SHU SUR OEMS
LW Ga DU a) re We Ka
My i}
i
Fats
DSH ! TER
ait i i
A a ee a Sea Ga MRR
ay cate tae th if iat Heeaee i ett st vate Hy Weed | Feel tt Dial
Nate iinet Hee Tene tt Waiter i BML Hits
eit ii ROH EN RAM GL in fy
HORMEL Les ete
Meminletyt \
aut F
i}
i Lhe iticrntiar ah
motu eee ene a,
Of ERD
ple
( Heese
peel
suit Hie
We: iat
itu hy
mate
An
i ithe
fee iB
Peau eia tte of yet ep atag
aE RMA
! BRM)
fit F Ane,
bleh
i
iy
Hi
Hitt
yhaty
sett stats
Aa Hot rai
ie en tocati
iat lpr i
;
i ) Hi i
aie i CH ee Satis
Halk t in ‘ Z He
SEH | 4 Heels 4 ti: tet Tai
AR aR
Bi
uri al
Hea ate
fait
it
ny
rule
Cornell Mniversity Library
BOUGHT WITH THE INCOME
FROM THE
SAGE ENDOWMENT FUND
THE GIFT OF
Henry W. Sage
1891
Fel ee
wi
Cornell University
The original of this book is in
the Cornell University Library.
There are no known copyright restrictions in
the United States on the use of the text.
http://www.archive.org/details/cu31924001807779
NOTES ON THE LIFE HISTORY OF BRITISH
FLOWERING PLANTS
Notes on
‘The Life History of
British F lowering Plants
BY
THE RIGHT HON. LORD AVEBURY, P.C.
Pres. of the Soc. of Antiquaries ; Trustee British Museum; For. Sec. Roy. Acad. ;
German Ord. Pour le Mérite ; Com. Legion of Honour;
D.C.L. (Oxon.), LL.D. (Cantab, Dubl, et Edin.), M.D. (Wiirzb.), F.R.S.,
F.L.S.,F.G.S.,F.Z.S., F.S.A., F.E.S.; Assoc. Acad, Roy, des Sci. Brux.;
Hon. Mem. R. Irish Acad., Amer. Ethnol. Soc., Anthrop. Soc. Wash. (U.S.),
Brux., Firenze, Anthrop. Verein Graz, Soc. Entom, de France,
Soc. Géol. de la Suisse, and Soc. Helvét. des Sci. Nat. ;
Mem. Amer. Phil. Soc. Philad., and Soc. d’Ethn. de Paris ; Corresp. Mem. Soc.
Nat. des Sci. Nat. de Cherb., Berl. Gesell. ftir Anthrop., Soc. Romana
di Antrop., Soc. d’Emul. d’Abbeville, Soc. Cient. Argentina, Soc.
de Géog. de Lisb., Acad. Nat. Sci. Philad., Numis. and Ant.
Soc. Philad., Amer. Entom. Soc, ; For. Assoc. Mem.
Soc. d’Anthrop. de Paris ; For. Mem. Amer. Antig. Soc. ;
For. Mem. Soc. Espafiola de Hist. Nat.; For. Mem. Roy. Swedish Acad.
of Sci. Upsala; For. Mem. Danish Acad. of Sci. and Lit. ;
Hon. Mem. New Zealand Inst.; Hon. Sec. Soc. Biol. Paris.
London
MACMILLAN AND CO,, Limirep
NEW YORK : THE MACMILLAN COMPANY
Lge
Fe
Yt
All rights reserved
PREFACE
SowerBy, Bentham, Hooker, Babington, and others
have given us good, and in some cases excellent works,
enabling us to determine and name our British plants,
but they mostly confine themselves to technical details,
with such additional particulars as enable the student
to distinguish one species from another. To these, how-
ever, in the main they confine themselves, and, no
doubt, in great measure, from considerations of space,
omit other points often of great interest, nor does it fall
within their intention to enter much into the economy
and life-history of plants.
Even Sowerby did not to any great extent fill up
the gap. He does not, I think, mention the remark-
able work of Sprengel, and the interesting researches
of Darwin, H. Miiller, Hildebrand, Delpino, and others
have been made since he wrote.
Kerner’s admirable work deals with plants gener-
ally, and comparatively little space, therefore, can be
devoted to British species.
Knuth’s Handbuch der Blutenbiologie relates
mainly to the relations of flowers and insects, as also
does my smaller work, British Wild Flowers, Con-
sidered in Relation to Insects.
Vv
vi BRITISH FLOWERING PLANTS
In another book, Flowers, Fruits, and Leaves, 1
have dwelt on the structure and forms of plants, but
from a general point of view.
In the present work I endeavour to supplement the
various excellent ‘“ Floras’”’ which we already possess,
not in any way to compete with them: to describe
points of interest in the life-history of our British
plants; to explain, as far as possible, the reasons for
the structure, form, and colour; and to suggest some
of the innumerable problems which still remain for
solution. I have followed the arrangement adopted
in Bentham’s Handbook of the British Flora, as being
one in very general use.
Dr. Rendle has been so kind as to see the proofs
through the press for me. This is a guarantee of
accuracy, and he has also made many valuable sugges-
tions.
Hicn Extms, Down, Kernv,
October 5, 1905.
CONTENTS
PAGE
INtRopucTION . , . 1
FLOWER é : , : : 3
FRuits anD SEEDS : ‘ 15
Leaves . é . : 20
Stam. ; . P ‘ ‘ 34
SENSE ORGANS 3 ‘ F : 42
DicoryLepons . r ; 47
CONIFER ; , ‘i 381
MonocorTyLeDons : i ; . 889
INDEX ‘ 3 : : ; 445
Vii
ILLUSTRATIONS
PAGE
Geranium sylvaticum (after Bentham) . ‘ 1
Lamium amplexicaule: cleistogamous flower 8
Section of do. . 8
Shoot of Rose 12
Whorl of Bramble leaves 13
. Longitudinal section through the growing oon of a winter
bud of Abies pectinata oe Sachs) 21
. Twig of Beech . 22
. Twig of Chestnut 22
. Twig of Norway Maple é 22
. Shoot of Black Poplar : 23
. Transverse section of leaf of Empetrum (after Kerner) 28
. Leat of Clover (Trifolium repens): position by day 30
Do. do. position by night 30
. Group of Dead and Stinging Nettles 30
. Twig of Lime . , 31
. Young shoot of Hornbeam_ . 32
. Longitudinal section through the ‘Jienetian of stem wal leaf of
Horse Chestnut in autumn (after Sachs) . ‘ 33
. Seedling of Glaucitum corniculatum . 34
. Frond strengthened by rolling (after Spencer) » 85:
. Portion of a grass stem; showing internodes surrounded by
leaf-sheaths (after Spencer) . 385
. Frond strengthened by mid-rib (@fter Aseneen) . 36
. Relation of stem and leaf in Dicotyledons (after Spencer) 36
. Single girder 3 i 38
. Double girder 3 og 38
. Multiple girder 3 38
. Section of a one-year-old shoot of Lime, oe woody roundies
separated by broad bands of soft (parenchymatous) tissue
(after Kerner) : i ‘ 39
ix a
BRITISH FLOWERING PLANTS
. Diagram of a young Dicotyledonous stem, showing approxima-
tion of the distinct bundles
. Arrangement of leaves of Carex
. Ranunculus aquatilis (after Bentham)
Do. also enlarged petal, showing fies basal
honey-gland
. Ranunculus bulbosus: flower, with different views of petal,
showing nectary ‘ : ; ‘
33. Helleborus fetidus: flowers in the first (female) condition,
the sepals partly removed, and the second (male) condition
(after Knuth)
4. Longitudinal section of seed of Daphne Siamtanwege gria
. Transverse do. do. ‘
. Delphinium elatum. a, Young flower, seen from the front, and
after removal of the calyx. 8, Section of a similar flower,
seen from the side; the right half of the calyx and of the
corolla has been removed. y, An older flower, seen from
the front, after removing the calyx. 6, Section of a similar
flower, seen from the side, after removing the right half of
the calyx. (After H. Miller)
. Aconitum Lycoctonwm. A, Flower in the second (female) con-
dition, seen from the side. B, Longitudinal section. (After
H. Miiller)
. Shoot of Berberry (Berberts vulgaris), sical three spines
. Flower of do. do. seen from above
. Pistil and two stamens of do. after the visit of an insect
. Capsule of Poppy ;
. Seedling of Glawctwm Senn as #
. Fumaria officinalis: flower (after Hildebrand)
Do. do. from which the sepals have —
removed (after Hildebrand)
. Sections of seed of Hesperis matronalis
Do. of Wallflower (Chetranthus Cheirt)
. Stsymbrium officinale: flowers in the first and second stages
(after Knuth)
. Seedling of Cress (Lepidium satan
. Section of seed of Lepidiwm graminifolium
Do. do. sativum .
. Raphanus sativus: seedling .
Do. germinating seedling
Do. outline of seed and various views of embryo
. Shoot of Helanthemum vulgare
PAGE
62
66
67
67
68
72
73
74
75
76
77
81
89
89
89
91
91
9]
93
FIG.
55.
56.
57.
58.
59.
60.
61.
62.
63.
64.
65.
66.
67.
68.
69.
70.
71.
72.
73.
74,
75.
76.
77.
78.
79.
80.
81.
82.
83.
84.
85.
86.
87,
88.
89. ‘
90-93. Sarothamnus (Broom): flower, ditnatrating explosive action
LIST OF ILLUSTRATIONS
Shoot of Helianthemum elandicum
Polygala vulgaris: section of flower (after H. Miiller) .
Do. flower opened out (after H. Miiler)
Viola canina: section of flower ; and stamen
Do. capsule with seed
Do. do. after ejecting the seeds
Do. with cleistogamous flower
Viola hirta, with fruit
Malva sylvestris, with stamens and stigmas fatten H. Miiller)
Do. rotundifolia, do. do.
Carpel of Malva moschata
Fruits and bract of Lime
Embryo of Lime
Seedling of Lime
Geranium pratense (after Bentham)
Do. young flower
Geranium sylvaticwm (after Bentham)
Herb Robert (@. Robertianwm) :
Geranium dissectum: dispersal of fruit
Do. Robertianum: do.
Seedling of Geranium sanguineum
Section through embryo of Geranium, showing the “adeile of
folding of the cotyledons . ‘
Awned fruit of Erodiwm glaucophyllum
Oxalts Acetosella: leat by sa and by sight (after
Darwin) . :
Transverse section of the motile organ of a leaflet of Butte
carnea (after Sachs)
Longitudinal section of same, and leaf-stalk fafter Sachs)
Oxalis Acetosella: arrangement of the chlorophyll grains in
a cell of the leaf: a, in diffuse light; 6, in sunlight; ¢,
in long-continued sunlight (after Sachs)
Flower of Balsam, in two stages (after Knuth)
Seedling of Acer Pseudo-platanus
Fruit and rolled cotyledons of do.
Transverse section of seed of Euonymus
Longitudinal do. do.
Embryo of Bean
Pod of Common Vetch, illustrating dehiscence
Lathyrus Nissolia : seedling
in pollination (after H. Miller)
PAGE
xl BRITISH FLOWERING PLANTS
FIG.
94. Shoot of Broom, showing bud protected by pedestal of last
year’s leaf
95. Lotus corniculatus (after Hewthaut).. ; : ‘
96-100. Do. flower, illustrating position of parts in
pollination
101-103. Flower of Genista tinctoria, illustrating method of
104.
105.
106.
107.
108.
109.
110.
111.
112.
113.
114.
115.
116.
117.
118.
119.
120.
pollination
Furze seedling : : :
Trifolium pratense: head of flower-buds with the pair of
protecting leaves
Trifolium repens: end of creeping shoot ‘
Do. — subterranewm: shoot showing buds at end, and three
older flower-heads which are turned down and beginning
to bury themselves :
Trifolium subterraneum : flower-head slightly magnified
Fruit of Hippocrepis
Staminal tube of Lathyrus .
Do. of Vicia
Stipules of Lathyrus maritimus : s
Do. do. with one of the stipules
turned back, revealing the rest of the leaf and bud
Stipule of Lathyrus grandiflorus
Do. do. pratensis
Stipules of do. 5 ‘
Do. do. with one of the lower stipules
turned back, and exposing the next younger leaf with its
stipules .
Stipules of Lathyrus latifolius
Do. do. with the lower stipule ‘eunrved, and
exposing the whole of the stipule of the next higher
leaf 4 : : ;
Stipules of Lathyrus ditties A, before the unfolding of the
leaf, in the natural position; B, with one stipule turned
back to show the leaf and shoot inside
121-124. Gewm urbanwm: style in three stages of devdlopment,
and ripe fruit
125-130. Scales of bud of Rose, sioutns successively ie first,
131.
132.
133.
134.
third, fourth, fifth, sixth, and ninth scale
Stem of Rose bearing expanding lateral bud
Epilobium angustifolium: flowering shoot
Epilobium parviflorum: flowering shoot
Inflorescence of Lythrum Salicaria
PAGE
170
LIST OF ILLUSTRATIONS
FIG.
135-137. Long-styled, mid-styled, and short-styled flowers of
Lythrum Salicaria
138. Drosera rotundifolia (after Bentham)
139, Do. anglica (after Bentham)
140. Do. rotundifolia: leaf enlarged, with the tentacles on one
side inflected (after Darwin)
141, Wild Chervil (Cherophyllum sylvestr é) (after Bentlaan
142, 143. Flowers of Wild Chervil in male and female state
144. Eryngium maritimum: petal seen in front and from the side
145. Lenticel from a branch of Sambucus nigra in the summer of
the second year
146. Viburnum Opulus: shoot, with flower and fruit (after Bentham)
147, Viburnum Lantana: shoot, with flower and young and ripe
fruit (after Bentham)
148. Seedling of Valerianella coronata
149. Chrysanthemum Partheniwm (after Bentham)
150-152. = Do. do. successive stages in the life of the
flower F i
153-155. Seeds of Calendula: side and front views and section of
hooked form, winged form, and grub-like form
156-158. Taraxacum officinale: section of part of a leaf grown in
shade, in diffused light, and in sunshine (after Peck)
159-161, Campanula Medium : section of bud, and of flower in first
(male) condition and in second (female) condition é
162. Arctostaphylos Uva-Ursi.: stamen seen from the side (after
H. Miller) ; :
163. Arctostaphylos alpina: section of flower (after H. Miiller)
164, 165. Erica Tetralic: section of flower and stamen (after Ogle)
166. Pyrola wniflora: section of flower
167. Primula elatior : section through the wall of a capsule lefae
Leclere du Sablon)
168. Primula farinosa : long-styled form and pollen
169. Do. short-styled do.
170-172. Cyclamen europewm: three stages in position of the
flower (after Kerner)
173. Anagallts arvensis: wall of capsule (after Leclere du Sibi:
174. Utricularia vulgaris: plant with flower and parts (after
Bentham) 5 ; ;
175. Utricularia vulgaris: flower and parts illustrating pollina-
tion mechanism (after Hildebrand)
176. Utricularia vulgaris: bladder much enlarged, containing a
small Crustacean which has been captured (after Darwin) .
Xili
PAGE
192
201
202
203
204
205
207
219
220
221
228
231
233
234
250
256
261
262
262
265
267
268
268
271
273
275
275
276
xiv BRITISH FLOWERING PLANTS
FIG.
177. Utricularia vulgaris: opening of bladder, seen in front, much
enlarged ‘ ' ‘ :
178. Utricularia vulgaris: mouth of bladder, seen sideways
179-180, Pinguicula alpina: transverse sections through leaf
181. Do. piece of epidermis of leaf, showing
the two kinds of gland (after Kerner)
182, 183. Fraxinus excelstor: samara with half removed and the
seed pulled out, and longitudinal section of seed .
184-186. Vinca minor: flower after the removal of the front part
of the corolla, with pistil and stamen :
187, 188. Menyanthes trifoliata: short-styled, and forms of flower
of long-styled (after Knuth)
189, 190. Myosotis versicolor: young and older co
191. Anther of Borage , ‘ :
192, 193. Lathrea: piece of an underground aliooty anid longi-
tudinal section through the same (after Kerner)
194. Lathrea: longitudinal section through a leaf (after Kerner)
195, 196. Lathrea: piece of the wall of a cavity, and plasmic
threads radiating from the cells of the little heads (after
Kerner).
197. Verbascum nigrum (after Beniliam) .
198. Scrophularia nodosa do.
199-201. Degitaks purpurea: section of flower, showing the
anthers in three stages (after Ogle)
202. Veronica Chamedrys (after Bentham)
203-205. Bartsva alpina: subterranean bud, cross-section through
part of the bud, and the margin of a bud scale in section .
206, 207. Bartsta Odontites: flowers with short and long pistil
(after H. Miiller)
208. Seed of Melampyrum and chrysalis of Formica fusca
209. Kuphrasta officinalis: shoot, with flower, pistil, and fruit
(after Bentham) . ‘ : j
210. Huphrasia officinalis: partial section of flower, enlarged
211-213, Lamium albwm (White Dead-nettle) (after Bentham) with
flower and section of flower
214, Group of Dead-nettles and Stinging-nettles .
215. Diagram to show arrangement of stamens in Nepeta .
216. Diagram to show position of stamens in most Labiates
217, 218. Scutellaria galericulata: side and front views of flower
(after Knuth)
219, Teucrium Scorodonia: flower in ite first stata: with ninithers
erect
PAGE
277
278
280
280
282
285
288
296
297
303
304
305
306
310
313
314
318
318
319
322
322
326
328
330
330
331
336
LIST OF ILLUSTRATIONS
FIG.
220. Teucriwm Scorodonia: flower in the second state, with re-
curved anthers and exposed stigmas
221, Salvia officinalis: section of a young flower
222, Do. flower visited by 9 bee
223. Do. older flower :
224, 225. Do. stamens in their natural position ail when
moved by a bee . .
226. Plantago media (after Bentham) .
227. Leaf of Empetrum in transverse section (after ee 5
228, 229. Male and female flowers of Callitriche . :
230-232. Urtica dioica: vertical section through part of the leaf
of a Stinging-nettle, showing two hairs, from the lower
one of which the head has been broken, and tops of hairs
more magnified (after Kerner)
233, End of shoot of Hop
234. Flower of Elm (after Grenier and Godron)
235-248, Terminal bud of Elm, with analysis showing ihe com-
ponent scales
249, Branch of Beech
250. Branch of Spanish Chestnut
251. Fruit of Oak opened
252, Fruit of Nut opened
253. Winter bud of Beech
254-256. First, sixth, and eleventh pair of stipules of same
257. Diagrammatic transverse section of pair of stipules of same,
showing the extent to which they overlap
258. Bud of same after eleven pairs of stipules have been
removed
259-261. Twelfth, ‘hiciean ths and fourteenth pairs of stipules of
same, with leaf .
262. Stipule of the fifteenth pair with leaf
263. Last leaf discernible, occupying the centre of the bud
264. Junction of the wood of two seasons’ growth of same, showing
scars of the outer pairs of stipules that covered the winter
bud and which were unaccompanied by leaves
265, 266. Transverse sections of Beech leaf grown in sunshine wet
shade respectively (after Pfeffer) .
267. Root-tip of Beech with closely adherent vayectial mantle
(after Kerner) 5
268, 269. Bud of Spanish Ghiovtant and second scale depachel
270. Oak shoot
271. Oak bud
xv
PAGE
336
338
338
338
338
342
353
354
368
370
371
371
372
372
xvi BRITISH FLOWERING PLANTS
FIG,
272-292. Quercus pedunculata: pairs of stipules forming the scales
of the winter bud, sketched in the first week of May
293, Young female flower of Oak with involucre of scales
294. The same, cut lengthwise
295, Cone-scale of Birch .
296. Diagram of a three-flowered group from the female eatitin at
Birch (after Eichler)
297. Pair of fruits of Hornbeam .
298. Diagram of a pair of female flowers of Hoenbeuns fatter
Eichler)
299. Pair of fruits of Hazel, sak in its involucre
300. Plan of arrangement of a male flower of Hazel (after
Eichler)
301, 302. Female and male flowers of Hival
303. Populus nigre: terminal winter bud, showing a pair of
persistent stipules belonging to a leaf of last season
304. Black Poplar shoot ‘
305. Pinus sylvestris: fragment of terminal bud representing
seven tiers of scales of the winter bud
306. Pinus sylvestris: a detached scale-base
307. Do. analysis of terminal bud
308. Do. apex of branch
309. Picea excelsa: apical and two lateral buds showing pedestals
of leaves after the green portion has been removed
310-315. Picea excelsu: normal and perfect leaf, and successive
modifications to form scales
316-318. Picea excelsa: inner scales after iiiew have Alsiiedtina
about the middle of April
319. Diagrammatic section of Arum
320. Flower of Lemna trisulca (after Le Maout aid Tecate
321-323. Position of the chlorophyll granules in the cells of the
frond of Lemna trisulea in darkness, in diffused light,
and in sunlight (after Stahl)
324-327. Potamogeton natans: palisade cell of leaf i in diffused light
and in sunshine, with sections of same (after Stahl)
328. Diagrammatic section of Orchid flower (after Darwin)
329. Orchis mascula (after Bentham)
330. Orchis mascula: side view of flower, with sepals a petals
cut off except the lip, of which the near half is cut away,
showing relation of pollinia and nectary (after Darwin)
331, Orchis mascula: front view of flower, with sepals and petals
removed except the lip (after Darwin)
PAGE
402
402
FIG.
332,
333,
334,
335
337.
338.
339.
340.
341,
342, :
344,
345.
346.
347.
348,
349.
350.
351.
352.
LIST OF ILLUSTRATIONS
Orchis mascula : the two pollinia (after Darwin)
Ophrys aptfera (after Bentham)
Cephalanthera grandiflora (after Bentham) ;
336. Cypripedium Calceolus: front and side views of flower .
Iris Pseud-acorus, showing relation of petal, stamen, and
stigma .
Allium ee (after Benth)
Seed of Narthecium
Pistil of Colchicum autwmnale (after Grenier and Godron)
Flower of Juncus articulatus (after Grenier and Godron)
343. Male and female flowers of Sedge (Carex acuta)
Carex paludosa: vertical section through part of a leaf,
showing protection of stomata from moisture by papilla-like
outgrowths of the surface (after Kerner) .
Diagram of a spikelet of Wheat dissected (from Ward after
Oliver)
Diagram of a spikelet of catia ai asecied (from
Ward after Oliver)
Leaf of Poa trivialis
Poa annua: transverse section of half of leaf, including the
median keel, and showing the motor cells (after Ward)
Nardus stricta: transverse section of leaf showing support-
ing tissue and motor cells (after Ward)
Awned fruit of Stipa pennata
Margin of leaf of Festuca set with barbs
Arrhenatherum avenaceum: spikelets and anthers in various
stages illustrating pollination (from Ward after Kerner)
Xvil
PAGE
402
408
410
413
415
421
422
425
426
430
430
431
432
432
433
433
434
436
440
GLOSSARY
Accumbent (p. 77), of the radicle when lying parallel with the edges of
the cotyledons.
Achene (p. 47), a one-seeded fruit with a thin dry wall, which does not
split open when ripe.
Albumen, see Endosperm.
Alien, a plant which has presumably been introduced by human
agency.
Anatropous (p. 365), of the ovule, turned through 180°, so that the
micropyle points towards the placenta.
Androdiccious, having hermaphrodite and male flowers on different
plants.
Andromonecious, having hermaphrodite and male flowers on the same
plant.
Anemophilous (p. 5), of plants in which the pollen is carried to the
stigma by the wind.
Anther, that portion of the stamen which contains the pollen.
Arillus, arilloid, or aril, a growth on the outside of the seed-coat.
Berry, a fruit which, except for the outer skin, is succulent or juicy, as
in Grape or Gooseberry.
Bipinnate (p. 49), twice pinnate (q.v.), the pinne again pinnately divided.
Biternate (p. 49), with three parts, each of which again divides into three.
Bract, a leaf from the axil of which springs a flower or flower-bearing
shoot.
Bracteole (p. 371), a small bract, situated on the flower-stalk.
Caducous, falling early, as the sepals of Poppy.
Calyx (p. 3), the outer whorl of the flower.
Capsule, a dry many-seeded fruit, opening when ripe to allow the seeds
to escape.
Carpels, the leaves which make up the gynecium or pistil.
xix
XX BRITISH FLOWERING PLANTS
Carpophore (p. 17), fruit-bearer, applied to the axis of the fruit in
Umbellifers which splits lengthwise and bears the two mericarps.
Chlorophyll (p. 32) the pigment to which leaves owe their green
colour.
Cleistogamous (p. 8), of plants which, besides the usual conspicuous
flowers, have others which are smaller, generally uncoloured, and do
not open.
Corolla (p. 3), the second whorl of the flower. In most cases this is the
coloured part.
Corymb, an inflorescence in which, owing to the inequality of their
stalks, the flowers stand on one level.
Cyme, a definite inflorescence, one in which the main axis ends at once
in a flower,
Deciduous, lasting for a time, but ultimately falling, as opposed to
persistent.
Decussate, crossing at right angles, like the pairs of leaves in Dead-
nettle,
Dehiscent, opening when mature, as an anther or many fruits.
Dichogamous (p. 4), of flowers in which the anthers and stigmas do not
mature simultaneously.
Diclinous, having all the flowers on any one plant either male or
female ; that is to say, either with stamens but no pistil, or pistil but
no stamens.
Dicotyledon, having an embryo with a pair of seed-leaves or cotyledons.
Dimorphous, of species in which there are two forms of flowers, differing
in the relative position of the anthers and stigma.
Dicecious (p. 4), having the stamens and pistil situated not only in
distinct flowers, but also on separate plants.
Disk, an outgrowth of the floral axis, often secreting honey.
Drupe, a fruit the inner wall-layers of which are hard, forming a
“stone,” as in plum.
Endosperm, the food-store present in many seeds along with the embryo.
Entomophilous (p. 5), of plants in which the pollen is carried to the
stigma by insects.
Epidermis, the outermost layer of cells of a leaf or young stem.
Epigynous, situated upon the ovary.
Equitant (p. 378), when leaves are folded one over the other in the
bud.
Exalbuminous, without albumen (endosperm), when the embryo occupies
the whole seed.
GLOSSARY xxi
Filament, the stalk of the anther.
Follicle, a several-seeded pod-like fruit, which splits when ripe down
one side only, as in Larkspur or Columbine.
Geotropic (p. 45), affected by the stimulus of gravity.
Glabrous, not hairy.
Glume (p. 431), the bract of a grass flower.
Gynodiccious, having hermaphrodite and female flowers on different
plants.
Gynomonecious, having hermaphrodite and female flowers on the same
plant.
Heterogamous, having male, female, and hermaphrodite flowers, or any
two of them united in one head, as in Composite.
Heteromorphous, having more than one form of flower.
Heterostyly, when two or more forms of flowers are characterised by
styles of different lengths.
Homogamous, of flowers in which stigmas and anthers are functional at
the same time.
Hypogynous, arising below the ovary on the floral axis.
Incumbent (p. 76), of the radicle when lying parallel with the faces of
the cotyledons.
Indehiscent, not opening when mature.
Involucre, an association of bracts round the base of a flower or in-
florescence.
Lanceolate, shaped like the head of a lance.
Lenticel (p. 219), a small area of loosely arranged cork cells allowing the
passage of air.
Linear, narrow, with parallel sides, like a grass leaf.
Loculicidal dehiscence, of a capsule, splitting down the middle line of
each carpel.
Mericarps (p. 17), one-seeded portions of a compound fruit which
separate when ripe.
Micropyle, the aperture between the ovule-integuments through which
the pollen tube reaches the embryo-sac.
Monecious, having stamens and pistil in separate flowers, but on the
same plant.
Monocotyledon, having an embryo with a single seed-leaf or coty-
ledon.
xxil BRITISH FLOWERING PLANTS
Monomorphous, of species in which all the flowers resemble one another
in the relative position of the anthers and stigmas.
p, one-thousandth part of a millimetre.
Nectary, that part of the flower which secretes honey.
Obovate, of a leaf which is egg-shaped (ovate) in outline, but attached at
the narrower end.
Orthotropous (p. 364), of the ovule, standing erect, the micropyle being
at the opposite end to the stalk.
Palmate, of a leaf, with divisions spreading from a common point.
Panicle, a branched inflorescence with stalked flowers.
Pappus (p. 231), the hairy development which replaces the calyx in
Composite.
Parenchyma, thin-walled cellular tissue, with cells not much longer than
broad.
Pentamerous, with parts in fives.
Pericarp, the wall of the fruit.
Perigynous, situated around the ovary.
Petals, the leaves of the corolla.
Pinnate, of a leaf, with divisions arranged in a series right and left of an
axis, as the barbs of a feather.
Pinnatifid, of a leaf, when pinnately cut about half way to the mid-rib.
Pistil, the central organ of the flower. It generally consists of one or
more ovaries and stigmas ; the stigma is often raised on a stalk, called
the style.
Placenta, the part of the ovary on which the ovules are borne.
Plumule, the bud in the embryo which will develop into the stem and
leaves of the plant.
Polygamous, having male, female, and hermaphrodite flowers on the
same or on distinct plants.
Pome, a fruit in which the succulent floral receptacle surrounds and is
completely merged with the pistil, asin Apple and Pear.
Protandrous, of flowers in which the stamens come to maturity before
the stigmas.
Protogynous, of flowers in which the stigmas come to maturity before
the stamens.
Raceme, an inflorescence consisting of an elongated axis bearing stalked
flowers, the youngest at the top. %
Radical, of leaves springing from a shortened stem, thus appearing to
come from the root.
GLOSSARY xxiii
Radicle, the root of the embryo.
Receptacle, the axis of the flower, generally more or less thickened.
Rhizome, an underground stem, generally more or less thickened.
Rostellum (p. 401), the non-receptive third stigma of an Orchid flower.
Samara, a winged fruit.
Scape, a leafless stem bearing flowers.
Sclerenchyma, hard tissue, for support (mechanical tissue).
Sepals (p. 3), the leaves of the calyx.
Septicidal dehiscence, of a capsule splitting along the septum which
separates the constituent chambers.
Silicula or silicule (p. 85), w siliqua which is not longer than broad.
Siliqua, the fruit characteristic of Cruciferee, opening longitudinally by
two valves which separate from a central septum.
Spike, like a raceme (q.v.), but with sessile flowers.
Stamens (p. 4), the parts of a flower which generally stand next the
corolla, on the inner side. They usually consist of a stalk or filament,
and an anther, containing the pollen.
Staminode, a barren stamen, generally much reduced in size.
Stigma (p. 4), that portion of the pistil on which the pollen must be
deposited in order to fertilise the flower.
Stipule, an appendage of the base of the leaf, generally borne in
pairs.
Stoma, the month or aperture between two adjacent epidermal cells.
Style, the stalk of the stigma.
Testa, the secd-coat.
Tetramerous, with parts in fours.
Transpiration, the giving off of water-vapour by green leaves.
Trimorphous, of species in which there are three forms of flowers,
differing in the relative position of the anthers and stigma.
Tricecious (p. 110), having hermaphrodite, male, and female flowers on
distinct plants.
Tripinnate (p. 50), thrice pinnate (y.v.).
Umbel, an inflorescence in which several stalked flowers spring from
one point ; the youngest flowers are nearest the centre.
Viviparous (p. 442) when the seed is replaced by a green shoot, as in
several Arctic and Alpine grasses.
Fic. 1.—Geranium syleaticum.
CHAPTER I
INTRODUCTION
Our knowledge of the origin and past history of our
British Flora is still very incomplete. The researches
of geologists, however, and especially of Mr. Clement
Reid, have made it probable that before the glacial
period the flora of the British Isles did not materially
differ from the present. Some, at any rate, of our
northern forms were already here, as well as other more
southern species, such as the Hawthorn (Crategus)
and some, such as the Spruce Fir, which were driven
away, or rather killed out, by the cold, and have never
returned. Some of our plants have been introduced by
man intentionally, and others, the so-called weeds of cul-
tivation, unintentionally. Some which might be thought
to be thoroughly established—the Lime, for instance,—
though they produce abundance of fruit, never or scarcely
ever reproduce themselves by self-sown seed. Even the
Common Elm is said to produce perfect seed two or
three times only in a century.
The northern limit of plants is not determined merely
by the average temperature ; it depends on the respective
“Lg B
2 BRITISH FLOWERING PLANTS CHAT.
summer and winter temperatures, on the amount of
sunshine, of moisture, and various other factors. For
instance, some plants can stand a severe winter, pro-
vided the summers are sufficiently hot; others are
satisfied with moderate warmth in summer, but cannot
stand a severe wmter. Hence some plants will thrive
at Paris, but cannot maintain themselves in Kent;
while others flourish near London, but are killed by the
colder winters of Paris.
Apart from their systematic distribution in natural
orders, plants fall into certain great biological groups,
differing according to the poitit of view from which we
consider them. Thus they are annual, biennial, or
perennial, according as they run through their life-
history in one or two seasons, as do many of our herbs,
or persist for several or many years, as in the case of
some herbaceous plants like the Nettle, and all the larger
plants which become shrubs or trees. They may be
evergreen, retaining their leaves for more than one
season, so that the tree is never bare, as in Holly, Pines,
or Yew; or deciduous, shedding at the end of each grow-
ing season the leaves which expanded earlier in the same
year. Again, while most live on land, many are aquatic.
In some the pollen is carried by the wind, in others by
animals, especially insects.
ANNUALS AND PERENNIALS
In very dry localities we find an unusual proportion
of annual species, which come up during the wet season,
if there be one, or after the rains which occasionally
occur. According to Boissier, annual species rise to their
maximum on the hot coast region of Granada, where,
out of 1070 species, 542 are annual, 46 biennial, and
482 perennial.
Alpine and Arctic conditions, on the other hand,
favour perennial species. These generally have strong
roots which go deep into the ground, and are thus pro-
tected from cold, while on the return of more genial
conditions they throw out aerial shoots. In the moister
I INTRODUCTION 3
regions of the tropics, also, there is a great preponder-
ance of perennial species, but with this difference, that
while in cold regions the persistent parts are under-
ground, in the form of woody stems, or bulbs, tubers, ete.
protected by the soil against extreme cold, in hot regions
they require no such protection, and are to a great
extent aerial.
Uniform climates also appear to favour perennial
species. In the Sandwich Islands, for instance, species
of Violet and Geranium, of Composites and Caryo-
phyllaceze, become shrubby.
We owe to Messrs. Bonnier and Flahault a very
interesting memoir on the flora of Dauphiné from this
point of view. They found—
Annual, Perennial.
In the region below the Pine forests . 60 per cent. 40 per cent.
» Pine and Grass region oo ee 67,
» Upper Alpine , . GO. 5, 94 Cy
As regards the character of the soil, etc., they give the
following table :—
Annual and ,
# e Perennial.
Biennial.
Stony and sandy places 32 per cent. 68 per cent.
Dry meadows j : 97s, 90°3 ,,
Damp ,, F ‘ 2 ISS. sy 857s,
Woods and bushy places 4 55 96
Aquatic é , 26 =, 974
Arable fields : . 888 ,, 112 .,
Many plants, as, for instance, Mignonette (Reseda
odorata), which are habitually annual, become biennial
if the flower-buds are pinched off.’
Tur FLOWER
If we examine a common flower, such, for instance,
as a Geranium (Fig. 1), we shall find that it consists of,
first, an outer envelope or calyx, sometimes tubular,
sometimes consisting of separate leaves called sepals ;
secondly, an inner envelope or corolla, which is gener-
ally more or less coloured, and which, like the calyx, is
1 Hildebrand, in Engler’s Bot. Jauhro, ii. (1881).
4 BRITISH FLOWERING PLANTS CHAP.
sometimes tubular, sometimes composed of separate
leaves called petals; thirdly, of one or more stamens,
consisting of a stalk or filament, and a head or anther,
in which the pollen is produced; and fourthly, a pistil,
which is situated in the centre of the flower, and consists
generally of three principal parts—the ovary comprising
one or more compartments at the base, each containing
one or more ovules; the style; and the stigma, which in
many familiar instances forms a small head at the top of
the style or of the ovary, and to which the pollen must
find its way in order to fertilise the ovule. But though
the pistil is thus surrounded by one or more rows of
stamens, and though most flowers are capable of fertilisa-
tion by their own pollen, still it is a great advantage to
a species that the flower should be fertilised by pollen
from a different stock. How, then, is self-fertilisation
prevented ? There are three principal modes. Firstly,
in many species the stamens and pistil are in separate
flowers, sometimes borne on different plants. Secondly,
even when the stamens and pistil are in the same
flower, they are in many species not mature at the same
time. This was first observed by Sprengel in Hpz/obium
angustefolium as long ago as 1790. In some cases the
stigma has matured before the anthers are ripe, while
in other and more numerous cases the anthers have
ripened and shed all their pollen before the stigma has
come to maturity. Thirdly, there are many species in
which, though the anthers and stigma are contained in
the same flower and are mature at the same time, they
are so situated that the pollen can hardly reach the
stigma of the same flower.
