165, 223, 226, 235,
339, 406, 407, 430, 434, 437, 439, 442
Conceveiba macrophylla, 198
CONIFERÆ, 56, 65, 103, 114, 191, 245, 369, 435
Conium maculatum, 114
Conostephium, 120
Convallaria maialis, 73, 150, 250, 296, 360, 367, 375, 400, 442, 507
Polygonatum, 507
CONVOLVULACEÆ, 114, 137, 150
Convolvulus, 73, 114, 137, 142, 150,
296, 510
arvensis, 20
Sepium, 20, 108, 250
tricolor, 505
Conyza squarrosa, 20
Corallorhiza innata, 238
Circeia, 410
Corchorus acutangulus, 397
Coreopsis, 20, 73, 114, 138
Drummondi, 339
Cornus, 37, 44, 358
mas, 358, 374
sanguinea, 44
suecica, 374
Coronilla, 106, 113, 149, 295
Emerus, 502
Correa, 72, 73, 370
Cortusa Mathioli, 133, 138, 263
Corydalis aurea, 280
solida, 243
tuberosa, 235, 336, 238
Corylas Avellana, 21, 31, 48, 66, 114,
349, 354, 364, 365, 368
Cotoneaster microphylla, 21
Cotula foetida, 19, 20
CRASSULACEÆ, 113
Crassula, 113
arborescens, 26, 31
Cratægus, 82, 113, 149, 295, 364, 404, 419
Crus galli, 503
monogyna, 44, 400
Cratægus Oxyacantha, 57, 66, 78, 317, 370, 503, 508
tanacetifolia, 107, 162
Crepis, 271
virens, 20
Crinum, 432
Crocus, 29, 35, 45, 67, 287, 289, 296, 319, 361, 399, 400, 434, 462
aureus, 506
nudiflorus, 302
pusillus, 506
vernus, 506
Crozophora tinctoria, 198
CRUCIFERÆ, 73, 76, 98, 113, 136, 139, 141, 148, 257, 297, 364, 379,
406, 410, 428, 442, 500
Cryptomeria japonica, 103, 114, 245, 435
Cucubalus, 149
Cucumis, 36, 82, 138, 248, 259, 326, 367
CUCURBITACEÆ, 71, 80, 81, 137, 247
Cucurbita, 197, 201, 250, 307, 310, 365, 474
Cuphea miniata, 211, 424
Cupressus funebris, 218
CYCADEÆ, 56, 369
Cyclamen, 67, 104, 114, 296, 319, 359, 360
linearifolium, 329
Cyclodon, 80
Cydonia vulgaris, 71, 79, 295, 423
japonica, 503
Cynanchum fuscatum, 369
nigrum, 369
Cynosurus cristatus, 169
CYPERACEÆ, 115, 138, 150, 169, 350
Cypripedium, 27, 92, 381, 386
candidum, 401
Hookeræ, 386
insigne, 91
Cyrtanthus, 177
Cytisus, 113, 295, 336
albus, 502
Laburnum, 21, 66, 157, 189, 222, 226, 231, 238, 356, 459
nigricans, 15, 104
D.
Dactylis, 115
glomerata, 169
Dahlia, 44, 72, 188, 244, 433
variabilis, 20
Danaë, 60
Daphne indica, 21
odora, 21
Datura, 285, 291, 296, 365, 378, 407
Datura arborea, 505
cornigera, 505
chlorantha, 505
fastuosa, 296, 379, 450, 505
humilis, 505
Daucus Carota, 53, 57, 82, 113, 121, 124, 125, 137, 149, 244, 250, 252,
256, 260, 262, 296, 298, 339, 365, 368, 369, 370, 457, 504
Delphinium, 44, 136, 148, 225, 283, 286, 295, 344, 364, 367, 374, 388,
399, 407
Ajacis, 250, 252, 261, 271, 339, 500
amoenum, 261
cheilanthum, 500
Consolida, 373, 500
crassicaule, 252, 256, 261, 271, 339
dictyocarpum, 271, 432
elatum, 20, 126, 237, 238, 261, 267, 271, 309, 310, 339
elegans, 500
grandiflorum, 500
peregrinum, 219, 226
Dendrobium, 227
nobile, 94, 398
normale, 224, 383
Desmodium canadense, 271
marylandicum, 467
Deutzia, 295
crenata, 503
Dianthus, 67, 113, 121, 129, 137, 139, 145, 146, 149, 166, 261, 268,
289, 295, 297, 310, 360, 364, 371, 379, 397, 471
arboreus, 501
barbatus, 325, 404, 501
Caryophyllus, 501
corymbosus, 501
deltoides, 501
hybridus, 501
plumarius, 501
Poiretianus, 501
sinensis, 370, 501
Dictamnus, 121, 122, 137, 140
albus, 256, 271
Fraxinella, 252, 262, 271, 278, 280
Dielytra, 236, 237
Digitalis lutea, 60
orientalis, 238
purpurea, 20, 40, 44, 73, 98, 121, 129, 137, 150, 226, 233, 238,
296, 298, 315, 365, 373, 398, 459, 472, 505
DILLENIACEÆ, 398
Dionæa, 308
Muscipula, 310
Diosma, 369
Diphaca, 365
Diplotaxis, 136, 148, 364
muralis, 252, 458
tenuifolia, 73, 250, 261, 274, 280, 397, 398, 430
DIPSACACEÆ, 86, 107, 114, 138
Dipsacus, 419, 429
fullonum, 20, 62, 66, 281, 320, 321, 325
Gmelini, 325
pilosus, 20, 325
sylvestris, 10, 20
Dipterocarpus, 249
Ditaxis lancifolia, 380
Dodecatheon, 138
Dodonæa viscosa, 20
Draba, 364
Dracocephalum austriacum, 238
moldavicum, 20
speciosum, 320, 325
Dracontium pertusum, 25
Drosera intermedia, 170, 265, 271, 277, 473
E.
