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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 gemmae 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 Compositae, 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 _Nymphaea 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 _Nymphaea_ 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 _Baeckea 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_ (Mueller) 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. Placentae 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 _Crataegus_ 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 Alexandrae_ 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.
Linnaeus 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, Jaeger, 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 'Elements,' 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 vertebrae, &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 versa_, 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 Gaertner, 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 Teratologie Vegetale,'
Strasburg, 1845.
[2] In some instances diagrams and formulae 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 AEtna, 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. Linnaeus, 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 fasciae evadat et compressus_"
(Linn., 'Phil. Bot.,' 274). A similar opinion was held by J. D. Major in
a singular book entitled 'De Planta, 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 striae, 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 deg.], 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 deg.], 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 saepe in Ranunculo, Beta, Asparago,
Hesperide Pinu, Celosia, Tragopogone, Scorzonera Cotula foetida_,"
Linnaeus 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!
Althaea rosea!
Lavatera trimestris.
Geranii sp.
Tropaeolum 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.
Stapeliae sp.
Lysimachia vulgaris!
Androsace maxima.
Primula veris inflor.!
denticulata inflor.!
Polemonium coeruleum.
Convolvulus sepium!
arvensis!
Plantago media.
*Euphorbia Characias.
exigua.
* Cyparissias.
Suaeda maritima.
*Celosia sp.
Beta vulgaris inflor.!
Phytolacca sp.
[Greek: beta]. _Woody._
Berberis vulgaris.
Hibiscus syriacus!
Acer pseudo-platanus!
Dodonaea 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.!
Spiraea 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.
Suaeda 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. _Tiliae_,' 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 _Tropaeolum
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.=--Linnaeus 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 europaea!
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?
Codiaeum 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. Veget.,' pl. iii, fig. 1.
[16] 'Bull. Acad. Roy. Bruxelles,' t. xviii, p. i and p. 591.
[17] 'Linnaea,' 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. Veget.,' pl. xvii, fig. 3, and pl. xlviii, fig. 2.
[23] 'Mem. Acad. Toulouse,' 1862.
[24] Bonnet, 'Recherches Us. feuill.,' pl. xxi, fig. 2.
[25] De Candolle, 'Mem. Leg.,' pl. v, fig. 14.
[26] 'Phil. Bot.,' Sec. 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 _Umbelliferae_. 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 Vegetale,' 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,
'Linnaea,' 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.
Crataegus 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.!
AEschynanthus 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, 'Mem. 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, 'Linnaea,' xi, p. 423, _Colchicum_. Michel,
'Traite 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
_Caprifoliaceae_, _Rubiaceae_, &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 Nefle 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 _Leguminosae_, 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 _Caesalpinia 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 caespititium_,
_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.
'Mem. 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 _Cycadeae_, _Coniferae_, &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 _Crataegus
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] 'Mem. Acad. Toulouse,' 5th Series, vol. iii.
[39] Linnaea, 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] 'Mem. 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. Veget.,' tom. ii, p. 781.
[52] Sched. de monstr. plant. 'Act. Helv.,' tab. i, fig. 8.
[53] 'Mem. greffe,' loc. cit., tab. xxiv, p. 334.
[54] 'Bull. Soc. Bot. Franc.,' 8, pp. 73 and 351, tab. ii; and Roese.
'Bot. Zeit.,' x, p. 410.
[55] _Nymphaea lutea_, _AEsculus 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 Veget.,' 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 Veget.,' 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 _bona 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:
monosis]) 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:
dialyo]), 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 "dedoublement," 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 _Danae_, Webb, 'Phyt. Canar.,' p. 320, describes the
fascicles of flowers as in "crenulis brevibus ad marginem ramulorum
dispositis." Sometimes, on the other hand, _Danae_ 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 _Coniferae_, 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 europaeus dissectus.
Chelidonium majus laciniatum!
Glaucium luteum.
Brassica oleracea!
Tilia parvifolia laciniata.
asplenifolia!
Acer platanoides laciniatum.
crispum.
AEsculus 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.
Crataegus 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 caeruleum.
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, 'Mem.
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. Linne 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 _Polygalaceae_. 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] 'Mem. 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 _Rosaceae_ and _Pomaceae_ 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 _Rosaceae_, _Pomaceae_, _Umbelliferae_, less
commonly in _Leguminosae_, 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 _Labiatae_ 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 _Lobeliaceae_.
In the _Compositae_, 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!
Compositae! 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 (_Malvaceae_) become double, one
of the first stages of the process is often the disjunction of the
stamens, and a similar dissociation occurs in _Leguminosae_ and
_Compositae_, as in _Tragopogon_, as related by Kirschleger, in
_Hypochaeris_ 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 _Cruciferae_ and
_Umbelliferae_.
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, 'Traite du Citronnier.'
[83] 'Ann. des Science Nat.,' 3rd series, 1844, vol. i, p. 294.
[84] 'Org. Veget.,' 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 _bona 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
heterologue" 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 adhaerens_ 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 _Rosaceae_, 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 _Pomaceae_. 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, _Crataegus 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 _Pomaceae_ 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 _Rosaceae_ 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 _Saxifragaceae_, _Cucurbitaceae_, _Myrtaceae_, _Bruniaceae_,
_Rubiaceae_, 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 _Umbelliferae_, 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 _Campanulaceae_ 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 _Campanumaea_ 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
_Campanumaea_ they adhere to the base of the tube of the corolla."[87] In
this order, then, as in _Saxifragaceae_, _Bruniaceae_, &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 _Onagraceae_ (_Jussieua_), as also in _Cactaceae_ (_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 _Cucurbitaceae_, 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!
*Crataegus!
*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 _Cobaea 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, 'Praecurs. 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, 'Traite general de Botanique,'
p. 57. Bentham, 'Journ. Linn. Soc.,' vol. x, p. 104 (Structure of
_Myrtaceae_), 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 aestivum_, 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
_Compositae_, _Dipsacaceae_, &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 versa_,
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
_Orchidaceae_ 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 Cruciferae.
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 _Gesneraceae_.
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 _Primulaceae_ 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
_Caryophylleae_, _Cucurbitaceae_, _Papaveraceae_, 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, ser. 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 spirae 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.