Another circumstance which makes for cross-fertilisa-
tion is the prepotence of pollen from another plant of
the same species. If plants of several varieties are
grown together, the seeds cannot be reckoned on to
come true. lJiven after twenty-four hours Darwin
found that pollen from another plant exercised a pre-
dominant influence. He placed on several stigmas of a
long-styled Cowslip (Primula veris) plenty of pollen
I INTRODUCTION 5
from the same plant, and after twenty-four hours added
some from a short-styled dark-red Polyanthus, which is
a variety of the Cowslip. From the flower thus treated
thirty seedlings were raised, and all these without ex-
ception bore reddish flowers; so that the effect of the
plant’s own pollen, though placed on the stigmas twenty-
four hours previously, was quite destroyed by that of
the red variety. In rare cases the pollen, if placed on
the stigma of its own flower, acts like a poison !
In most of our trees—Oaks, Beeches, Spanish Chest-
nuts, Conifers, and many herbaceous plants—the pollen
is carried by wind, and the plants are therefore said to
be anemophilous. In such cases there is a tremendous
waste of pollen. We all know the clouds produced by a
Scotch Pine. Wind-fertilised flowers, as a rule, are small,
green, and regular; the pollen is dry and dusty, often
round and generally smooth. The stigmas are covered
with long hairs or papille, thus offering a larger surface
to the pollen and increasing the chances of fertilisation.
On the other hand, in the great majority of flower-
ing plants the pollen is carried from one flower to
another by insects. Such flowers are called entomo-
philous. They are generally large, and coloured—
yellow, white, red, or blue. They often emit scent and
produce honey, both of which serve to attract insects.
They also present great diversities of form and struc-
ture, often being irregular. The pollen is often angular,
with teeth, spines, or furrows, and more or less sticky.
Bees and humble bees play a most important part
in carrying pollen from flower to flower.
Every one knows how important flowers are to
insects; every one knows that bees, butterflies, etc.,
derive the main part of their nourishment from the
honey or pollen of flowers; but it is, on the other hand,
only recently that we have realised how much the flowers
themselves are dependent on insects. Yet it has, I think,
been clearly shown that if insects have been in some
respects modified and adapted with a view to the
acquirement of honey and pollen, flowers, on the other
6 BRITISH FLOWERING PLANTS CHAP.
hand, owe their scent and honey, their form and colour,
to the agency of insects. Thus the lines and bands by
which so many flowers are ornamented have reference
to the position of the honey; and it may be observed
that these honey-guides are absent in night flowers,
where they, of course, would not show, and would there-
fore be useless, as, for instance, in Lychnis vespertina or
Silene nutans. Night flowers, moreover, are generally
pale; for instance, Lychnis vespertina is white, while
Lychnis diurna, which flowers by day, is red.
It must be borne in mind that, as a rule, each work-
ing bee keeps during each journey to a single species
of plant. It is interesting that this fact: was mentioned
by Aristotle. It has been questioned, probably because
male bees have been watched, and they are not so con-
stant as the females. For them it is not so important.
Male bees take no share in the provision of food, and
their time is of no value. Hence neither of the two
reasons which influence female bees apply to them. One
advantage to the bees is the economy of time resulting
from doing the same thing over and over again; but
another, no doubt, is thatthe pollen of different species
is kept separate and not mixed together.
Working bees waste no time, and fly quickly.
Darwin timed humble bees at 10 miles an hour, and
I believe hive bees are considerably more rapid. I have
often watched them, and seen them visit some twenty
flowers in a minute; and though one would suppose
that when flowers are numerous many must be missed,
this does not appear to be the case. Darwin, for in-
stance, near Bournemouth, in the course of a long
walk examined several hundred flowers of Heath (Lica
Tetralix), and every one had been visited. Nay, each
flower is visited several times a day. In the case of
Dictamnus Fraxinella he found the visits amounted
to thirty in a day. Of course, however, in the case
of many species the visits are comparatively few and
far between.
1 Avebury (Lubbock), Flowers, Fruits, and Leaves.
I INTRODUCTION 7
Flowers may be divided into groups according to
the manner in which the anthers and stigma are pro-
tected against wet and cold.
1. Pendent or hanging flowers: as, for instance,
some Campanulas, Heaths, Rhododendrons, Rosacez
(Geum), Solanaceze (Atropa), Boragineee (Pulmonaria),
Ranunculacez (Aquilegia), Liliaceee (Convallaria), Ama-
ryllidaceze (Snowdrop, Leucojum), ete.
2. Others are more or less horizontal: as, for instance,
Viola, Aconitum, most Labiates, as Lamium (Dead-
nettle), Nepeta (Ground Ivy), Stachys, Prunella, ete. ;
Leguminose, Scrophulariacese, as Antirrhinum (Snap-
dragon), Linaria, Mimulus, ete.
3. Others are upright, but the anthers and stigmas
are arched over by the sepals or petals, or both: as, for
instance, among Ranunculacez, Trollius and Eranthis.
4, Others are protected by the leaves : as, for instance,
Tilia (Lime) and Impatiens (Balsam).
5. Another group stand upright, but («) the passage
is so narrow that rain and dew cannot enter, or (0) it is
partly closed by projections or (c) by hairs: as, for in-
stance, some Primulas and Geraniums.
6. Some flowers are upright by day or in sun-
shine, but hang down at night or in rain: as, for
instance, some Campanulas (C. patil), Scabiosas,
Geraniums (G. Robertianum), Epilobiums, Anemones,
Saxifrages, ete.
Sometimes it is the flower-stalk which bends, some-
times, as in Epilobium, the ovary.
7. In some cases the flowers or flower-heads close :
as, for instance, many Composites, Crocus, Gentians,
Campanulas, Peonies, Flaxes, Water-lilies, Anemones,
Erythrea.
Sometimes the anthers themselves open or close:
according to the weather : as, for instance, in Alchemilla
(Lady’s Mantle), Laurus, Plantago, Thesium, etc. Those
of Thesium alpinum are said to close in 30 seconds if
moistened.
In addition to the ordinary coloured flowers, some
8 BRITISH FLOWERING PLANTS CHAP.
plants have a second kind in which the petals are absent,
or at any rate minute, and which do not open. For
instance, in some of the Violets—V. odorata, canina
(p. 98), ete.,—hesides the blue flowers with which we
are all so familiar, there are others almost without
petals and stamens, which indeed have scarcely the
appearance of true
flowers, but in which
numerous seeds are
produced. “Cleisto-
gamous” flowe1s, as
these have been called,
occur in Lamiwm am-
plexicaule (Fig. 2),
Oxalis Acetosella, Trv-
folium subterraneum,
and other plants be-
ga ria er Fra. i al of longing to very different
togamous flower. groups.
The flowers of water
plants also fall into certain well-marked groups.
In the first we may place those which have a con-
spicuous coloured flower and are adapted for fertilisation
by insects: as, for instance, the Water-lilies, Water
Ranunculi, Limnanthemum, MHottonia, Utricularia,
Lobelia Dortmanna, Alisma, Hydrocharis, Stratiotes.
These project singly, or in terminal bunches, above
the water. They have undergone no special modifica-
tion, though the flower-stalk is more or less strengthened
so as to maintaim them in an upright position, and the
leaves are often arranged so as to serve the same purpose.
Hair-like outgrowths are sometimes found in the flower
(eg. Limnanthemum) which will prevent the nectar
from being flooded by water which may be splashed in.
They are generally white or yellow, which makes them
more conspicuous against the bluish water. Lobelia
Dortmanna is the only blue flower in the group, but, as
Schenck says,’ we must remember that blue is in any
1 Die Biologie der Wassergewiichse,
I INTRODUCTION 9
case by no means a common colour. Such flowers if
kept under water, by flood or otherwise, sometimes
become cleistogamous (see above): as, for instance, in
Ranunculus aquatilis, Alisma natans, Subularia
aquatica, and Illecebrum verticillatum.
To a second group belong certain species in which
the flowers raise themselves into the air, but which are
not large or conspicuous, and which are presumably
wind-fertilised : as, for instance, Myriophyllum, Potamo-
geton (Pondweed), and some Sparganiums.
In a third group the flowers as well as the leaves are
submerged. Callitriche is an intermediate form; some
species have aerial, others submerged flowers. The
flowers are very simple, arranged in the axils of the
leaves—the males reduced to a single stamen, the
females to a pistil.
As typical of this group I may mention Cerato-
phyllum demersum. The flowers are surrounded by a
whorl of minute bracts: the female consists of a small
ovary with a single style; the male of from 12 to 20
oblong sessile anthers. The pollen, as in all submerged
flowers, has no extine.
Zostera, the Grass-wrack of our shallow seas, has the
small flowers enclosed in a sheath at the base of certain
leaves, which do not materially differ from the rest, but
are somewhat smaller. They are arranged in two rows,
with alternately male and female flowers. They are
protogynous, and the pollen is peculiar, being thread-
like, but without motion.
Lastly, there is a small group, of which Vallisneria is
the best-known form, and which in our flora is repre-
sented by Ruppia. The flowers are very simple, and
consist of two bilocular anthers and an ovary with four
carpels. The spadix or stalk on which they grow is at
first short. The anthers open first, and eject the pollen,
which, being lighter than water, at once rises to the
surface. Immediately afterwards the spadix lengthens
rapidly, carrying the female flower to the surface, where
it meets the floating pollen. In Vallisneria the male
10 BRITISH FLOWERING PLANTS CHAP.
flowers are on a separate part of the plant, but are
set free and rise to the surface, on which they float
in some numbers around the female flowers, one or
more of the dehiscing anthers coming in contact with
the stigmas.
While some water plants (Utricularia, Hottonia, and
Lobelia, for instance) ripen their seeds in the air, by far
the larger number after flowering draw the ovary down
under water. In many cases the shell of the fruit
develops air cavities, which, when the seeds are ripe,
carry them up again to the surface, and thus promote
dispersal. No doubt in many cases birds carry them
from one river or lake to another. It is easy to
understand that the seeds and fruits of water plants
do not develop wings or parachutes, which in so many
land plants serve this purpose; nor do we find cases in
which they are thrown or jerked.
It would appear that the chances of the ovule being
fertilised and the seed coming to maturity are, on the
whole, fewer in water plants than in land plants. On
the other hand, the constant supply of water renders the
vegetative orowth more luxuriant. Hence we find that
aquatic plants are generally perennial. In our own
flora Subularia aquatica and Najas marina are the
only annual species.
Freshwater plants, for obvious reasons, do not reach
high latitudes or great altitudes. In temperate regions,
however, the species have, as a rule, very wide ranges,
not only in many cases round the world, but even
reappearing in islands far from the mainland, mainly,
we can hardly doubt, through the agency of water
birds. Najas marina is a very good instance. Widely
spread in the north temperate zone, it occurs also in
Australia, the Sandwich Islands, Chnsinies, Venezuela,
Brazil, etc.’
Another remarkable peculiarity of flowers which I
think, as I suggested in a lecture to the British Asso-
ciation at Belfast in 1874, has reference to their
1 Rendle, Trans. Linn. Soc. (Bot.) ser. 2, vol. v.
I INTRODUCTION 11
relations with insects, is the habit of “sleeping,” which
characterises certain species.
Many flowers close their petals during rain, which
is obviously an advantage, since it prevents the honey
and pollen from being spoilt or washed away. Every-
body, however, has observed that even in fine weather
certain flowers close at particular hours. This habit of
going to sleep is surely very curious. Why should
flowers do so?
Tn animals we can understand it; they are tired and
require rest. But why should flowers sleep? More-
over, some flowers sleep and not others, and those which
do sleep keep different hours. The Daisy opens at sun-
rise and closes at sunset, whence its name “ day’s-eye.”
The Dandelion (Taraxacum officinale) is said to open
about seven and close about five; Arenaria rubra,
to be open from nine to three; NMymphea alba, from
about seven to four; the common Mouse-ear Hawkweed
(Meracium Pilosella), from eight to three ; the Scarlet
Pimpernel (Anagallis arvensis), to waken at seven and
close soon after two; Tragopogon pratensis, to open at
four in the morning and close just before twelve, whence
its English name, ‘‘ John-go-to-bed-at-noon.” Farmers’
boys in some parts are said to regulate their dinner-
time by it. Other flowers, on the contrary, open in the
evening.’
Now, it is obvious that flowers which are fertilised
by night-flying insects would derive no advantage from
being open by day; and, on the other hand, that those
which are fertilised by bees would gain nothing by being
open at night. Nay, it would be a distinct disadvan-
tage, because it would render them liable to be robbed
of their honey and pollen by insects which are not
capable of fertilising them. It may be observed also
that wind-fertilised flowers do not sleep; and that some
of those flowers which attract insects by smell emit
1 In my own observations the opening and closing were more gradual and
more dependent on the weather than I should have expected from the state-
ments quoted above.
12 BRITISH FLOWERING PLANTS CHAP.
their scent at particular hours; thus, Hesperis matron-
alis and Lychnis vespertina smell in the evening, and
Habenaria bifolia is particularly sweet at night.
Besides the means of attracting welcome guests,
many plants have adopted various devices for barring
access to their stores of honey of insects whose visits
would be of no use in transferrig pollen. For instance,
in aie case of bee flowers,
small flying insects are
kept from the nectar by
barriers of stiff hairs which
they are not strong
enough to pass—e.g. Tro-
peolum. Creeping insects,
as ants, are frequently
kept back by sticky hairs
on the stem or flower-stalk
—as in many Saxifrages.
A large proportion of
dicotyledonous flowers
have five sepals and five
petals. Why is this?
It is probably to be ex-
plained by the phyllo-
taxy, or arrangement of
the leaves on the stalk.
The petals, as Goethe
seems first to have sug-
gested, are modified
leaves. Now if we ex-
amine a Rose shoot (Fie.
4) we shall find that the
leaves are arranged in a
spiral round the stem in
such a manner that with
whatever leaf we start the sixth comes directly over it,
the seventh over the second, and so on. In fact, the
leaves form whorls of five, one over the other. This is
still more evident in those species which have a five-
Fic. 4,.—Shoot of Rose.
I INTRODUCTION 13
angled stem. If we hold it so that the youngest leaf
(1) of the piece of shoot figured sits on the uppermost
ridge in Fig. 5, the leaf immediately above (2) rises not
from the next ridge, but the next but one, that on the
lower left-hand side. The next (3) sits on the ridge
on the upper right-hand side. No. 4 is on the left.
Finally, leaf No. 5 is on the ridge forming the lower
right-hand edge of the stem. I say finally, because this
completes the series. Leaf No. 6 is on the same ridge
Fic. 5.—Whorl of Bramble leaves.
as, and corresponds to No. 1, leaf No. 7 to leaf No. 2,
No. 8 to No. 8, and so on.
The leaves, in fact, are not on the ridge next to
the ones immediately above and below, but on the next
but one. Thus, then, each whorl consists of five
leaves arranged in a double spiral round the stem.
This is known as the 2/5 arrangement. Incidentally it
throws light on the pentagonal form of the stem. The
arrangement is, however, not quite so obvious as would
otherwise be the case—firstly, because the stem is often
somewhat twisted, and, secondly, because the petiole of
the leaf is itself sometimes bent, so that the leaf may
14 BRITISH FLOWERING PLANTS CHAP.
take the position to secure the fullest amount of light.
In Fig. 5 this arrangement is clearly shown. Now if
we imagine the intervals between the leaves suppressed,
we shall see that they would lie in whorls of five. In
fact, the five sepals form one such whorl and the five
petals another. We may test this suggestion by taking
the case of the Lilac and Privet, which have 4
sepals and 4 petals. Here the leaves are opposite,
each pair at right angles to those above and below.
Here, therefore, the whorl of leaves would consist, not
of five, but of four. There are indeed some excep-
tions which must be otherwise accounted for. For
instance, in genera which contain species of different
sizes the number of sepals and petals is. often less in the
smaller than in the larger ones.
Flowers with parts in fours are also frequently met
with in orders where the pentamerous arrangement is
the more common. Caryophyllacez is a good example.
Taking our British genera, we find in the smaller
flowered ones—such as Cerastium, Stellaria, and
Sagina—the number of parts sometimes 4 instead of 5.
Assuming, as we may, that all had a common penta-
merous ancestor, we regard the tetramerous forms as
resulting from the dropping out of one member from
each whorl. In other cases, however, the tetramery is
due, not to a loss, but to a fusion of parts. Thus most
species of Veronica have 4 sepals and a 4-lobed corolla.
There is no doubt, however, that the upper petal
represents two which have become united. It is very
often larger than the others, and sometimes its double
origin is indicated by a notch. In some cases, more-
over, both petals are developed, and we have a penta-
merous corolla, bringimg Veronica into line with the
other members of its family, Scrophulariness, where the
corolla is formed on a pentamerous plan. The tetra-
merous calyx is explained by the loss of the upper-
most sepal; in pentamerous species this, however, is
developed. In one of our commonest British orders,
Cruciferee, the flower is built on a 4-plan, but we
I INTRODUCTION 15
cannot correlate this with the leaf-arrangement or
derive it in any simple way from a pentamerous flower
—it is a remarkably constant type of flower, and the
story of its development is lost. Last come such cases
as the Lilac and Privet, where the leaves are in pairs,
and opposite, so that the whorl would consist of four
leaves.
FRUITS AND SEEDS
As regards fruits and seeds, one main point to be
considered is the mode in which they are dispersed.
From this point of view they may be divided into
various classes :—
Seeds or fruits with wings, which are carried by
wind.
Seeds or fruits with feathery appendages, carried
by wind, and sometimes, as in Willow, floated by
water.
Seeds in capsules which open at the top, the seeds
being jerked out by wind.
Seeds or fruits with hooks, which are carried by
animals,
Fruits which are eaten and the seeds thus carried by
animals.
Seeds which are thrown by the plants.
To the first category, viz., those with wings, belong
mainly trees: as, for instance, Pines and Firs, Syca-
mores and Maples, Elms and Birch; while though the
fruit of the Lime is not itself winged it is attached to a
leafy bract which serves the same purpose. The same
is the case with the Hornbeam.
The next class, those with hairy appendages, is very
extensive. To it belong the Willows and Tamarisks,
many Grasses, Bulrushes, Cotton-grass, Willow-herbs,
Dandelion, Thistles, and many other Composites, etc.,
ete.
Examples of plants in which the fruits or seeds are
provided with hooks are found in Agrimony, Bur-
parsley, Burdock, Carrot, Cleavers (Galium), Enchanter’s
16 BRITISH FLOWERING PLANTS CHAP,
Nightshade (Circea), some Forget-me-nots, etc. That
these hooks really serve to attach the seeds to passing
animals is shown by the interesting fact that they are
characteristic of low plants. In our flora they do not
occur on any plant which exceeds 2 or 3 feet in height,
nor do they occur on water plants.
On the other hand, this argument does not apply to
seeds which are eaten and thus carried by animals,
especially by quadrupeds and birds. To this class
belong all those popularly known as fruits and nuts, viz.,
Apple, Pear, Plum, Hazel, Beech, Oak, etc., ete.
It is interesting that while more or less green and
inconspicuous when immature, in many cases as they
become ripe they assume bright colours, especially
orange, red, purple, and dark blue. It seems probable
that it is an advantage for fruits which ripen when the
leaves are still green to be red, as this gives the greatest
contrast. On the other hand, red would not be con-
spicuous against faded leaves which are brown, or even
sometimes themselves reddish. For such fruits, blue or
black would be more advantageous, and, as a matter of
fact, many heath and moor species have bluish or black
fruit, as, for instance, the Bilberry, the allied Vacciniwm
uliginosum, or the Black Bearberry.
In some cases the juicy pulp only is assimilated,
and the hard seeds pass through uninjured; but even
digestible seeds often pass undigested; moreover, we
know that small birds continually fall victims to
hawks, etc., and perish from accidents, so that the cases
are numerous where undigested seeds have a chance of
growing.
The northern birds, as Mr. Reid points out,’ generally
come to us in autumn when the seeds are ripe, and must
bring many southwards with them.
Many plants develop their seeds in capsules, which
open at the upper end, so that while the seeds lie
quiet while it is calm, they are jerked out by a high
wind. This is the case, for instance, in Poppies, in
1 Origin of the British Flora.
I INTRODUCTION 17
which the tiny seeds are jerked out through small
holes round the upper edge of the capsule. In many
Campanulas the capsule opens by pores at the base
of the capsule, which, however, becomes inverted when
mature.
One of the most interesting groups of seeds are those
which are thrown by the plants themselves, as, for
instance, in the Geraniums, Oxalis, some Violets, Car-
damines, Euphorbias, ete. It is remarkable how much
in these cases the mechanism differs.
Some seeds mimic small insects, and are no doubt
picked up, and carried some distance before the
mistake is discovered, by birds (see, for instance, the
Mallows), or even by insects, as in the case of Melam-
pyrum.
A large number of species have very minute seeds.
These, of course, have a larger surface in proportion to
their weight, and are readily carried by wind without
any special provision for the purpose. Arctic and
Alpine species very generally belong to this class.
Many seeds and fruits develop air cavities, which
renders them lighter, and thus facilitates dispersal.
This is specially the case in water plants, and the seeds
are thus enabled to float.
In the great family of Umbellifers, as a rule, the
‘“carpophore” splits lengthwise, and the two mericarps,
each containing a seed, hang loosely by their upper
ends to the two whip-like filaments. The dry plants
are very elastic, and sway backwards and forwards in
the wind, until at last some strong gust tears the
mericarps off and carries them away.
Even when there is no special provision for dispersal,
seeds must be often carried about on the feet of animals
and the flanks of wallowing quadrupeds.
Another point to be considered with reference to
seeds is the character of the surface. Some are smooth
and shining, some reticulate, some pitted. Those with
hooks or hairs have already been mentioned. Reticula-
tions often, as, for instance, in Geraniums, fit into
C
18 BRITISH FLOWERING PLANTS
CHAP,
TREES, SHRUBS, AND CLIMBING SHRUBS NATIVE OR
NATURALISED IN BRITAIN
Clematis Vitalba
Berberts vulgaris
Lime (Tilia ewropea)
Maple (Acer campestris)
Sycamore (Acer Pseudo- _platanns)
Spindle Tree (Euonymus) .
Buckthorn (Rhamnus catharticus)
Rhamnus Frangula .
Sloe (Prunus) .
Rose (Rosa)
Apple (Pyrus Malus)
Pear (Pyrus communis)
Hawthorn (Crataegus)
Medlar (Mespilus)
Ivy (Hedera)
Cornel (Cornus)
Elder (Sambucus)
Guelder Rose (Viburnum).
Honeysuckle (Lonicera)
Arbutus (Arbutus)
Holly (lex)
Ash (Fraxinus)
Privet (Ligustrum)
Elm ‘Ulmus)
Hop (Humulus)
Alder (Alnus) 1
Birch (Betula) .
Hornbeam (Carpinus)
Nut (Corylus) .
Beech (Fagus) .
Oak (Quercus) .
Willow (Salix)
Poplar (Populus)
Pine (Pinus)
Fir (A bies)
Yew (Taxus)
=
Edible. |
x XX xX xX xX XXX XxX xX xXX XX
x
x
Seed or Fruit.
Hairy. Winged.
Hooked.
1 Some species of Alder have winged fruit.
i INTRODUCTION 19
depressions in the carpels. In other cases, perhaps, they
serve to promote dispersal by diminishing the specific
gravity of the seeds. It has been suggested that the
smooth surface of many seeds is perhaps an advantage
by enabling them to pass through the body of an animal
without being digested. Another explanation may be
that seeds which are thrown by the plant, or jerked by
the wind, would no doubt go further if the surface was
smooth, because it would offer less resistance to the air.
It may be convenient to say a few words as to the
fruits of trees with reference to the dispersal of the
seeds. Nature, as we have already seen, has devised
several plans for the dispersal of fruits and seeds. For
instance, some are edible, and are carried by animals ;
some are hairy or winged, and are carried by currents
of air; some have hooks, and become entangled in fur
and hair.
That these differences of structure are really adapta-
tions comes out clearly if we take some definite group, such
as our common forest trees, shrubs, and tall climbing
plants; not, of course, a natural or botanical group,
for they belong to a number of different orders, but
a group characterised by attaining to a height of,
say, over eight feet. We will in some cases only
count genera; that is to say, we will count all the
Willows, for instance, as one. These trees and shrubs
are plants with which we are all familiar, and are about
thirty-six in number. Now of these thirty-six no
less than twenty-two have edible fruits or seeds, such
as the Plum, Apple, Arbutus, Holly, Hazel, Beech,
and Rose; three have seeds which are provided with
feathery hairs; and all the rest, namely, the Lime,
Maple, Ash, Sycamore, Elm, Hop, Birch, Hornbeam,
Pine, and Fir, are provided with a wing. Moreover, as
will be seen by the following table, the lower trees and
shrubs, such as Cornel], Guelder Rose, Rose, Thorn,
Privet, Elder, Yew, and Holly, have generally edible
fruits, much eaten by birds. The winged seeds or
fruits characterise the great forest trees.
20 BRITISH FLOWERING PLANTS CHAP.
In considering the importance of these provisions
we have not only to bear in mind the desirability of the
seeds being scattered beyond the shadow of the parent
plants, and the soil which has been more or less exhausted
by them, but must also remember the vicissitudes of
climate through which our islands have passed. Before
the glacial period our flora seems to have been, on the
whole, very much what it is now. During the glacial
period our plants were driven south, a few of the Arctic
and Alpine species only remaining in the extreme south
and west. During this period there seems to have been
certainly one, and possibly several comparatively mild
periods, so that the whole, or nearly the whole, of our
plants have been compelled at least twice, probably
several times, to migrate long distances.’ Perhaps for
this reason our flora is highly specialised for dispersal,
or rather the species best organised in this respect are
those which have been able to re-establish themselves
here.
The methods of packing the embryo in the seed-coat,
the germination of the seed, and the characters of the
seedling afford interesting subjects for study. Some
account of these will be found in my books on Seedlings.
LEAVES
The leaf originates as a slight protuberance of the
bud. Fig. 6 represents a longitudinal section through
the growing point of a winter bud of Abies pectinata
(Silver Fir), and shows the commencement of two
leaves (b, 6). It also illustrates the cellular structure
of young tissue.
The nourishment absorbed by the roots from the
soil passes as crude sap into the leaves and is there
elaborated. Carbonic acid gas is absorbed from the air
by means of the stomata,—minute slit-like apertures
between two epidermal cells which guard the entrance
(guard-cells), and, by contraction, close it at night and
in dull weather. The stomata allow communication
1 Reid, Origin of the British Flora.
I INTRODUCTION 21
between the outside air and the intercellular spaces in
the leaf-tissue, which are specially developed on the
lower face of the leaf (see Fig. 11 below). Through
the stomata also escapes the surplus water in which the
nitrogenous and other mineral food has been carried up
from the roots to the leaves. Some of the water is
required for nutrition and as cell-sap to maintain the
turgescence of the tissues, but a large proportion serves
only as a carrier, and is ultimately given off, or trans-
pired, through the stomata. They are very numerous.
Fic, 6.—Longitudinal section through the growing point of a winter bud of Abies
pectinata, x about 200. WS, apex of growing point; 6, 6, youngest leaves ;
7, cortex ; m, pith.
It is estimated, for instance, that on such a leaf as
that of the Oak there are not less than 2,000,000.
The carbon is assimilated and the oxygen released, at
least in part. It is remarkable that plants do not take
up carbonic acid from the soil. It might have been
expected that the roots, ramifying as they do in earth
more or less saturated with water containing carbonic
acid in solution, would absorb what is so important
an element in their food. This function is, however,
mainly performed by the leaves, and especially under
the influence of daylight. It is carried on by
protoplasm containing “chlorophyll granules.” These
are roundish green corpuscles, which give their peculiar
22 BRITISH FLOWERING PLANTS CHAP.
colour to leaves. On them depends the life of plants,
and ultimately, therefore, of land animals also.
Every one knows that plants grown in the dark are
unable to produce
Fia. 7.—Twig of Beech,
chlorophyll. But though light is
necessary for its production, and
though the leaves of our plants are,
as a rule, arranged so as to secure
the greatest amount of light, still it
becomes injurious if too intense.
In our own country leaves are
generally arranged so as to secure
the maximum of light and air, as,
for instance, those of the Beech
(Fig. 7), the Spanish Chestnut
(Fig. 8), and the Maple (Fig. 9).
We have, however, some shade-
loving species, and in hotter regions
the tendency becomes greater to
avoid the too brilliant sunshine.
As familiar examples may be men-
tioned the leaves of the Black Poplar (Fig. 10) and
Eucalyptus, which
Fic, 8.—Twig of Chestnut
(Castanea).
are vertical, and those of several
Fig. 9.—Twig of Norway Maple.
New Zealand Veronicas, which are placed in four rows,
one under the other. The summer shoots sometimes
produced on our forest trees are often pale, the bright
I INTRODUCTION 23
light having checked the formation of chlorophyll.
Young shoots, especially, require protection from the
action of light, which would otherwise check the forma-
tion of chlorophyll. This is afforded in several ways,
of which the principal are—by the
thick and often glossy epidermis; by
the position of the leaf; by the struc-
ture of the leaf; by the arrange-
ment of the chlorophyll granules ; by
change in their form; by hairs, which
often fall off when the leaf is fully
developed ; by stipules—either those
of the same leaf, as in the Hop
(Humulus), or of an older leaf, as
in the Pea. The latter safeguards
are useful also in other ways; for
instance, as a protection against cold,
against insects, etc. s
Again, the presence of red colour Fis. 10.—Shoot of Black
: ‘ Poplar (Papulus nigra).
is very common in young shoots, when
it perhaps serves to protect the chlorophyll in the
delicate tissues from too much light; and this seems to
have been taken advantage of and developed in the
corolla and other parts of the flower, as an attraction
to insects.
In ordinary parlance, when we speak of a leaf we
think only of the leaf blade. The leaf blade is only
one part of the leaf, which, if complete, may be
regarded as consisting of four parts—the blade, the
stalk, the stipules, and the base. One or more of these
parts, however, may be wanting. In some cases, for
instance, the leaf is sessile ; in others the blade is absent.
Stipules are the two small leaflets which often occur
just above the base of the leaf, as, for instance, in the
Violet, Pea, Rose, ete. Linnzus gave them the name
from stipula, a little straw. This term happily
expresses their appearance in the case of the Beech.
In this species they drop early, and in spring make
the ground under Beeches almost brown. In this case,
24 BRITISH FLOWERING PLANTS CHAP.
as in many others, they serve to protect the young
leaves. Every one who loves a garden knows to his
cost how delicate young leaves are; how susceptible
to cold, so that often—too often—the bright promise
of spring is ruined by a single cold night. Moreover,
young leaves require protection not merely from cold
but from too great heat, from dryness, moisture, and
light, as well as against the attacks of animals.
The principal modes by which they are protected
are :—
1. By the preceding leaves, as in Hypericum.
2. By the base of the preceding leaf, which persists
through the winter, as in Spartium, sometimes forming
a cup, covering the bud as in Philadelphus, the Mock
Orange or Syringa of gardens.
3. By scales which represent modified outer leaves,
as in Willows.
4. By scales which represent leaf-stalks, as in
Maples and Ash.
5. By scales which represent stipules, as in Beech
and Oak. If an Oak bud be carefully opened, more
than forty scales will be counted before coming to a
true leaf.
6. By the two connate stipules of a leaf, as in Elm
and Spanish Chestnut.
7. By two connate stipules belonging to different
leaves, as in the Hop.
8. By spines.
9. By furry hair.
10. By gum, resin, or mucus.
Leaves may be arranged in various classes: ever-
green or deciduous, broad or narrow, opposite or
alternate, entire or divided, hairy or smooth, ete. ete.
Deciduous plants keep their leaves on longer as the
summers lengthen. The Cherry (Prunus Cerasus) keeps
its leaves longer in Southern Europe, and in Ceylon is
evergreen.
Broad leaves are generally horizontal, narrow leaves
more or less upright. Thus many trees and herbs, such
I INTRODUCTION 25
as the Daisy, have broad horizontal leaves ; while grasses
have more or less upright and narrow ones. The
Plantain and Drosera give good illustrations. Plantago
media and Drosera votiundifolia have broad flat
leaves; while in Plantago lanceolata and Drosera
anglica they are narrow and upright.
Hairs on plants fulfil numerous functions: they
prevent undue transpiration, hence the hairiness of so
many species of hot dry countries, as the Riviera; they
also protect the plant from too brilliant sunshine ;
again, they keep moisture from clogging the stomata,
or breathing pores, and are thus useful in cold foge
districts, as, for instance, our northern heaths and
moors. Such hairs are dry and contain air; but another
sort are juicy and conduct or even themselves absorb
moisture, as, for instance, is said to be the case with
those on the Chickweed. In some cases hairs protect
plants from being eaten by browsing quadrupeds, and in
many they prevent ants and other creeping insects from
obtaining access to the flowers and robbing them of their
honey. Hairs intended to perform this function are
often rendered more effective by pointing downwards.
Water plants and those living in damp _ localities
have no need of hairs and are glabrous. Some species,
such as Selene inflata and Polygonum amphibiim, are
glabrous in damp, and hairy in dry places. Their leaves
are also much cut up, often into long linear segments.
I have suggested' that the object of this is to expose
as large a surface as possible to the action of the water.
We know that the gills of fish consist of a number
of thin plates, which while in water float apart, but
have not sufficient consistence to support even their own
weight, much less any external force, and consequently
collapse in air. The same thing happens with these thin,
finely-cut leaves. In still water they afford the greatest
possible extent of surface with the least expenditure of
effort in the formation of skeleton. This is, I believe,
the explanation of the prevalence of this form in sub-
\ Flowers, Fruits, and Leaves.
26 BRITISH FLOWERING PLANTS CHAP.
aqueous leaves. Again, in still air the conditions,
except so far as they are modified by the weight, would
approximate to those of water, but the more the plant is
exposed to wind the more would it require strengthening.
Hence perhaps the fact that herbs, which, of course, are
less exposed to wind, so much oftener have finely-cut
leaves than is the case with trees. We may instance
those of many Geraniums, Umbellifers, Delphiniums,
Buttercups.
There are, moreover, many groups of plants which,
while habitually herbaceous, contain some shrubby
species, or vice versa. Let us take some groups of this
description in which the herbaceous species have their
leaves much cut up, and see what is the character of
the foliage in the shrubby species. The vast majority
of Umbellifers are herbaceous, and with leaves much
divided, the common carrot being a typical example.
One Kuropean species, however, Bupleurum fruticosum,
is a shrub attaining a height of more than 6 feet, and
has the leaves coriaceous and entire.
Common Groundsel (Senecio vulgaris) again is a
low herb with much cut leaves. Some species of
Senecio, however, are shrubby, and their leaves assume
a totally different character, Senecio laurifolius and
S. populifolius having, as their specific names denote,
leaves respectively resembling the Laurel and Poplar.
In the genus Oxalis, again, there is a shrubby species,
O. Laureola, with leaves like those of a Laurel.
One common type of leaf is that of which the Laurel
may be taken as an example. Such leaves are more
or less oval, somewhat tough, caducous or evergreen,
and with the stomata, as a rule, on the lower surface.
They are adapted to resist wind, and are charac-
teristic of trees and shrubs. To this type belong,
besides those of Laurel, the Laurustinus, the Way-
faring tree, Evergreen Oak, Holly, Beech, Hornbeam,
Elm, Pear, ete.
In others the leaves are larger, but, perhaps as a
protection from the wind, are pinnate, with more or
I INTRODUCTION OF
less oval leaflets, as in Ash, Mountain Ash, Robinia
(Acacia of gardeners), ete.
Palmate leaves form another type: as, for instance,
those of Sycamore, Maple, Plane, Guelder Rose.
Jungner regards the palmate form also as an
adaptation to resist wind. He observes that species
with palmate leaves are particularly abundant in
windy countries and districts. The elastic stalks
enable them to arrange themselves so as it were to
turn their back to, and fly like flags in, the wind.
As we have seen, the leaves of aquatic plants are in
many cases divided into filiform segments, thus exposing
a large surface to the action of the water. On the other
hand, floating leaves have a tendency to be circular.