Ebenus cretica, 26
Eccremocarpus scaber, 222, 226, 326
Echeveria, 113
Echinophora maritima, 252
Echium pyrenaicum, 20
simplex, 20
vulgare, 374
Echinocactus, 149, 178, 417
Elegia, 115
Empetrum nigrum, 197
Encamptodon perichætialis, 174
EPACRIDACEÆ, 120, 137
Epacris, 103, 137
impressa, 61, 379, 504
Epidendrum, 114
elongatum, 107
Stamfordianum, 401
Epimedium, 23, 226
Musschianum, 390
Epiphyllum, 328
Epipactis palustris, 325
Epilobium, 81, 137, 273
angustifolium, 20
hirsutum, 246, 250, 252, 256, 262,
281, 442
palustre, 271
tetragonum, 503
Episcia bicolor, 170
EQUISETACEÆ, 189, 350
Equisetum, 61, 325
fluviatile, 325
limosum, 325
Telmateia, 323, 325
Eranthis hyemalis, 23, 70
ERICACEÆ, 114, 119, 137
Erica, 21, 73, 137, 296
cinerea, 504
hyemalis, 378, 504
multiflora, 372
Tetralix, 286, 310, 405, 406, 504
Eriobotrya japonica, 295
Erodium, 463
Ervum Lens, 20, 25, 66
Erucago, 136
Erucastrum Pollichii, 271
canariense, 280
Eryngium, 113, 368, 442
viviparum, 104
Erysimum, 136, 148
Barbarea, 252
cheiranthoides, 252
officinale, 252
Erythrochiton hypophyllanthus, 32, 174
Escholtzia crocea, 250
Eucomis, 103
Eugenia Jambos, 369
Euonymus japonicus, 20
latifolius, 369
EUPHORBIACEÆ, 114, 150, 369, 395
Euphorbia, 114, 150, 365, 371, 395
Characias, 20
Cyparissias, 20, 244
Esula, 198, 307, 310
exigua, 20
geniculata, 253, 256
helioscopia, 56
Lathyris, 244
rosea, 369
palustris, 106, 299
Peplus, 162
pusilla, 244
segetalis, 281
F.
Faba, see _Vicia_
vulgaris, 397
Fabiana, 237
Fagus silvatica, 65, 66, 197, 318, 370, 459
Festuca, 115
nemoralis, 169
ovina, 169
Ficaria, (see _Ranunculus Ficaria_)
ranunculoides, 70, 295, 500
FICOIDEÆ, 43
Ficus Carica, 114, 204, 435
stipulata, 332
Filago, 114
germanica, 108
FILICES, 21, 190, 447
Fourcroya, 115
Fragaria, xxxvi _adnot._, 250, 295
alpina, 271
botryformis, 47
monophylla, 396
vesca, 20, 70, 116, 195, 275, 281, 406, 503
Fraxinus excelsior, 13, 21, 66, 325, 396, 421
Ornus, 21
Fritillaria imperialis, 21, 45, 296, 462, 506
Meleagris, 506
Fuchsia, 35, 38, 44, 57, 81, 91, 127, 199, 247, 250, 288, 290, 291,
292, 294, 295, 316, 359, 360, 364, 367, 400, 443
globosa, 503
Funckia, 369
G.
Gagea, 365, 367
arvensis, 375, 508
Gaillardia, 269, 271
Galanthus, 296
nivalis, 300, 506
Galeobdolon luteum, 226, 238
Galeopsis, 429
Ladanum, 238
ochroleuca, 44
Tetrahit, 429
Galium Aparine, 205, 325
Mollugo, 321, 325
verum, 325
Gaudichaudieæ, 334
Gardenia, 296, 377
florida, 504
Fortuniana, 504
radicans, 504
Gaura biennis, 20
Genista, 295
tinctoria, 502
sibirica, 502
Scoparia, 502
GENTIANACEÆ, 137, 150, 505
Gentiana, 71, 73, 137, 150, 252, 296
Amarella, 166, 305, 310, 371, 505
campestris, 250, 299, 442
purpurea, 389
GERANIACEÆ, 113, 137, 501
Geranium, 20, 137, 221, 246, 250, 252, 292, 295, 418
columbinum, 461
nodosum, 34, 65
pratense, 501
sylvaticum, 501
GESNERACEÆ, 38, 114, 222, 505
Gesnera, 33, 44, 95, 171, 339, 357, 427
Geroltiana, 88, 89
zebrina, 355
Geum, 121, 137, 465
coccineum, 275
rivale, 122, 130, 131, 250, 252, 281, 503
Gilia capitata, 281
glomeruliflora, 253, 271
Gladiolus, 21, 296
tristis, 506
Glancium luteum, 66
Gleditschia, 30, 177, 364
triacanthos, 44, 48
Glochidion, 310
Gloxinia, 171, 206, 207, 222, 226, 238, 284, 291, 296, 365, 451, 506
Glyceria aquatica, 169
fluitans, 169, 278
Godetia, 295, 510
Godoya, 374
Gomphia, 281
Gongora, 35
Goodenia ovata, 21, 31
GRAMINACEÆ, 115, 138, 278, 350, 391
Gratiola, 296
Guarea, 508
Gypsophila, 149
H.
Habenaria, 138, 238
chlorantha, 382
Halenia, 222
heterantha, 222, 226
Hedera Helix, 65
Hedypnois, 114
Helianthemum, 132, 137, 295, 404
vulgare, 501
Helianthus, 38, 44, 66
annuus, 20
tuberosus, 20
Helleborus, 23, 288
foetidus, 442
olympicus, 284
Heliotropium peruvianum, 510
Helwingia, 174
Hemerocallis, 138, 296, 310, 507
disticha, 507
fulva, 507
Hepatica, 295, 463
triloba, 500
Heracleum, 82, 113, 137, 150, 262, 365, 368
Sphondylium, 252, 256, 339
Hermesia castaneifolia, 194
Herreria parviflora, 141, 150
Hesperis, 19, 136, 295
matronalis, 20, 252, 280, 325, 500
Heterocentron, 354
Hibiscus, 137, 293, 295, 297, 360, 510
albus, 501
flavescens, 501
Rosa sinensis, 501
Syriacus, 20, 501
Hieracium, 138
aureum, 17
præaltum, 339
Pilosella, 20
umbellatum, 20
HÏPPOCASTANEÆ, 501
Hippeastrum, 296
equestre, 506
Hippuris, 196
vulgaris, 325, 406
Hodgsonia, 326, 474
Holeus mollis, 169
Honckenya peploides, 196, 406, 461
Hordeum, 115, 351
nepalense, 174, 175
trifurcatum, 174, 175
Humulus Lupulus, 193, 244, 435, 472
Hyacinthus, 138, 150, 262, 296, 360, 361, 486 _adnot_
comosus, 409
orientalis, 21, 45, 48, 54, 172, 189, 286, 299, 348, 507
Pouzolzii, 170
Hydrangea, 417
Hydrocera triflora, 359
HYDROCHARIDACEÆ, 506
Hydrocharis, 296
morsus ranæ, 506
Hydrocotyle, 113
HYDROPHYLLACEÆ, 138
Hydrophyllum, 138
Hymenocallis, 404
americana, 462, 463
Hyoscyamus, 430
Hypericum, 442
perforatum, 369, 458
Hypnum triquetrum, 49
Hypochæris, 73, 138
radicata, 250, 339, 437, 457
Hyssopus officinalis, 20, 325
I.
Iberis, 295, 364
amara, 500
umbellata, 500
Ilex Aquifolium, 21, 66, 447
Impatiens, 161, 231, 295, 299
Balsamina, 238, 502
Imperatoria, 82
Indigofera, 459
Inula, 20
Ionopsidium acaule, 362
Ipomoea, 296, 510
pandurata, 505
IRIDACEÆ, 138, 506
Irina, 64
glabra, 65
Iris, 138, 286, 296, 359, 360, 361, 365, 401, 430
Kæmpferi, 506
sibirica, 506
versicolor, 45
Isochilus, 386
Ixia carminosa, 84
Ixora, 296
grandiflora, 504
J.
Jasione, 20, 114
JASMINACEÆ, 137, 504
Jasminum, 137, 296, 360, 400
grandiflorum, 288, 505
hirsutum, 505
nudiflorum, 21
officinale, 21, 505
Sambac, 505
Jatropha Pohliana, 254, 256
Juglans, 244, 400
nigra, 396
regia, 66, 193
JUNCACEÆ, 115, 167, 169
Juncus, 115, 317
articulatus, 431
conglomeratus, 325
uliginosus, 107
Juniperus virginiana, 194
sinensis, 217
Jussicua, 81, 180
Justicia oxyphylla, 25
K.
Kerria, 295
Knautia arvensis, 20, 114
Kochia Scoparia, 430
L.
LABIATÆ, 138, 429
Laburnum (see _Cylisus_), 65, 157, 189, 222, 226
Lacistema, 359
Lactuca, 114
sativa, 11, 20, 33, 44, 313
Lambertia, 365
Lampsana, 114
Lamium, 73, 238, 361
album, 62, 63, 66, 86, 409
amplexicaule, 404
purpureum, 66, 325, 404
Larix, 114
europæa, 21, 90, 245, 435
microcarpa, 192
Lathyrus latifolius, 262
tuberosus, 30
Laurus, 296, 362
nobilis, 506
Sassafras, 250, 331, 506
Lavatera trimestris, 20
Lebeckia, 459
Lecythis, 149, 180
LEGUMINOSÆ, 48, 71, 73, 106, 113, 122, 137, 139, 146, 147, 149, 272,
276, 429, 434, 444
Leitneria floridana, 194
Leontice, 125
Leontodon, 17, 20, 44, 163, 243, 442
Lepidium, 148, 364
sativum, 57
Lepyrodia hermaphrodita, 197
Leskea sericea, 49
Leucanthemum, 86
Leucobryum giganteum, 194
Leucoium, 150, 296
æstivum, 84, 138, 350
vernum, 350, 506
Lilium, 73, 106, 115, 296, 367, 375, 421
auratum, 73, 289, 400
bulbiferum, 45
candidum, 21, 286, 325, 375, 507
cruentum, 21
lancifolium, 35, 400, 443
longiflorum, 310
Martagon, 21, 286, 325, 507
tigrinum, 306, 310
Linaria, 137, 229, 230, 233, 296, 316, 361, 365, 367, 405
æruginea, 238
chalepensis, 238
Cymbalaria, 238
decumbens, 238
Elatine, 238
origanifolia, 238
Pelisseriana, 238
pilosa, 238
purpurea, 20, 44, 238
spuria, 238
triphylla, 238
vulgaris, 162, 226, 234, 235, 238, 316, 374, 505
triornithophora, 238
Linum, 335
Linum usitatissimum, 20
Liquidambar, 362
Listera ovata, 398
LOBELIACEÆ, 72, 114
Lobelia, 211, 424
Lolium, 86, 113, 115, 351
perenne, 61, 169, 325
Lonicera, 38, 44, 73, 82, 226, 271, 281, 296, 297
brachypoda, 358
Caprifolium, 408
Periclymenum, 66, 226, 251, 256, 262, 263, 338, 379, 404, 406, 504
Xylosteum, 252, 358
Lopezia, 298, 410
Lotus, 113, 295, 360, 510
corniculatus, 104, 377, 436, 502
uliginosus, 363
Lowea, 396
Lunaria, 136, 364
Lupinus, 106, 165, 226, 280
polyphyllus, 238
Lycaste Skinneri, 93, 95, 291
Lychnis, 113, 137, 148, 295
chalcedonica, 501
Coronaria, 107, 510
dioica, 67, 252, 262, 280, 404, 464
flos cuculi, 501
sylvestris, 252, 501
vespertina, 501
Viscaria, 501
Lycium, 365, 367
europæum, 250
Lycopersicum, see _Solanum_
esculentum, 389
Lysimachia, 119
Ephemerum, 271, 281
nummularia, 505
vulgaris, 20, 87
Lythrum, 335
Salicaria, 374
M.