Some plants have both these forms of leaf,—rounded
ones on the surface ; others finely divided, below. This is
the case, for instance, with some species of Ranunculus.
Leaves growing in damp and shady places—shade
leaves as they may be called—are large, flat, smooth,
and delicate. Those of Petasites, Lactuca Scariola,
Dentaria, Orobus, Paris, Lunaria, Mercurialis perennis
(Dog's Mercury), Impatiens (Balsam), etc., belong to
this type. In dry, arid regions, such as the Riviera,
they would not survive a day.
Another type of leaf may be called ericoid, as the
Heaths afford typical and familiar examples. That of
Empetrum (Fig. 11) is a striking example. They are
evergreen, rolled at the edges, leathery, small, and
crowded. They suit cold and damp, and hot and dry
localities. To the former they are adapted, as they
present a smaller surface to the cold air, and especially
because, as the stomata open into the space which is
more or less completely enclosed by the rolled edges,
and are, moreover, also as a rule protected hy hairs,
they are not liable to be clogged by moisture, but are
in a position to fulfil their important function as soon
as the sun comes out, and even to some extent during
rain. But though it is important that the power of
evaporation should be protected, it is, on the other
28 BRITISH FLOWERING PLANTS CHAP.
hand, equally necessary that it should not be too rapid,
for in severe weather the frost often checks the supply
of water by the roots, even though they go to a con-
siderable depth.
The same safeguards against too rapid evaporation
render them suitable to hot dry regions. The leatheri-
ness of the leaves is also, no doubt, a protection against
browsing quadrupeds, as also are the aromatic properties
of many such species. Besides the Heaths, Azalea,
Empetrum (Fig. 11), Silene acaulis, and some Saxi-
frages belong to this type.
Another northern type is that represented by
ZeAaauee
Zee: eg 089
eases
008 Seo, NORE
‘0 WG
S Ni \
one
SS pa
SporsSoe
ap aenccoyel
b) aguyeeeesase rt
eT
Wer ous
IS.
aS
iy
<4 $4 pack
Fic, 11.—Transverse section of leafof Empetrum. u, upper face; 6, under face ;
8, stoma, shown closed by the approximation of the guard-cells.
Cerastium alpinum. The tapermg form carries off
the moisture, which, moreover, is kept from the stomata
by matted woolly hairs. The result is that as soon as
the sun comes out transpiration becomes possible. On
the other hand, they are less suitable where there is
much snow.
Other leaves of the same type are Salix lanata and
S. repens (two of the Arctic Willows), Gnaphaliwm
supimum (Arctic or Dwarf Cudweed), Bartsia alpina,
the Mountain Forget-me-not (Myosotis silvatica),
Cotoneaster vulgaris, and Hieracium Pilosella, one
of our commonest Hawkweeds.
Another type may be called “snow leaves.” Of this
group Viola palustris is an example. The leaves seem
I INTRODUCTION 29
specially adapted to localities often covered by snow.
The stalk enables the leaf to orient itself so as to secure
as much sunshine as possible; the crenellations, which,
in other plants with the same habit and similar leaves,
are often replaced by teeth, probably retain air between
them and thus tend to mitigate the temperature. Junguer
has shown the probability of this by experiments on
Veronica officinalis. The more or less circular form is
perhaps an advantage from this point of view, as the
result is that the teeth or crenellations are nearer together
than they would be if the leaf were more elongated.
In snowy regions the absence of hair is an advantage..
To the same type belong one of our Arctic Willows
(Salix herbacea), Arctic Birch (Betula nana), Bear-
berry (Arctostaphylos alpina), Whortleberry (Vac-
cinium Vites-Idea), Chrysosplenium, some Saxifrages,
and, somewhat modified, the Cloudberry (Rubus Chame-
morus), and Lady’s Mantle (Alchemilla vulgarvs).
Some species have the radical leaves of this type,
while those on the stem are narrow and elongated : as,
for instance, the Harebell (Campanula rotundifolia),
some Composites, and Alpine Penny-cress (Zhlasp:
alpestre).
Thick and fleshy leaves constitute another type.
This form reduces the transpiring surface, and affords
space for the storage of liquid. Such leaves, therefore,
are specially adapted for dry places. When it rains
the roots suck up a supply of moisture, which the
leaves only part with slowly. They are characteristic,
for instance, of the order Crassulacee. Thus Sedum
anglicum lives on dry sandy soil, walls, etc.; other
examples occur in S. dasyphyllum, S. album, S.
villosum, S. acre (Stonecrop), S. sexangilare, and
S. rupestre; also in Cotyledon Umbilicus, Semper-
vivum tectorum (Houseleek), and in other families,
Inula crithmoides and Crithmum maritimum, which
grow on hot sandy shores, and many foreign species—
the Mesembryanthemums and some of the Cacti, for
instance.
30 BRITISH FLOWERING PLANTS CHAP.
Many leaves “sleep” at night, that is to say, they
assume a position different from that taken in the day.
This is, however, a different phenomenon from the sleep
Fig, 12.—Leaf of Clover (Trifolium repens). Fic. 13.—Position by night.
Position by day.
of flowers, and due to quite a different cause. As a
rule they turn either up or down, thus assuming a more
or less vertical position. This serves as a protection
against cold, the result being that they expose less
surface to the sky. The
Acacia (Robinia), Ox-
alis, Trifolium (Clover),
(Figs. 12 and 13) are
cases In point.
Against the attacks
of animals leaves are
protected in various
ways: by a leathery
texture, by spines, by
felted hair, by bitter or
aromatic sap, etc. Some
plants, which are com-
paratively unprotected, mimic others which are more
fortunate. Thus the leaves and general habit of the
Dead-nettle closely resemble those of the Stinging-
nettle. Fig. 14 represents a group, those on the right
being Stinging-nettles, those on the left the white Dead-
right, and Dead-nettles on the left.
ena CaS,
I INTRODUCTION 31
nettle, one of them in flower. So close is the resem-
blance that after getting the photograph I went back to
the spot on which they were growing to assure myself
that there was no mistake,
There is a remarkable point about some of our
forest trees and shrubs, which Vaucher! seems to
have been the first to notice, namely, that the
Fic. 15.—Twig of Lime. S¢, terminal bud ; B, lateral buds.
terminal buds die, and that very early. Fig. 15 repre-
sents a twig of Lime drawn at the end of May; the
terminal bud and stipules (st) are very small, and
easily drop off. If a branch be examined a little later,
it will be found to be terminated by a scar, left by the
true terminal bud, which has dropped away, so that the
one which is apparently terminal is really axillary.
Fig. 16 represents the end of a shoot of Hornbeam
(Carpinus Betulus) taken in July, and shows how
1 MMém. Soc. de Phys. et d’ Hist. Nat. Genéve, i. 296 (1822).
32 BRITISH FLOWERING PLANTS CHAP.
snugly the bud nestles between the stump of the
terminal shoot and the petiole of the leaf. The same
thing occurs in the Elm, Birch, Hazel, Lilac, Willow, and
others. In these and many other species the bud situated
apparently at the end of the branchlets is in reality
axillary, as is shown by the presence of a terminal scar,
due to the fall of the true ter-
minal bud. I have found that
even at the end of May the ter-
minal buds of the Lime have
almost all died and fallen away.
But why do the terminal buds
wither away? In some cases the
bud contains a definite number
of leaves, but in the genera above
mentioned the number is inde-
Fia. 16.—Young shoot of Horn- p -
beam. x 2% 9, base of finite—more than can come to
ecols te igre ans maturity ; and yet the rudiments,
minal shoot, the upper part Which are constructed to produce
of which has alveady cropped true leaves, cannot modify them-
off; s, scar of stipule. :
selves into bud scales. Thus in
the Ash, Maple, Horse-chestnut, and Oak, which have
true terminal buds, there are comparatively few leaves ;
while in the Elm there are about seven; Hornbeam,
eight; Lime, eight ; Willow, fifteen; and Lilac, fifteen.
In the above species it is generally the uppermost lateral
bud or buds which develop, but in some cases, as in
Viburnum Opulus (Guelder Rose), Gymnocladus, and
others, these also perish, and as a rule only the lower
ones grow, and the upper part of the stem dies back.
The fall of the leaf in autumn is by no means a simple
process, or a mere case of death. In the first place, the
chlorophyll substance is too valuable to be lost and
thrown away. Sachs has satisfied himself that it
passes out of the leaf, down the petiole, and thus
migrates into the persistent parts of the plant, and is
stored up for future use. With the general disappear-
ance of the cell contents, the protoplasm and cell
nuclei are dissolved, the chlorophyll corpuscles lose
1 INTRODUCTION 33
their normal outlines, the starch disappears, and the
colouring matter changes, leaving in many cases a large
number of small bright yellow granules, to which the
yellow tints of autumn are due. In many cases the
cell sap becomes bright red. Sachs has been able by
chemical examination to follow the materials (and
especially the starch), and also the most valuable
chemical materials (especially the potash and phos-
phoric acid), down the petioles, into the twigs, where
Fic. 17.—Longitudinal section through the junction of stem and leaf of Horse
Chestnut in autumn. 4a, parenchyma forming the outer cortex of the twig ; 3,
external cork layer of the same ; ¢ and e, parenchymatous tissue at the base of
the leaf-stalk ; d, separating layer, the continuity of which is already broken in
the upper pait.
they are preserved, evidently to nourish the growing
buds of the following spring. While these changes are
taking place a new layer of cells is formed across the
base of the petiole (Fig. 17, d). These cells gradually
adhere less and less closely together, so that at last the
slightest touch or the gentlest wind brings the leaf to
the ground. That this is not a mere case of death of
the leaf, but, on the contrary, is a vital process, we
may easily convince ourselves by breaking a branch
during summer. In that case it is killed, the new
layer of cells is not formed, and the leaves remain
firmly attached to the twig.’
1 Avebury (Lubbock), Buds and Stipules.
34 BRITISH FLOWERING PLANTS CUAP.
The first leaves or ‘‘ cotyledons” generally differ
very much from the leaves which follow. Klebs—
writing as lately as 1884—refers to these differences,
and expressly says that they are “an enigma.” I have
sugeested’ as an explanation
that the cotyledon develops
in the seed, and the leaf
in the bud, and that the
conditions of the two are
very different.
In the same work I have
in a variety of cases en-
deavoured to indicate the
reasons for the various forms
assumed. Fig. 18, which
represents the seedling of
the Horned Poppy, may be
taken as a typical case
showing the gradual passage
from the simple filiform
cotyledon to the fully de-
veloped leaves. In other
cases the cotyledons them-
Fic. 18.—Glaueivun corniculatum. Seed. Selves are more complex.
ling: (Nei ee) “neowkednr i Kxamples ave mentioned,
and reasons suggested for
the differences under the Violet, Radish, Geranium,
Lime, Oak.
THe STEM
There are two ways in which a prostrate, stemless
plant may raise itself into the light and air. One would
be by bending itself round so as to form a tube (Fig. 19).
We can imitate this by a sheet of paper, which is much
less pliable and more rigid if rolled up. In such cases
the opposite edges will often unite, or, in botanical
language, will become adnate, at any rate below, often
remaining free above. Of such a growth an ordinary
1 Avebury (Lubbock), A Contribution to our Knowledge of Scedlings.
I INTRODUCTION 35
Grass (Fig. 20) may be taken as a familiar instance,
the axis being supported and enclosed by the rolled
leaf sheaths. These plants form the great division of
Monocotyledons or Endogens.
In a second series of plants the necessary stiffness
is given (Fig. 21) by the thickening and hardening of
the midrib. In this case the axis is not enclosed, as in
the former, by the rolled-up frond, and the stem, not
Y,
Fia. 19.—Frond, strength- Fic. 20.—Portion of a grass stem ; successive internodes
ened by rolling. are surrounded by the leaf-sheaths (s) ; 7, ligule.
being surrounded by the leaves, is able to enlarge and
expand by successive additions. Fig. 22 represents
diagrammatically part of the stem of such a plant as
a Thistle, and it is obvious that the midrib of the leaf
is an included part of the stem. Hence arises the
characteristic secondary growth of the exogenous stem.
In the first series it 1s obvious that the leaves are
necessarily successive. Consequently the plant is mono-
cotyledonous. On the contrary, in the second, two leaves
may, and in seedlings generally do, grow simultaneously,
36 BRITISH FLOWERING PLANTS CHAP.
and hence they are termed dicotyledonous. Herbert
Spencer ingeniously suggested that this explains the
general connection between monocotyledonous germina-
tion and so-called endogenous growth in the stem, on
Fic. 21.—Frond strength-
ened by midrib.
the one hand; dicotyledonous germi-
nation and exogenous growth, on the
other. The fact that it throws light
on these fundamental relations adds
very greatly to the probability of the
hypothesis, which, however, cannot
yet be said to be generally accepted.’
Considering the sizes of trees, their
height and weight, it is really wonder-
ful how they are able to support
themselves and resist the force of the
wind. The roots fix them firmly in
the ground, and the framework of the
stem is so constructed as to give
immense strength. The hard “ bast”
cells, from which woody fibres differ
but little, are said to have in some trees a bearing
capacity equal even to that of steel. Besides the
woody fibres, the stem of a tree contains bark, cork, soft
tissue or parenchyma, vascular and other bundles, pith,
etc. These are by no means arranged
at random. The forces acting on and
bending the stem of a forest tree tend to
extend the tissues on the convex, and
compress them on the concave side. In
the centre they vanish. The strengthen-
ing material must obviously be applied
where the force to be resisted is greatest,
ae, near the bark. The arrangement
Fie, 22.
may be compared to that by which a girder is strength-
ened at the side with flanges. In other species there is.
another or there may be several series of woody bundles,
-each with a group of vascular cells, always lying on the
inner, or central, side.
1 See Herbert Spencer, Principles of Biology, vol. ii.
I INTRODUCTION 37
In most cases the stems of plants are round, but in
others they are triangular, quadrangular, pentagonal,
elliptical, or of other forms. The bare fact is stated in
many books of botany, but I have not come across any
in which an explanation is given, or even attempted.
Yet it will, I suppose, be generally admitted that there
must be a reason for all these differences.
If an engineer is constructing a bridge, or an
architect is building a house, he must consider how to
make it safe, and secondly, how to economise the
material as much as possible. The strongest form
which can be given to a solid body, in the formation
of which a given quantity of material is to be used,
and to which the strain is to be applied under given
circumstances, is that form which renders it equally
liable to rupture at every point. So that when, by
increasing the strain to its utmost limit, the solid is
nearly breaking at any one point, it may be nearly
breaking at every other part. If there are any parts
which are not nearly at the eve of rupture it is
obvious that from such points some of the material
might be removed without increasing the danger of
rupture.
If the stem of a plant is acted on by wind, one side
will be extended, the opposite compressed, while between
them there will be a neutral surface; and both extension
and compression will be greatest along the surface
furthest from the neutral axis. It follows, therefore, that
the material cannot be in the state bordering on rupture
at every point of a section at the same time, unless all
the material of the compressed side be collected at the
same distance from the neutral axis, and likewise all
the material of the extended side, z.e. unless, in the
words of Professor Moseley,’ ‘‘the material of the ex-
tended side and the material of the compressed side
respectively be collected into two geometrical lines
parallel to the neutral axis.” The two bars are in
practice connected by a cross rod, or web as it is techni-
1 See Moseley, Engineering and Architecture.
38 BRITISH FLOWERING PLANTS CHAP,
cally called. This need not be so strong as the flanges.
It has not the same force to resist, and may be a lattice
or open work.
The applications of these principles in architecture
has led to the well-known “ girder” (see Fig. 23), in
which the material is
co _ collected in two more
|| or less thin flanges
united by a narrow
nel oI yib. In some sub-
Fia. 23.—Single Fig. 24.—Double stances—in cast iron,
girder. girder. for instance—as Mr.
Hodgkinson has
shown,’ the resistance to compression is much greater
than the resistance to extension, and in the strongest
girder, therefore, the greater flange may be on the
extended side. If the forces to be resisted act in two
directions at right angles to one another, two girders
must be combined, as in Fig. 24. If the forces come in
all directions, a series of girders would be required (Fig.
25). This is the case in the stems of trees (see Fig. 26).
Now in the stems of plants the strength is given by
tissues known as hard bast, libriform cells, or scleren-
chyma, which are collectively termed, in ordinary
language, woody fibres. The hard bast
lie (asereas
of some plants equals steel in its power
of resistance. Hence its use for string,
ropes, ete. The “ web” consists of vas-
cular bundles and parenchymatous cells.
Here strength is not required. In some rales
cases—for instance, In many Grasses—
the centre is hollow. If the mechanical ™% jytbrle
or woody tissue formed a pillar in the
centre of the stem, there would evidently be a great
waste of strength (see Fig. 25).
An erect stem which is liable to wind pressure, some-
times from one side and sometimes from another, must
be strengthened in all directions. Hence a series of
1 Mem. Manchester Phil. Soc. vol. iv.
I INTRODUCTION 39
‘wocdy bundles arranged round the stem are required,
and as a matter of fact we find
a series of groups of woody
fibres ranged round the stem
(Fig. 26). In low-growing
herbs they may be widely sep-
arated by soft cellular tissue ;
and the more force the plant
has to resist the more they are
developed, and the greater pro-
portional space they occupy. In
the young shoot they are some Fic, 26.—Diagram of section of a
distance apart, but gradually one-year-old shoot of Lime, show-
approximate ( Fig. 27) until at ing woody bundles separated by
broad bands of soft (parenchyma-
length they are only separated tous) tissue. Mechanical. tissue
by what are known as the ‘fin ne pets
medullary rays. In dicoty-
ledonous trees a layer of wood is, as we know, laid
on, as it were, each year, so that the age of the tree
may be estimated by the rings, and the whole form
wedge-shaped masses of wood, separated by narrow
medullary rays. Being thus arranged at equal dis-
tances round the central neutral axis, the stem naturally
assumes the prevalent round form. Whatever the size
of the plant, whether it is a small herb, or a giant of
the forest, the same rule applies.
So far as the structure of round monocotyle-
donous stems is concerned, the subject is dealt with
by Schwendener in a masterly memoir, Das mechanische
Princip in anatomisch Bau der Monocotylen.
This being so, the question arises, Why do any stems
assume other forms?’ Let us take first the plants in
which it is quadrangular. In a species where the
leaves are arranged round the stalk, like the spokes of
a wheel, the resistance required is equal all round (see
Fig. 25). On the other hand, if the leaves are ‘“ decus-
sate” or opposite, each pair being at right angles, this
above and that below, then the strain of the wind acts
1 Avebury, Rep. Brit. Assoc. Cambridge (1905).
40 BRITISH FLOWERING PLANTS CHAP.
mainly in two directions at right. angles to one another,
and the stem would require additional strength in two
directions—in fact, the double girder (Fig. 24). This
being so, for plants with opposite decussate leaves
quadrangular stems
would be most suit-
pith able. Three excep-
tions, however, at
parenchyma least must be made.
conducting vessels In trai ] in g an d
woody fibres
cortex water plants
strength is less re-
quired. The first
se i em | wre supported by
1G. 27.—Diagram of young dicotyledonous stem, i
showing approximation of the distinct bundles. the ground, and
little exposed to
the wind. The second are supported by the water in
which they live.
As regards trees, the twigs grow in all directions,
and the tree therefore, as a whole, has to meet strains
in all directions. From this point of view it is interest-
ing that there are some cases of shrubby plants—such
as the Box—where the young shoots are quadrangular,
but gradually become round. We should expect, there-
fore, to find quadrangular stems mainly in erect
herbaceous plants with opposite leaves. Now let us
see how far the facts bear this out. Do quadrangular
stems and opposite leaves go together? As a matter
of fact all our English flowering plants with square
stems have opposite leaves. It is not so invariably the
case that plants with opposite leaves have square stems,
but for herbaceous plants it is the rule, and the ex-
ceptions are susceptible of explanation. Since, then, we
find no cases of quadrangular stems without opposite
leaves, and that most species which have opposite leaves
have quadrangular stems, it is a fair inference that the
form of the stem is connected with the arrangement of
the leaves. The pentagonal form of the Bramble stem
has been already referred to (p. 13).
I INTRODUCTION 41
We now come to the question of triangular stems.
They occur principally among Monocotyledons. While
among Dicotyledons the number of
parts which go to make up a whorl VN
is generally four or five, in Mono- HAN
cotyledons the number is frequently EX
three (Fig. 28). Moreover, the base LX
of the leaf usually encircles or
sheathes the stem or base of the next
leaf. No doubt, as we have already Fis. 28.—Arrangement of
seen, there is in this arrangement saceomioa
some loss of strength. This is not, however, of supreme
importance as the plants in question, being compara-
tively small, grow in sheltered situations and in close
association, so that each is protected by the rest.
The triangular form prevails among the Rushes,
Bulrushes, Sedges, ete. It is not, however, universal
in Monocotyledons. Grasses, as we all know, have
round stems. In fact, Sedges may generally be known
from Grasses in this way. Sedges have triangular
stems, Grasses have round stems. While the leaves
of Sedges and the parts of the flower are in threes,
those of Grasses are often in twos and the leaves
are “distichous,’ 7%e. in two rows or ranks (Figs.
28 and 20). It is remarkable, however, that one
Grass—a Chinese species of Bamboo—has a quad-
rangular stem. It is so remarkable that it long ago
attracted the attention of the Chinese, who attribute
the origin to the fact that one of their holy men had a
squared walking-stick made of this Bamboo. He stuck
it into the ground, and, in consequence of his sacred
character, it at once grew, retaining, out of respect to
him, its square form.
The flinty stems of Grasses help to increase their
rigidity, and are probably also a protection against
snails and other animals.
The stem of trees, as a rule, is thickest at the base,
where it requires to be firmly anchored in the ground,
then diminishes for a few feet, gradually reaching a
42 BRITISH FLOWERING PLANTS CHAP.
minimum, and soon increasing again and attaining a
maximum, after which it tapers to the summit. This
conforms to the ideal proportions of a pillar of uniform
resistance.
These considerations, then, seem to throw, at any
rate, some light on the different forms assumed by the
stems of plants. They may seem obvious, but excepting,
indeed, as regards the round and compressed forms, I do
not find them stated in botanical works, and, indeed, I
was myself for a time in some doubt on the subject.
Thus, then, we see that plants adopted for themselves,
thousands and indeed millions of years ago, principles
of construction, adapted to secure the greatest strength
with the least expenditure of materials, which have been
gradually worked out and applied to our buildings by
the skill and science of our architects and engineers.
THE Sense OrnGans oF PLANTS
We all remember the old aphorism of Linneus:
“Stones grow; plants grow and live; animals grow,
live, and feel.” Plants, however, feel, though there is
no reason to suppose that they can enjoy or suffer.
The movements of plants, especially the “sleep” of
flowers and leaves, which have been already referred to,
and the circumnutation of climbing plants—all such
movements imply sensitiveness.
It may seem at first sight somewhat far-fetched to
speak of the sensitive organs of plants. We cannot,
of course, attribute consciousness to them, but the
mechanism which originates and produces movement
presents remarkable analogies and similarities in the
two kingdoms. As in animals so also in plants, we find
papillz or processes which localise, and thus enhance,
the pressure on limited portions of the protoplasm.
Any one who has ever suffered from the elevation of a
papilla, or a few papillae, on the skin, will realise the
effect produced by confining the pressure, which is
generally spread over a comparatively large surface, to
a limited area. Again, the transmission of impressions
I INTRODUCTION 43
by hairs or bristles exists, though it is not so general,
in‘the vegetable as in the animal kingdom.
Haberlandt has written several interesting memoirs
on what he calls the Sense Organs of Plants.’ Some
plants have papille, which, projecting above the
general surface, localise and thus intensify the effect of
any pressure. In other cases there are special stiff
bristles supported by a cellular base, at the side of
which is a sensitive tissue, which is, of course, com-
pressed if the bristle is pressed against it, even only
slightly. In fact, the concentration of impression is the
main principle of these organs. The feeler bristles of
Aldrovanda were described by Cohn more than thirty
years ago.
Sensitive organs are as yet known in a minority
of plants only; perhaps because the majority have no
need for any such special arrangements. It is not,
however, too much to say that the potential power is
there, ready to spring into action if the need arises.
The sensitiveness of plants is indeed in some cases
astonishing.
Darwin’ showed that the tentacles = Drosera were,
affected by a tiny bit of woman’s hair yg%y of an inch in
length, and weighing -s+g5 of a grain!—a weight
quite imperceptible to our nerves.
The tendrils of climbing plants are amongst the
most sensitive organs in the vegetable kingdom. They
will react to a piece of cotton-wool or silk weighing
only ‘0002 of a milligram, while the most sensitive part
of our skin would perceive nothing until the weight
reached ‘002 of a milligram. The sensitiveness of the
tendril is therefore much greater than ours.
Many of the lower Algz have a red eye spot. It is
probable that the red substance is not the actual
perceptive element, but that this property rests rather
in the associated colourless plasma, and that the red
1 His last memoir is ‘‘Die Sinnesorgane der Pflanzen,” Ges. Deut. Natur-
forscher und Arzt, 1904.
2 Tnsectivorous plants.
44 BRITISH FLOWERING PLANTS CHAP.
colour intercepts the passage of the light and concen-
trates its effect. Darwin showed that the points of
growing Grass leaves were peculiarly sensitive to light,
but in this case no special organs have heen yet
detected. The positions assumed by leaves are also in
most cases, no doubt, determined by the influence of
light, as Vochting has shown.’ The cells of the
epidermis are to some extent like the lenses of eyes.
They are flat below, and more or less convex externally.
The middle part of the cell-wall is sometimes itself
thickened. In certain plants some cells only of the
epidermis project and form lenses, thus increasing
the similarity to the “eyes” of some of the lower
animals.
We are so accustomed to the fact that the roots of
plants grow downwards and the shoots upwards, that
it scarcely occurs to most people to ask how this is
effected. The classical experiments of Knight called
attention to the subject, and showed that it is gravity
which enables the plant to orient itself But in this
case how does gravity act? Darwin’ showed that the
sensitiveness of the root is concentrated in the tip. If
this be removed the root cannot properly determine its
direction until a fresh tip has been produced.
It was first suggested by Berthold,? and soon after-
wards Haberlandt and Némec* almost simultaneously
brought forward strong arguments in support of the
view, that this is due to the presence of movable starch
grains which lie free in the cells, and naturally fall to, and
accumulate on, the lower cell-wall. These starch grains,
in fact, perform the same function as the “ statocysts ”
of animals, which were formerly termed “ otocysts” and
supposed to be auditory organs, but are now generally
regarded as enabling the animals to balance themselves.
The distribution of these free starch grains is quoted
in support of the theory. They occur in all organs
1 «Uber d. Lichtstellung der Laubblitter,” Bot. Zeit. xlvi. (1888).
2 Movements of Plants. 3 Protoplasma mechanik, 1886.
4 Ber. Deut. Bot. Ges. xviii. (1900).
I INTRODUCTION 45
capable of bending. They do not occur in stalks, or
non-geotropic roots such as those of the Ivy or Mistletoe,
while plants which develop starch grains nowhere else,
produce them in the root tips. Again, the flowers and
leaves of many plants which adopt special positions with
reference to the earth develop starch grains; while
those of allied species, which assume no definite position
do not produce starch grains.’
CoNnCLUSION
One result which comes out with increasing clear-
ness from recent investigations is the great amount
of variability. In fact, it is becoming more and more
a surprise how the older botanists can have regarded
species as fixed and invariable. This is not only the
case in genera, such as Rubus and Hieracium, the
species of which have long been recognised as extremely
variable and difficult to define; but it may almost be
said that, as a rule, when plants are studied under
dissimilar conditions, or in various parts of their area,
they will be found to present considerable differences,
so that, as our knowledge advances, the definition and
limits of species become, not more easy and definite,
as might perhaps have been expected, but more and
more difficult and debatable.
Perhaps no part of Botany is more interesting
than the manner in which plants adapt themselves
to circumstances. The reasons suggested are in some
cases more or less hypothetical. Systematic and Mmor-
phological botany may, no doubt, be treated with
scientific precision, by omitting all attempt at explana-
tion. Such works are often models of lucid description,
and afford a solid foundation on which to construct the
history of plant lifee To many, indeed, systematic
botany is the most interesting department of the
science; to others it is the entrance and outer court
1 See, for a general discussion on the subject, F. Darwin, Rep. Brit. Assoc.
Cambridge (1905) ; also Nature, 1904.
46 BRITISH FLOWERING PLANTS CHAP. I
of the temple ; and when we realise that for every shade
of colour, for all the exquisite beauty of flowers, for the
endless difference in the size, forms, and textures of
leaves, for the shape and colour of fruits and seeds, there
are, if we only knew them, good and sufficient reasons,
Nature seems endowed with new and vivid life, with
enhanced claims on our love, wonder, and devotion.
Fic. 29.—Ranuneulus aquatilis.
CHAPTER II
DICOTYLEDONS
RANUNCULACE
Tus interesting family consists principally of herbs.
Clematis, however, is a woody climber. The group is
widely extended in temperate and northern regions, but
except on the highlands is almost completely absent
from the Tropics. Clematis, however, and an allied
genus extend into sub-tropical or even tropical districts.
The embryo is generally minute; it is so in all the-
British species. The petals are sometimes small or
absent, in which cases the sepals are often white or
coloured (Clematis, Anemone, Caltha, Trollius, Hranthis,
Aconitum), generally white or yellow, but sometimes
red, blue, or violet. Honey is often absent (Clematis,
Thalictrum, Anemone, Adonis), and insects come for the
pollen only. The nectaries are sometimes on the ovary
(Caltha), sometimes on the stamens (some Anemones),
often on the petals (Ranunculus, Helleborus, Trollius,
Aquilegia, Aconitum, etc.), rarely on the sepals (some
Peeonies).
In Thalictrum the achenes are ribbed, in Ranun-
culus they are wrinkled (water forms) or smooth, in
47
48 BRITISH FLOWERING PLANTS CHAP.
some slightly hairy, in others (R. arvensis, R. parvi-
florus) covered with tubercules or spines which are
often more or less hooked, and no doubt serve to pro-
mote the dispersion of the seeds. In some (R. scapi-
gerus, R. multiscapus, etc.) the style itself is hooked.
In other cases dispersion is aided by the presence of
wings, or (some species of Clematis) by a long feathery
process consisting of the persistent style. This prob-
ably serves another useful purpose by fixing the seed
to the damp soil, thus helping the seedling to escape
from the testa.
CLEMATIS
The flowers are honeyless, and are visited by insects
for the sake of the pollen. They have white or coloured
sepals and no petals. The genus is widely spread over
the globe.
Of this genus we have only one species, C. Vitalba.
It has a woody stem, and climbs by means of the
stalks of the leaves, which are opposite, compound,
and without stipules. The flowers are sweet, greenish-
white, and small, but conspicuous from being collected
in clusters, whence Dodoneus gave it the name of
Vitalba—the White Vine. There are no petals; the
sepals are four in number, the stamen and carpels
numerous. The persistent style of the one-seeded fruit
is produced into a long feathery awn, which, as in other
similar cases, assists in the dispersal by wind, and has
originated one of its English names—Old Man’s Beard.
The other, Traveller’s Joy, given it, I believe, by Gerard,
refers to its partiality for roadside and other hedges.
In other species of the genus the style is short and
beardless. :
Clematis is visited and fertilised by several species of
flies and bees which feed on the pollen. Most flowers
are visited by small insects for the sake of their pollen,
and I only mention such visits when they assist
in the fertilisation. It is slightly protogynous. It
prefers calcareous soils, and is very luxuriant on chalk,
Ir RANUNCULACEAE 49
growing to a height of 20 to 80 feet. It is a southern
form, extending to the Mediterranean, and not reaching
to our northern counties. It is not regarded as a
native of Ireland, but is naturalised there. It flowers
in July and August.
THALICTRUM
The species of this genus are also, as a rule, pollen-
flowers. Their conspicuousness is due to the numerous
stamens. In one species the anthers are yellow; in
T. aquilegifoliwm of Southern Europe they are violet.
The species are widely dispersed over the temperate and
colder regions of the northern hemisphere. They are
variable, and botanists differ much as to the number.
The most distinct British forms are TZ. alpinum,
T. minus, and T. flavum.
T. alpinum is a graceful little plant 4 to 10 inches
high. The leaves are biternate and glaucous beneath ;
the flowers form a drooping, simple, terminal raceme.
The sepals are slightly purplish. The pollen is probably
earried by the wind. It is probable that this species
once occupied most of the northern hemisphere south
of the great glaciers. It grows on the mountains of
Wales and Scotland and all over the northern hemi-
sphere as far north as Nova Zembla, descending to
lower levels towards the north. In Iveland it is very
rare,
T. minus.—In this species also the pollen is probably
wind-borne, but the flowers are sparingly visited by flies,
beetles, and bees. The flowers are mostly drooping.
The leaflets are roundish. It occurs from the Hima-
layas to Greenland and North Africa, but does not
ascend so high or reach so far north as T. alpinum, and
prefers calcareous districts.
T. flavum.—In this species, on the contrary, the
flowers are mostly erect, and the pollen is carried by
insects, especially flies. It is 2 to 4 feet high, and not
uncommon along the banks of streams. The stem is
erect, branched, and furrowed. ‘The leaves are bipin-
E
50 BRITISH FLOWERING PLANTS CHAP.
nate; the sheathing leaves or stipules serve to protect
the bud and also to hold moisture; the leaflets are
wedge-shaped or obovate. The anthers open in sun-
shine and close in rain. According to Edgeworth, 7.
flavum has two forms of pollen. Unfortunately he
merely makes the statement and gives no particulars.
Fruits of this species are of frequent occurrence in
preglacial beds in Norfolk and Suffolk.
ANEMONE
Perennial herbs with radical leaves. There are 4-20
sepals, no petals, and numerous stamens. In some
species the petioles of the cotyledons are connate to the
summit, or nearly so. One of the most striking features
in the genus is the three-leaved involucre, the leaves of
which are sometimes stalked, sometimes sessile, some-
times resembling the ordinary leaves, at others quite
different. In A. Hepatica they are small, undivided,
and together resemble a calyx. The fruits are often
wind-borne, sometimes by means of a long feathered.
awn, sometimes by silky hairs ; in other cases the fruit
is flattened, with a narrow wing (A. narcissiflora) ;
lastly, in some the awn is hooked, and catches on to
the hair of any passing animal.
A. Pulsatilla (Pasque-flower) is silky, with tri-
pimnate leaves, violet sepals, and yellow stamens.
The outer series of stamens differ somewhat from the
rest, and may possibly be regarded as representing petals.
The flowers are protogynous, and remain open two to four
days. Honey is secreted by the outer stamens. The
flowers are visited by several species of bees and some
other insects. Their life-history is curious and interest-
ing. When they open they face the sky, and the
stalks are quite short. The stigmas are numerous and
ready for fertilisation. After two days the peduncle
has elongated, the flower inclines slightly, and the
anthers begin to open. The sepals, which are concave,
have grown longer, and thus protect the pollen more
effectively. The flower closes in the evening, and thus
I RANUNCULACE4 51
some of the pollen is deposited on the sepals. After
another two days the stalk is ten or even twenty times
as long as it was at first, and the flower hangs over by
day as well as by night. The sepals have more than
doubled in length, and have become convex instead of
concave. If not already fertilised, the stigmas are
almost sure to receive pollen from the sepals when the
flower closes at night.
The achenes have feathery awns, and the peduncles
lengthen considerably after flowering, perhaps in order
to increase the chances of dispersion of the seeds.
The plant grows in high pastures throughout most of
Europe, but is rare in England (occurring in certain
counties only, on calcareous soils), and does not occur
in Scotland, Ireland, or Wales. The root-stock is stout,
woody, and penetrates deeply into the ground, thus
enabling the plant to maintain itself better in the dry
situations where it grows.
A. nemorosa (Wood Anemone) prefers woods and
copses. It is one of the few plants which are able to
grow under beech trees, probably because it flowers
early, and its period of active vegetation is over before
the beech leaves are out. It thus escapes the com-
petition of other plants, and is also protected against
the wind. The Wood Anemone has a creeping rhizome,
which throws up the leaves and flowers. The flower-
stalk bears no true leaves, but an involucre of three
bracts, which in this species resemble the leaves. The
sepals are white, often tinged with pink, or, very rarely,
blue. The achenes are downy, without awns. The
flowers (March to May), which are honeyless, are visited
by pollen-collecting bees, flies, and a few beetles. When
they first open they are upright when it is fine, but
bend over in wet weather and at night, and gradually
become drooping. The bending movement is a not
infrequent method of protecting pollen or honey from
becoming wetted. According, however, to Van Tieghem,
honey is secreted by the receptacle.