Mælenia, 403
Mæsa, 145, 371
MAGNOLIACEÆ, 122
Magnolia, 288, 388, 440
Campbelli, 427
fuscata, 304, 310, 427
MALPIGHIACEÆ, 137, 334, 403, 404, 406
Malus, 78, 79, 388, 389, see _Pyrus_
MALVACEÆ, 137, 149, 288, 292, 295, 362, 395
Malva, 295
crispa, 448
moschata, 501
rotundifolia, 501
sylvestris, 252
Mangifera, 159, 369
Marchantia, 174
Marcgraavia, 23
umbellata, 332
Masdevallia, 27, 95
Mathiola, 136, 148, 295
annua, 361, 500
incana, 20, 38, 44, 68, 299, 500
glabrata, 500
Matricaria Parthenium, 281
Maxillaria, 383
Medicago, 137, 149, 262, 295, 364, 502
lupulina, 404, 432
maculata, 218, 271
Melastoma, 74, 125, 424
Melia Azedairach, 21
Melianthus major, 298, 407
Melilotus, 137, 139, 147, 149, 262
arvensis, 374
leucantha, 432
macrorhiza, 271
officinalis, 404
Melittis, 361
Mentha, 238, 361, 459
aquatica, 325
viridis, 325
Mercurialis, 62, 194, 365
annua, 198
perennis, 66
Mesembryanthemum, 26
Metrosideros, 103
Miconia, 355
Mimosa, 365
Lophantha, 31
Mimulus, 73, 284, 296
luteus, 505
Mnium serratum, 49
Mirabilis, 296, 418
Jalapa, 506
Modecca, 326
Mollugo Cerviana, 398
Momordica Elaterium, 20
Monarda fistulosa, 298
Morus, 193, 354, 459
Mozinna, 399
peltata, 194
Musa, 245, 407
Muscari, 408, 461
comosum, 340, 467
MUSCI, 174
Mussænda, 249, 283, 429
Myosotis cæspitosa, 281
palustris, 375
scorpioides, 20
Myosurus, 440
Myristica moschata, 194
MYRTACEÆ, 80, 149, 362, 395
Myrtus, 295, 310
communis, 503
N.
Narcissus, 21, 67, 138, 286, 296, 360, 365, 443
aureus, 506
biflorus, 34, 45, 506
chrysanthus, 38, 45
concolor, 506
Cypri, 506
Jonquilla, 506
incomparabilis, 38, 45, 301, 506
italicus, 506
lobularis, 506
major, 154
montanus, 301
poculiformis, 506
poeticus, 24, 33, 301, 506
pseudo-narcissus, 506
Tazetta, 45, 300, 506
Telamonius, 506
Nasturtium, 136, 271
amphibium, 181
Nelumbium, 295
speciosum, 500
Nepeta diffusa, 238
Nepenthes, 328, 473
Nephrodium molle, 447
Nerium Oleander, 62, 66, 296, 301, 377
odorum, 505
Neuropeltis, 32
Nicandra physaloides, 458
Nicotiana, 23, 31, 73
rustica, 281
Nigella, 220, 262, 295, 297, 364, 374, 399
damascena, 226, 269, 271, 286, 375, 500
Nuytsia, 371
NYMPHÆACEÆ, 148
Nymphæa, 50, 141, 143, 148, 285, 295
alba, 162
dentata, 256, 261
guineensis, 170
Lotus, 277, 280
O.
Octadenia, 364
Odontoglossum Alexandræ, 387, 403
Uro Skinneri, 463
OEnanthe, 82, 114, 360, 365, 457
crocata, 80, 359, 457
OEnothera, 44, 367
striata, 252
Olea europoea, 21, 157, 420
ONAGRACEÆ, 81, 137, 406, 503
Oncidium, 67, 114, 227
abortivum, 462
bicolor, 45
Cebolleta, 107
Oncidium cucullatum, 91
heteranthum, 224
ornithorhyncum, 43
Ononis minutissima, 404
monophylla, 396
Opercularia, 38
Ophrys, 114
apifera, 360, 398
aranifera, 35, 42, 45, 238, 298, 383, 384, 385, 386, 398
insectifera, 27, 301, 382
fucifera, 506
Opuntia, 81, 113, 149, 180
fragilis, 107, 178
monacantha, 178
Salmiana, 107, 178, 179
ORCHIDACEÆ, 27, 34, 42, 91, 112, 114, 128, 138, 150, 153, 209, 223,
290, 345, 360, 366, 367, 380-387, 397
Orchis, 138, 150, 153, 154, 227, 296
conopsea, 238
latifolia, 238
mascula, 153, 154, 238, 299, 387, 506
militaris, 387
Morio, 238, 382, 384, 387, 506
palustris, 366
papilionacea, 238
pyramidalis, 128, 238, 506
sambucina, 63, 66
simia, 238
Ornithogalum, 114, 360, 365, 367
longebracteatum, 171
OROBANCHACEÆ, 137
Orobanche, 73, 137, 209, 296, 505
gracilis, 442
Orobus, 295
vernus, 502
viscosus, 502
Ouvirandra, 458
OXALIDACEÆ, 403
Oxalis, 295, 329, 404, 459
Acetosella, 404
carnea, 502
P.
Pæonia, 295, 300, 364, 399, 407
Moutan, 500
officinalis, 261
paradoxa, 500
tenuiflora, 500
PALMACEÆ, 155
Panax, 331
Papaver, 289, 295, 297, 473
bracteatum, 28, 304, 310, 500
nudicaule, 310
orientale, 250
Papaver Rhoeas, 429, 458, 500
somniferum, 28, 305, 310, 500
PAPAVERACEÆ, 99, 500
PAPILIONACEÆ, 397, 502, see _Leguminosæ_
Paris quadrifolia, 31, 358, 360, 367, 396
Paritium, 137
Parnassia, 364
Paronychia serpyllifolia, 473
Parthenium inodorum, 243
Passiflora, 137, 201, 301, 365, 463, 473
coerulea, 185
palmata, 185
quadrangularis, 181
PASSIFLORACEÆ, 137
Pastinaca, 82
sativa, 272
Pavia, 137
Pedicularis, 238
euphrasioides, 238
sylvatica, 44, 223, 226, 238
Peganum, 363
Pelargonium, 22, 23, 25, 63, 107, 113, 208, 221, 225, 295, 336, 360,
373, 389, 418, 419, 434
grandiflorum, 86
inquinans, 30, 226
zonale, 106, 226, 501
Peltaria, 137
alliacea, 250, 251, 252
Pentstemon, 226, 455
Pereskia, 107, 113, 149
Bleo, 179
Perilla, 459
Persica (_Amygdalus_)
vulgaris, 44, 250, 252, 503
Petalostylis, 296
Petunia, 254, 256, 291, 296
nyctaginiflora, 505
violacea, 34, 44, 250, 253, 505
Phaius grandiflorus, 107, 509, 510
Phalænopsis, 238
amabilis, 227
equestris, 231, 238
Schilleriana, 224
Pharbitis, 73
Phaseolus, 21, 298, 364
PHILADELPHACEÆ, 113, 137, 149
Philadelphus, 113, 137, 142, 149, 295, 364, 367
coronarius, 503
speciosus, 178, 298
Philyra brasiliensis, 198
Phleum, 115, 138
phalaroides, 169
pratense, 325
Phlomis, 138
biloba, 72
fruticosa, 119, 238
Phlox, 73
Phoenix dactylifera, 318
Phylica, 325
Phyllanthus longifolius, 198
Phyllarthron, 64, 396
Phyteuma odoratum, 271
orbiculare, 20
spicatum, 166, 252
Phytolacca, 20
Picea, see _Abies_
Lowii, 203
nobilis, 203
Nordmanniana, 203
Webbiana, 203
Picrasma, 509
Pimpinella magna, 66
Saxifragra, 66
Pinckneya, 429
Pinus, 11, 19, 114, 318, 346, 471, (see _Abies_, _Larix_, _Cedrus_)
alba, 192
pinea, 90, 218
Pinaster, 13, 21
sylvestris, 21, 349
Pistacia Lentiscus, 197
Pisum, 137, 295
sativum, 27, 30, 31, 95, 166, 302, 372, 432, 472, 502, 510
Platycodon, 296
grandiflorum, 504
PLANTAGINACEÆ, 114
Plantago, 114, 136
Coronopus, 458
lanceolata, 61, 104, 108, 110, 111, 243
media, 20, 111
major, 65, 108, 109, 111, 243, 372, 374
maritima, 108
Platanus, 50
Plectranthus fruticosus, 238
PLUMBAGINACEÆ, 114
Plumbago, 360
Poa alpina, 169
annua, 169
bulbosa, 169
pratensis, 169
trivialis, 169
Podalyria myrtillifolia, 44
Podocarpus, 426
Podophyllum, 295
peltatum, 500
Podospermum laciniatum, 247, 250
Poggendorffia, 294
Pogonia ophioglossoides, 238, 386
Poinsettia, 340
Polemonium coeruleum, 20, 66, 253, 305, 310, 404
Polianthes, 296
Polygala vulgaris, 399
POLYGONACEÆ, 114, 138, 150
Polygonatum anceps, 42, 45
multifolium, 23, 31
Polygonum, 114, 365
orientale, 31, 390
viviparum, 106, 169
Polypodium anomalum, 190
POMACEÆ, 70, 71, 77, 79, 142, 405, 503
Pomaderris elliptica, 355
Pomax, 38
Populus, 202, 309
alba, 66
Portulaca, 295
Potamogeton, 329
bifolium, 434
Potentilla, 139, 140, 149, 295, 374, 438
alpestris, 503
argentea, 280
anserina, 503
major, 374
nepalensis, 250, 252, 275, 280
reptans, 503
Tormentilla, 503
Poterium, 113
Sanguisorba, 107
polygamum, 281
Primula, 71, 73, 114, 121, 138, 150, 296, 335, 360, 365, 367
acaulis (see _vulgaris_), 45, 248, 250, 308, 310, 377, 504
Auricula, 45, 133, 271, 282, 504
denticulata, 20, 504
elatior, 45, 250, 504
calycanthema, 283
imperialis, 103
officinalis, 250, 283
prænitens, 271, 504 (see _sinensis_)
sinensis, 24, 45, 95, 98, 103, 133, 253, 256, 262, 263, 271, 281,
297, 314, 315, 389, 429, 441, 449
variabilis, 104
veris, 17, 20, 35, 39, 45, 105, 164
villosa, 504
vulgaris, 17, 70, 106 (see _acaulis_ and _officinalis_)
PRIMULACEÆ, 98, 114, 118, 121, 133, 138, 150, 262, 339, 366, 504
Prismatocarpus, 114, 150, 178
Prunella vulgaris, 226
Prunus, 137, 203, 295, 300, 360, 364, 367 (see _Cerasus_, _Amygdalus_,
_Persica_)
Armeniaca, 44
Cerasus, 74
domestica, 366, 464
Lauro Cerasus, 21, 446
spinosa, 44
Prunus sylvestris, 21
Pseudostachyum polymorphum, 168
Psittacanthus, 371
Ptelea, 364
Pterandra, 290
Pteridophyllum, 331
Pterisanthes, 328
Pteris quadriaurita, 333
Punica Granatum, 21, 295, 325
Pyrethrum, 114
inodorum, 431
Parthenium, 339
Pyrus, 82, 107, 113, 121, 137, 149, 203
communis (Pear), 36, 66, 162, 178, 422, 423, 503
dioica, 304
japonica, 161
Malus (Apple), 44, 78, 79, 166, 210, 250, 282, 295, 310, 325, 327,
375, 406, 420, 503
spectabilis, 508
torminalis, 325
Q.