The plant prefers calcareous soils, but is spread all
52 BRITISH FLOWERING PLANTS CHAP,
over the northern hemisphere, and in Scotland reaches
to 2800 feet.
ADONIS
A. autumnalis.—An annual cornfield weed, 6-8 inches
high, glabrous or slightly downy. The leaves are tri-
pinnatifid, with fine linear segments. The sepals are 5,
petals 5-10, scarlet with black bases, a remarkable com-
bination, for black is a very rare colour in petals, and
only occurs in one other English species, curiously
enough again associated with scarlet, and in another
cornfield weed, the Poppy. ‘The carpels are many,
one-ovuled and arranged in a head which sometimes
lengthens. It flowers from May to September. Accord-
ing to Knuth, the brown pollen-grain presents remark-
able differences in form; there is no honey. The flowers
are upright when it is fine, but bend over in wet
weather. The only insect visitor recorded is the hive
bee. The plant grows in Central and Southern Europe,
Western Asia, and North Africa. In Scotland and
Ireland it is rare.
Myosurvus
M. minimus.—This curious little plant is a small
annual, only 1-5 inches high, with short, linear leaves
dilated at the very base and surrounding the crown.
From the axils of the leaves a greater or less number
of leafless scapes arise, bearing each a solitary flower.
The latter has five, rarely six or seven, sepals, which
have a small spur behind, and are appressed to the
scape. The small, narrow, greenish-yellow petals are
similar in number and have a tubular nectary at the
apex of the filiform claw. Inconspicuous as they are,
it is yet evident that they serve to attract insect
visitors. The flower is almost exclusively visited by
small flies. Before the petals have dropped, the
receptacle begins to elongate, ultimately reaching a
length of 1-1} inches, and bearing a dense mass of
achenes, with short persistent styles.
II RANUNCULACE 53
The plant is a cornfield weed, affects sandy and
gravelly soils, and flowers in May and June. It is
widely distributed in the temperate regions of the
northern hemisphere, but does not extend far north, in
our own country not beyond Cumberland. An allied
species occurs in America. The name Myosurus, or
Mouse-tail, is well chosen from the elongated receptacle.
RANUNCULUS
The genus is almost world wide, but the greater
number of species belong to the northern hemisphere.
It extends far into the Arctic regions, and some species
rise to great heights. There are at least 150 well-
marked species, but some botanists make many more.
When the flower first opens, the anthers are turned
towards the centre. Gradually the filaments of the
outer whorl twist round, so that
the anthers which in the mean-
time have opened stand just over
the nectaries, situated at the base
of the petals, and are sure to be
brushed by insects coming in
search of the nectar. The follow-
ing day these stamens move out-
wards and their place is taken by 5, 99 panunculus rs
the next whorl. This process con- tits. The enlarged petal
tinues until all the stamens have ne Hie Past Boney
had their turn. The leaves, as in
many herbaceous species, are much cut up, especially the
subaqueous leaves of the aquatic Ranunculi (Fig. 30).
The species of Ranunculus are generally perennials.
R. sceleratus is sometimes annual, sometimes biennial.
R. arvensis is annual. It is a weed of cultivation, and
such plants are generally short-lived.
The genus falls into two divisions—(1) those floating
in water or creeping on mud, with white flowers and
wrinkled carpels; (2) terrestrial or not floating, with
yellow flowers and smooth or tuberculate carpels. The
former are often regarded as forming a distinct genus,
/) =|
54 BRITISH FLOWERING PLANTS CHAP.
Batrachium. Like most other water plants they are
glabrous, while the land species are generally hairy.
The forms are very variable, and some botanists make
numerous species, which Bentham and Hooker reduce to
two—fk. aquatilis, in which the lower leaves are finely
cut up, and the receptacle is usually hairy; and
R. hederaceus, in which all the leaves are rounded with
broad lobes, and the receptacle is glabrous.
R. aquatilis—The most interesting feature is the
possession of the two kinds of leaves (Fig. 30). Those
which float on the surface are rounded in outline and
cut more or less into three or six wedge-shaped, obovate
or rounded lobes; while the submerged leaves are
divided into numerous fine linear segments. It is a
very variable species, and has great power of adapting
itself to different conditions, such as the depth of the
water or the rapidity of the stream. It will also grow on
land, in which case, however, the habit is very different.
The leaves are so far adapted to their surroundings that
the submerged ones cannot live out of, nor the floating
ones under, water. The size of the flower varies consider-
ably. The petals are 5 or sometimes more in number, the
stamens from 8 to 20. It has a slight scent, and secretes
honey in a nectary at the base of each petal ; the honey-
gland is not protected by a scale. The yellowish base
of the petal serves to guide insects towards the honey.
It grows and flowers freely, sometimes quite covering
small pieces of water. It is visited by many small
flying msects, especially flies. If the water is high the
flowers remain submerged and closed and fertilise them-
selves. The plant extends to all temperate regions.
R. hederaceus is smaller, and does not produce the
finely divided, submerged leaves. It secretes very little
honey, and is not much visited by insects. This species
is common in Western and Northern Europe.
Our other species of Ranunculus are yellow.
R. sceleratus, so called from its bitter acrid juice,
which raises blisters on the flesh, and from the time of
the Herbalists is referred to as thus used by beggars to
u RANUNCULACEE 55
excite sympathy. It is in some respects an intermediate
form between the land and water species of the genus,
as the achenes are only slightly wrinkled and furrowed.
It grows on muddy banks, often extending into the
water. The stem is thick and hollow. The submerged
foliage differs from the aerial, and more nearly resembles
that of the aquatic species. The flowers are small and
pale yellow, the petals scarcely longer than the sepals,
which are reflexed. There is no scale over the nectary.
The carpels are small, in a dense head which gradually
becomes oblong. As an annual it can easily establish
itself wherever a suitable situation offers. The species
is spread over Europe and temperate Asia, as far south
as Bengal. It appears to be visited almost exclusively
by Diptera (flies). M. Vesque has made the interesting
observation that if it is grown in damp air the stomata
become more numerous, and appear on the upper as
well as on the lower sides of the leaves.
R. Lingua.—This, which is our largest species, grows
to a height of 3 or 4 feet, and has beautiful golden-
yellow flowers, some 2 inches in diameter, in a loose
panicle. It lives on the edges of lakes and in shallow
water. The stem is erect, stout, and hollow. The
upper aerial leaves are long, lanceolate, and entire, or
with a few small teeth. It has thus adopted one of
the forms so characteristic of water plants. The lower
submerged leaves are cordate, broad, and obtuse. The
flowers are protogynous. At the base of each petal is
a large nectary, which secretes a copious supply of honey.
Fertilisation is almost exclusively due to flies. Since
the anthers open towards the outside of the flower, and
also bend outwards as they mature, self-fertilisation is
difficult, though not impossible, owing to the oblique
position of the flower; it seems to have but little effect.
The plant is common in the temperate parts of Europe
and Asia.
R. Flammula somewhat resembles R. Lingua, but is
much smaller and slenderer, with decumbent, rooting
stems. It is sometimes hairy and sometimes glabrous.
56 BRITISH FLOWERING PLANTS CHAP.
The upper leaves are lanceolate or linear, the lower
ones broader, and all slightly toothed. The flowers are
protandrous, the outer stamens opening first, and turn-
ing the pollen outwards. The stigma is, however,
mature before the innermost stamens have shed their
pollen. The insect visitors are not numerous. They
comprise the hive bee and some species of Halictus, a
few beetles, one or two Lepidoptera, and several species
of flies.
R. acris, repens, and bulbosus.—These species offer
some very interesting problems. A. acris is erect and
tall; R. repens, as the name denotes, is a creeping plant ;
while . bulbosus has the stem thickened at the base into
Fic. 31.—Ranunculus bulbosus. 1, Flower; 2, front
view of petal, showing nectary (7); 3, side view of
same; 4, base of last, more enlarged.
a sort of bulb. Moreover, it differs from the other two
in that the sepals bend downwards in the middle—a
character we have just noticed in R. sceleratus which
recurs in Jt. horsutus and some foreign species.
R. acris is softly hairy, the hairs generally spreading,
but deflexed on the lower parts of the stem, and appressed
on the peduncles. In A. repens the hairs are longer and
looser. . budbosus is generally somewhat hairier. In
all three the leaves are much divided, but in R. acris
the divisions are finer. In &. acris the outline is
rounded, in A. repens it is ovate; the leaves of &.
bulbosus resemble those of R. acris, but are broader.
The peduncle is glabrous and furrowed in R. bulbosus,
hairy and furrowed in FR. repens, hairy but not furrowed
in f. acris. The carpels are glabrous in R. acris and
I RANUNCULACE 57
Tt. repens. There is a nectary, half concealed by a scale,
at the base of each petal. According to Verhoeff, the
flowers of R. repens secrete more honey than those of
FR. acris; the petals are broader and more brilliant,
and they ‘also stand closer together. The arrangements
of the flowers are, however, similar, and while, as a
rule, the hive bee confines itself to one species of flower
in a journey, these three are, according to H. Miiller,
visited indiscriminately. The sap is very acrid, which
protects them and some other species from browsing
quadrupeds. They are visited by flies, small bees,
the hive bee, Lepidoptera, and beetles, partly for the
honey and partly for the pollen. The flower of R. acris
lasts seven days.
R. auricomus (Goldilocks).—This is a spring species.
It grows in woods and copses, flowering before the
shrubs and trees are in full leaf. It is perennial,
6-10 inches high, and nearly glabrous, having only
a few appressed hairs. The radical leaves have long
stalks, and are rounded or reniform; the upper ones
are more cut up. H. Miiller gives fioures of the
petals showing considerable variation, and a_ transi-
tion to the condition of those species in which, as
in Winter Aconite, they are reduced to mere honey-
containing vessels. Where the petals are aborted, the
sepals become more petaloid, and are frequently fringed.
The carpels are downy. It is visited by bees, flies, a
few beetles, and some Lepidoptera. According to Edge-
worth, it has two forms of pollen. The plant is found
in Northern and Central Europe, and Asia as far south
as Northern India.
R. Ficaria (Pilewort or Lesser Celandine).—Also an
early spring species, flowering from March to May. It is
a glabrous plant, and the root-stock bears oblong or cylin-
drical root-tubers. The flowers are large, about one inch
across, numerous, and golden yellow, each on a separate
peduncle, which also bears one or two small leaves.
Most of the leaves, however, are radical, cordate, and
stalked, thick, smooth, and shining. There are 3 sepals
58 BRITISH FLOWERING PLANTS CHAP.
and 8-12 petals. The carpels are rather large, in a
globular head, and smooth. The structure of the flower
resembles that of the preceding species and of R. acris.
The number of stamens varies considerably. The flowers
are generally sterile, though the visits of insects are
numerous, and the plant generally propagates itself by
the tubers. It is a remarkable fact that this species,
which flowers so freely, rarely sets its seeds. Some
specimens produce purely female flowers. The plant
is found throughout Europe and in Western Asia and
North Africa.
R. hirsutus has a stem 6-8 inches in height. It
agrees with R. bulbosus in its foliage, and in having the
sepals reflexed, but the flowers are paler, smaller, and
more numerous. The hairs are spreading or reflexed ;
and the achenes have a series of tubercles within a
broad margin. The pollen is yellow, round or oval,
with three longitudinal furrows, and 30-37 » in diameter.
Warnstorf says that the flower produces no honey,
R. arvensis (Hunger-weed, Starve-acre).—An unde-
sirable cornfield weed, which flowers and seeds with the
wheat. It is an erect, branching, glabrous annual, 6-18
inches high. The upper leaves are deeply cut into
three linear-lanceolate lobes. The pale yellow flower is
very characteristic of this species, which also differs
from the preceding species in having the achenes large,
few, flattened, and covered on both sides with straight
or often hooked prickles, which contribute to the dis-
semination of the seeds. It varies considerably in the
number of stamens and carpels. Some of the flowers
contain no stamens.
CALTHA
This genus contains but few species, only one of
which is British. The name is derived from the Greek
word xéAafos, a cup, suggested by the golden cup-like
flower, to which also we owe the common name King-
cups.
Caltha palustris (Marsh Marigold or King-cups) is a
11 RANUNCULACEAE 59
glabrous perennial with annual shoots about a foot long.
The large kidney-shaped, glossy leaves are long-stalked,
and have large membranous stipules. The flowers are
1-2 inches across, with 5 golden-yellow sepals, but no
petals. Honey is secreted abundantly in two shallow
depressions at the base of each carpel, and the flowers
are visited by many beetles, flies, and bees. Besides the
ordinary flowers, it is said that in France and the Tyrol
some have no pistil. The plants grow in marshy places,
and flower from March to May. The species is very
widely distributed in temperate and cold regions both
of the northern and southern hemispheres.
TROLLIUS
T. europeus (Globe Flower; Old German Tyrol, a
globe) is an erect perennial glabrous herb, 1-2 feet
high, with large, pale yellow flowers. The leaves are
palmately lobed, the lower ones not unlike those of
Ranunculus acris ; the upper ones few, small, and nearly
sessile. The sepals, 5-15 in number, are rounded, con-
cave, and converge into a globe, nearly concealing the
petals. The flower is slightly scented. It does not
open far, so that the stamens and pistil are pretty well
protected by the sepals. In wet weather it closes more
completely. The insect visitors are not very numerous.
The seeds are trigonous, black, usually shining, and
smooth but finely dotted. The plant grows in damp
mountain pastures in North and Central Europe.
HELLEBORUS
The plants of this genus are coarse perennial herbs.
The flowers have 5 large sepals, and 8-10 small, tubular
two-lobed honey-containing petals. The stamens are
numerous ; the carpels few, each becoming when ripe a
follicle with several seeds.
Of this genus we have two species—ZJZ. feetidus, with
a large close panicle of drooping flowers, which are green,
60 BRITISH FLOWERING PLANTS CHAP.
often tinged with brown or purple; and H. viridis, with
three or four yellowish green flowers. Both are proto-
gynous. The petals are modified (Figs. 32, 33, m) into
remarkable, more or less conical, elongated cups, which
serve as nectaries. The hanging position and the close
application of the sepals completely protect the honey
from rain, and conceal the flowers from many insects.
When the flower opens, the styles turn outwards so as
to stand just under the nectaries. Subsequently they
move inwards, and their place is taken by the stamens,
which then, and not till then, open their anthers.
H. foetidus (Stinking Hellebore) is probably protected
from grazing quadrupeds by its disagreeable smell and
TOL
{|
ON
Fic. 32.—Helleborus fetidus. Fic. 33.—Helleborus fotidus. Flower in the
Flower in the first (female) second (male) condition. &, calyx; 2,
condition ; the sepals partly nectaries ; a, unripe anther; a’, ripe and
removed. open anther ; s, stigmas.
taste. It grows in stony and calcareous places in
Central and Southern Europe, extending some way up
the valleys, and occurs in Hampshire and Sussex, but
is perhaps a doubtful native.
H. viridis—The flowers are more open and the nectar
is more abundant than in the preceding species. They
are, however, less conspicuous on account of their green
colour, being indeed the largest green blossoms in our
flora. They are visited by bees and humble bees, but
not very frequently. The plant is found in woods in
calcareous districts throughout Western and Central
Europe, and in our southern and south-eastern counties.
ul RANUNCULACEE 61
DELPHINIUM
Annual or perennial herbs with much-divided leaves.
The 5 sepals are coloured, the back one ending in a
hollow spur. There are 2-4 small
petals, in the British species two,
which are joined together, and each
lengthened into a spur, lying in
that of the calyx. The 1-5 carpels
form each a several-seeded dry fruit.
The embryo is very small.
D. Ajacis (Common Larkspur).—
An annual erect herb, 1 14 feet
high ; glabrous or slightly hairy ;
with branches few and spreading,
and leaves divided into fine linear
segments. The flowers are blue,
reddish, or white, in terminal ,, pi tiie tation Ge
racemes. The spurs of the two seed of —Delphinium
petals are united on the under side — Stpietar, ooverm
into an inner spur, open along its
upper surface. The honey is at the base of the spur,
and only accessible to the bees which have the longest
proboscis, as, for instance, Bombus hortorum. The
solitary follicle is either glabrous or
pubescent. The flowers are pro-
tandrous. The seeds are black and
angular, with transverse, acute,
wavy, and continuous ridges.
The plant is a cornfield weed,
Fic. 35.—Trans. section of NOt a native, and rare except in
seed of Delphinium Cambridgeshire. The name is de-
a ia «12, 4 yived from some marks at the base
of the petals which have a fancied
resemblance to AI AT.
D. elatum (Fig. 36), a Southern European species, has
been well described by H. Miiller. The five sepals (se)
are brightly coloured ; the upper one is produced into a
long spur (x). The two upper petals are also produced
62 BRITISH FLOWERING PLANTS CHAP.
into spurs which lie within the former, and secrete
honey. In order to reach this, it is necessary for the
bee to press its proboscis between the upper and lower
petals (pe), through the interval (m). The lower
wall of this orifice is in front closed by the lower petals,
Fic. 36.
Delphinium elatum. u, A young flower, seen from the front, after removal of the
calyx. , Section of a similar flower, seen from the side ; the right half of the
calyx and of the corolla has been removed. ‘y, An older ‘flower, seen from the
front, after removing the calyx. 6, Section of a similar flower, seen from the
side, after removing the right half of the calyx.
which are turned upwards and sideways, so as to form
the lower wall of the orifice leading to the nectary, and
to cover the stamens and pistil. Immediately behind
the entrance to the tube, however, these petals contract
so as to leave a space (m). The stamens (a) and pistil
lie below this space, and as the stamens ripen they
successively raise themselves and their anthers pass
a RANUNCULACE 63
through this space, as shown in Fig. 36, a, 8, a’, so that
the proboscis of the bee, in passing down to the honey,
can hardly fail to come in contact with them. After
shedding their pollen, they turn down again, and when
each anther has thus raised itself and again retired, the
pistil in its turn takes possession of the place, as shown
in Fig. 36, y, 6, st, and is thus so placed that a bee
which has visited a younger flower and there dusted its
proboscis can hardly fail to deposit some of the pollen
on the stigma. Fig. 36, a, represents a young flower
seen from the front after the removal of the calyx; it
shows the entrance leading to the nectary, in which are
seen the heads of two mature stamens, a’, while the
others, a, are situated in a cluster below. Fig. 36, ,
represents a section of the same flower. Fig. 36, y,
represents a somewhat older flower in the same position
as Fig. 36, a. In this case the stamens have all shed
their pollen and retired, while the stigmas st, on the con-
trary, have risen up, and are seen projecting into the
spacem. Fig. 36, 5, represents a side view in section of
this flower. Anthophora pilipes and Bombus hortorum
are the only two North European insects which have a
proboscis lone enough to reach to the end of the spur of
Delphiniwm elatum. <A. pilipes is, however, a spring
insect, and has already disappeared before the Delphinium
comes into flower, which in the neighbourhood of Lipp-
statt appears to depend for its fertilisation entirely on
Bombus hortorum, though Boissier assures us that in
France and in the Alps it is visited by several other
species.
The leaves are cut up into linear segments. I have
already suggested (ante, p. 24) one probable reason for
this. Another advantage of leaves being cut up is that
they let light through to those below. Of course there
must be some shadow; but as the sun moves across the
sky, one part of the lower leaves after another is lit
up, and this is sufficient for them. Species like the
Mulleins, with entire leaves, form a conical pyramid,
the lower leaves thus being well lighted; while those
64 BRITISH FLOWERING PLANTS CHAP.
with cut leaves, the Larkspur and Fennel (Feeniculum),
for example, rise up in cylindrical columns, and the lower
leaves are lit through the interstices of the upper ones.
D. elatum is an Eastern Mediterranean species.
AQUILEGIA
Perennial herbs, with flowers in racemes. The 5
sepals are petaloid. The 5 petals each end in a long
horn-shaped spur. The 5 carpels form each a several-
seeded follicle.
A. vulgaris (Columbine) is characterised by its large,
drooping, blue or pale purple flowers and much-divided
leaves. Honey is secreted at the ends of the spurs
of the petals, which reach a length of 15-22 mm., and
are just wide enough at the entrance to receive the head
of a humble bee. Only those, however, with the longest
proboscis (Bombus hortorum and B. agrorum) can reach
the honey. Other species, as Sprengel observed long ago,
have hit upon the device, adopted also in the cases of many
other tubular flowers, of biting a hole through the spur
and thus robbing the flower of its honey. This is said
to be most frequently done by B. terrestris, but other
species, including the hive bee, avail themselves of the
access thus afforded. H. Miiller observed a humble bee
(B. terrestris) come to one of these flowers and lick the
base of the sepals. Finding no honey there, she tried
the petal, but her proboscis was too short, and after
thrusting her head in as far as it would go, and vainly
trying to reach the honey, she gave it up, went round
to the end of the spur, bit a hole through, and so was
able to suck the honey. After this she visited several
other flowers, and, without losing time by trying other
means of access, at once bit holes in the spurs. He
thinks that each humble bee begins by satisfying
herself that she cannot obtain the honey without biting
a hole, or using one already made. I have found almost
all the Columbines in my garden thus bitten through.
The follicles are upright, and open at the top. When
agitated by the wind they scatter the seeds in all
rm RANUNCULACEE 65
directions. The seeds are black, shining and smooth to
the naked eye, but with very fine granulations. In
seeds which are thrown, smoothness is probably an
advantage.
The name Aquilegia was given from a fanciful
resemblance of the spurs of the petals to the claws of
an eagle; Columbine from that of its flowers to a
nest of doves. The plant grows in Europe, as far north
as Scandinavia, and in temperate Asia.
ACONITUM
Perennial herbs, with leaves much divided; the
segments are palmate. The 5 sepals are coloured ; the
large upper helmet-shaped one suggests the common
name Monkshood. The small petals (2-5) are enclosed
in the sepals, the two upper forming small, irregularly-
spurred, honey-containing bodies on long stalks (Fig.
37). The stamens are numerous, and the 3-5 carpels
form each a several-seeded follicle. The Aconites are
especially adapted to humble bees, and their distribution
on the earth’s surface coincides with that of Bombus,
extending over Hurope, Central Asia, and parts of North
America.
A. Napellus (Monkshood or Wolfsbane).—The stem
is strong and erect, 14-2 feet high. The dark blue
flowers are on erect pedicels, forming a handsome
terminal raceme. They are protandrous. The large
upper hood-like sepal is not only part of the decoration
of the flower, but seems to protect the two nectaries, the
stamens and the ovary. The three lower sepals combine
to protect the inner parts of the flower. The two upper
petals are modified into the remarkable nectaries. ‘hey
‘secrete a rich supply of honey. The humble bee alights
on the lower sepals, and presses into the cavity of the
flower, which it just fills It thus rubs against the
anthers and dusts its under surface with pollen. When
the anthers have all shed their pollen, the pistil lengthens,
- go as to rise into the place which the anthers previously
occupied. The bee, therefore, can hardly fail to dust
F
66 BRITISH FLOWERING PLANTS CHAP.
its breast with pollen from the anthers of flowers when
just expanded, and to deposit some on the stigmas of
older ones. The flowers are fertilised exclusively by
humble bees. The species with short proboscis often
pierce the spur, and thus obtain access to the honey, as
in Aquilegia. The plant is very poisonous, and is said
to have been formerly used to destroy wolves, whence
the name Wolfsbane. Any one who has spent a
holiday in Switzerland must have noticed in the Alpine
meadows that the cattle leave the clumps of Aconite
untouched. Darwin’ quotes from Dr. Ogle a curious
illustration of the protection afforded by this poison.
Ogle examined 100 stems of the white variety, which is
harmless, and found that every single flower had been
perforated by humble bees. Flowers so treated are
robbed of their honey without being fertilised. The
blue flowers of neighbouring plants were, however, none
of them perforated. They were being visited by bees
in the normal manner, and would therefore set their
seeds. The seeds
are jerked out of
the follicles by the
wind. They are tri-
angular, black or
deep brown, and
much wrinkled. The
angles are evidently
due to mutual pres-
Fic. 37.—Aconitum Lycoctonum. A, flower in the sure.
second (female) condition, seen from the side. The plant is a
Nat. size. - B, longitudi ion. G
at. size. - B, longitudinal section. x about 2. native of Europe
The upper stamens have already fallen.
and temperate Asia,
and is found wild in Britain only in Wales and a few
counties of western England.
In the yellow-flowered A. Lycoctonum, which, how-
ever, is not British (Fig. 37), the petals are even more
remarkable than in A. Napellus.
1 Cross- and Self- Fertilisation of Plants, p. 428.
I BERBERIDACE.E 67
BERBERIDACEA
Berberis vulgaris (Berberry) is the only British
species of this family, and
even this is a doubtful native.
It is a glabrous pale-green
shrub, with yellow, acid wood,
6 or 8 feet high, with long
branches arching over at the
ends. The leaves are alter-
nate or in clusters, obovate,
and sharply toothed. The
primary leaves are changed
into seven, five, or three
thorns, and the axillary bud Fie. 38.—Shoot of Berberry (Berberis
develops leaves, which is the jis) sowie ene
reason for their being in clus- —_, stem; Z, Z, leaves on a lateral
ters. The flowers are yellow, —‘tovtamhinginthe asl of he pn
in graceful drooping racemes, to short subulate spines; L’, L’,
with a peculiar smell. The a
parts are in alternating whorls
of three, including 6 sepals, 6 petals, each with two
orange nectaries at the base,
and 6 stamens. The system
\ of fertilisation was well de-
) scribed by Sprengel. The
stamens lie close to the petals
. and almost at right angles
)} to the pistil, as shown in
Fig. 39. The honey-glands
(n n) are twelve in number,
situated in pairs at the base
of the petals, so that the
SSS honey occupies the angle
Fic, 39.—Berberis vulgaris. Flower between the bases of the
oan rg ee * stamens and of the pistil.
The papillary edge of the
summit of the pistil (Fig. 40, e) is the stigma. In open
68 BRITISH FLOWERING PLANTS CHAP.
flowers of this kind it is, of course, obvious that insects
will dust themselves with the pollen and then carry it
with them to other Howers. In Berberis, however,
both advantages, the dusting and the cross-fertilisation,
are promoted by a very curious contrivance. The
bases of the stamens are highly irri-
table, and when an insect touches them
the stamens spring forward to the
position shown in Fig. 40 and strike
the insect. The effect of this is not
only to shed the pollen over the in-
sect, but also in some cases to startle
M16. a. Pistilaed too ib and drive it away, so that it carries
stamens, after the the pollen thus acquired to another
nian cee pace flower. It is visited by bees, wasps,
flies, and beetles.
The fruits show the characteristic features of those
adapted for dissemination of the seeds by serving as
food for animals. The fruits themselves are juicy and
red, with a pleasant taste. In other cases they are
generally sweet, but in the Berberry have a pleasant
bitter taste. The seeds have a hardened endosperm
and a crustaceous testa, so that they are’not digested.
The Berberry had long been suspected by farmers
of exercising an injurious influence on wheat, and they
generally therefore rooted it out of hedges: The sus-
picion, however, was regarded as groundless, until it
was found that the plant (Pucconia gramainis) to
which “rust”? is due passes through two phases: in
one it lives on wheat, in the other on the Berberry.
The second phase had been regarded as a distinct
fungus, Aicidiwm berberidis ; it forms yellowish-brown
pustules on the leaves and young shoots in the early
summer.
Il NYMPHAACEE 69
NYMPH-EACE (Water-Litigs)
Perennial, herbaceous, aquatic plants. The very
numerous parts of the flower are arranged in a close
continuous spiral; sepals passing gradually into petals,
and these into stamens. ‘The sepals and petals are on a
fleshy disk, which surrounds the many-chambered, many
ovuled ovary, and is crowned by the sessile, radiate
stigmas. The embryo is very small. In our two
British species the carpels develop air-cells, which
enable the seeds to float on the surface of the water,
and thus ensure their dispersal. The flowers are
effectively protected against creeping insects by their
aquatic habit. They are large, white, or yellow and more
or less scented, yet they are not much visited by insects,
principally by flies and a few beetles. The seeds, which
are nutritious, and eaten by some birds, are embedded
in a slimy mass, so that some of them can hardly fail to
adhere to the feathers, and thus be carried from one
lake to another. They are crustaceous, deeply cordate,
glabrous, shining, and pale yellowish grey. In germina-
tion the cotyledons remain in the seed.
In Nymphea the petals are large, without a nectary,
and the stamens are inserted on the surface of the ovary.
In Nuphar the petals are small, with a nectary, and the
stamens are inserted below the ovary.
Nymphea alba (White Water-lily).—The floating
leaves are 5-10 inches across. In the leaves of most
plants transpiration takes place mainly from the under
side, where the majority of the stomata are situated. The
under side of the floating leaves of water-plants have, how-
ever, lost this power, and have no stomata, transpiration
being confined to the upper face. It is interesting that
some species of Nelumbium, which raise their leaves
above the surface, have incomplete stomata on the under
side, as if they were making an effort to recover the
structure which their ancestors had lost. The upper
1 Areschoug, ‘‘Der Einfluss des Klimas auf die innere Organisation der
Pflanzen,” in Engler’s Bot. Jahrb. ii. (1881-82).
70 BRITISH FLOWERING PLANTS CHAP.
surface of the leaf is protected by a covering of wax,
and rain falling on it collects in drops. Moreover, the
surface of the leaf where it joins the stalk is slightly
raised, and the edges are bent up and down in waves.
The result is that the raindrops roll away to the edge on
the slightest rocking movement. This gives also a peculiar | .
appearance to the shadow of the leaf, which assumes the
form of radiating dark strips with intermediate light
bands. The leaves are often purple on the under side
from the presence of anthocyan, which, by changing
light rays into heat, promotes the work of the leaf.
The flowers lie on the surface of the water, and are
the largest and perhaps the finest of our native flowers.
The carpels are embedded in a thick receptacle, radiating
from the centre. The flowers open towards the middle
of the day, and close in the evening and in wet weather.
The anthers open with the flower, or sometimes a day
later. They bend over the stigma, and thus in the
absence of insects ensure self-fertilisation. The flowers
smell of honey, and the stigma exudes a small quantity
of fluid, which, however, can hardly be called honey.
The plant occurs throughout Europe, Northern and
Central Asia, and North America.
NupHar
N. lutea (Yellow Water-lily).—The leaves are of
two kinds—floating and leathery, and submerged and
membranous. The 5 or 6 yellow sepals are concave and
much larger than the petals. The petals and stamens
are numerous. The numerous carpels are radiating, fleshy,
and united, but separating when ripe; the stigma has
14-20 rays. The flowers have a faint scent resembling
brandy. Honey is secreted by the outer surfaces of the
petals, and collects in the angle between the petals and
sepals. The stigma is ripe when the flowers expand, the
anthers a little later, beginning from the outside. The
yellow pollen grains are large, ellipsoidal, and rough. The
flowers are visited by a few beetles and flies. The geo-
graphical range is nearly the same as that of Nymphiea.
Ir PAPAVERACEE 71
PAPAVERACEZ
The Papaveraceze are herbs, mainly of the north
temperate regions. The stem contains a white, yellow,
or orange milky juice. The leaves are radical or alter-
nate. ‘The sepals are generally 2, rarely 3, falling when
the flower opens. The 4 petals are crumpled in the bud.
The stamens are numerous. The ovary is free, really one-
celled, but often divided into more or less closed chambers
by many-seeded parietal placentas. The fruit is a
capsule, opening by pores or valves. The seeds contain
albumen and a minute embryo. Papaveraceee belong
mainly to the north temperate zones of both hemi-
spheres.
The British species may be known from those of all
other orders by possessing 2 sepals and 4 petals.
PAPAVER
P. Rheas. — An crect, branched annual, 1-2 feet
high, roughened by spreading or adpressed hairs or
bristles ; the leaves are pinnatifid and finely denticulate.
The large flowers have deep scarlet petals, generally black
at the base; the capsule is nearly globular and smooth,
with 8-12 radiating stigmas. The stamens open in the
bud, so that some of the pollen inevitably falls on the
stigma, but according to Hoffmann the plant is self-
sterile. The pollen is greyish green, in form spherical,
or nearly so, freely granular, and 37°5 » in diameter.
The plant produces no honey, but is visited for the sake
of the pollen. The petals, though large, are thin and
weak, so that insects naturally alight on the summit of
the ovary, and thus dust themselves with pollen which
they carry to another flower. They are visited by bees,
flies, and beetles. As Grew quaintly said, the petals in
the bud “are crambed up within the empalement by
hundreds of little wrinkles or puckers ; as if three or four
Cambrick Hankerchiefs were thrust into one’s pocket.”
The flower-heads hang down when in bud, but raise
72 BRITISH FLOWERING PLANTS CHAP.
themselves gradually into an upright position before
they open. Véchting’ found that if the ovary is
destroyed this change does not take place. On the
other hand, the usual change took place even when all
the other parts of the flower were removed. When the
capsule is ripe a series of little doors
open (Fig. 41) near the summit, through
which, when the plant is swung by the
wind, the seeds come out, and are thus
thrown to some distance. This throws
light on the at first sight remarkable
fact that in so many plants which have
capsules they open, not, as we might
perhaps at first sight have expected, at
the bottom, but, on the contrary, at the
summit. The little doors close when it
is wet, and are protected from rain by
overhanging eaves.
P. somniferum.—This species is so
called because opium is obtained from
it. It is a glaucous green erect annual,
i glabrous or with a few hairs on the
Fie. 41.—Capsule of Peduncles, about 3 feet high. The
a Poppy. a, indi- leaves clasp the stem at the base, and
gates Jevel of aPe~ are oblong, toothed or lobed. The large
flowers are bluish white, with a purple
or nearly black base. The flower remains open for
two days. The flat summit of the ovary forms a con-
venient alighting stage for insects, which dust them-
selves with pollen. They cannot alight on the petals,
which, though large, are thin. The large capsule is
globular.
The plant occurs as an escape from cultivation in
our southern counties and in the Fens. It is widely
cultivated in temperate and warm regions in Europe,
Asia, and North Africa. Mr. Reid says it was culti-
vated in Neolithic times, and its seeds have been found
in the Swiss lake-dwellings.
1 Die Bewegungen der Bliithen und Fruchte. Bonn, 1882.
re PAPAVERACEE 73
P. hybridum.—In this species also the capsule is
globular, but it is covered with numerous, spreading
bristles. The filaments of the stamens are dilated
from the middle upwards. It is a hative of Central
and Southern Europe, North Africa, and Western Asia
to North India, and of England except the extreme
north.
P. dubium.—The capsule in this species is oblong,
glabrous, and narrowed at the base. Its range is rather
more northerly than that of the last species.
P. Argemone has a club-shaped capsule. The
filaments of the stamens are dilated from the middle
upwards, as in P. hybridum.
Its geographical range is
nearly the same as that of
P. hybridum and Rheas.
When ripe the valves detach
themselves from the top of
the fruit-stalk.
GLAUCIUM
G. luteum (Horned
Poppy).—So called from its
long curved pods, which are
10-12 inches long. The
flower lasts two days. The
seeds are brown, with ridges
enclosing more or less square
areas. It is found on sandy
sea-shores all round the
Mediterranean and the
Atlantic shores as far as Fic. 42.—Glaucium corniculatum. Seed-
Scandinavia, and is com- ling. Nat. size, The numbers indi-
cate successive leaves following the
mon round our shores, but cotyledons (c).
less so in Scotland.
Fig. 42 represents a seedling of a nearly allied
species, and shows the gradual development from the
simple filiform cotyledons to the comparatively complex
leaves.
74 BRITISH FLOWERING PLANTS CHAP.
CHELIDONIUM
C. majus (Common Celandine) occurs in waste places
and hedge-rows, but is a doubtful native. The edges
of the leaves sometimes produce buds. The plant is
protected by a feetid yellow sap. The seeds are black,
shining, and deeply pitted in longitudinal rows. The
ridges, however, are rounded so that when jerked out of
the capsule they would offer but little resistance to the
air (see p. 65).
In the Welsh Poppy (Meconopsis cambrica) the
black or deep brown seeds have a close network of rather
deep, generally pentagonal alveole. In some foreign
species of the genus the seeds are covered with papille.
The seeds of Remeria hybrida, a weed of cultivation
found in dry soil in the eastern counties, are deeply
pitted in lines following the curvature of the outline.
FUMARIACEX
FuMARIA
F. officinalis —The common Fumitory is a glabrous,
delicate green, trailing annual, with much-divided leaves
and white or red
flowers in racemes
of 1-2 inches. The
sepals are small (Fig.