Quercus, 51
Cerris, 66
pubescens, 66
R.
Raphanus sativus, 161, 252, 327, 360, 369
RANUNCULACEÆ, 113, 122, 136, 148, 195, 246, 339, 410, 499
Ranunculus, 19, 55, 113, 119, 258, 288, 295, 296, 297, 360, 367, 407
aconitifolius, 500
acris, 67, 250, 436, 500
aquatilis, 458
asiaticas, 500
auricomus, 195, 285, 397, 406, 461, 469
bulbosus, 17, 20, 44, 195, 406, 500
bullatus, 500
Ficaria, 70, 96, 195, 261, 368, 406
fluitans, 433, 437
gramineus, 500
Lingua, 44, 67
Philonotis, 20, 339
tripartitus, 20, 46
repens, 23, 252, 261, 500
RESEDACEÆ, 137, 148
Reseda, 67, 137, 141, 148
lutea, 252, 271
Luteola, 61, 112, 399
odorata, 20, 44, 280
Phyteuma, 252, 261
RESTIACEÆ, 115, 167, 189, 350, 463
Restio, 115, 194
Rhamnus catharticus, 463
Frangula, 280
Rhinanthus crista galli, 238
Rhodiola rosea, 197
Rhodora, 73
Rhododendron, 72, 73, 91, 133, 137, 176, 289, 290, 296, 453
indicum, 504
linearilobum, 72
Rhus Cotinus, 62, 66, 348, 409, 467, 472
Toxicodendron, 66
Ribes, 296
nigrum, 66, 296
sanguineum, 503
Richardia æthiopica, 337, 358
Ricinus communis, 198, 300
Ricotiana, 364
Robinia, 365
Pseudacacia, 44, 204, 317, 325, 396
ROSACEÆ, 70, 71, 77, 80, 113, 121, 122, 137, 149, 246, 274, 405, 406,
502
Rosa, 21, 77, 79, 82, 113, 121, 130, 137, 139, 149, 151, 152, 162,
176, 184, 185, 186, 204, 246, 247, 250, 257, 258, 262, 271, 274,
288, 289, 295, 367, 368, 394, 473, 502
alpina, 209
arvensis, 307, 310, 404
Banksiæ, 502
berberifolia, 396
canina, 502
centifolia, 31, 502
Carolina, 502
cinnamomea, 502
damascena, 502
diversifolia, 280
Eglanteria, 502
gallica, 31, 502
indica, 502
moschata, 502
nivea, 502
pimpinellifolia, 502
rubiginosa, 502
spinosissima, 502
sulphurea, 502
RUBIACEÆ, 45, 80
Rubia tinctorum, 322, 325
Rubus, 137, 252, 279, 399, 406, 429, 465
arcticus, 67
cæsius, 281, 285, 502
corylifolius, 502
fruticosus, 66, 281, 374, 380, 461, 502
Idæus, 396
rosifolius, 502
Rudbeckia, 82, 114, 127
Ruellia clandestina, 403, 404
Rumex, 45, 138, 150, 325
arifolius, 278, 281
crispus, 304, 310, 448
scutatus, 278, 281, 431
Ruscus, 328, 470
aculeatus, 60, 318, 348, 445
Russellia juncea, 20
RUTACEÆ, 137, 149
Ruta, 363, 367, 371
S.