43), 2 in number,
lanceolate, and often
toothed.’ The petals
Fie. 43.—Fumaria officinalis, Flower much en- are 4. The upper
lnged. sepa wp, upper metal Le Over One ig produced into
a short spur or
pouch behind, and in front forms a sort of hood over
the rest of the flower. The lower petal is narrow and
pointed. The two middle ones are united at the base,
1 Hildebrand, Pringsheim’s Jahrbuch fiir Wiss. Botanik, 1869-70.
II FUMARIACE 75
and with the ethers form a tube which encloses the
stamens and pistil. They are, moreover, hinged near
the base (Hig. 44), and if an insect visits the flower it
is thus able to press down the middle petals and thus
dust itself with pollen, or deposit pollen on the stigma,
as the case may be. When the insect leaves, the petals
spring up again into
their former “position.
The stamens are in
two groups of three.
The upper group send
a glandular process
(Fig. 44) or nectary
into the pouch of the
upper pet al. LNG are, di Fimnants officinalis. Flower from
ovary contains two which the sepals have been removed; the
petals separated, exposing one of the staminal
ovules, only one of groups, which consists of a perfect anther (sf),
which forms a seed and two lateral half-anthers (a). h, hinged
‘ base of median petals ; , nectary.
This occurs in many
other groups of plants; perhaps it is an advantage in
lightening the fruit, and thus tending to promote dis-
persion. The flowers appear to be but little visited by
insects. Knuth characterises them as bee-flowers. Bees,
however, do not seem to take much notice of them.
Perhaps they are fertilised by night insects.
The species of Fumaria belong mainly to the Medi-
terranean region. Our common form, which some
authorities break up into several species, is now spread
almost over the whole world.
CoryYDALIS
C. claviculata.—A climbing plant, rising to a height
of several feet by the leaves, which end in branched
tendrils. Charles Darwin in Climbing Plants refers to
it as being exactly intermediate between a leaf-climber
and a tendril-bearer. The mechanism of the flower
resembles that of Fumaria. In C. claviculata, how-
ever, and some other species, the two small petals, when
once pressed down, do not spring back. The pistil is
76 BRITISH FLOWERING PLANTS CHAP.
protected by the upper petal. Some. species have a
more or less rudimentary pouch at the base of the
lower petal, and a corresponding trace of a nectary at
the base of the lower group of stamens. This seems
to indicate that the one-spurred genera, Corydalis and
Fumaria, are descended from two-spurred forms such
as Dielytra.
The flowers of C. cava, according to Hildebrand, are
absolutely sterile with their own pollen. The seeds are
black and shining, and very finely pitted.
CRUCIFERA
This great and important order is distinguished by
having 4 sepals, 4 petals, and 6 stamens, 4 longer than
the remaining 2. ‘The 4 petals are arranged im a cross,
whence the name Cruciferze, or cross-bearers. There are
2 carpels, united to form, when ripened, a pod. There
are at least 1200 species, mostly inhabiting the temperate
regions of the old world, but forming a considerable part
of the vegetation of Arctic regions. They are almost all
insect flowers and homogamous. They present great
Fic, 45.—Sections of seed of Hesperis matronalis, x10, R, radicle ; C, cotyledons.
The radicle is incumbent or parallel with the faces of the cotyledons.
differences in the number and position of the nectaries,
and in the position of these in relation to the stamens
and the pistil. The great majority, if not all, produce
honey. The seeds are oblong, sub-globose, or flattened
and margined or winged, and almost always exal-
buminous,’ the embryo occupying the whole seed. The
embryo is generally curved, with the radicle incumbent
1 Except in some species of Isatis.
It CRUCIFER 77
(Fig. 45), or accumbent (Fig. 46), as in the Wall-
flower (Chetranthus Cheirt).
The order is generally divided into two great groups
—(1) those with a dehiscent pod, (2) those with an
indehiscent pod, containing one seed or several separated
by partitions. The first group again falls into two—
Siliquosee, in which the pod is three to four times as
Fic. 46.—Sections of seed of Wallflower (Chetranthus Cheiri). x 10. R, radicle ;
C, cotyledon, The radicle is accumbent, or parallel with the edges of the
cotyledons.
long as broad, and Siliculose, in which it is globular
or broad and more or less compressed. The compression
is sometimes parallel to the partition, as in Alyssum or
Draba; sometimes at right angles to it, as in Capsella
(Shepherd’s Purse) or Lepidium (Cress).
The edges of the leaves in some species (Cardamine
and Nasturtium) produce buds.
CHEIRANTHUS
C. Cheiri (Wallflower) is glabrous, or with adpressed
hairs, forked from the base. Forked and stellate hairs
are frequent in this family; they afford a better pro-
tection from loss of moisture by the plant, and also
a more efficient shade from excessive sunlight than
would simple hairs. The flowers are rather, large, and
vary in colour from pale yellow to deep red. There are
two nectaries situated at the base of the two short
stamens. The honey sinks into the depressions at the
base of the sepals. The anthers open inwards, and
almost close the mouth of the flower. It is visited by
bees and flies; those with short probosces cannot reach
78 BRITISH FLOWERING PLANTS CHAP.
the honey, but must content themselves with pollen.
The seed is oblong, oval,’ much compressed laterally,
with the edges produced all round into a thin mem-
branous wing, which probably serves for dispersal. The
embryo occupies the whole interior. The cotyledons are
broadly ovate, entire, flat, and adpressed face to face.
They take, therefore, approximately the form of the seed.
The Wallflower is a native of Central and Northern
Europe, and occurs as an alien, growing on old walls,
in this country.
BarRBAREA
B. vulgaris (Winter-cress or Yellow Rocket).—The
yellow flowers attain a diameter of 4 inch. The half-
concealed honey is produced in abundance by six
nectaries, of which the two at the base of the short
stamens are often confluent; it collects in the hollows
at the base of the sepals. The insect visitors are bees,
flies, and beetles. The leaves are often violet below
from presence of anthocyan. The plant, which is very
variable, is generally glabrous, but sometimes pubescent.
It is widely distributed in the north temperate zone.
NastTuRTIUM
The Nasturtium of botanists is, I need hardly say,
not the Nasturtium of gardeners, which is a Tropzolum.
The true Nasturtiums are annual or perennial, with
small white or yellow flowers, and a linear or oblong
pod. They live by the side of ponds or streams.
N. amphibium.—The flowers are yellow. The six
nectaries at the base of the stamens form a ring. The
anthers of the four long stamens are about on a level
with the stigma, and open inwards, so that insects
in search of honey touch the stigma with one side
of the head, the anthers, or rather one of them,
with the other. According to Warnstorf, however, the
anthers, as they open, make a half turn, so carrying the
pollen away from the stigma, and making self-fertilisa-
: “Avebury (Lubbock), Seedlings, vol. i.
Il CRUCIFERAE 79
tion more difficult. The insect visitors are bees, flies,
and beetles. The pods are oblong and turgid.
InN. silvestre the nectaries do not meet, but form
four teshy glands. The pods are linear, and more or
less curved; the seeds are rather less numerous. Why
should two plants so similar and so nearly allied have
such different pods ?
CaRDAMINE
C. pratensis (Cuckoo-flower).—The flowers are larger
than in most of its allies, agd more visited by insects.
There are four nectaries—two at the bases of the two
shorter stamens, and two smaller ones at the base of the
two longer ones. The honey collects at the bowed base
of the sepals. The pouches of the two sepals correspond-
ing to the larger nectaries are more roomy than the
others. The yellow anthers make a quarter turn when
opening. On the contrary, in the case of the two short
stamens the anthers open inwards. According to Hilde-
brand, the plant is self-sterile. In addition to bees,
flies, and beetles, the flowers are visited occasionally by
butterflies and hawkmoths.
C. amara (Bitter Cress) agrees in many respects with
C. pratensis, but the anthers are purple.
C. hirsuta is a common weed in gardens, with erect
stems about a foot high. The leaves are pinnate, the
flowers small and white; the petals are sometimes absent.
The name is far from appropriate, as the plant is almost
glabrous, having only a few scattered hairs. Though the
flowers are so small, they are not entirely deprived of
insect visits, in the absence of which, however, as the
anthers are close to the stigma, the plant fertilises
itself. The inner layers of cells of the walls of the pod
gradually come to a condition of great tension, so that
when ripe the walls of the pod detach themselves at the
slightest touch from below upwards, fly off elastically,
and scatter the seeds. In this country it is annual, but
plants grown by Kerner in his Alpine garden became
perennial. The same change occurred in various other
80 BRITISH FLOWERING PLANTS CHAP.
annual species, and is interesting in connection with the
preponderance of perennial species in Alpine and Arctic
districts.
C. impatiens.—This species is happily named from
its habit of throwing its seeds as in the preceding
species.
DENTARIA
A genus of herbs with creeping, scaly root-stock,
from which the name is derived (Latin dens, a tooth).
D. bulbifera, a rare plant occurring in the south
of England, is the only* British representative. It
grows in damp woods, and like other inhabitants of
such localities has large, flat delicate leaves. As, more-
over, the leaves inhabit places where, and appear at a
season when, the leaf supply is abundant, the plants
run their risk, and need no special protection from
browsing quadrupeds. In dry, arid regions where the
food for goats, sheep, etc., runs short, they would not
last a day.
To the same category belong Lunaria, Orobus vernus,
Paris, Mercurialis (Dog’s Mercury), Impatiens (Balsam),
Arum (Lords and Ladies), and Petasites (Butter Bur).
The flowers are large, and honey is formed in four
nectaries at the base of the stamens, but insect visits
are rare. Knuth never saw any, nor have I been more
fortunate. Pods indeed are seldom formed, but small
ovoid bulbs grow at the base of the leaves, and by them
the plant is generally propagated.
HEsPERIS
H. matronalis—A hairy plant, with violet flowers
# inch in diameter. The nectaries are two fleshy,
green glands at the base of the two short stamens.
The long stamens reach just to the opening of the
flower, but after shedding their pollen they are said to
grow rather longer, which is very unusual. The anthers
open inwards, and self fertilisation is easy. The
flowers are, however, visited by several insects; about
1 CRUCIFERZ 81
twenty species have been observed, but this is probably
by no means all. I have given (ante, p. 76) the embryo
of this species as an illustration of an “ incumbent”
embryo. The genus is named from the Greek hesperos,
evening, because it becomes specially sweet at night,
which generally indicates fertilisation by moths. In
support of this I may mention that H. Miiller’s daughter,
Miss Agnes Miiller, saw several species of moths visiting
the allied species, H. tristis. No evening insects, how-
ever, are as yet recorded.
The plant is a native of Central and Southern Europe
and Russian Asia, except the extreme north; it is found
in England only as an escape from gardens.
SISYMBRIUM
8. officinale (Hedge-mustard).—The plant is hairy,
and seems to have a peculiar affinity for dust. There
is a honey-gland on each side of the two short stamens.
When the flower opens, the pistil and the longer stamens
project slightly. The shorter stamens are enclosed in
Cc
a
3S .
a
k
A B
Fig. 47.—Sisymbrium officinale. A, Flower in the first stage. 3B, Flower in the
second stage. kh, sepal; c, petal; u, anther of one of the longer stamens ; «’,
that of a shorter one; s, stigma ; w, nectary.
the flower, but the anthers are open. All six stamens
then grow a little so that the anthers of the shorter ones
reach the stigma, while those of the longer ones project
slightly beyond it. The flower is therefore adapted for
cross-fertilisation, but may also be fertilised by its own
pollen. It is visited by bees, flies, and butterflies. It is
a native of the north temperate zone of the old world,
and has been introduced into the United States.
G
82 BRITISH FLOWERING PLANTS CHAP,
8. Irio (London Rocket).—So called because it came
up in great numbers in the spring after the fire of
London.
S. Sophia (Flixweed).—The flowers are small and
inconspicuous, the petals only half as long as the sepals,
and nearly the same colour. * It used to be thought of
special value in healing wounds, whence the name
Sophia, short for sophia chirurgorum, “the wisdom of
surgeons.
ALLIARIA
A. officinalis (Sauce Alone; Jack by the Hedge).—-
A common hedge-bank plant, with a strong smell of
garlic when bruised. There are four glands in the flower,
but, according to Knuth, only the two at the base of
the short stamens secrete honey. This collects in four
drops in the space between the stamens and the pistil.
Perhaps it may be connected with the fact that the
honey thus passes inwards, and not, as in allied species,
outwards between the stamens and the sepals, that the
sepals drop early.
ErRysIMUM
E. cheiranthoides——In this species also the honey is
secreted by the nectaries at the base of the short stamens,
those belonging to the longer ones being rudimentary.
The pod is covered with stellate hairs.
Brassica
B. oleracea (Cabbage).—There are four nectaries
—two at the base of the inner sides of the two short
stamens, the other two between the roots of the
longer ones. It seems doubtful, however, whether the
latter secrete any honey. The honey accumulates
between the bases of the longer stamens, and insects
seeking it could therefore not fertilise the flower. Is
this perhaps the reason for the diminution or absence
of secretion from these glands? The flowers are visited
by bees, especially the hive bee, and beetles. The
It CRUCIFERA 83
cabbage is one of those plants in which the stomata are
on the upper surface. They are protected by a waxy
secretion, so that water runs off in drops as off a duck’s
back. The plant is found on maritime cliffs round
Europe as far as our southern counties. It is the
source of many forms of the cabbage, cauliflower,
brussels sprouts, etc. The seedling resembles that of
the Radish (see p. 91).
B. Sinapis (Charlock).—A cornfield weed with hispid
stem and leaves and bright yellow flowers. The bud
opens early in the morning, and the stigma is already
ripe. The anthers are still closed, so that in this stage
the flower must be cross-fertilised if fertilised at all.
The next morning the four longer stamens have
elongated and twisted round so as to face outwards,
away from the stigma. They form a sort of arch over
it. The third day the ovary has elongated, thus
bringing the stigma up to the anthers, and almost
ensuring self-fertilisation.
B. nigra (Black Mustard).—As regards the structure
of the flower this species does not materially differ from
the preceding. The cotyledons also are similar, and as
. in the Cabbage, Radish, and other Crucifers they are
somewhat kidney-shaped (Fig. 51) and unequal. I will
endeavour to explain the reason for this when we come
to the Radish.
B. campestris—This is supposed to be the parent
stock of the Turnip (B. Napus). It is biennial, and
during the first year, when the stem remains very short,
the plant occupies itself by laying in a stock of nourish-
ment in the underground root formed from the portion
of the original stem (hypocotyl) between the cotyledons
and the upper part of the primary root. In the
following year the erect leafy and flowering stem is
produced at the expense of this store.
DIPLOTAXIS
The genus is distinguished from Brassica by having
the seeds arranged in two rows, whence the name.
84 BRITISH FLOWERING PLANTS CHAP.
D. tenuifolia—Only the two nectaries at the base of
the shorter stamens secrete honey. Yet the others are
larger. The two sepals outside the secreting glands are
upright, the others are spreading. The anthers of the
short stamens open inwards. ‘The flowers are visited
by flies, bees, and butterflies, but only a few species of
each are recorded as visitors.
D. muralis—In this species all the glands secrete
honey, and all the sepals are similarly oblique.
DRaABA
D. aizoides.—The flowers are at first golden yellow,
gradually becoming white. This is the first flower we
have come to which changes colour. I will discuss this
interesting point later on. When the flower opens, the
stigma projects above the anthers, which are shorter
and not yet ripe. They gradually elongate and open
when they reach the level of the stigma, over which
they bend, so that if it has not been visited by insects
the flower fertilises itself. Miller records in the Alps as
visitors 13 flies (7 Muscidee and 6 Syrphidee), 10 butter-
flies, and 1 beetle. The plant is not a genuine native;
occurring only on rocks and walls at Pennard Castle,
near Swansea.
ALYSSUM
Two species occur in Britain, but neither is a true
native—A. calycunum, in which the calyx is persistent
and the seeds two in each cell; and A. maritémum, in
which the sepals fall off after ‘flowering, and there is
only one seed in each cell.
In A. calycinum the stamens present differences
resembling those which also occur in Allium. The
shorter ones have a small appendix at each side. This
species is also interesting as being one of those in
which the petals change colour, being first yellow and
then white.
The flowers of A. maritimum (Sweet Alison) have a
very sweet scent of honey. The seeds are compressed
ul CRUCIFERA 85
and winged, which doubtless helps towards dispersion.
Moreover, when wetted the cells at the edges of the
wing swell up and ultimately burst, liberating a
mucilage, which is useful in fixing the seed to the damp
earth.
CocHLEARIA
A genus of perennial herbs with small white flowers
and inflated pods. There are about twenty-five species
in temperate and Arctic regions, chiefly littoral and
alpine. ‘Two are British.
C. officinalis, subsp. danica.—The subglobose silicule
is two-celled, with four to six seeds in each cell, and
opens by two turgid valves. The small ellipsoid seeds
are somewhat compressed laterally, with a rather deep
notch at the base. The deep brown seed-coat is covered
with large crystalline, truncate, or slightly funnel-
shaped tubercles, in lines following the curvature of the
seed. When the seeds are placed in water the truncate
tubercles gradually elongate, becoming several times
longer than they were in a dry state, and hyaline or
transparent, showing striated and filiform thickenings
internally ; they also lose their truncate form, becoming
obtusely conical. They do not burst, even after having
been for some time in water. Many of those lying
above the water merely become many times larger than
they were previously and dome-shaped, showing a very
fine internal striation. Such mucilaginous cells when
pushed into surrounding soil must serve to fix the seed
effectually during germination, but they may also aid
in the dispersal of the seeds.
C. Armoracia (Horse-radish) has nectaries at the base
of the stamens, but in C. officinalis Knuth could find
none. The former is, however, visited by a good many
insects for the sake of the honey. The plant, which is
found on waste ground, is not a native. Its origin is
unknown ; it is suggested that it is a cultivated form of
a Hungarian species, C! macrocarpa.
86 BRITISH FLOWERING PLANTS CHAP.
SUBULABIA
S. aquatica (Awlwort).—This is a small aquatic
plant generally not more than two, seldom three, inches
high. It usually grows entirely under water, and the
flowers are cleistogamous. Sometimes, however, it is
aerial, in which case the flowers open. The anthers
and stigma ripen simultaneously and are closed together.
Scott Elhot, in Dumfriesshire, observed a fly on the
flower, and this appears to be the only insect visitor on
record. It is named from subula, an awl, from the
shape of the leaves, a form recurring in other submerged
herbs, as, for instance, in the Quillwort (Jsoetes).
SENEBIERA
S. didyma.—The silicule or fruit is so much con-
stricted as to be almost two-lobed, whence the specific
name from the Greek 8éSvuos, twin. It is reniform, much
compressed laterally, notched, and deeply and irregularly
pitted, ultimately separating into two indehiscent pieces,
each containing a solitary seed conforming rather closely
to the cavity. The seed is reniform, laterally compressed
and rugulose, with longitudinal furrows corresponding to
the outline of the folded cotyledons and radicle. The
coat is pale yellow, thin, somewhat transparent, and
densely and finely rugulose. The notch at the base of
the fruit favours its temporary attachment to passing
animals, and in this way the seeds may often be carried
from the parent plant. The species is a native of
temperate South America, but has been introduced into
many countries. It is well established on the sea-coast
of Hampshire, South and West Wales, South and West
Ireland, and appears sporadically elsewhere.
Tuuaspi (Penny Cress)
The name is derived from the shape of the pods.
T. alpestre.—There are not a few plants in which the
petals change colour, but this does not often happen in
the case of the anthers. Those of this species, however,
i CRUCIFERA 87
are first yellow, then reddish purple, and finally black.
As insect visitors 17 species of bees, 9 flies, 2 butter-
flies, 2 saw-flies, 1 wasp, and 1 beetle are recorded. The
seeds are smooth. The plant grows in mountain dis-
tricts in Great Britain.
T. arvense.—Nectar is secreted by small green glands
on each side of the base of the shorter stamens. The
anthers of the four longer stamens open inwards at the
same time as, and on the same level with, the stigma,
so that in the absence of insect visits self-fertilisation is
almost certain to occur. According to Kerner the
flower is slightly protogynous. The seeds are covered
with concentric strie.
T. perfoliatum.—The arrangement of the flower
agrees with that of the preceding species. The seeds are
smooth. The plant is recorded in Great Britain only
from limestone in Oxford and Gloucester.
TEESDALIA
T. nudicaulis.—This is one of the species in which
the seeds produce a mucous secretion by means of which
they adhere to passing animals, and are thus carried
about. Possibly also the mucus may tend to fasten
them to damp ground, and also prevent them from
being eaten.
CAPSELLA
C. Bursa-pastoris (Shepherd’s Purse).—The name
Capsella was given to this genus from the resemblance
of the pod to a small purse. The species is said to be
called ‘“‘shepherd’s purse” because there is no money in
it. The radical leaves form a rosette on the ground, and
are very variable in shape, being sometimes entire,
sometimes pinnatifid, with a larger ovate, or triangular
terminal lobe ; sometimes glabrous, sometimes pubescent.
The four nectaries are situated at the two sides of the short
stamens. The longer stamens are about as long as the
pistil, so that the plant can easily fertilise itself Willis
found gynomoneecious and gynodicecious plants, con-
88 BRITISH FLOWERING PLANTS CHAP.
ditions supposed by some to be due to cold, as the
hermaphrodite plants are said to come on later in the
season. Warnstorf also remarks that in the earlier
flowers the stamens are often incomplete.
LEPIDIUM
From Aeris, a scale, in allusion to the flattened pods.
The outer layer of the seed-coat contains a mucilaginous
adhesive substance which rapidly absorbs moisture and
serves to fix them as soon as they are brought into
contact with damp earth.
L. Draba has six small, green nectaries between the
bases of the six stamens. The anthers open inwards,
but the stamens bend outwards, thus for the time check-
ing self-fertilisation. Insects, therefore, turn different
sides of their body to the stamens and the stigma, thus
favouring cross-fertilisation. Subsequently the parts
close up, so that in the absence of insects the flower
fertilises itself The plant is slightly protogynous.
The longer stamens at first place themselves behind the
petals, so that insects do not touch them, and after
a while move inwards so as to touch and fertilise the
stigma. The pollen of the shorter stamens, on the
contrary, serves entirely for cross-fertilisation. The
plant is a native of South-Eastern Europe and
Western Asia, which has been introduced or become
established in many places in fields, banks, and railway
cuttings.
L. sativum (Cress) has four nectaries. While the true
British species of Lepidium have entire cotyledons, in
the Cress they are divided into three long narrow lobes
(Fig. 48). 1 have suggested the following reason for
this in my book on seedlings.’
Fig. 49 represents a section through the seed of
L. graminifolium, which may be taken as representing
the ordinary arrangement in the genus. The seeds,
conforming to the shape of the capsule, are somewhat
triangular, with the radicle in the narrow end. The
1 On Seedlings, vol. i.
ra CRUCIFERAE 89
embryo occupies the whole of the seed, there being no
endosperm. In ZL. sativum (Fig. 50) the seed is of the
same form, but nearly twice as thick; if, therefore,
the cotyledons were to occupy the whole additional
Fic, 49.—Section of seed of Lepidium
graminifolium. x 15.
ie
Fic, 48.—seedling of Cress (Lepidium Fic. 50.—Section of seed of Lepidium
sativum). x 3, sativum x 15.
re
space, they would become extremely thick. In endo-
spermic seeds this would be simply filled by endosperm.
In Lepidium, however, this device cannot be resorted
to; but the two lobes just fill up the vacancy.
CAKILE
C. maritima.—aA sea-shore plant. The anthers of the
long stamens project above the flower, so that the pollen
would fall just on to the stigma. At the same time
cross-fertilisation is also provided for. The flower has a
sweet scent, and four nectaries, two at the base of the
short stamens, two at the base of the longer ones.
Some fifty insects are on record as visitors. As in
so many other seaside plants, the leaves are fleshy.
M. Lesage has found that the leaves of several inland
plants tend to become fleshy if they are treated with
water containing salt.’
1 Constantin, La Nature tropicale.
90 BRITISH FLOWERING PLANTS CHAP.
CRAMBE
C. maritima.—This species is peculiar in having
the pod apparently stalked, owing to the lower joint
being seedless and consequently slender. The flowers
have a diameter of 12 mm. and form a large head.
The sepals support and enclose the petals, thus forming
them into a tube. The claws of the petals, the stamens,
and pistil are at first yellowish green, then clear violet
red. The anthers, however, are and remain yellow.
There are two large green round nectaries at the base of
the longer stamens, and two smaller at the base of the
shorter ones. The longer stamens terminate in two
projections between which the anther is seated. Knuth
supposes that they serve to guide the proboscis of visit-
ing insects. The flower is slightly protogynous, and
the stigma is ripe when the flower opens. The longer
stamens reach rather higher than the stigma. The
larvee of a small beetle (Meligethes) are often found in
the flower, feeding on the honey. Knuth thinks, how-
ever, that the injury thus done is more than compensated
by the part they play in fertilisation.
The plant grows on sandy shores and stony places in
Western Europe.
RaPHANUS
R. Raphanistrum.-— A cornfield plant. The petals
are sometimes white with violet veins, sometimes light
yellow with dark yellow veins. The stigma is about at
the same level as the anthers of the shorter stamens,
which open inwards, so that self-fertilisation is ensured
in the absence of insects. There are four nectaries.
The pods when ripe have no longitudinal septum,
but the seeds are separated by a pithy substance.
The cotyledons resemble those of Brassica. The seed
(Fig. 53, A) is oblong, thick, and slightly narrower
at one end than the other. There is no endosperm,
so that the embryo occupies the whole seed, and as
this is somewhat deep, the cotyledons, in order to
1 CRUCIFERA 91
occupy the whole space, are folded and arranged one
over the other, like two sheets of notepaper, as shown
=
Fic. 51.—Raphanus sativus. Seedling. Fic. 52.—Raphanus sativus. Germinat-
Nat. size. ing seedling, x 2, showing the coty-
ledons still folded.
in Fig. 53, B-D, the radicle being folded along the
edge. Fig. D represents the embryo a little opened
rT
Fie. 58.— Raphanus sativus. A, outline of seed, x 4; m, micropyle; , hilum.
B, embryo taken from the seed, x 4. C, embryo, x 4, vertical section. D,
embryo, seen from the side, x 4; 0.c, outer cotyledon ; ¢.c, inner cotyledon ;
r, radicle ; ¢, testa,
out, and Fig. C’ a section showing the radicle and
the outer and inner cotyledons. To this folding the
emargination is due. If a piece of paper be taken,
92 BRITISH FLOWERING PLANTS CHAP.
folded on itself, cut into the form shown in Fig. 53, A,
with the fold along the edge from m to h, and then
unfolded, the reason for the form of the cotyledon
becomes clear at once.
RESEDACEA
ResEepa (Mignonette)
In this genus the flower-bud is open, and the maturity
of the flower is indicated by the appearance of honey
which is secreted in a cup-shaped cavity of the disk,
covered over by the three upper petals, which form a
lid completely closing the nectar-holder. It is thus
contained within a closed box, the lid of which must be
prised up before it can be removed. According to
Miiller, the most frequent visitor is the bee Prosopis,
which has a flat trowel-shaped proboscis which it uses
in plastering its cell. The nectar-gland bears such an
obvious correlation to this form of proboscis as to favour
the conclusion that in Reseda we have a flower specialised
for cross-fertilisation by short-lipped bees.’ The seeds
are black, smooth, and shining, and so much curved as
to be nearly circular in outline.
R. lutea.—The flower is scentless and yellowish green.
The anthers open at the time when the secretion of
honey commences, and the stamens bend towards the
pistil. The stigma ripens simultaneously so that self-
fertilisation can easily take place. At the same time,
according to Darwin,” it has generally little or no effect.
The honey, however, attracts many small insects, which
bring pollen from other flowers. The petals are peculiar.
They consist of three upper lobes, of which the central
is narrow and club-shaped, and a lower flap which serves
to protect the honey. The leaves are much divided.
R. Luteola (Dyer’s Weed) has entire leaves, and the
flowers form long, pointed spikes.
? Report, British Association, 1883, ‘‘On the Nectar Gland of Reseda,” by
Professor A. 8. Wilson, M.A.
° He also found the Garden Mignonette (R. odorata) to be self-sterile.
1 CISTACES 93
CISTACEE
HELIANTHEMUM
The name is derived from ‘wos and dvOeuov, sun-
flower. In some species the flowers bend over in wet, and
follow the sun in fine weather.
Vaucher, in his Mistoire
Physiologique des Plantes,
writing on the Rock Roses
(Helianthemum), — observes :
“ Jindique dans ce genre deux
principaux objets de recherche.
Le premier est la raison pour Ps, Sine tino
laquelle certaines especes ont
des stipules tandis que d’autres en sont privées.” This
suggestion started me on the study of stipules. No one,
so far as I know, had
attempted to answer
Vaucher’s question,
which is one of consider-
able interest, and might
be asked with reference
to several other groups
besides the genus Helli-
anthemum. The results
of my observations have
been embodied in several
Memoirs which the Lin-
nean Society has done me
the honour to publish in
their Journal, and which
have been collected in
: ans my book On Buds and
Fic. wm na vulgare. Stipules. H. vulgare
(Fig. 55) has stipules,
HT. elandicum (Fig. 54) has none. Now on examining
the various species of the genus I found that, where the
94 BRITISH FLOWERING PLANTS CHAP.
leaves have broad bases and thus protect the bud in
their axil, there are no stipules, while on the other hand
where the leaves are narrow the bud is protected by
stipules. HH. guttatwm is a very instructive case. The
upper leaves have stipules, while the lower ones have
none. Now the lower leaves have broad leaf-bases,
which effectually protect the bud, and they are exstipu-
late; the upper leaves, on the contrary, are narrow at
the base, but they are provided with stipules. The
reason for the presence or absence of stipules seems, then,
quite obvious, so far as the Rock Roses are concerned ;
and the evidence is strengthened by finding similar
relations in other genera.
H. vulgare.—The flower is large and bright yellow.
Though producing no honey it is visited by a good
many insects for the sake of the pollen.
H. polifolium.— In this species the stamens are
sensitive. They stand upright, but if touched bend
down to a horizontal position, slowly resuming their
original attitude in about fifteen seconds.
H. canum.—The flower, according to Briquet, is
opened and closed by movements of the sepals. The
stamens are not sensitive. The flower is protogynous,
and as the anthers open outwards self-fertilisation is
almost excluded. The leaves are white underneath and
sometimes on both sides.
POLYGALACEZE
Chiefly tropical and southern. The only European
genus is Polygala, the Milkwort.
P. vulgaris—A variable species presenting several
forms often regarded as distinct, but from their varia-
bility considered by Bentham and Hooker to be varieties.
The two inner, coloured, petal-like sepals are termed
“wings.” They give the flowers a papilionaceous aspect.
The petals form a tube to the inside of which the
I POLYGALACE 95
stamens are attached in two bundles (Fig. 56, a), and
which contains a number of white hairs pointing down-
wards, while near the upper end are ;
two groups of finger-like lobes. The
pistil (Fig. 56, st) occupies the axis of
the flower, and ends in a spoon-shaped
hollow. The short stamens lie just
over this hollow, and shed their pollen
into it, after which they withdraw a
little to the side. Close behind the
hollow is a projection which terminates
in a very viscid disk. When the pro-
boscis of an insect is forced down the
tube in search of honey, it comes in
contact with this viscid disk, and being prc, 56.—section of
thus rendered adhesive, when it is Peygala vulgaris.
‘ a,anthers; co,petals;
withdrawn carries some of the pollen sepals; 'st, stigma,
with it, and
thus conveys it to the next
flower, where it is stripped off
the retreating proboscis by the
edge of the viscid disk, and is
thus accumulated in the stig-
matic hollow. P. vulgaris is
sometimes blue and sometimes
pink or white or striped; why
is this? It is, moreover, a vari-
Fic. 57.—Polygala wigaris. Flower able species in other respects,
opened out. Enlarged. s, sepals ; ji :
co, corolla, the median petal ends @8, for instance, in the size and
in a hood (m) bearing a pair of proportions of the different
a a leaves. The use of the curious
finger-formed processes has not, I think, been satis-
factorily explained.
VIOLACE
Nearly world-wide. The northern species are gener-
ally herbaceous; those of tropical regions often shrubs
96 BRITISH FLOWERING PLANTS CHAP.
or trees. Viola is the only European genus, and extends
over most of the world.
Viota (Violet)
The flowers are yellow, white, blue, or violet, which
indeed has derived its name from the flower. The lower
petal is spurred, giving its peculiar form to the flower.
The anthers of the two lower stamens, as Sprengel
first pointed out, send each (Fig. 58) a projection into
the spur of the petal; all five have a membranous
Fic. 58.—Viola canina. 1, Section of a flower. 2, Stamen. a, anther; c, mem-
branous expansion of connective ; f, filament ; h, hairs on petal to which pollen
grains have become attached; n, nectary; 0, ovary; p, petal; po, pollen;
s, sepal ; st, stigma,
appendage, which together form a cup into which the
pollen is shed. The pistil projects upwards and closes
the mouth of the flower. The stigma is shaped more
or less like a bird’s head. Insects only insert their
proboscis once in each flower. They naturally touch
the stigma first, then dust themselves with pollen
and transfer it to the next flower visited. The Violets
are as a rule bee-flowers, but some Alpine species
(V. calcarata, cornuta, ete.) have the spur elon-
gated and especially adapted for butterflies, while in
MW VIOLACEZ 97
V. lutea it is short and accessible to flies. In addi-
tion to the coloured flowers, some species, for instance,
V. caninua and V. hirta, produce others (Fig. 61, a, b;
see also Fig. 62, a, b) which do not open, in which the
petals are either absent or very imperfectly developed,
and the anthers produce very little pollen. When young
these cleistogamous flowers resemble the ordinary buds,
the central part of the flower being entirely covered by
the sepals. They set seed abundantly, much more, it
is said, than the coloured flowers.
V. canina.—The stock is at first short, gradually
lengthening. Fig. 58 (1) represents a flower cut in half
Fic. 59.—Viola canina, Capsule Fic. 60.— Viola canina. Capsule after
with seed, ejecting the seeds,
and Fig. 58(2)astamen. It is visited mainly by bees, but
also by a few butterflies and one or two pollen-eating
beetles. The stamens consist of a short filament, to
which the anther is attached, and a terminal membran-
ous expansion, while the two lower stamens also send
out each a long spur (Fig. 58, ~), which lies within the
spur of the median petal and secretes honey at its fleshy
end. The terminal membranous expansions of the five
stamens slightly overlap one another, and their points
touch the pistil, so that they enclose a hollow space. The
pollen differs from that of most insect-fertilised flowers
in being drier and more easily detached from the
anthers; consequently, when the latter opens the pollen
drops out ; and as the flower is reversed and hangs down,
the pollen falls into the closed space between the pistil
and the membranous termination of the stamens. The
H
98 BRITISH FLOWERING PLANTS CHAP.
pistil is peculiar, the base of the style not being straight
as usual, but thin and bent (Fig. 58). The stigma, st,
is the enlarged end of the pistil, and shows several
small fleshy projections. It will be obvious from the
above description that when a bee visits the flower its
head will come in contact with and shake the stigma,
thus opening, as it were, the box containing the pollen,
and allowing it to fall on the head of the bee. It is
thus carried away, and some can hardly fail to be
Fic. 61.—Viola canina. a, bud of cleistogamous flower ; b, older bud ;
¢, capsule open.
deposited on the stigma of the next violet which the
bee visits. The capsules are pendent when young, but
at maturity they erect themselves (Fig. 61, c), stand up
boldly above the rest of the plant, and open by the
three equal valves (Fig. 59) resembling an inverted
tripod. Hach valve contains a row of three, four, or
five brown, smooth, pear-shaped seeds, slightly flattened
at the upper, wider end. The two walls of each
valve, as they become drier, contract and approach one
another, thus tending to squeeze out the seeds. These
resist some time, but at length the attachment of the
IL VIOLACE 99
seed to its base gives way, and it is ejected several
feet, this being, no doubt, much facilitated by its form
and smoothness. I have known even a gathered speci-
men throw a seed nearly ten feet. Fig. 60 represents a
capsule after the seeds have been ejected. The pollen
is dry, smooth, white, and 44 long by 25 broad. The
hive bee is the most frequent visitor, but the flower
attracts several other species of bee, a few flies (Bom-
bylius), and butterflies.
V. hirta—The coloured flowers agree generally with
those of V. odorata, but have no scent. They are said
to be generally infertile. The cleistogamous flowers, on
the contrary, are very different (Fig. 62). They are
swollen, fleshy, pinkish, and nestle close to the ground.
It has been said, as for instance by Vaucher, that the
plants actually force these capsules into the ground,
and thus sow their own seeds. I have not, however,
found this to be the case, though, as the stalk elongates
and the point of the capsule turns downwards, if the
earth be loose and uneven, it will no doubt sometimes
so happen. When the seeds are fully ripe, the capsule
opens by three valves and allows them to escape. The
leaves of plants growing in shady woods tend to be
large, and in V. herta there is a shade-loving variety
with enlarged leaves, V. hirta var. macrophylla.
Now we naturally ask ourselves what is the reason
for this difference between the species of violets ; why
do V. odorata and V. hirta conceal their capsules
among the moss and leaves on the ground, while V.
canina and others raise theirs boldly above their heads,
and throw the seeds to seek their fortune in the world ?
If this arrangement be best for V. canina, why has
not V. odorata also adopted it? The reason is, |
believe, to be found in the different mode of growth
of these two species. V. canina is a plant with
an elongated stem, and it is easy, therefore, for the
capsule to raise itself above the grass and other low
herbage among which violets grow. V. odorata and
V. horta, on the contrary, have, in ordinary parlance,
100 BRITISH FLOWERING PLANTS CHAP.
no stem, and the leaves are radical, «.c. apparently
rising from the root, the stem being very short. Now,
under these circumstances, if the Sweet Violet attempted
to shoot its seeds, the capsules not being sufficiently
elevated, the seeds would merely strike against some
neighbouring leaf, and immediately fall to the ground.
Hence, I think, we see that the arrangement of the
Fic. 62.—Viola hirta. a, flower-bud ; 6, full-sized capsule.
capsule in each species is that most suitable to the
general habit of the plant.
The species is somewhat variable. Mr. Britton! found
that “among 1000 flowers gathered indiscriminately by
the sides of, and adjacent to, the ancient highway known
as Ermyn Street, between Epsom Downs and Leather-
head Downs, 305, or more than 30 per cent, were
abnormal, The variations ranged from slight diver-
1 Journal of Botany, 1904, p. 141,
II VIOLACE 101
gences in appearance to important modifications in
structure. Taking these latter first, 222 flowers showed,
in addition to the ordinary spur, saccate protuberances
at the base of the petals, suggesting incipient spurs, and
65 flowers two, three, or four spurs each. Of these 65,
3 possessed four spurs, 18 three spurs, and 44 two spurs
each. Two of the flowers with four petalline spurs
showed traces of a fifth rudimentary spur.” Elsewhere,
however, he found the proportion of abnormal flowers
much smaller.
“On the other hand, in V. sylvestris, out of 1000
flowers gathered at the beginning of May 1900, in the
wooded country about Farley and Chelsham, where the
plant is very distinct in appearance, only 4 flowers were
normal, the remaining 996 were distinguished by
the appearance at the bases of the petals of the slight
protuberances which suggest to my mind incipient spurs.
In the case of two flowers an auxiliary spur had been
developed from one of these sacs.” Again, in V. Revini-
ana, the “ examination of 1000 flowers gathered between
Bookham and West Humble showed that as many as 890
were marked by the formation of distinct sacs at the base
of the petals (in addition to the usual spur). Thirteen
of the remainder possessed the common feature that
some or all the petals were lobed in a varying degree.”
Mr. Britton suggests that the tendency to frequent
variation in the larger flowers may be due to the fact
that they seldom produce seed, and consequently that
the tendency to variation is not suppressed by cross-
fertilisation.
V. odorata.— The flowers are small, dark, and often
more or less concealed by the leaves, but, on the
other hand, make their presence known by their sweet
scent. According to MacLeod’ the concavity of the
pistil secretes a fluid which moistens the proboscis of
the insect, and thus causes the pollen to stick to it.
Sprengel, in his description of V. odorata, gives the
following list of questions and answers as regards this
1 Bot. Jaarb. vi.
102 BRITISH FLOWERING PLANTS CHAP.
species, passing over, however, the more general points,
such as the secretion of honey, the colour of the corolla,
the radiating lines on the petals, and the smell.
1. Why is the flower situated on a long stalk, which
is upright, but curved downwards at the free end ?—
In order that it may hang down ; which, firstly, prevents
rain from obtaining access to the honey ; and, secondly,
places the stamens in such a position that the pollen
falls into the open space between the pistil and the free
ends of the stamens. If the flowers were upright the
pollen would fall into the space between the base of the
stamen and the base of the pistil, and would not come
in contact with the bee.
2. Why does the pollen differ from that of most
other insect-fertilised flowers ?—In most of such flowers
the insects themselves remove the pollen from the
anthers; and it is therefore important that the pollen
should not easily be detached and carried away by the
wind. In the present case, on the contrary, it is desir-
able that it should be looser and drier, so that it may
easily fall into the space between the stamens and the
pistil. If it remained attached to the anther it would
not be touched by the bee, and the flower would remain
unfertilised.
3. Why is the base of the style so thin ?—In order
that the bee may be more easily able to bend the style.
4, Why is the base of the style bent?—For the
same reason. The result of the curvature is that the
pistil is much more easily bent than would be the case
if the style were straight.
5. Finally, why does the membranous termination
of the upper filament overlap the corresponding portions
of the two middle stamens ?—Because this enables the
bee to move the pistil, and thereby to set free the pollen
more easily than would be the case under the reverse
arrangement,
V. tricolor (Pansy).— This is a very variable
species. The stipules are large, leaf-like, and divided
into several more or less narrow lobes. Bentham and
II FRANKENIACKEAUA—CARYOPHYLLACE 1038
Hooker recognise three well-marked varieties: (1) V.
arvensis; annual, with small flowers; leaves narrow ;
a common weed of cultivation. (2) Garden Pansy ;
much larger, often biennial, or even perennial, and with
broader leaves; it easily degenerates, they say, into
V. arvensis. (8) V. lutea; generally perennial ; flowers
large, often yellow. A plant of mountain pastures. It
is annual with us, like so many other weeds of cultivation,
but becomes perennial in Alpine districts (see Cardamine
hirsuta, p. 79).
The Pansies do not produce cleistogamous flowers.
The form of the pistil is peculiar, but no reason has, so
far as I know, been suggested for the difference. In the
absence of insect visits the flowers of No. 2 last two to
three weeks, but set no seed, or very little. V. arvensis,
on the contrary, is self-fertile. The pollen grains are
in the form of four- or five-sided prisms. The seeds are
pale brown, crustaceous, obovoid, shining, and with a
pale corrugated arilloid at the base.
o
FRANKENTACEZ
Of this order we have only one species, Frankenia
levis. The sepals form a tubular calyx with four or
five teeth. The petals also number 4 or 5, with long
claws and spreading laminz. The seeds are very small,
with a straight embryo surrounded by albumen. It
occurs only on our south-east coasts from Yarmouth to
Kent.
CARYOPHYLLACEA
This order may be divided into two groups—(1)
Sileneze, in which the sepals are united into a tubular
or campanulate calyx; and (2) Alsinez, in which they
104 BRITISH FLOWERING PLANTS CHAP.
are free, or slightly connected at the base. The petals
are distinct, but held together by the sepals so as to
form a tube. The flowers generally secrete honey, or a
sweet sap, for which insects bore into the tissues. Most
of the group are fertilised by insects, but Silene Otites
is a wind-flower. In many species besides the herma-
phrodite, there are female flowers. Some are dicecious.
The hermaphrodite flowers are generally the largest,
and then the male, while the female are the smallest.
The stamens are normally 10, often, however, reduced
to 5. They are in two series, and the most usual
sequence is that the five outer anthers ripen first, then
the inner series, and then the styles. This we should
expect from the development of the plant, as the outer
are of course the earlier series. In some cases, however,
the styles are ripe before the anthers. In many cases
the flowers close at night and in bad weather. Some
have cleistogamous as well as normal flowers. Others
are night flowers. The ovary in most cases forms a
capsule which eventually opens generally by five or ten
teeth, and the plant, swaying with the wind, ejects the
seeds. The dehiscence is due to the fact that the outer
cells contract more than the inner layers.
Di1antTuus
The fruit. is a capsule, ovoid, and with many seeds.
It opens at the summit by four teeth or short valves,
and the seeds are jerked out by the wind.
D. prolifer.—The flowers are small, pink, in compact
heads, gynodicecious and gynomoneecious; the herma-
phrodite flowers are homogamous. The flowers, being
small, and the honey sparing, are but little visited by
insects, but as the anthers and stigma ripen simul-
taneously, they easily fertilise themselves. According
to Kerner they live two days, and are open from 8 a.M.
to lpm. The seeds are black or dark brown, smooth
on the concave ventral face, and with obtuse, elevated
points on the convex portion.
D. deltoides.—Flowers solitary or two together, on
u CARYOPHYLLACEX: 105
short peduncles, small, scentless, pink, or spotted with
white ; sometimes white. The stamens! are united with
the petals at the base, and form a yellow, fleshy swelling
which secretes honey. The tube of the flower is so
narrow, and so nearly closed by the stamens and _pistil,
that the proboscis of Lepidoptera alone can reach the
honey, though flies and other insects visit it for the
pollen. The upper surface of the flower forms a flat
disk. The stamens are ten in number. Soon after the
flower opens five of them emerge from the tube, ripen,
and the anthers open. When they have shed their
pollen the other five do the same. During this period
the pistil is concealed in the tube; but after the anthers
have ripened and shed most of their pollen, it also
emerges, and the two long stigmas expand. Under
these circumstances the butterflies can hardly fail to
carry the pollen from the anthers of young flowers to
the stigmas of older ones. Flies also visit this species
to feed on the pollen, and though they cannot obtain
any nourishment from flowers in the later condition,
still they sometimes come to them, apparently by mis-
take, and must therefore occasionally fertilise them.
This species appears to have lost the power of self-
fertilisation.
D. Armeria and D. cesius are also protandrous. In
D. cesius (Cheddar Pink), which is very sweet, some
plants produce female flowers. This species is found in
Great Britain only on limestone rocks at Cheddar in
Somerset.
LYcHNIS
L. Githago (Corn Cockle),—The capsule opens by
five or ten teeth or short valves at the top. The flower
is generally protandrous, but in some districts homo-
gamous. The calyx has long green linear lobes which
project beyond the petals. The purple petals have long
claws, and are held together by the calyx. The lamina
bears no scale. Honey is secreted at the base of the
1 Avebury (Lubbock), British Wild Flowers, p. 65.
106 BRITISH FLOWERING PLANTS CHAP.
tube, which by its length and narrowness is adapted to
butterflies. Besides the usual Howers, there are other
smaller ones which contain no stamens. It is fertilised
by butterflies and moths. It is a weed of cultivation,
and, like so many other plants with a similar habit, is
annual. Our other species of Lychnis are all perennial
or biennial. The seeds are large, black, cuneate reni-
form in shape, with elevated points in lines following
the curvature of the seed.
L. Flos-cuculi (Ragged Robin).—The stems are slightly
downy below, and viscid above, probably to keep ants
from the flowers. The petals are cut into four linear
lobes. Why? The calyx is 6-7 mm. long; it has
teeth some 3 mm. in length, and keeps the corolla
together. Honey is secreted by the bases of the
stamens. The plant is protandrous, and the five outer
anthers ripen first.
L. Viscaria.—In general arrangements L. Viscaria
resembles the preceding species. It is glabrous, but
each segment of the stem is very sticky in the upper
part, which prevents creeping insects from obtaining
access to the flowers. The length of the tube and
narrowness of the passage render the Hower especially
adapted for butterflies.
L. vespertina.—This species is also viscid, but only
slightly so. The flower, which is white, opens in the
evening, generally about six o’clock, when also it becomes
very sweet. It closes about nine in the morning, be-
coming limp and faded, and looking almost dead, till
the following evening, though in dark gloomy weather
it sometimes remains open all day. The pale colour is
probably an advantage, as being the most visible in
twilight. These characteristics—white or light yellow
colour, and sweetness at night—are characteristic of other
species which are specially adapted for fertilisation by
moths. The honey is secreted by the base of the ovary.
There are three forms of flower—male, female, and
hermaphrodite. In the female the tube has a length of
20-25 mm.; in the male, 15-18 mm. The length of the
"I CARYOPHYLLACEZ 107
stamens and pistil also varies. Some plants are hairy,
some quite glabrous, and there appear to be in this
country * no intermediate forms.
L. diurna.—This species in many respects resembles
L. vespertina, and the two have by many botanists been
regarded as varieties. They are no doubt descended
from a common ancestor, but while LZ. vespertina has
gradually adapted itself to moths, opening at night and
closing by day, LZ. diwrna, on the contrary, is a bee
flower, opening by day and closing by night. It seems
probable that the common ancestor was red, which,
however, is not a suitable colour for night flowers.
Bees, as a rule, have a shorter proboscis than moths,
which may perhaps account for the fact that the tube
of the flower in ZL. diurna (12-15 mm.) is somewhat
shorter than that of L. vespertina. The seeds are black
or deep brown, large, and covered with points in parallel
longitudinal rows.
SILENE
This genus differs from Lychnis in having three
styles, and the capsules open with six teeth.
8. inflata.—Glaucous green, usually glabrous plants.
The flowers are protandrous, with white petals; they
are adapted to butterflies and humble bees. In
this interesting plant there are, according to Axell,”
three forms—those with both stamens and _pistils,
those with stamens only, and those with pistils
only; in the latter the flowers are smaller than in
the other two forms. Schulz has pointed out in
addition that some are gynomoncecious, and some
are andromoneecious. The tube of the flower is 10-12
mm. in depth, and wide enough to admit the pro-
boscis of a humble bee. Another remarkable point
about S. inflata is that while in most of the allied
species the calyx closely surrounds and thus supports
the petals, in this it is, as the name denotes, inflated so
? Bateson and Sammars; Roy. Soc. Report to Evolution Committee, 1902.
2 Om Anordn for Fan. Vart. Befruktn. p. 46.
108 BRITISH FLOWERING PLANTS CHAP,
as only to touch them at the base and summit. An
eminent French entomologist, M. Fabre, has pointed out
that while bees eat their way through the tough cocoon,
if this is enclosed in paper—even tissue-paper—-they
perish, not thinking of eating through a second, even
much thinner, obstacle. It has already been mentioned
more than once (see p. 64) that bees often rob tubular
flowers of their honey by eating through the base of the’
tube, and it has occurred to me that the inflation of the
calyx thus tends to protect the honey. I say tends,
because the device is not in all cases successful. The
legitimate visitors are butterflies, moths, and the humble
bees with long probosces. Kerner doubts whether
inflated calyces are in all cases intended to protect the
honey, because the proboscis of the average humble bee
is at least 8 mm. in length, and the distance between the
calyx and corolla is generally less. But his reasoning is,
I think, fallacious. In the first place, inside the calyx is
the corolla, and this the mandible could not reach.
With us the plant is generally glaucous, and throws
off moisture, except in the angles between the leaves,
where rain collects, and is no doubt absorbed. There is,
however, a variety—puberula—with short curly hairs,
and in the hot dry climate of the south the plant
develops a thick covering of hair, probably as a pro-
tection against too rapid transpiration.
8. nutans (Nottingham Catchfly).—This is also a
protandrous, nocturnal moth-flower. The life of the
flower lasts three days, or rather three nights. The
stamens are ten in number, arranged in two sets, the
one set standing in front of the sepals, the other in
front of the petals. Like other night flowers, it is
white, and opens towards evening, when it also becomes
extremely fragrant. The first evening, towards dusk,
the five stamens in front of the sepals grow very rapidly
for about two hours, so that they emerge from the
flower; the pollen ripens, and is exposed by the burst-
ing of the anther. So the flower remains through the
night, very attractive to, and much visited by, moths.
1 CARYOPHYLLACEX 109
Towards three in the morning the scent ceases, the
anthers begin to shrivel up or drop off, the filaments
turn themselves outwards, so as to be out of the
way, while the petals, on the contrary, begin to roll
themselves up, so that by daylight they close the
aperture of the flower, and present only their brownish-
green under sides to view, which, moreover, are thrown
into numerous wrinkles. Thus, by the morning’s light,
the flower has all the appearance of being faded. It
has no smell, and the honey is covered over by the
petals. So it remains all day. Towards evening, how-
ever, everything is changed. The petals unfold them-
selves; by eight o’clock the flower is as fragrant as
before, the second set of stamens have rapidly grown,
their anthers are open, and the pollen again exposed.
By morning the flower is again “ asleep,” the anthers
are shrivelled, the scent has ceased, and the petals rolled
up as before. The third evening, again the same process
occurs, but this time it is the pistil which grows : the long
spiral stigmas on the third evening take the position
which on the previous two had been occupied by the
anthers, and can hardly fail to be dusted by moths with
pollen brought from another flower.’ Schulz questions
this description, which, however, tallies with my own
observations ; but it is possible that the flowers behave
somewhat differently in different localities. They are
sometimes visited by insects during the day. The
name “‘Catchfly”” has been given it because the upper
part of the stem is viscid and small flies are often
glued to it. The object, no doubt, is to prevent ants
and other creeping insects from robbing the flowers of
their honey. After flowering the ovary is at first
pendent, but by the time the seeds are ripe has become
upright, so that they do not drop out of themselves,
but are pushed out and scattered when there is any
wind. After fertilisation the plant ceases to be viscid.
S. noctiflora is also a night flower, opening about six
in the evening, and is probably fertilised by moths.
1 Avebury (Lubbock), Fruits, Flowers, and Leaves, p. 40.
110 BRITISH FLOWERING PLANTS CHAP,
S. acaulis is tricecious. It is richly visited by
insects.
S. Otites, on the contrary, is said to be generally
wind-fertilised. The flowers are yellowish green, small,
and numerous. They are dicecious, the male flowers
being the more numerous. Hermaphrodite flowers also
sometimes occur. In the north Frisian island Rém, and
in the Tyrol, both kinds of flowers secrete honey and are
visited by insects. In mid-Germany, according to
Schulz, the nectaries of the male flowers secrete no
honey, and though the female flowers still produce
some, yet from the close adherence of the calyx and
corolla it is not accessible to insects in the normal way.
SAPONARIA
While Lychnis has 5, or rarely 4, and Silene 3 styles,
in Saponaria there are only 2.
8. officinalis (Soapwort) is a protandrous moth-flower.
The calyx forms a tube 18-21 mm. in length. The
pink, or white, petals are obcordate, and abruptly con-
tracted into a long narrow claw. The five outer stamens
ripen first, and open their anthers just over the flower.
When they have shed their pollen they shrivel up and
make way for the inner five stamens. When these, in
their turn, are exhausted, the two stigmas elongate and
take up the same position. The honey is in the base
of the long tube, and only accessible to hawkmoths and
some moths. The hawkmoths Sphinx ligustrz, S. con-
volvulr, and Macroglossa stellatarum (the Humming-
bird hawkmoth) appear to be the most frequent visitors.
The flowers are very sweet at night; in the day their
scent is faint. The plant is protected by a poisonous
ingredient in the sap.
ALSINEE
In the second division of the Caryophyllacez the
sepals are separate, or but slightly connected at the
base. The petals therefore can separate, and the honey,
which is generally secreted at the base of the stamens,
II CARYOPHYLLACEAE 111
being thus rendered more accessible, the flowers, though
generally small, are much visited by insects, especially flies
and the smaller species of bees. The normal number of
stamens is 10, but there are often fewer. Generally it is
the inner circle, or some of them, which have disappeared ;
but in some cases not only the inner circle but some
even of the outer have disappeared; Stellavia media
(Chickweed), for instance, has generally only 3 instead
of 5. The disappearance is sometimes complete, but
sometimes rudiments, more or less developed, still remain.
The pistil, however, is always present. In some cases
the complete and female flowers are on the same, some-
times on different, plants. As usual, the female flowers
are smaller than those which possess stamens. As in the
preceding subfamily, the anthers of the outer stamens
generally open before those of the inner circle. The
pistil generally ripens after the anthers. Most of the
species secrete honey at the base of the petals. The
flowers have a tendency to close in wet and gloomy
weather, and present many gradations towards cleisto-
gamy. Stellaria media, var. pallida, has in some
neighbourhoods become completely cleistogamous.
ARENABIA
A. serpyllifolia.—Bentham and Hooker describe this
species as an annual, and so, no doubt, in Britain it is;
but on the summit of the Pyrenees it is said to live
for several years.
SAGINA
The flowers are small and solitary. The petals are
sometimes absent.
S. procumbens has 4, rarely 5, sepals and petals,
with a corresponding number of stamens. The stamens
have nectaries at the base. The flowers are often, per-
haps generally, self-fertilised. They are visited by
Collembola, ants, and other small insects. :
S. Linnezi, on the contrary, is slightly protogynous.
It is larger than the preceding species. The petals,
112 BRITISH FLOWERING PLANTS CHAP.
sepals, styles, and valves of the capsule are 5, the
stamens 10,in number. The plant is perennial. The
flowers are visited by flies and small beetles, but in bad
weather they remain closed and fertilise themselves ; as
also do those of
S. nodosa, which resembles the preceding, though the
leaves are shorter and the petals longer in proportion.
It forms small perennial tufts. In some of the flowers
the stamens are more or less suppressed. The complete
flowers are protandrous.
STELLARIA
In most of the species of this genus petals are
sometimes wanting.
S. graminea.—The stems are quadrangular and
straggling. The petals are narrow and deeply cleft.
The nectaries are 5, at the base of the 5 outer
stamens. The flowers are protandrous. The five outer
stamens just raise themselves over the opening of the
flowers, and the anthers open. After a while they
bend outwards and downwards, and the inner circle
take their place. These then go through the same
movements, while the styles elongate, raise themselves,
and in their turn eventually curl outwards and down-
wards. The result is that insects visiting the flower for
the sake of the honey can hardly fail to dust themselves
with the pollen of flowers in the first two stages and
transfer it to the styles of older flowers. In the absence,
however, of insect visits, the styles can hardly fail to come
in contact with one or other of the anthers, and thus
the flower fertilises itself. Besides these complete flowers
there are others in which the stamens, or some of them,
are more or less incompletely developed. The flowers
differ considerably in size in different districts. They
are visited by bees, butterflies, moths, beetles, and flies.
S. Holostea (Stitchwort).—This species is larger and
stronger than the preceding. The structure and life-
history of the flower is similar. The nectaries are
yellow. The stems are quadrangular.
II CARYOPHYLLACEA: 113
8. media (Chickweed).—Some of the stamens are
generally more or less suppressed, being thus reduced
from 10 to 8, 6, or even 2 The violet anthers
ripen about the same time as the stigmas. If not
already visited by insects, the flower is almost sure to
fertilise itself when it closes. According to Celakovsky,
the variety Boreana is cleistogamous. Bateson has
made some experiments with seeds from cross-fertilised
and self-fertilised flowers. The former were found to
be more vigorous in the proportion of 100:91. A
remarkable peculiarity of the Chickweed is, that while
the rest of the plant is glabrous, there is a line of com-
paratively large hairs running down the stem, and a few
long ones on the leaf-stalks. Bentham says of this line
of hairs that they “run down one side of the stem.”
This does not exactly express the case. The leaves are
opposite decussate, ze. each pair is opposite and at
right angles to the pairs immediately above and below.
The bases of the two leaves form a small cup. In many
cases a flower-stalk rises between the leaves. The line
of hairs is always on the side opposite the flower, and
changes its place, therefore, at each node. The stalks of
the leaves are somewhat hollowed above, and their edges
are fringed with long hairs. These and the hairy ridges of
the stem are easily wetted, and retain for some time the
rain that falls on the leaves. It is said to be absorbed
by the lower part of the hairs. It is probable that the
line of hairs serves to conduct the rain-water from each
cup to the one below.’ These hairs are full of sap, and
act quite differently from the dry hairs, by means of
which so many plants protect themselves against too
rapid transpiration.
Seeds of Stellaria media are among the most com-
mon in recent geological strata. Mr. Clement Reid
cites it from various localities from preglacial to
neolithic times.
1 Lundstrom, Act. Nov. Upsal. 1884-85.
114 BRITISH FLOWERING PLANTS CHAP.
CERASTIUM
White flowers, with half-concealed honey.
C. arvense.—The general arrangements of the flower
agree in the main with those of Stellaria Holostea.
Besides the complete flowers, there are other smaller
ones with more or less rudimentary stamens.
C. vulgare—Bentham calls this a protean species,
and by other botanists it has been divided into several,
even as many as 20 to 30. In the facts of their life-
history they agree in the main with the preceding
species.
SPERGULA
In the preceding genera of the family the leaves have
no stipules. They are, as a rule, sessile, and broad at
the base, thus protecting the young bud. In Spergula
and Spergularia, however, the base of the leaves is
narrow, but provided with two stipules, which, with the
base of the leaf, serve the same purpose.
S. arvensis.—A cornfield weed. The stipules are
small and scarious. The stamens are normally 5, but
often fewer, and in some flowers absent. The flowers
remain closed in bad weather and fertilise themselves.
The seeds often have a wide, scarious border.
SPERGULARIA
8. rubra.—The stipules are much larger; the
arrangement of the flower resembles that of the pre-
ceding species. The seeds also are often bordered,
especially in the variety marina. The plant is found
on sand and gravel in waste places, especially near the
sea. The stipules develop early; they are connate at the
base, scarious, persistent, and inserted just beneath the
leaves, completely enclosing them in bud, covering their
bases even when fully developed. This is a very unusual
arrangement.
II PORTULACE.E—HYPERICACEE 115
HoLostEUM
H. umbellatum.—The flowers are protandrous. The
stamens vary from 2 to 5—3 being the usual number.
Each has a green fleshy nectary at the base. The
flower is visited by flies and bees, but often fertilises
itself. The flowers are three to eight in number, forming
an umbel. They are on long pedicels, erect when flower-
ing, then turned down, but erect again when the seeds
are ripe.
POLYCARPON
P. tetraphyllum.—The flowers are very small, and
may almost be said to be cleistogamous, as indeed they
have been by Wiesner.’
PORTULACEX
Monta
M. fontana—The seeds are comparatively large,
black, and somewhat shining. The testa is covered with
relatively large tubercles, densely arranged in lines
following the curvature of the seed.
CLAYTONIA
C. perfoliata.—This species also has intensely black
orbicular seeds. It is a North American plant which
has become naturalised in Britain.
HYPERICACEA
Hypericum (St. John’s Wort)
This is the only British genus of the family. The
most characteristic feature is the large number of
1 Biologie der Pflanzen, 1889.
116 BRITISH FLOWERING PLANTS CHAP.
stamens, which are united in three or five bundles.
The flowers secrete no honey, but are much visited
for the sake of the pollen. Hence, perhaps, the ad-
vantage of producing so many stamens. They also
add considerably to the conspicuousness and beauty of
the flowers.
H. calycinum and H. Androsemum (Tutsan) are
undershrubs, with large oval leaves, often grown in
shrubberies. H. Androsemum is probably native;
HZ. calycinum has become naturalised in some of our
southern counties.
H. perforatum (Common Hypericum).—The stem is
generally round, but sometimes slightly angular. The
leaves have numerous pellucid dots, looking like per-
forations, and giving its name to the plant. There are
generally some black dots on the under side of the leaves,
and on the petals, but not on the pointed sepals. The
stamens are numerous and of different lengths; the
shortest ones ripen first, then those of intermediate
lenoths, and the longest last. These only are as long
as the pistil, and fertilise it if it has not already
received pollen from another flower. The capsule is
erect, and opens at the apex, so that the seeds are
scattered by the wind. The seeds are oblong, narrowed
at each end. They are dark brown, and strongly reticu-
lated in polygonal areole. The flowers are largely visited
by pollen-loving insects. H. Miiller mentions over forty
species, and some others have since been added to the list
by Loew, MacLeod, Willis, and others. Ido not find
any sug gestion as to the use of the pellucid dots. They
contain an aromatic oily liquid, and may perhaps serve
to prevent the plant from being eaten by browsing
quadrupeds or by insects.
H. dubium.—The stem is sometimes round, but
sometimes slightly quadrangular ; it is perhaps ina state
of transition. The leaves are nearly destitute of pellucid
dots, and the petals and stamens have fewer black dots.
The sepals are blunt.
H. quadrangulum.—In this species the stem is dis-
II LINACEE 117
tinctly quadrangular. The leaves have numerous pellucid
dots, and a few black ones. The sepals are pointed.
H. humifusum.—The stems are trailing. In bad
weather the flowers do not open, and may be described
as pseudo-cleistogamous.
H. pulchrum.— The stem is upright and slender; the
leaves broadly cordate, and clasping the stem. The
broad and obtuse sepals are fringed at the top with
black glandular teeth.
H. montanum.—The sepals are fringed with black
glandular teeth, and lanceolate. The leaves are ovate or
oblong, with or without pellucid dots.
H. hirsutum has downy stems. The leaves are hairy
underneath, with pellucid dots. The sepals are narrow,
with rather long glandular teeth.
H. Elodes.—This is a small creeping bog plant 6-8
inches long. Like many other species with a similar
habit, it is clothed with loose, woolly, whitish hairs,
which probably serve to protect the stomata from being
clogged with moisture. Each of the petals has at the
base a divided scale, which perhaps secretes honey, and
at the base of the stamen clusters are small divided
glands, which are pressed against the ovary and perhaps
also secrete honey.
LINACEA
Linum (Flax)
Homogamous flowers, with concealed honey. The
parts are in fives. Each of the five cells of the ovary is
divided into two by a nearly complete partition. The
seeds, as we know from the familiar linseed poultice,
secrete a mucilaginous, adhesive substance, which exudes
freely as soon as the seeds are moistened. This is use-
ful to the plant in glueing the seeds to the damp earth.
The flowers in many species are dimorphous, in some
even trimorphous. In some species they close up at
118 BRITISH FLOWERING PLANTS CHAP.
night and in wet weather. The capsules open by ten
longitudinal slits, the lignified part being thinner and
less compact along the lines of dehiscence.
L. catharticum.—The anthers and stigma are about
at the same height; but at first the stamens are curved
outwards. As, however, they gradually turn inwards,
and, moreover, as the flower closes at night if it rains, it
can easily fertilise itself. The stem is quadrangular; the
lower leaves are opposite, the upper alternate.
L, usitatissimum (Common Flax).—An annual, with
erect stem and alternate leaves. The sepals are pointed.
The flowers are much larger, and of a beautiful blue,
but in structure resemble those of the preceding species.
They are visited by butterflies and moths, humble bees,
and bees, as well as flies. The value of flax fibres for
thread is mainly due to the “bast” fibres, the cells of
which attain the unusual length of 20-40 mm. They
are, moreover, as strong as iron.
L. angustifolium.—Like the preceding, but sometimes
perennial ; decumbent in habit, and with smaller flowers.
L. perenne.—A perennial, with alternate leaves. The
sepals are obtuse, the petals large, but not so large as
in the Common Flax. The flowers are dimorphous, as
in the case of the Cowslip and Primrose; that is to
say, the anthers are in some flowers above the stigma,
while in others the stigma is above the anthers. The
two forms never occur on the same stock, and the
object is to ensure cross-fertilisation ; insects carrying
the pollen from the long-styled flowers to the short-
styled, and vice versa. Darwin,’ since confirmed by
Hildebrand, has shown that the long-styled form is
sterile, and the short-styled nearly sterile, to pollen of
its own form. In the long-styled forms the stigmas
first face inwards; but as the insect must insert its
proboscis outside the ring of broad filaments, it would
not touch the stigma. Subsequently, however, the
stigma turns itself round, and thus faces and touches
the proboscis.
1 Darwin, Forms of Flowers.
ret MALVACEE 119
RaDIOLA
This genus represented by R. millegrana, differs from
Linum in having the parts of the flower in fours, and
the sepals united to near the middle. It is a minute
annual, not native in Britain, but not infrequent as an
escape from cultivation.
MALVACEZ
Sepals and petals 5. Below the calyx are three or
five bracts forming an involucre. The stamens are
numerous, and the filaments are united in a tube round
the pistil. The flowers are protandrous.
Lavatera (Tree Mallow)
Involucre three-lobed. The carpels, 10 or more in
number, are arranged in a ring round a common axis ;
resembling a flat loaf. When ripe they split off singly,
and are remarkably like small brown or green cater-
pillars or centipedes. The effect of this may perhaps
be to induce birds to carry them about.
L. arborea.—Very local. Principally on the south
and west coasts and on the Bass Rock.
AttHa&A (Marsh Mallow)
Involucre six- to nine-lobed. The Hollyhock belongs
to this genus.
A. officinalis (Marsh Mallow) occurs south of the
Clyde in marshes near the sea.
Matya (Mallow)
M. sylvestris (Common Mallow, Fig. 63).—Honey is
secreted at the bases of the petals. When the flower
120 BRITISH FLOWERING PLANTS CHAP.
opens the anthers are arranged in a cone over the as
yet undeveloped stig-
mas. After they have
shed their pollen they
become limp and droop,
as in Fig. 68, 2. The
styles then elongate,
and take the position
previously occupied by
the stamens. The
flowers are much visited
by insects, and as the
Fic, 63.—1, Malva sylvestris ; 2, stamens (a) ‘ ‘
and stigmas (st) of same. styles are not ripe until
the anthers have shed
their pollen, the flower can hardly fertilise itself, which
under the circumstances is not necessary. Perhaps for
the same reason it does not matter that the honey is
not thoroughly protected. Knuth gives a list of over
Fic, 64.—1, Malva rotundifolia ; 2, stamens (a) and stigmas (st) of same.
fifty insect visitors recorded by H. Miiller, himself, and
other observers. The bees generally visit the flowers
for the sake of the honey, but one species, at any
rate, Chelostoma nigricorne, comes for the sake of the
pollen.
M. rotundifolia is homogamous, or nearly so. The
flowers are smaller, and the visits of insects less frequent.
1 MALVACE.® 121
The styles, however (Fig. 64, 2), twine themselves
among the stamens, so that the
flower can hardly fail to fertilise
itself.
M. moschata.— The leaves
are more divided, the flowers
large and crowded at the sum-
mits of the branches. The back
of the carpels is rounded and
hispid (Fig. 65).
The seedlings of Mallow are 1%. 85. Curpel of Halen
interesting. I have discussed
them and the cause which has determined the form of
the cotyledons in my work On Seedlings, vol. i. p. 40.
TILIACEH
A large tropical and semi-tropical order, represented
in Britain by a single species, the beautiful Lime tree.
Bentham and Hooker regard it as “truly wild in
Southern and Western England, and perhaps in Ireland.”
In spite, however, of these high authorities I doubt it.
Tru1a (Lime Tree or Linden)
The indigenous form of Northern Europe is the
small-leaved species T. parvifolia. The species we
generally plant, 7. platyphyllos, which has much
larger leaves, is probably of South European origin,
though it is considered by some authorities to be
truly wild in Herefordshire, Radnorshire, and the
West Riding. The flowers are very sweet - scented,
smelling strongly of honey. They are pendulous, and
so arranged as to lie under and be protected by the
broad leaves. The nectaries are at the base of the
calyx. The flowers are protandrous, and so richly
visited by insects that cross-fertilisation is well assured.
Nevertheless, though the visits of insects are so numerous
192 BRITISH FLOWERING PLANTS CHAP.
that the whole atmosphere round a flowering Lime is
filled by the “murmurs of innumerable bees,” the
species of insects visiting it are few, and Knuth only
records twenty. The peduncles are bordered or winged
half-way up by a long, narrow, leaf-like, persistent bract
(Fig. 66). When the fruits drop this catches the wind
and thus the seeds are dispersed. The flowers are incon-
spicuous. The strong scent is quite sufficient to attract
insects, and bright colours are therefore unnecessary. A
remarkable point about the scent of the Lime is that it
is said to be strongest about thirty yards from the tree,
as if the strength was brought out by some action of
the air as it gradually diffuses. A similar observation
has been made in the case of the Vine."
The expanding leaf-buds assume a drooping position,
so that the leaves look as if they were being poured out.
The advantage thus gained is that
radiation of heat is much less than
it would be if the leaves were to
assume at once their permanent posi-
tion. Darwin has shown that this
position really does tend to check the
effect of radiation. His experiments,
he says, ‘‘show that leaves com-
pelled to remain horizontal at night
suffered much more injury from frost
than those which were allowed to
assume their normal vertical position.”
The winter buds are described in
my Buds and Stipules. The foliage
leaves are stalked, broadly heart-
shaped or nearly orbicular, often
oblique, glabrous above, and more or
less downy underneath, especially in
tne Lae angles Gh the principal ae The
stipules are large and beautiful—a rich
crimson or even a bright ruby. On the under side of
the leaves at the base where the nerves diverge are more
' Step, Wayside and Woodland Trees.