Sagina, 397
procumbens, 501
Sagittaria, 296, 329
latifolia, 507
sagittifolia, 325, 507
Salisburia adiantifolia, 61
Salix, 166, 168, 244, 310, 326, 349
babylonica, 202, 257, 262, 299, 309, 326
calyculata, 29
capræa, 271, 299
cinerea, 41, 45, 189, 299
fragilis, 357
monandra, 29
nigricans, 299
pendula, 357
repens, 194
silesiaca, 299
vitellina, 21
Salpiglossis straminea, 44
Salvia, 226
officinalis, 66
pratensis, 36
Verbenaca, 87
Sambucus, 296, 359, 360, 365, 367
nigra, 21, 55, 66, 164, 325, 396
racemosa, 66
Sanguinaria, 295
canadensis, 500
Sanguisorba, 113
officinalis, 107
SANTALACEÆ, 122, 138, 150
SAPINDACEÆ, 137, 448
Saponaria, 28, 67, 76, 149, 295, 297, 300, 360, 379
officinalis, 97, 301, 501
Sarothamnus, 360, 363
Scoparius, 363
Saxifraga, 33, 44, 106, 113, 296, 390
crassifolia, 307, 310
decipiens, 288
foliosa, 281
granulata, 298, 504
irrigua, 20
longifolia, 404
Saxifraga mutata, 20
SAXIFRAGACEÆ, 80, 81
Scabiosa, 35, 106, 114, 138, 141, 296, 297, 429
agrestis, 252
arvensis, 325
atropurpurea, 62, 66
Columbaria, 252, 281
Scandix, 125
Schismatopera distichophylla, 194
Schoenodorus, 364 _adnot_
Schoenus cephalotes, 245
Schoenodon, 365
Sciadopitys verticillata, 352
Scilla, 296
autumnalis, 507
nutans, 507
Scirpus lacustris, 325
Scolopendrium D'Urvillei, 332
vulgare, 64, 314, 326, 328, 459, 467
Scorzonera, 19
octangularis, 247, 250
Scrophularia, 114, 455, 463
aquatica, 226, 238, 262, 281
arguta, 334
nodosa, 44, 106, 281
SCROPHULARIACEÆ, 114, 121, 137, 150, 222, 505
Secale cereale, 55, 115
Sechium edule, 81, 202
Sedum cristatum, 18, 20
reflexum, 20
Selenipedium caudatum, 224, 227
Selinum, 82, 114
caruifolium, 281
Sempervivum, 105, 113, 204, 509
montanum, 310
sediforme, 164
tectorum, 292 _adnot_, 308, 310
Senecio, 44, 114
vulgaris, 247, 250, 252, 339, 432, 437, 439, 457
Serissa, 296, 377, 504
Sesamum, 365
indicum, 238
Seseli, 113, 281
coloratum, 166
Sideritis, 238, 365
Silaus, 113, 365
Silene, 44, 137, 148, 295, 301
conica, 68
Otites, 464
inflata, 501
Sinapis, 57, 136, 270, 295, 371
arvensis, 181, 250, 261, 264, 271, 280, 501
Sinningia purpurea, 431
Sisymbrium, 136
officinale, 250, 261, 271, 280
Sisymbrium tenuifolium, 252
Slateria, 74
SOLANACEÆ, 150, 430, 505
Solanum, 73, 125, 150, 296, 360, 365, 367, 370, 424, 453
amazonicum, 430
Dulcamara, 66, 288, 430, 504
esculentum, 74
cornutum, 430
Lycopersicum, 38, 44, 74, 171, 391, 442
tridynamum, 430
tuberosum, 54, 142, 288, 333, 420
Vespertilio, 430
Sophora, 55
Spartianthus, 295
junceus, 502
Spartium, 295
junceum, 18, 21
Scoparium, 21
Spathiphyllum, 245
Spilanthes, 138, 365
oleracea, 44
Spinacia oleracea, 31, 197
Spiræa, 21, 137, 295
Filipendula, 503
oblongifolia, 252
prunifolia, 503
Reevesii, 503
strobilacea, 503
Ulmaria, 503
Spiranthes, 319
Splachnum vasculosum, 49
Stachys, 138, 339, _adnot_
germanica, 310
lanata, 375
sylvatica, 74, 253, 271, 281
Stackhousia juncea, 334
Stangeria paradoxa, 172
Stapelia, 20
Staphylea pinnata, 30
Stauntonia latifolia, 194
Stellaria, 148, 404, 406
media, 271, 279, 280
STELLATÆ, 396, 408
STERCULIACEÆ, 362, 464
Sterculia platanifolia, 20, 256
Sternbergia, 296
lutea, 506
Stratiotes aloides, 406
Strelitzia juncea, 459
regina, 25
Streptocarpus Rexii, 15, 44, 226, 227, 461
Strophanthus, 326
Suaeda, 365
fruticosa, 430
maritima, 20, 21
Suregada, 198
Symphoricarpus racemosus, 66
Symphyomyrtus, 38
Symphytum, 71, 138, 365
officinale, 253, 262, 263, 271
Zeyheri, 271
Syringa, 296, 360, 367
persica, 44, 61, 66, 284, 505
vulgaris, 79, 505
T.