Il MALVACE.E 123
or less triangular spaces, enclosed by the under side of the
leaf, the walls of the nerves, and a fringe of long hairs.
Attention to these was first called by Lundstrém,’
who regards them as abodes—‘ domatia”—for mites.
That they are not pathogenic, he proved by growing
seedlings and carefully keeping mites away. This was,
however, no easy matter, for the mites lay their eggs in
the fruit, in which indeed there is, he considers, a special
cavity prepared for the purpose. In this way the
mites develop pari passu with the young plant. During
the day the mites remain at home in the domatia, but
at night, and sometimes during dull days, they run
about all over the leaves, which,
however, they do not appear to
attack. He suggests—and the
theory, though not proved, is
probable—that the mites are
useful in eating the spores of
fungi, which might otherwise
grow on and injure the leaves.
M. Areschoug thinks he has ob-
served that when the mites are
numerous the leaves are specially
large and healthy. In certain
genera some species have domatia and others not; in
the former the leaves are generally smooth, and in the
latter protected by hairs. Similar domatia occur on
the leaves of many other forest trees, as the Oak, Elm,
Sycamore, Alder, Holly, ete.
The seedlings of the Lime (Fig. 68) are interesting *
and peculiar. The cotyledons are leafy, and palmately
five-lobed, somewhat like a hand. This form is very rare,
if not unique. The seeds are obovoid; the embryo is at
first straight, but ultimately follows the curvature of the
seed (Fig. 67). Ifthe leaf grew continuously in a hollow
form, it is obvious that it could not unfold without
rupturing itself. If any one will take a common tea-
Fic. 67.—Lime embryo.
1 Nova Acta Reg. Soc. Sci. Upsala, ser. 3. xiii. fase. 2 (1887).
2 See Avebury (Lubbock), On Seedlings, i. p. 282.
124 BRITISH FLOWERING PLANTS CHAP.
cup and try to place in it a sheet of paper, the paper
will, of course, be thrown into ridges. If these ridges
be removed and so much
left as will lie smoothly
inside the cup, it will
be found that the paper
has been cut into lobes
more or less resembling
those of the cotyledons
of Tilia. Or if, con-
versely, a piece of paper
be cut out into lobes
resembling those of the
cotyledons, it will be
found that the paper
will fit the concavity
of the cup. The case is
i almost like that of our
own hand, which can
= be opened and closed
; conveniently owing to
the division of the five
fingers. The Lime
flowers freely, but scarcely ever ripens its seeds in our
country. Niageli has calculated that a fine Lime tree
contzins 20,000,000,000,000 cells.
Fic, 68.—Seedling of Lime.
GERANIACEZ
GERANIUM
Our twelve British species of this beautiful genus,
while presenting considerable differences, agree in so
many respects that they may conveniently be considered
together. Five are perennial, generally with large
flowers ; seven are annual, with smaller flowers. They
are generally wayside plants or weeds of cultivation.
II GERANIACEZ 125
The large-flowered species are protandrous, the inner row
of stamens generally opening first. The flowers are
much visited by insects and dependent on them for
fertilisation. The species with smaller flowers are less
visited by insects and less dependent on them. Honey
is richly secreted by five nectaries, generally at the
outer side of the base of the inner stamens. It is
protected from rain and from creeping insects by a
number of fine hairs just above the base of the petals.
The presence of these hairs on
the petals of G. sylvaticum
started Sprengel on his clas-
sical study of flowers. He
argued that the great Creator
would have made nothing in
vain, and therefore that even
these tiny hairs must be of
some use.
In the large-flowered
species, as, for instance, in G.
pratense (Figs. 69, 70), all
the stamens open, shed their
pollen, and wither away before
the pistil comes to maturity.
The flower cannot therefore
fertilise itself, and depends
entirely on the visits of insects
for the transference of the pollen. In G. pyrenaicum,
where the flower is not quite so large, all the stamens
ripen before the stigma, but the interval is shorter, and the
stigma is mature before all the anthers have shed their
pollen. It is therefore not absolutely dependent on
insects. In G. molle, which has a still smaller flower,
five of the stamens come to maturity before the stigma,
but the last five ripen simultaneously with it. Lastly,
in G. pusillum, which is least of all, the stigma ripens
even before the stamens. Thus, then, we have a series
more or less dependent on insects, from G. pratense,
to which they are necessary, to G. pusillum, which is
Fic. 69.—Geranium pratense.
126 BRITISH FLOWERING PLANTS CHAP.
quite independent of them ; while the size of the corolla
increases with the dependence on insects. In those
species in which self-fertilisa-
tion is prevented by the circum-
stance that the stamens and
pistil do not come to maturity
at the same time, the stamens
generally ripen first.
G. pratense agrees in many
respects with G. sylvaticum
(Fig. 71), but the flowers in the
former are larger, and the pedi-
cels of the fruit spreading or
reflexed instead of erect. The
Fic. 70. — Geranium pratense plant 1s generally covered with
(young flower). Five of the glandular hairs. These species
are visited by certain butter-
flies, moths, flies, and beetles, as well as by bees; G.
phewm, on the contrary, almost exclusively by bees,
possibly, as Knuth has suggested, because the hanging
position of the flower is incon- ~, 3.9
venient for other insects. G. Oe ND bh Ry
dissectum, G. columbinum, and es yer
G. pusillum are protogynous. AVL had!
In the last species the five outer Qyi ZA
stamens rarely develop anthers. NI
I have discussed the relations of |
: ; aw
the Geraniums to insects at some- SIN
what greater length in my British NR
Wild Flowers considered in re- . guls \
lation toInsécts. G. Robertianum
does not possess the fringes of 4
hairs by which, as already men- ee
tioned, the honey is in G. sylva-
ticum protected against the access
of rain or creeping insects; on
the contrary, the petals are entirely glabrous. The
flowers, however, turn over and hang down in wet
weather. Moreover, the flower is less open than usual.
Fic. 71.—Geranium sylvaticum,
y
I GERANIACE 127
On the contrary, it forms a distinct tube, the entrance
to which is sutticiently protected against rain by the
stamens and pistil.
In G. sylvaticum, besides the usual complete flowers,
there are, according to Lindman, smaller ones in which
the stamens are more or less abortive ; while Schulz has,
in South Tyrol, found others in which the pistil is wanting.
These are of large size; but on the higher Scandinavian
mountains Eckstam has observed male flowers of small
size.
A popular name for the Geranium—Crane’s Bill—
refers to the long beak of the fruit, which is part
of the curious arrangement for the dispersal of the
seeds. In G. Robertianum (Herb Robert), for in-
stance, after the flower has faded, the central axis
eradually elongates (Fig. 72, c, d,e). The seeds, five
in number, are situated at the base of the column, each
being enclosed in a capsule, which terminates upwards
in a rod-like portion, which at first forms part’ of the
central axis, but gradually detaches itself. When the
seeds are ripe the ovary raises itself into an upright
position (Fig. 72, e); the outer layers of the rod-like
termination of the seed capsule come to be in a state of
reat tension, and eventually detach the rod with a
jerk, and thus throw the seed some little distance. Fig.
72, f, represents the central rod after the seeds have
been thrown. In some species, as, for instance, in
G. dissectum (Fig. 73), the capsule rod remains
attached to the central column, and the seed only is
ejected. It will be remembered that the capsule
opens on its inner side; hence if the carpel merely
bursts outwards the only effect will be that the
seed will be forced against the outer wall of the carpel
and not be ejected, because the opening is not on the
outer but on the inner side. This difficulty has been
overcome in different ways. In some species, as, for
instance, in G. dissectum, a short time before the
dehiscence, the seed-chamber places itself at right
angles to the pillar (Fig. 73, a). The edges then
128 BRITISH FLOWERING PLANTS CHAP.
separate, but they are provided with a fringe of hairs
just strong enough to retain the seed in its position, yet
sufficiently elastic to allow it to escape when the carpels
burst away, remaining attached, however, to the central
pillar by their upper ends aie 73,0), In the common
Fig. 72.—Herb Robert (Geranium Robertianum). u, bud; 6, flower; e¢, flower after
the petals have fallen; @, flower with seeds nearly vipe : e, flower with ripe
seeds ; f, flower after throwing seeds,
Herb Robert (Fig. 74) and some other species (G.
molle, pusillum, lucidum, pyrenaicum, etc.) the arrange-
ment is somewhat different. In the first place, the
whole carpel springs away (Fig. 74, b, c). The seed-
chamber (c) detaches itself from the rod of the
carpel (b), and when the seed is flung away remains
attached to the latter. Under these circumstances it is
pa
GERANIACEZ 129
unnecessary for the chamber to raise itself from the
central pillar, to
which, accordingly,
it remains close
until the moment
of disruption (Fig.
74, a). The seed-
chamber is, more-
over, held in place
by a short tongue,
which projects a
little way over its
base, while, on the
other hand, the
lower end of the
rod passes for a
short distance be-
tween the seed-
capsule and the
central pillar. The
seed-capsule has
also near its apex a
curious tuft of silky
hair (Fig. 74, ¢),
the use of which I
will not here stop
to discuss. As the
result of all this
complex mechan-
ism, the seeds, when
ripe, are flung to
a distance which is
surprising when we
consider how small
the spring is. In
their natural habi-
tat it is almost im-
possible to find the
Fic. 73.—G@eranium dissectum. a, just before throw-
ing seed ; 4, just after throwing seed ; c, the capsule
still attached to the rod ; d, the seed.
Fic. 74.—Geranium Robertianum. a, just before
throwing the seed ; 0, the rod thrown off; ¢, the
carpel and seed.
seeds when once thrown. I therefore brought some into
K
130 BRITISH FLOWERING PLANTS CHAP.
the house and placed them on my billiard-table. They
were thrown from one end completely beyond the other,
in some cases more than twenty feet. The mechanism by
which this is effected has been described by Leclere du
Sablon.’ He suggests that the fibres forming the rods
are thicker and therefore contract more on the outer side,
thus throwing the rods into a state of tension, so that
eventually they burst away.
In some Geraniums the seeds are reticulate, and in
others they are smooth. This seems to me to be con-
nected. with their relation to the carpel. This is shown
in the following table :—
G. sylvaticum
»y pratense
« rotundifolium
+ columbinum
» dissectum,
fore not detached, hairy, not reticulate.
| Seeds thrown and reticulate.
G. Robertianum
» lucidum
»» pheeum Carpels thrown, reticulate. Seeds smooth.
yy molle
»» pusillum
In Erodium, also, the seeds remain in the carpel, and
are practically smooth, the
reticulations, if present,
being very small.
In the seedlings the
Fie. 76.—Section through em-
bryo of Geranium, show-
ing the mode of folding
of the cotyledons.
two “halves”’ of each coty-
ledon are unequal. This
Fie. 75.—Seedling of Geranium is due to the manner in
i ac which the cotyledons are
folded. In the Cabbage and Mustard we have seen that
1 Ann. Sci. Nat. ser. 6, xviii. (1884).
II GERANIACEE 131
one cotyledon is folded inside the other ; in the Geranium
they are convolute, one half of each being folded inside
one half of the other—the inner halves being the smaller,
the outer the larger ones.
The species differ considerably as regards hairs. In
G. sanguineum and G. pheum they are long and
spreading. In G. sylvaticum, G. pratense, G. pyrenat-
cum, G. Robertianum, G. molle, and G. dissectum those
on the upper part of the stem are glandular, while in
G. sylvaticum the lower part is glabrous or with re-
flexed hairs. In G. pratense those below are appressed ;
in G. pyrenaicum, soft and short ; in G. molle, long, soft,
and spreading; and in G. Robertianum, few and soft.
(7, dissectum varies a good deal, but generally has long
reflexed hairs; while G. lucidum is glabrous or nearly
so. The leaves of G. sanguineum assume a vertical
position in bright sunlight.
The Geraniums of warm regions are generally
annuals or biennials. The comparatively few Alpine
species are, as usual, perennial.
ERODIUM
Of this genus we have three species: E. maritimum
has simple ovate leaves, while £. moschatum has the
leaves pinnate with ovate segments, and FE. cicutarium
pinnate with pinnatifid segments. Nectaries are present
as in Geranium. The five stamens facing the petals are
without anthers.
E. cicutarium—This species was well described by
Sprengel. There are two varieties of FE. cicutarium,
(a) genuinum and (b) pimpinellifolium. According to
Ludwig, in the usual form, FE. cicutariwm, var. genu-
unum, the flower is homogamous or slightly protogynous.
The anthers place themselves close to the stigmas, so
that self-fertilisation is almost certain. The flower opens
about 7 4.M., and by mid-day the petals have fallen. It is
perfectly fertile with its own pollen. On the other hand,
1 Avebury (Lubbock), On Seedlings, i. 298.
132 BRITISH FLOWERING PLANTS CHAP,
E. cicutarium, var. pimpinellifoliwm, is protandrous,
and fertilised by insects. The flowers are larger, and
the two upper petals shorter, broader, and deeper red
than the three lower ones, which, being elongated, form
a convenient alighting stage for insects. The upper
nectaries are larger and secrete more honey than the
lower ones. When the flower opens the pistil is -short
and undeveloped. First the upper and then the lower
anthers open on the side turned away from the pistil.
Gradually the filaments turn outwards, and on the
second day the pistil has elongated and the stigmas are
mature. The petals generally fall on the second day.
Finally, the stigmas curl over and often come in contact
with the anthers, so that in case of need the flower is
self-fertilised. It would appear, however, that the flower
differs somewhat according to localities. Besides the
complete flowers there are others without
anthers, sometimes on the same, some-
times on special stocks. These are
generally smaller. The flowers of LF.
moschatum are, according to Ludwig,
homogamous or weakly protogynous. LE.
maritumum, according to the same author,
is sometimes pseudo-cleistogamous.
The Erodiums have a beak like that.
of Geranium, but the action is different.
The carpels do not open, but contract
over the seeds, which thus remain
attached to the awn, which is twisted
and hairy, as shown in Fig. 77, which
represents a seed of EL. glaucophyllum.
Nigeli has shown that the cell-wall is
composed of parallel lamelle of alternate
\ degrees of density and refractive indices.
Fic. 77.—Awnea Lhe first series of lamelle are seen in
fruit of Zrodium transverse sections of elongated woody
glaucophyit@m. cells, as concentric shells, alternately
light and dark, traversing the surface of the cell, and
are in reality the edges of parallel lamelle of alternate
rt GERANIACEAE 133
densities. There are usually two systems of parallel
lamellz, and they may be inclined to the axis of the
cell at almost any angle. Very frequently the two
systems wind spirally round the axis in opposite
directions. Now, according to Hofmeister,! when the
tissue of the cell- wall expands during imbibition it
is chiefly due to the swelling of the less dense
strie ; and we have seen that these strie are spirally
arranged, therefore it is probable that the imbibition of
water will result in spiral tension; and spiral tension
will result in torsion—just as when a string is fastened
to one end of a rod, and is coiled spirally round it, and
the free end is pulled, the rod will tend to rotate on its
axis.” Francis Darwin found that individual cells rolled
themselves up. If this explanation be correct, it would
seem to follow that the rods of Geranium do not twist,
because the strie are transverse and not inclined.
Hildebrand, on the other hand, accounted for the action
of the awn by the difference between the contraction of
the woody fibres and that of the comparatively soft
parenchyma, while Leclerc du Sablon accounts for it by
the fact that the outer cells of the rod are more com-
pletely lignified, and therefore contract more than the
inner ones. The spiral winding he explains by-the
fact that the woody bands are curved with the con-
cavity outwards. In Geranium, when the rods are not
spiral, the bands are not curved.
The amount of the spiral twisting in the awn
depends upon the degree of moistness ; and the seed may
thus be made into a very delicate hygrometer, for if it be
fixed in an upright position the awn twists or untwists
according to the degree of moisture, and its extremity
thus may be so arranged as to move like a needle on
a register. It is also affected by heat. Now if the
awn were fixed instead of the seed, it is obvious that,
during the process of untwisting, the seed itself would
1 Lehre v. d. Pfhlanzenzelle (1867).
2 Francis Darwin, ‘‘On the Mechanism by which certain Seeds bury them-
selves in the Ground,” Zrans. Linn. Soe. ser. 2, Bot. i..
134 BRITISH FLOWERING PLANTS CHAP.
be pressed downwards, and, as M. Roux has shown, this
mechanism thus serves actually to bury the seed. His
observations were made on an allied species, Hrodiwm
ciconium, which he chose on account of its size. He
found that if a seed of this plant is laid on the ground
it remains quiet as long as it is dry, but as soon as it is
moistened—z.e. as soon as the earth becomes in a con-
dition to permit growth—the outer side of the awn
contracts, and the hairs surrounding the seed commence
to move outwards, the result of which is gradually to
raise the seed into an upright position with its point
on the soil. The awn then begins to unroll and con-
sequently to elongate upwards, and he suggests that, as
it 1s covered with reversed hairs, it will probably press
against some blade of grass or other obstacle, which will
prevent its moving up, and will therefore tend to drive
the seed into the ground. If, then, the air becomes
drier the awn will again roll up, in which action M.
Roux thought it would tend to draw up the seed; but
from the position of the hairs the feathery awn can
easily slip downwards, and would therefore not affect
the seed. When moistened once more it would again
force the seed further downwards, and so on until the
proper depth was obtained.
LE. cicutarium is sometimes nearly glabrous, some-
times has glandular hairs; and in E. moschatum glan-
dular hairs are always present, giving the plant a strong
odour of musk, whence it derives its specific name. In
E. maritimum the hairs are soft and often glandular.
OXALIS
Of this genus we have two species—O. Acetosella
with white, O. corneculata with yellow flowers. Some
of the foreign species are trimorphic (see Primrose and
Lythrum), some dimorphic, others, including the two
British, monomorphic.
O. Acetosella (Wood-sorrel).—This is one of the plants
regarded as the Shamrock. The leaves have a pleasant
IL GERANIACEX 135
acid flavour. They are very delicate, and adapt them-
selves to differences of light in four ways—by movements
of the whole leaf, by change of angle, by movements
of the chlorophyll within the leaf, and by changes in the
form of the chlorophyll grain. In strong sunshine the
leaflets close slightly and move downwards (Fig. 78),
so that the rays fall on them less directly ; and also at
night, serving as a protec-
tion against cold. Dar-
win’s experiments clearly
showed that leaves which
were compelled to remain
horizontal at night suffered
more from frost than those . b
which were allowed to Fre. 78.—Ovalis Acetusella. a, Leaf seen
assume a vertical position.? neta ern day. 6, Leaf seen from
The motile organs are
the very short stalks which connect the leaflets with
the common leaf-stalk. Fig. 79 represents a trans-
verse section in O.ralis carnea. Beneath the skin or
epidermis is a: mass of parenchyma surrounding an axial
strand, containing the vascular tissue enclosed in a
sheath. Fig. 80 gives a longitudinal section. The par-
enchyma presents no important differences. If the
lower part swells and the upper contracts, as in Fig. 78,
the leaflet rises; if the reverse, it sinks. The change is
rendered possible by the extrusion or absorption of water.
It is remarkable that if the leaves are covered up at
night so that they receive no light they will still open
in the. morning.” The movements are mainly due to
the chemical rays. If the yellow, orange, and red rays
are excluded, the plant reacts as if in white light; on
the contrary, if the violet and blue rays are shut out,
and the red end of the spectrum only allowed to “pass
through, the plant behaves as if in darkness.
Under normal conditions the cell represents a turgid
bladder; the watery cell-sap being imprisoned by the
1 Movements of Plants.
2 Sachs, Lectures on Physiology of Plants.
136 BRITISH FLOWERING PLANTS cHar.
elastic cell-wall and its lining of living protoplasm.
Such an escape of water as is responsible for the move-
ment is rendered possible only by this property of the
protoplasmic lining undergoing some change, or, in
other words, by the hitherto non-permeable protoplasm
becoming permeable in consequence of the stimulus,
and thus letting water escape. It must at the same
Fic. 79.—Transverse section of the motile organ of a leaflet of Oxalis carnea. G,
axial vascular strand; 0, epidermis; ep, parenchyma; ch, inner layers of
parenchyma ; s, sheath of vascular strand.
time be added that we can at present form no idea why
this change in the protoplasm occurs in consequence of
a stimulus, or with what molecular changes it is con-
nected ; all we know at present is that the externally
perceptible effects of stimulation so far as described
are caused by the change referred to in the protoplasm
itself.
The movements of the chlorophyll grains within
the cells were first noticed by Bohm. They have
been well described by Stahl. The central tissue of
0 GERANIACE 137
the leaves of O. Acetosella consists of three layers.
The upper one consists of more or less blunt cones,
the two lower ones of star-shaped cells, leaving large
intercellular spaces between them. Some healthy leaves
were laid flat on a plate and exposed to the rays of
the sun falling perpendicularly on them. By pouring
——_
AE ES 3
SAYER SU
SN
i = Gea
SScox 7]
OS
OS
ST
ELTA NS
SES = =
—S SSN
——————
\ Ey
as)
Q
a
Fic. 80.—Longitudinal section of leaf-stalk and motile organ, 006, of one of the
leaflets of Oxalis carnea in the day position. yp, epidermis of leaf-stalk; ff,
midrib of leaflet ; GG, vascular bundles ; m, pith of leaf-stalk.
fresh water over them the leaves were prevented from
becoming too warm. Other leaflets were protected
from the direct rays of the sun by means of paper
shades. After an hour the marked leaflets were placed
in alcohol in order to fix the cell-contents in their
natural position. The decolorised leaflets were so
transparent that mere observation with transmitted
light was sufficient to demonstrate the different dis-
138 BRITISH FLOWERING PLANTS CHAP.
tribution of the chlorophyll corpuscles in the shaded
leaflets and those exposed to the sun. In diffused
daylight the chlorophyll grains arrange themselves so
as to receive the largest amount of light (Fig. 81, a);
if the sunshine becomes stronger they collect on the
cell-walls parallel to the rays, so as to receive less
(Fig. 81, 6) and if it continues they finally collect
in lumps at the ends of the cells (Fig. 81, c).’ This
wonderful power of adaptation only exists in certain
species.
The flowers are homogamous. They bend over
(
(i)
0
@ %aC\eo
iy
ms b
0
Fic, 81.—Arrangement of the chlorophyll grains from the lower parenchymal layer
of Owalis Acetosella: uw, in diffuse light; 6, in sunlight ; c, in long-continued
sunlight.
in wet weather. The nectaries are five fleshy pro-
jections at the bases of the petals, but the Howers
are not much visited by insects. They are open,
according to Kerner, from 9 a.M. to 6 P.M. The plant
also produces cleistogamous flowers, first observed by
Michelet.” The style varies considerably in length,
showing perhaps a tendency to dimorphism. As so
often happens with cleistogamous flowers, they bury their
seeds in the ground.
When the flower fades the peduncle turns down-
wards, and the flower’s head conceals itself among the
leaves. When the seeds are ripe it straightens again,
and then lifts the capsule well above the leaves.
. ' Fora similar case see Lemna; for one in which the form of the grains
changes see Potamogeton ; for a change in the structure of the leaf see the
Dandelion and Fagus (the Beech).
2 Darwin, Forms of Flowers.
It GERANIACE 1389
The species is also interesting as one of those in
which the plant throws its seeds to a considerable
distance ; or rather the seeds throw themselves—a unique
case in our English flora. The capsule is five-chambered,
and contains two shining black seeds in each cell;
the seeds are attached to the central pillar. The walls
of the capsule opposite the middle of each chamber
are very thin. The outer coat of each seed is a trans-
parent covering, within which is a smooth, hard black
testa. The outer coat contains four to five layers of
parenchymatous cells. The cells of the inner layer are
smaller than those of the outer, closely compressed, and
gradually become very turgescent. This is not the case
with the outer layer. Finally, the coat splits down one
side, the inner cells expand at once, thus turning the
coat inside out, the inner and now larger layer coming
to the outside, while the originally outer layer is turned
inwards. The result of this is that the seed is jerked
out to a considerable distance. Owing to the elevation
of the capsule the seeds fly clear of the leaves.
In the arrangement of the flower O. corniculata does
not materially differ from O. Acetosella. The pod is
more elongated.
Impatiens (Balsam)
Of this genus three species now occur wild in Britain :
I. Noli-me-tangere (Touch-me-not), a rare species with
yellow flowers, found in damp woody places in moun-
tainous districts; and two others—J. fulva, an American
species, with orange flowers, and I. parviflora, a Russian
species, with very small yellow flowers, which have
become naturalised in various places. The flower is
very peculiar, and is thus admirably described by Ben-
tham. The sepals and petals are “all coloured, and
consist usually of 6 pieces, viz. 2 outer, opposite
(sepals), flat, and oblique; the next (upper sepal,
although by the twisting of the pedicel it hangs lowest)
large, hood-shaped, ending below in a conical spur; the
fourth (lower petal, but uppermost from the twisting of
140 BRITISH FLOWERING PLANTS CHAP...
the pedicel) much smaller, but yet very broad and some-
what concave; the 2 innermost (petals) very oblique
and irregularly shaped, more or less divided into two
unequal lobes.” ?
The flower-buds are at first above the leaves, which
are folded and stand up round them like a screen. As
the buds open the flower-stalk grows longer and turns
down under the leaf from the axil of which it springs.
The leaf flattens itself and fixes the flower-stalk in
position by one of the lobes of its heart-shaped base.
When expanded, the flower hangs horizontally under
its leaf, from which the rain rolls off as from a roof.
“
Fig. 82.—Flower of /mpatiens Roylei. (The Balsam common in gardens, often self-
sown.) A, Flower in the first stage. The anthers (a) stand over the entrance
to the flower. B, Flower in the second stage. The stigmas (s) are over the
entrance to the flower ; », nectary. Nat. size.
The two larger-flowered species are protandrous
humble bee flowers. Some of the American species
are fertilised by humming-birds. The honey is con-
‘tained in the spur of the hooded sepal. The stamens
are short, with very short thick filaments lying against
the roof of the flower, so that a humble bee sucking the
honey would necessarily dust its back with pollen. The
anthers are ripe when the flower opens (Fig. 82, A).
At that time the pistil is immature, but it gradually
ripens (Fig. 82, B), and the result is that bees can
hardly fail to carry the pollen from younger flowers
to older ones. °
I, Noli-me-tangere also produces cleistogamous
1 Bentham, British Flora.
II GERANIACES 141
flowers ; indeed, in the upland valleys of the Tyrol it is
said to produce cleistogamous flowers only, in which the
pollen grains are separate, not tied together by threads
as in the open flowers. In the ordinary ones such a
provision would be useless. According to Snyder and
Meehan, in the United States L fulva is visited by
humming-birds.
The capsule is five-chambered. The dividing walls
are thin, and eventually separate themselves from the
centre, which thus becomes a pillar standing in the
middle of the fruit. As the fruit dries the cells imme-
diately below the epidermis are in a state of gradually
increasing tension, more so than the layers below.
Moreover, while the carpels of Geranium are straight,
and thus assume a position like that of a watch-spring,
those of Impatiens turn slightly to one side (the night),
the result of which is that in contracting they resemble
a corkscrew. Finally, the fruit bursts, the valves roll
up suddenly like a watch-spring, and fly off, carrying
the seeds with them. In this case, therefore, the
elastic tissue is part of the ovary—not, as in the pre-
ceding genus, the outer coating of the seed itself.’
Moreover, while in Geranium the inner cells swell
and the valves curve outwards, in this case it is the outer
layer which is elastic and the valves curve inwards. It
is interesting and suggestive that our genera of this
family should present such different modes of arriving
at the same object.
The leaves are thin, flat, and delicate, as in other
species which inhabit damp and shady localities (see
Dentaria, p. 80).
1 Zimmermann explained the dehiscence by the tension of the woody layer ;
Steinbrinck, by the difference between the tension of the woody layer and of the
outer epidermis, which is also Eichholz’s view (Pringsheim’s Jahrb. Wiss. Bot.
vol. xvii. (1886)).
142 BRITISH FLOWERING PLANTS CHAP.
ACERACE
ACER
Of this genus two species occur in the British Isles,
the Sycamore and the Maple.
A. Pseudo-platanus (Sycamore) has leaves somewhat
resembling those of the Plane, whence the name. It
is a native of Central Europe, and has no claim to
be considered indigenous, though an ancient intro-
duction. In autumn the leaves often present a number
of black blotches, looking like drops of tar, each about
half an inch in diameter. These are due to a parasitic
fungus, Rhytisma acerinum. The leaves are opposite,
and at an acute angle with the axis of the branch. A
glance at Fig. 9 will show how beautifully Maple leaves
are adapted to their conditions. The blades of the leaves
of the upper pair form an angle with the leaf-stalks, so
as to assume a horizontal position, or nearly so; the leaf-
stalks of the second pair decussate with those of the
first, and are just so much longer as to bring up that
pair nearly, or quite, to a level with the first; the
third pair decussate with the second, and are again
brought up nearly to the same level and immediately
to the outside of the first pair, so as to form a some-
what flat arch. In well-grown shoots there is often a
fourth pair on the outside of the second. If we look at
such a cluster of leaves directly from in front we shall
see that they generally appear somewhat to overlap;
but it must be remembered that in temperate regions
the sun is never vertical. Moreover, while alternate
leaves are more convenient in such an arrangement as
that of the Beech, it is more suitable in such cases
as the Sycamores and Maples that the leaves should
be opposite, because if, other things remaining the
same, the leaves of the Sycamore were alternate, the
sixth leaf would require an inconvenient length of
petiole.
II ACERACE.E 145
If we look at the winter bud of a Maple or Syca-
more (and the same is the case with many other trees,
as, for instance, the Horse Chestnut), we shall find it
covered by a number of brown leathery scales which
are, like the leaves, opposite and decussate, so that one
might at first sight be disposed to regard them as a
simple form of leaf. On looking more closely, however,
we shall soon find one which shows a scar or three
small teeth at the summit. When the plant begins
to grow in spring, some of the scales, especially on
certain trees, enlarge somewhat, and show small but
Fig. 83.—Seedling of Acer Pseudo-platanus. Half nat. size.
often well-developed leat-blades at their tip. In the
Norway Maple these scales enlarge and assume a
beautiful red colour, so that the growing bud looks
almost like an opening flower. These bud-scales,
therefore, are evidently the bases of leaf-stalks. If,
without waiting for the spring, we open a bud in
summer, say in July, we shall find five or six pairs
of scales, each pair at right angles with the preced-
ing, and then a beautiful little crown of tender green
leaves.
The cotyledons are narrow and ribbon-like (Fig. 83).
I have suggested the following explanation :—“ The fruit
(Fig. 84) is winged, the seed somewhat obovoid and ex-
albuminous—that is to say, the embryo, instead of lying
144 BRITISH FLOWERING PLANTS CHAP.
embedded in food-material, occupies the whole cavity of
the seed. Now, if we wish to pack a leaf into a cavity
of this form, it would
) be found convenient to
choose one of a long
strap-like shape, and then
roll it up into a sort of
ball. This is, I believe,
the reason why this form
of cotyledon is most suit-
: able in the case of the
Fic. 84,—Fruit and rolled cotyledons (A, B) Sycamore.” 1
of Sycamore. Nat. size.
A. campestre (Maple).
—A common plant in thickets and hedgerows. Native
in England, and naturalised in Scotland. Here, as
in the Sycamore and other species of the genus, the
flowers contain either functional stamens and a central
pistil rudiment, or a functional pistil and short stamens,
the anthers of which do not open. That is to say, the
flowers are functionally male or female. The distribu-
tion of the two kinds varies remarkably, sometimes
occurring together on the same inflorescence, or at
others distributed on different trees.
CELASTRACEZ
This is a large family, of which we have only one
representative.
EvonyMus
E. europeus (Spindle Tree).—A glabrous shrub 5-15
feet high. The leaves are opposite, and the shoots more
or less quadrangular. The flowers are greenish, and
1 Avebury (Lubbock), On Seedlings, vol. i.
WI CELASTRACEZ—RHAMNACE 145
protandrous, with exposed honey. They are tricecious.
The staminate flowers contain a rudiment of the pistil,
and the pistillate rudimentary stamens. According to
Darwin’s experience, the apparently hermaphrodite
flowers are, as a rule, functionally male, and in com-
paratively few cases produce seed.’ The flowers are
Fic. 85.—Transverse section of seed of Fic. 86,—Longitudinal section of seed of
uonymus. x8. Euonymus. x 8.
principally visited by flies. The capsule, enclosing four
to five cells, opens in as many valves along the middle
of each cell. The pod is red when ripe, and when
opened shows the seeds enclosed in a brilliant orange
or red arillus. The embryo is embedded in albumen.
It consists of two cotyledons (Fig. 85 and Fig. 86)
and the radicle (Fig. 86). The cotyledons, which is
very unusual, are quite green.
RHAMNACEA
We have only one genus, Rhamnus, the Buckthorn,
with two species. 2. catharticus, the Common Buck-
thorn, has the leaves toothed, and fruit black; while R.
Frangula, the Alder Buckthorn, has the leaves entire,
1 Forms of Flowers.
L
146 BRITISH FLOWERING PLANTS CHAP.
and fruit dark purple. The flowers in both species are
small and greenish. In R. Frangula the petals, teeth
of the calyx, and stamens are 5 in number; in J.
catharticus the parts are in fours.
R. catharticus.—The flowers are dicecious, each con-
taining the rudiments of the other sex; the male is
larger than the female. They are sweet-scented, but
not much visited by insects. Darwin distinguishes
four forms—(1) a long-styled male, (2) a short-styled
male, (3) a long-styled female, and (4) a short-styled
female.
R. Frangula.—The flowers are complete, and more or
less protandrous. Honey is secreted by the inner surface
of the calyx. The petals are small, and each covers one
of the anthers, forming a sort of small cap. The anthers
are at about the same level as the stigma, and as they
open inwards insects coming for the honey would touch
them with one side of the head, and the stigma with
the other, thus probably effecting cross-fertilisation.
According to Warnstorf, the flowers in the neigh-
bourhood of Ruppin are homogamous. Schulz states
that in some districts the pistil is longer than in others.
They are visited by bees, humble bees, wasps, and flies.
LEGUMINOSA
We now come to the great and interesting order
Leguminose, which falls into three groups, of which one
only, the Papilionaceze, is represented in Britain. Of
this we have eighteen genera. The flowers, says Ben-
tham,” are “in axillary or terminal racemes or spikes,
rarely solitary. Sepals combined into a single calyx,
more or less divided into 5 or fewer teeth or lobes.
Corolla very irregular, consisting of 5 petals. The
upper one, called the standard, is outside of all in the
l Handbook of the British Flora.
u LEGUMINOS.4& 147
bud, and usually the broadest; the two lateral ones,
called wings, are between the standard and the two
lower ones, which are inside of all, and united more or
less by their outer edge into a single one called the
keel, ‘the claws of all five petals remaining free.
Stamens, 10; the filaments in the British species
either monadelphous, all united in a sheath round the
ovary, or diadelphous, when the
upper one is free and the other
nine united in a sheath. Ovary ‘ F
single, one-celled, with one, two, ° ¢
or more ovules arranged along :
the inner or upper angle (the one
next the standard) of the cavity. d :
g : Fic. 87.—Embryo of Bean. c, coty-
Style simple. Fruit a pod, ledon ; 7, radicle ; :, plumule.
usually opening in two valves.
Seeds with two large cotyledons, and no albumen.”
It is probable that all flowers which have an
irregular corolla are fertilised by insects. The advan-
tage of the irregularity is that it tends to compel the
insects to visit the nectary in one particular manner,
and thus to fertilise the flower. In the present group
the result is that insects necessarily alight on a particular
part of the flower, when their weight in many cases
causes certain mechanical effects by which the pollen is
transferred to the body of the insect, and thus carried
from one flower to another. In the Leguminose the
lower parts of the stamens coalesce into a hollow tube
(Fig. 99), the inner walls of which, at their base, secrete
honey in some species, though not in all. In the
former, one or more of the stamens is detached, as in
the Lotus (Fig. 100, a), or atrophied, so as to leave a
space through which bees can introduce their proboscis
into the tube. In those species which do not secrete
honey this is unnecessary, and the stamens are all fully
developed and united.
The wings often present certain projections or bosses
which lock into corresponding depressions in the keel.
The result is that if a bee lights on and depresses the
148 BRITISH FLOWERING PLANTS cHAr.
wings, the keel goes with them; and when the weight
is removed, all three rise together again.