Tabernæmontana, 296
coronaria, 504
Tacsonia pinnatistipula, 294
Tamus communis, 21
Taraxacum, 164 (see _Leontodon_)
Taxodium, 114
distichum, 444
Taxus baccata, 11, 21, 90
Tetragonia, 113
expansa, 142, 180
TETRAGONIACEÆ, 149
Teucrium campanulatum, 226, 233, 238
Thalictrum, 205, 500
minus, 307, 310
Thea, 295, 502
Thelymitra, 224
Thesium, 121, 123, 138, 150
Thlaspi arvense, 250, 271
bursa-pastoris, 252, 428
Thuja occidentalis, 319
orientalis, 21
Thymus Serpyllum, 325, 405, 406
Thysselinum, 137, 365
palustre, 437, 457
Tigridia, 360, 361, 365
Pavonia, 35, 462
Tilia asplenifolia, 66, 459
europæa, 22, 30, 65
parvifolia, 66
Tiliaceæ, 137, 362
Tithonia, 26
Tofieldia, 296
calyculata, 300
Torenia scabra, 406
Torilis, 82, 149
Anthriscus, 256, 271, 281, 339, 406, 441, 442
Tradescantia, 245, 296, 360, 365, 367, 404
virginica, 88, 507
Tragopogon, 19, 20, 73, 114, 431
orientale, 250
pratense, 247, 250, 442, 457
Trapa natans, 202, 364
Trichostomum rigidulum, 49
Trifolium, 106, 113, 121, 137, 139, 149, 295, 360, 364
Trifolium hybridum, 262, 399, 406, 407
pratense, 20
repens, 20, 23, 68, 70, 98, 145, 146, 226, 231, 238, 250, 252, 256,
260, 262, 265, 271, 276, 279, 356, 368, 397, 399, 406, 407, 434,
436, 438, 502
resupinatum, 20
Trillium grandiflorum, 507, 510
Trinia vulgaris, 405
Triphasia aurantiaca, 369
Triticum, 86, 115, 350, 391
repens, 106, 325
vulgare, 55, 113
Triumfetta, 137, 252, 259, 260, 262, 265, 271, 280
Trollius europæus, 66, 295, 500
TROPÆOLACEÆ, 149, 501
Tropæolum, 149, 398, 283
majus, 20, 222, 225, 226, 232, 238, 251, 252, 254, 256, 271, 280,
295, 310, 406, 442, 501
minus, 501
Tulipa, 35, 45, 67, 75, 84, 85, 138, 262, 300, 302, 348, 359, 360,
361, 365, 367, 388, 390, 421
Gesneriana, 31, 250, 310, 315, 442, 507
sylvestris, 507
Turritis, 271
glabra, 252
Typha, 189
U.
Ulex, 295, 360
europæus, 377, 502
Ulmus americana, 66
campestris, 31, 52, 62, 157, 325, 353, 427
UMBELLIFERÆ, 37, 71, 73, 80, 107, 113, 121, 127, 131, 132, 137, 139,
140, 143, 149, 150, 162, 244, 257, 261, 339, 358, 395, 405, 406,
407, 437, 439
Uredo candida, 279
URTICACEÆ, 114
Urtica dioica, 62, 66, 194
Usteria, 283
V.
Vaccinium, 68
Valantia cruciata, 44
VALERIANACEÆ, 114
Valeriana, 114, 165, 419
dioica, 325
officinalis, 325
Valisneria spiralis, 319, 433
Verbascum, 73, 116, 137, 225, 253, 430
australe, 35
nigrum, 226, 251
phlomoides, 281
Thapsus, 404
Verbena, 67, 68, 506
Veronica, 60, 150, 296, 334, 360, 361, 365, 375, 505
austriaca, 66
Beccabunga, 468
Chamædrys, 442
latifolia, 459
longifolia, 325
spicata, 325, 374
Viburnum, 44, 296, 417
Opulus, 473
Vicia, 30, 365, 369, 472
Faba, 434
Vinca, 137, 296
herbacea, 389
major, 505
minor, 44, 99, 358, 390, 505
rosea, 31
Viola, 23, 137, 225, 229, 289, 295, 297, 405
grandiflora, 501
hirta, 226, 238
odorata, 20, 94, 220, 226, 238, 286, 404, 429, 501, 508
tricolor, 461, 501
VIOLACEÆ, 137, 334, 403, 406, 500
Viscum album, 56, 369, 509
VITACEÆ, 137
Vitex incisa, 238
Vitis, 417
vinifera, 20, 29, 34, 44, 66, 137, 157, 182, 183, 211, 280, 374,
422, 424
W.
Wedelia perfoliata, 442
Weigela rosea, 358
Welwitschia, 162, _adnot_
Wildenovia, 115, 167, 168
Wistaria, 364
sinensis, 226
X.
Xanthosoma appendiculatum, 31
Xanthoxylum, 21
Xylophylla, 328
Y.
Yucca, 361
flexilis, 361
Z.
Zamia, 170
Zea Mays, 21, 113, 136, 191, 197, 300, 310, 350, 369, 466
Zingiber Zerumbet, 224, 227
Zinnia, 44
elegans, 20
Zygopetalum maxillare, 398
ERRATA.
The reader is requested to make the following corrections:--
Page 182. Fig. 94 should be 94*.
Page 194. The reference 3 applies not to the nutmeg but to the hop,
figured at p. 193.
Page 309. Fig. 165 legend--for _Sempervivun tecotorum_ read _Sempervivum
tectorum_.
PRINTED BY J. E. ADLARD, BARTHOLOMEW CLOSE.
Transcriber's Notes:
Page xx and 202:
208. Passage of pinnate to palmate leaves in horse-chesnut 439
'chesnut may be old spelling for chestnut?'. Changed as most are
spelled chestnut.
Page 65:
Naturforscherversammlung
Changed Naturvorschefversamlung to Naturforscherversammlung to match
other occurrence. (See footnote 528).
Page 145:
So far as the andraecium is concerned, the stamens
Changed to androecium to match other occurrences.
Page 149:
Echinocactus changed from Echinocatus to match other
occurrences.
Page 397:
The species mentioned are _Ambrina ambrosiodes_,
Changed to ambrosioides to match index page.
Page 502:
Medicago sp., ? ., Europe.
The ? mark replaces a blank in original for a missing attribution.
Page 503:
ONAGRARIÆ changed to ONAGRACEÆ to match other occurrences, especially
the index referrence.
Footnote 126:
'Neue Denkschriften der allgemeine Schweizerischen
Gesellschaft,' Perhaps this should be: allgemeinen. Unchanged.
Index
Alströmeria, 319, 326
Changed to Alstroemeria to match referenced pages.
DIPSACACEÆ, 86, 107, 114, 138
All dipsaceæ changed to dipsacaceæ to match index and current spelling.
Errata changes listed were made.
Inconsistent hyphenation:
co-existent and coexistent
Lauro-cerasus and Laurocerasus
mid-rib and midrib
outgrowth and out-growth
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