As a good illustration of the general arrangement
of the flowers we may take the Sweet Pea, because,
though it is not an English species, it is so common a
garden flower, and is of a convenient size. When visit-
ing it for the sake of the honey, insects do not generally
alight directly on the keel, but rather on the wings,
which are more conveniently situated ; the two, however,
are relatively so arranged, that when a bee alights on
the wings it presses down the keel, which is locked
with the two wings by a projection and corresponding
depression ; thus a portion of the pollen and also the
tip of the pistil are forced out at the point of the
keel, and against the breast of the bee, until on the
removal of the pressure the elasticity of the flower
causes the various organs to resume their former
position.
The Leguminosz are, as a rule, adapted for fer-
tilisation by bees, though in some cases by Lepi-
doptera.
As regards the mechanism of the flower, Delpino has
divided the Papilionacee into four divisions, which,
however, are connected by numerous intermediate
stages :—
1. Those in which not only the pollen but also
some of the stamens are pressed out. The stamens and
the pistil remain outside the keel as long as the pressure
of the visiting bee lasts, but afterwards return imme-
diately to their former position. Such blossoms permit
several successful visits.
(a) Honey is excreted: Melilotus, Trifolium, Galega,
Onobrychis, Astragalus, Oxytropis, Phaca, Ornithopus,
Hedysarum.
(b) The sweet juice remains in the cellular tissue,
and must therefore be bored for: Cytisus (some
species of this genus show gradations towards 3 a).
2. Explosive flowers: those in which the flower
bursts on pressure and ejects the pollen, the stamens
II LEGUMINOSAE 149
and the pistil springing out of the keel elastically.
Such blossoms permit only one useful visit.
(a) Honey-containing flowers: Medicago.
(b) Honeyless flowers.
(a) The bee touches the pollen and the stigma
with its under side: Genista, Ulex.
(8) The bee is powdered with pollen and stigma
on the back: Sarothamnus (Broom).
3. Piston mechanism: those -in which the pressure
of the bee pumps out, as it were, a certain quantity of
pollen ; the flower resuming its original form when the
pressure is removed. The thickened filaments press the
pollen in single portions out of the top of the keel.
Frequent insect visits are necessary for its fertilisation.
(a) Honey-containing flowers: Lotus, Anthyllis,
Tetragonolobus, Hippocrepis.
(b) Honeyless flowers: Ononis, Lupinus, Coronilla.
4, The brushing arrangement: that in which, on
the pressure of the bee, the
pollen is swept out by a brush :
of hairs situated on the end
of the pistil. This case does
not seem to differ much from
the preceding.
(a) The top of the pistal
is straight: Lathyrus, Pisum,
Vicia, Lens, Robinia.
(b) The top of the pistil is
twisted in the form of a snail:
Phaseolus.
The power of self-fertilisa-
tion seems to be lost in some
species of Phaseolus, Onobry-
chis, and Sarothamunus ; and Fic. 88.—1, Pod of Common Vetch.
to be much diminished in ‘The line ab shows the direction
others, as in Trifolium repens 3% weedy Hires 2, Pol of
and Viera Faba. open.
Some species throw their
seeds, owing to the elasticity of the pods, which,
150 BRITISH FLOWERING PLANTS CHAP.
when ripe, open suddenly with a jerk. In Genista
each valve of the pod contains an outer layer of woody
cells, so strongly lignified that their internal cavity
is almost obliterated.
The inner layers are
less lignified and
contract less. In
Vicia, Lathyrus, etc.,
the fibres do not
pass straight up the
pod, but are crossed,
and consequently
when the pod bursts
it does not, as in
the case of Carda-
mine, roll up like a
watch - spring, but
twists itself more or
8 less like a corkscrew
(Fig. 88).
The seeds, as
already mentioned,
contain no surround-
\ ing albumen, as, for
instance, those of
Euonymus (see Fig.
86), but are entirely
occupied by the em-
bryo. If any one
will examine the
seeds of a Bean, a
Pea, or a Laburnum,
for instance, he will find that they fall easily into
halves (Fig. 87), the seed-leaves or cotyledons (c ¢);
that at one end is the little root or radicle (7); while
between them is the minute shoot (s) which will develop
into the future plant. Every one knows split peas.
Who split them? Nature. The halves are the two
cotyledons. One result of the fleshiness of the coty-
Fic, 89.—Lathyrus Nissolia, Seedling. Nat, size
S, seed containing the cotyledons.
HW LEGUMINOS 151
ledons is that frequently the cotyledons are subterranean
and do not leave the seed (Fig. 89). In some cases,
as, for instance, in the Ground Nut of the West Indies
(Arachis hypogea), the plants themselves force the
seed-pods into the ground. Some foreign species, but
I believe no British, produce also cleistogamous flowers.
SAROTHAMNUS
S. scoparius (Broom).—The stems are wiry and
green, having to some extent taken over the functions
of the leaves, which are small and sometimes almost
absent. The flowers produce no honey, but are visited
for the sake of the pollen. Of the ten stamens, five
Fig. 90. Fig. 91.
Fics. 90-93.—Sarothamnus (the Broom),
Fic. 90.—Flower before explosion.
Fic. 91.—Flower seen from above after removal of the standard and wings.
Fic, 92.—Flower seen from the side after explosion of the short stamens. The
standard and wings have been removed.
Fic. 93.—Flower seen from the side after complete explosion.
are long and five short. When a bee alights on an
opening bud it presses its head under the standard,
and the pressure of its hind feet tends to separate the
wings and consequently to open the keel, which at. first
is closed by the cohesion of the upper edges (Fig. 92).
When this is opened to a certain distance the short
stamens suddenly appear (Fig. 93). The anthers had
already opened in the bud, and they thus dust the under
side of the bee with pollen. When the bud is older, or
if the bee exercises greater pressure, the split of the edges
152 BRITISH FLOWERING PLANTS CHA.
of the keel proceeds towards the point, against which the
stigma is closely pressed, the pistil being in a state of con-
siderable tension. As soon as the stigma is set free the
flower explodes, the pistil bends itself as in Fig. 93 and
rubs itself against the bee’s back, followed almost imme-
diately by the longer stamens and a shower of pollen.
The explosion is facilitated by the narrow-
ness of the claw of the keel, which is re-
duced to a mere thread. After explosion
the keel hangs down, and the flower gapes
widely. Humble bees, hive bees, and
Eucera (one of the solitary bees) are alone
capable of exploding the flower, but when
this is once effected many insects come
Fic. 94.—Shoot of to partake of the pollen. Humble bees
oo and hive bees, on the contrary, never con-
bud B protected descend to visit exploded flowers.
ee ete «Ln winter the bud, as in many allied
species, is protected by the persistent con-
cave pedestal of the last year’s leaf (Fig. 94).
Spartium junceum (Spanish Broom), so often grown
in our shrubberies, agrees in most important particulars
with the Common Broom.
Lotus
L. corniculatus (Bird’s-foot Trefoil) (Fig. 95), so called
from the resemblance of the head of pods to the foot of a
bird. As in many other leguminous plants, the leaflets
have the power of movement, to which we have already
referred ; rising and approaching one another at night.
The anthers burst and emit their pollen before the
flower opens, and indeed before the petals have
attained their full size. At this time the ten stamens
form two groups, five of them being longer than
the others; but by the time the flower opens they
are all of the same length, though the five outer
ones are somewhat swollen at the end; a difference
which subsequently becomes still more marked. The
pointed end of the keel is now filled by a mass of pollen
1 LEGUMINOS 153
(Figs. 99, 100, po), while the anthers, having discharged
their contents, begin to shrivel up. The free ends of the
five outer stamens continue, however, to increase in size ;
so that, with the pollen mass, they completely fill up the
cavity of the keel. When the flower opens, the pistil,
stamens, and pollen occupy
the position shown in Figs.
99, 100. The five inner
stamens, having discharged
ther pollen, have become
useless, shrivelled up, and lie
in the broader part of the
keel; the five outer ones, on
the contrary (Fig. 99, /),
which still have an im-
portant function to perform,
lie behind the pollen mass,
and keep it in its place.
Each of the wings has a
projection (Fig. 97, c) which
locks into a corresponding
depression of the keel (Fig. 98, c),so that if the wings
are depressed they carry the keel with them. Now,
when an insect alights on the flower, its weight
depresses the wings, and as they again carry with them
the keel, the latter slips over the column of stamens,
thus forcing some of the pollen otit at the end of the
keel and against the breast of the insect. As soon as
the insect leaves the flower this resumes its natural
position, and the pollen is again snugly protected. It
will be observed (Fig. 99) that one stamen is separated
from the rest. The advantage of this is that it leaves
a space through which the proboscis of the bee can
reach the honey, which is situated inside the tube
formed by the united stamens. In those Leguminose
which have no honey the stamens are all united
together. Such flowers are, nevertheless, in spite of
the absence of honey, visited by insects for the sake
of the pollen.
Fie. 95.—Lotus corniculatus,
154 BRITISH FLOWERING PLANTS CHAT.
This is a polymorphic species ; sometimes glabrous,
sometimes very hairy ; sometimes erect, sometimes low
and spreading.
Fig. 100.
The colour of the flower also varies
Fras. 96-100.—Lotus corniculatus.
Fie. 96.—Flower seen from the side and
in front.
Fic. 97.—Ditto, after removal of the
standard.
Fic. 98.—Ditto, after removal of the
standard and wings.
Fig. 99.—Ditto, after removal of one
side of the keel.
Fic. 100.—Terminal portion of Fig. 99
more magnified.
a, the free stamen; 6, bend in
filament of free stamen; ¢, the
place where the wings lock with
the keel ; e, entrance to the honey ;
Jf, stamens ; g, tip of keel; 4,
keel ; po, pollen; st, stigma; std,
standard ; ¢, staminal tube; w,
wing ; <y, in Fig. 99 marks the line
of section as shown in Fig. 100.
—sometimes plain yellow, but often more or less
streaked or flushed with crimson, becoming a deep
rich orange.
GENISTA
This is the “Genet” from which the Plantagenets
took their badge and their name. We have three
species, but they are much more numerous in Southern
I LEG UMINOS As 155
Europe, where some of the species have trifoliate leaves ;
ours are all single-leaved. One of our species, G. anglica,
is spinous. Of the other two, G. pilosa has the corolla
and pods hairy ; the other, G. tinctoria, glabrous. The
Genistas are pollen flowers, 7c. honeyless.
G. tinctoria.—The ten anthers! lie in two distinct
rows. While the flower is still in the bud, the four upper
anthers of the outer row are already on the point of
opening, while those of the inner circle have not nearly
reached their full size. These four anthers now open
and shed their pollen into the space at the apex of the
keel, after which they shrivel up. The fifth, although
it has attained its full
size, remains closed. The
next process is that this
anther and those of the
second row also open,
and the pollen occupies
the end of the keel be-
tween the anthers and
the stigma, as in Lotus. Fig. 102. Fig. 103.
While, however, in Lotus, Fics. 101-103.—Flower of Genista tinctoria.
when the insect leaves the te eon
flower and the pressure 1s Fic. 103.—After being visited.
thus removed, the keel Pettey ig a en
resumes its position and
the stamens and pistil are again protected, in G. tinc-
torva, on the contrary, the flower opens once for all. The
keel is at first nearly parallel to the standard (Fig. 101).
This position is, however, one of tension; the keel is
retained in it by the union of its upper margins, which
enclose and retain the curved pistil, which presses against
them like a spring. The sides of the keel have near the
base a projecting lobe (Fig. 103, m), which locks with one
at the corresponding part of the wing. When an insect,
alighting on the flower, presses open the keel in search
of pollen, as soon as the curved end of the pistil is set
free it springs up with a jerk, the keel, on the contrary,
1 Avebury (Lubbock), British Wild Flowers.
156 BRITISH FLOWERING PLAN'S CHAR.
springs back (Fig. 103), and the pollen is ejected in a
shower. It appears that the flowers do not open of
themselves if insects are prevented from visiting them.
The plant is sometimes: glabrous, sometimes with
scattered hairs. The pods are always glabrous, except in
the variety humifusa, found only in the Lizard district
and at St. David’s Head, Pembroke.
G. anglica.—The arrangement in this species and in
G. pilosa resembles that of G. tenctoria, but when open
the flowers do not gape so widely. The lower branches
are converted into short thorns. There are two forms
of leaves. Those of the sterile branches are linear or
narrow lanceolate; those of the flowering branches
obovate and very obtuse. The plant is quite glabrous.
G. pilosa, a prostrate plant found on gravelly heaths
in the southern portion of England, but rare, is, as the
name implies, hairy.
ULEX (Furze or Gorse)
Of this genus we have two species: U. curopeus,
our common Gorse, with hairy sepals
and bracts about half a line long;
and the Dwarf Furze, U. nanus,
with nearly glabrous sepals and
scarcely perceptible bracts. The
arrangement of the flowers is on
the same plan as in Genista. In
the mature plant the leaves are
reduced to spines, but if we ex-
amine a seedling (Fig. 104) we shall
find that the cotyledons are suc-
ceeded by several trifoliate leaves,
with ovate leaflets. These gradu-
ally become narrower, more pointed,
and stiffer, thus passing into spines.
Fie. 104.—Furze Seedling. Hence we can hardly doubt that the
present Furze is descended from
ancestors with trifoliate leaves.!
1 Avebury (Lubbock), Flowers, Fruits, and Leaves.
MI LEGUMINOS.E 157
ONONIS
We have two species—one (O. arvensis, Rest-harrow)
is perennial, and often thorny ; the other (O. reclinata)
is annual, and the peduncle is jointed beneath the
flower. Ononis does not secrete honey, and conse-
quently there is no need for the ‘separation of the
upper stamen, which in this genus is attached to the
rest. Again, in Ononis all the stamens are thickened
at the end; the outer ones, however, much more so
than the inner ones. The inner ones, on the contrary,
produce much more pollen than the others—a difference
of function which is even more marked in the Lupins.
The keel forms a tube, closed except at the end, where
there is a small orifice through which the pollen is
pressed.
Both our species are somewhat variable. O. arvensis
is sometimes prostrate, sometimes erect, generally
clothed with short spreading hairs, and more or less
glutinous, but sometimes glabrous. The hairs are
either scattered or collected in two opposite lines. The
lateral leaflets are sometimes wanting. The plants are
usually spiny, but show much variation in this respect,
and some forms are unarmed. O. reclinata is slightly
hairy, often viscid.
MEeEpIcCAGo
This is a large genus, of which we have in Britain
Six species. Two are perennial, MW. sativa (Lucerne),
with purple flowers, and M. falcata, with yellow flowers,
sometimes passing into blue or violet. The other four
species are annual. M. lupulina (Black Medick) has
one seed in the pod, the others several. M. minima is
downy, with nearly entire stipules. IM. denticulata
and M. maculata are nearly glabrous. In M. denticulata
the pod has two to three loose spires, in M@. maculata
it is nearly globular. The flowers secrete honey.
In some species the pods are round, flattened, and roll
along the ground like little green wheels, as in the
«
158 BRITISH FLOWERING PLANTS CHAP.
curious MM. scutellata of North Africa; others are
covered with hooks, and carried by animals.
M. sativa (Lucerne).—Much cultivated, but not in-
digenous. It is a native of the Eastern Mediterranean
recion. It produces honey, and one stamen is detached
from the rest. As in Genista and the Broom, the flowers
open once for all; but the elastic power is confined to the
upper stamens. In the Broom and in Genista the resist-
ance is obtained by the union of the upper edges of
the keel. These are also united in Medicago; but even
if they are separated no explosion takes place, the
flower being still locked together by four processes, two
of which point forwards and two backwards. These fit
so beautifully that the proboscis of a humble bee is
sufficient to unlock them and release the stamens;
though, according to Henslow, the hive bee is unable
to do so. Hildebrand, however, has observed that in
the absence of insects it fertilises itself! The plant is
nearly glabrous.
M. falcata.—In this species the pod is merely curved.
The flower is easily exploded, even by flies.
M. lupulina (Black Medick).—The flowers are minute,
but in general structure resemble those of M. sata.
They are mostly fertilised by hive bees, yet how in-
finitesimal must be the quantity of honey which they
can obtain from so small a flower! This species is
annual with us, but becomes perennial in Alpine districts.
It is more or less hairy.
M denticulata.—In this species and some others,
especially in Southern regions, the pod is edged with
rows of hooked or curved prickles. These no doubt serve
to catch hold of any passing animal, and thus facilitate
dispersal. They may also be useful in other ways. If
the pod is rolled about by wind they would help to
attach it as soon as it came to any damp earth. They
would also tend to deter birds from eating the seeds.
It has been suggested” that the larger ones prevent
1 Avebury (Lubbock), British Wild Flowers.
2 Riviera Nature Notes. By C. C.
e
II LEGUMINOS 159
the Southern harvesting ants from dragging them
down into their nests. I have seen Medicago pods
lying in little heaps at the entrances to such nests in
Italy and Algeria. The plant is slightly hairy, some-
times glandular.
MELILOTUS
Of this genus we have three species. JZ. albus has
white flowers, M. officinalis and M. arvensis yellow ; the
former has the pods irregularly, the latter transversely,
wrinkled. The general structure of the flower resembles
that of Medicago, but at one place the epidermal cells
of the wings are interwoven with those of the keel, so
that they may almost be said to have grown together.
They therefore move together when pressed down by an
insect, but on the removal of the weight resume their
original position.
The leaves sleep at night, the leaflets becoming
vertical. In doing so the leaflets could, of course, twist
so that their upper surfaces should face to either side.
As a matter of fact they face north, but as they move at
the same time towards the terminal leaflet, the upper
surface of the one faces about N.N.W., and that of the
other N.N.E. The terminal leaflet, on the other hand,
twists to either side, the upper surface sometimes facing
east and sometimes west, generally indeed west. It
also ‘‘ moves in another and more remarkable manner, for
whilst its blade is twisting and becoming vertical, the
whole leaflet bends to one side, and invariably to the
side towards which the upper surface is directed; so
that if this surface faces the west the whole leatlet bends
to the west, until it comes into contact with the upper
and vertical surface of the western lateral leaflet. Thus
the upper surface of the terminal and of one of the two
lateral leaflets is well protected.” * Darwin proved ex-
perimentally that leaves which were forced to remain
horizontal suffered more from frost.
1 Darwin, Movements of Plants.
160 BRITISH FLOWERING PLANTS CHAP,
TriFoLium (Clover)
The seed-pods are protected in several ways. In
T. subterraneum by the rigid, persistent flowers; in
T. fragiferum by the swollen calyx; in TL. globosum
by large brushes of hairs which completely envelop
them. Those of 7. badium are flattened. In this
genus also leaf movements may be observed ; for in-
stance, in the common White Clover (Z’ repens).
If we take a leaf with an upright stalk and three
horizontal leaflets, we find at night that the lateral
leaflets twist and approach one another until their
upper surfaces come in contact, bending down at the
same time at right angles to their original position,
until the midribs form an angle of about 45° with
the petiole. The terminal leaflet, on the contrary, rises
up and turns over so as to form a sort of roof over
the other two leaflets, with its lower surface turned
upwards. In TL. pratense the leaflets rise at night,
thus presenting a smaller radiating surface, and
Darwin found that leaves which were prevented from
doing so suffered more from frost. The autonomous
movements of the leaflets of 7. pratense are very
considerable; the terminal leaflet may accomplish a
movement of 30°-120° in the course of one and
a half to four hours. “If such a plant, previously
exposed to daily variation of light, be illuminated in the
evening and thenceforth kept continuously in the light,
no further closing movement corresponding to the daily
period is to be observed even on the following evening,
apparently because it is obscured by the autonomous
movements, which go on with an amplitude of as
much as 100°, and with a rhythm of about two hours.
These autonomous movements continued also unchanged
while the plant was kept constantly illuminated for
two days longer.” *
The stipules offer many points of interest. For
1 Sachs, Physiology of Plants.
I LEGUMINOS. 161
instance, the common Red Clover (7) pratense) has
the strongly veined connate stipules (Fig. 105) ovate,
the free part short, tri- :
angular, and ending in a
setaceous, applied point.
The upper ones are some-
what dilated. In White
Clover (7. repens, Fig. 106)
they are all comparatively
narrow, and subulate at the
free end. This difference
may perhaps be accounted Fic. cal ia pratense, Head
for by the different arrange- eee Se ae
ment of the flower-bud. In
T. pratense the head is sessile (Fig. 105), and the bud is
protected by the broad stipules. Hence, also, perhaps
the upper ones are more dilated than the others, as they
have to cover the young flower-head. In 7. repens, on
the contrary, the peduncle elongates (Fig. 106), while
the flower-head is still very undeveloped, indeed scarcely
broader than long, and without any projecting corollas.
The young flower-head pushes out from the plant and
lies flat on the ground, selecting a suitable situation
for its development. The figure shows a bud in an
early state, the corollas quite uncoloured and enclosed
by the calyces, but already with a long peduncle,
carrying it far beyond the stipule, st. 7. mediwm
also has stipules, much narrower than those of 7.
pratense."
T. repens (White Clover).—According to Darwin,
the flowers of White Clover are self-sterile. The wing
and keel are at one point grown together. The claw of
the wing is very narrow, which greatly facilitates the
pumping action. The upper surfaces of the leaflets are
glabrous. The cells of the epidermis are thin-walled ;
they are raised in the middle, and in the depressions
are small openings. At the edge of the leaf is a fringe
of long hairs. The under side of the leaves, except near
1 Avebury (Lubbock), On Buds and Stipules.
M
162 BRITISH FLOWERING PLANTS CHAP.
the centre, is coated by a waxy substance which is
secreted by glandular hairs, from the bases of which fine
lines radiate. The epidermis is quite smooth. The
upper part of the leaf is not wetted, even by heavy
rain, except just at the outer edges, where it is caught
by the teeth and the fringe of hair, and conducted to
the under surface, which is soon covered by a film of
moisture ; and it is interesting to see how rapidly drops
falling on the upper are thus conducted to the under
Fic, 106.—Trifolium repens. End of creeping shoot. ss, stem ; st, stipule ; p, leaf-
stalk ; fl, very young flower-head. Nat. size.
side. It does not, however, wet the whole surface, but
hangs like an hour-glass, suspended from the edges and
the midrib, which are wetted, and presumably absorb
moisture. This arrangement of the leaf explains the —
presence of stomata or air pores on the upper surface,
as well as below.’
T. fragiferum (Strawberry Clover).—In this species
the. arrangement of the flower is similar to that of
the preceding species, but after flowering two of the
lobes of the calyx become much inflated, and often
pink, so that the whole flower-head assumes more or
1 Lundstrém, Acta Nova Unsal. 1884-85.
IL LEGUMINOSAE 163
less the appearance of a strawberry. This may some-
times lead to the fruit being gathered and carried to
a certain distance. The swollen calyx would also
sob the same purpose in aiding distribution by the
win
T. pratense (Purple Clover)—In this species the
nine under stamens have coalesced with the claws of
the keel and the base of the wings and standard, thus
forming a tube 9-10 mm. in length, at the end of which
is the honey, inaccessible therefore, excepting to humble
bees, hive bees, and Lepidoptera. ‘According to Darwin,
it is self-sterile, which, however, Kerner denies. It is
said, however, to have produced no seed in New
Zealand until the colonists introduced humble bees.
Our commonest humble bee, Bombus terrestris, has a
proboscis just too short to reach the honey, but often
obtains access to it by biting a hole through the base
of the tube. The breach thus made is utilised by many
other insects. Knuth gives a list of those recorded by
various observers, amounting to over fifty. In America,
according to Robertson,’ it is much visited by Lepidop-
tera. In Germany the numbers observed are 8
butterflies out of a total of 25 species; in the United
States no less than 138 out of 20. It must, however, be
remembered that the United States are very rich in
Lepidoptera. The leaves are not wetted by rain, but
the moisture collects between the stipules, and is there,
probably, in part absorbed.
T. incarnatum and T. medium agree in the above
points with 7. pratense, but in the former the tube is a
little shorter.
T. arvense (Hare’s-foot Clover).—This happily named
species begins with a globular flower-head like its allies,
which, however, gradually elongates, forming a cylin-
drical column, like a soft brush, owing to the long fine
hairy teeth of the calyx.
T. agrarium.—tIn this and some allied species the
corolla, which is at first yellow, turns brown, shrivels
1 Botanical Gazette, xvii. (1892), p. 177.
164 BRITISH FLOWERING PLANTS CHAP.
up, and forms a sort of balloon serving for the dissemina-
tion of the small fruit.
T. subterraneum.—In most clovers the head contains
from 50 to over 100 florets. In this, on the contrary,
only a few (3-5) florets become complete flowers. The
Fic. 107.—Trifolium subterranewm. Shoot showing buds at end, and three older
flower-heads which are turned down and beginning to bury themselves.
others, proceeding from below upwards, are gradually
reduced to stiff spines, forming a rigid pointed head.
The complete florets stand upwards,
but after they have flowered the
peduncle bends over (Figs. 107, 108),
turns towards the ground, and grows
downwards, sometimes elongating to
the extent of 6 or even 9 inches,
forcing the flower-head into the
Fic. 108.—Trifolium sus ground to a depth of 4 or $ inch, an
ferraneum. Flower-heal, gperation much facilitated by the
slightly magnified. a :
peculiar construction and arrange-
ment of the imperfect florets. The florets are, as Darwin
has shown, no mere passive instruments. So soon as
the flower-head is in the ground they begin, commencing
from the outside, to bend themselves towards the ped-
uncle, the result of which, of course, is to drag the flower-
head farther and farther into the ground. In most Clovers.
each floret produces a little pod. This would in the
present species be useless, or even injurious ; many young
plants growing in one place would jostle and starve one
another. Hence we see another obvious advantage in
the fact that only a few florets perfect their seed.’
1 Vaucher, Hist. Phys. des Plantes d’ Europe, vol. ii.
II LEGUMINOS.E 165
T. resupinatum.—This is a hive bee flower. It has
a strong scent of honey during the day, but is said to
become scentless in the evening, when the bees leave off
working. The calyx is glabrous, or hairy on the upper
side only, which aie flowering becomes much inflated,
arched, membranous, and veined. The leaves, however,
are the most interesting feature of the species, and are
very peculiar. The apical halves of the lateral leaflets
are covered with bloom, which is wholly absent on the
other side, so that if put in water one side of the leaflet
is wetted, while the other remains dry.’
T. hybridum.—The flowers are first white and then
red. After flowering they turn down so as to make
room for younger ones. The stem is hollow and erect.
ASTRAGALUS
Of this, which is one of the largest genera of flower-
ing plants, and widely distributed in temperate and
cold regions, we have three species: A. alpinus has
the flowers in a raceme and bluish purple, the other
two in a head or short spike; A. hypoglottis, purple ;
A. glycyphyllos, dingy yellow. The flowers contain
honey.
OXYTROPIS
Oxytropis is also a large genus widely distributed in
the cooler parts of the northern hemisphere. We have
two species, both Scotch alpines: O. campestris, con-
fined to the Clova Mountains, with yellow flowers tinged
with purple; and O. wralensis, with pale purple flowers.
ORNITHOPUS
O. perpusillus (Bird’s-foot) ; from the resemblance of
the fruits to birds’ claws. Neither H. Miiller nor Knuth
could find any honey in this species.
1 Darwin, More Letters.
166 BRITISH FLOWERING PLANTS CHAP.
HIPPOCREPIS
H. comosa (Horse-shoe Vetch) takes its name from
the shape of the joints of the seed-pod. The pod forms
almost a complete circle, the con-
cave margin of which is continuous,
while the convex side is thrown into
abrupt undulations (Fig. 109). It
might have been supposed that the
pod would break up at the narrowest
arts. As a matter of fact, how-
ever, the lines of dehiscence are
in the centre of the thickest parts,
so that the detached portions have the forms of horse-
shoes. Each segment would normally include two seeds,
but as a rule one is aborted.
¥ie. 109.—Fruit of Hippo-
crepis.
ANTHYLLIS
A. Vulneraria is our only representative of this genus,
which contains about twenty species, distributed through
the north temperate region of the Old World. It agrees
with Lotus in its general arrangement. The tube of the
flower is, however, elongated; and in consequence this
species is only visited by bees with long tongues. In
the young flower, though the pistil is in the keel, and
necessarily in contact with the pollen, H. Miiller has
observed that the stigma is dry, and that pollen which
falls on it is easily shaken off. Subsequently, however,
when most, or all, of the pollen has been removed, the
stigma becomes sticky, and pollen adheres closely to it.
The pollen grains are short six-sided prisms with striated
angles. The dried and swollen calyx helps the disper-
sion of the fruit. The whole plant is covered with short,
appressed silky hairs.
Vicia (Vetch)
The Vetches (Vicia) are distinguished from the Peas
(Lathyrus) by having the style filiform or angular, and
u LEGUMINOS © 167
hairy on the outer side or all round; while in the Peas
the style is flattened, and hairy on the inner side only.
The termination of the staminal tube, moreover, is more
or less oblique (Fig. 111), while in the Pea (Fig. 110)
it is more abrupt. Several species of the genus have
“extra-floral”’ nectaries. They are situated on the under
side of the stipules, and are generally deeply coloured,
often black. The object is probably to attract ants,
Fic. 110.—Staminal tube of Lathyrus. Fic, 111.—Staminal tube of Vicia,
which then repay the plant hy carrying off any small
caterpillars, ete.
V. Cracca.—In this beautiful species the connection
of the wing and the keel is carried farther than in the
preceding genera. In fact, they are doubly interlocked,
so that it 1s difficult to separate without tearing them.
The anthers are ripe, and the pollen shed before the
flowers open, but according to Knuth the stigma is not
capable of impregnation until the delicate papille have
been scratched and torn by the bee. Though the parts
of the flower fit closely to one another, still from the
smallness of its size the honey is accessible to most
bees, and owing to the conspicuousness of its bunches of
bright blue flowers it is much visited by them. From
their arrangement and elasticity, the various parts of
the flower resume their original position after each
visit. The plant is sometimes covered with numerous
white silky hairs, sometimes has only a few appressed
hairs.
V. sepium (Bush Vetch).—The arrangement of the
flowers resembles that in V. Cracca, but the pistil,
instead of a single brush, bears two separate groups of
hairs, one on the inner and the other on the outer
side, each about 1m. in length. That on the inner side
168 BRITISH FLOWERING PLANTS CHAP.
consists of a single row of short hairs pointing outwards.
That on the outer side widens towards the stigma, three-
quarters of which they surround, and from which they
stand out straight, thus forming a sort of flat plate.
The longest hairs are in the centre. Access to the honey
is more difficult than in V. Cracca, and possible only
to powerful bees such as Bombus and Anthophora.
B. terrestris, therefore, often bites through the base of
the flower. The plant creeps about in shady places
and among leaves, and the lower part of the stem, which
is often covered up, is very weak and thin.
Latuyrvs (Pea)
In this beautiful genus nearly every species offers
some special point of interest. The general arrangement
of the flower has been already described (see ante, p. 148).
ee
Fig. 112. Fig. 118.
Fies. 112, 113.—Stipules of Zuthyrus maritimus. 14 nat. size. In Fig. 113 one
of the stipules is turned back, revealing the rest of the leaf and bud.
The stipules differ much : they are (1) large and leaf-like,
or (2) narrow and sagittate, or (3) narrow and semi-
sagittate, or (4) absent.
Lathyrus maritumus belongs to the first category.
The stipules (Fig. 112) are large, foliaceous, and develop
early.
In L. grandiflorus (Fig. 114) they are small, half-
11 LEGUMINOS.& 169
sagittate, narrow, and pointed. The upper and lower
limbs, moreover, do not lie in the same plane, but are
somewhat twisted relatively to one another. In other
species, as, for instance, in L. pratensis (Fig. 115), they
are sagittate.
Now, if we open the bud of L. maritinws (Fig. 118)
we find that the young leaves and stipules occupy most
of the space be-
tween the outer
stipules, which
cover and protect
both the leaves
and stipules of all
the younger ones,
as well as the in-
florescences and
their own leaf in
its earlier stages.
They are sessile,
cordate, un- /||
equally sagittate,
tho Sect oF the: Ppaiteg te, of F208 stleot ty
plant, with nume- Jlorus. 1} nat. size. size,
rous strong nerves radiating from the point of their
insertion on the axis. The smaller auricle is generally
ovate or triangular and entire; the larger one has three
or four cusps or teeth. The stipules form a very
efficient protection to the leaves till they attain a con-
siderable size.
In L. latifolius (Figs. 118, 119) the upper limb of
.the stipule also protects the younger leaves, which, how-
ever, have only one pair of leaflets, and not, therefore,
occupying so much room, do not require such wide
stipules. The stalk, however, being very wide, is not
entirely covered by the sheathing stipule. Consequently,
if the upper stipule had a lower limb on the outer side,
the latter would be exposed. ‘The lower limb, which is
on the inner side, lies snugly ensconced between the stem
170 BRITISH FLOWERING PLANTS CHAP.
and the older leaf (Fig. 119). Moreover, the function of
the stipule being to protect the young bud, it develops
early, and when it is full grown the lower limb is
equal in length to the internode below. Subsequently,
however, the internode becomes much longer, while the
stipule remains as before. But though the stipule may
Fig. 116. Fig. 117. Fig. 118, Fig. 119,
Fic, 116.—Stipule of Lathyrus Fras, 118, 119.—Stipules of Lathyrus latifolius.
pratensis, 1} nat. size. The lower stipule (st) has
Fie. 117,—One of the lower been removed in Fig. 119, exposing the
stipules is turned back ex- whole of the stipule (st’) of the next higher
posing the next younger leaf leaf.
with its stipules,
be correctly described as half sagittate, it sometimes
shows a minute tooth where the other barb would have
been, suggesting that it is descended from ancestors
which had a barb on each side.
In L. pratensis the stipules (Figs. 115-117) are
sagittate. Here, however, the petiole is round; the
wings lie one on each side of it (Figs. 116, 117), und
are fully covered by the stipule of the preceding leaf.
Thus, then, the difference between the sagittate and
II LEGUMINOS.E 171
semi-sagittate stipules appears to depend on the form
of the stem and the arrangement of the bud. Where
the stem is winged the outer barb of the stipule would
be exposed. In such cases the stipule is semi-sagittate.
In the Garden Pea (Lathyrus sativus, Fig. 120) the
stipules are not only large in bud, and in arrangement
resemble those of L. maritemus, but they continue to
grow, reaching a length of fully 3 inches, and 14 in
breadth, and act as a pair of leaflets, which they con-
siderably exceed in size.
L. sativus.—A hardy climbing annual, a native
of Southern Europe, cultivated in Britain. The large
standard as described by Kirchner’ has at the base
Fic. 120.—Stipules of Lathyrus sativus. A, before the unfolding of the leaf in
the natural position ; B, with one stipule turned back to show the leaf and
shoot inside.
two deep folds at right angles to one another, which
fit into corresponding depressions of the wing, and
thus lock the two closely together. The front edge
of the keel is strengthened by a wing-like process,
which is bent somewhat into the form of an §, so
that the point turns a little to the left. The keel,
it will be remembered, consists of two leaves, and
the point of the right one is arched outwards, while
1 Quoted by Knuth.
Le2 BRITISH FLOWERING PLANTS CHAP.
the left has a deep depression in which the point of the
pistil lies. The wings are closely connected with the
keel, the right wing, however, when it overlies the point
of the keel, has a fold, through which, when the flower is
pressed down by an insect, the stigma protrudes. The
stigma is widened above, and twisted to an angle of 90°,
so that its originally inner side, which bears the brush of
haus, comes to the left side; the smooth, originally outer
side, to the right. The anthers open in the bud, and the
pollen is swept out by the brush of hairs. It is not easy
to make this complicated and unsymmetrical arrange-
ment very clear without an actual specimen. The
flower is principally fertilised by the hive bee. The
stipules are very large, and partly fulfil the functions
of leaves, besides serving to protect their own leaf
(Fig. 120) in the young stage and all the rest of the
shoot.
L. pratensis——The arrangement of the flower in this
species resembles that of the preceding. The stipules
are broadly lanceolate and sagittate.
L. Aphaca.—In this curious species the leaves are
reduced to tendrils, and the ordinary functions of the
Jeaf are performed by large, broadly heart-shaped stipules.
In the seedling the first and second leaves are scale-like
and trifid, with three subulate points corresponding to leaf
and stipules. The third and fourth leaves are compound,
with one pair of leaflets and obliquely ovate stipules
of considerable size, and a tendril represented by a
small subulate point. The fifth and succeeding leaves
are reduced to asubulate point and a pair of triangular
foliaceous stipules. The subulate point develops into a
simple tendril on the middle and upper portions of the
stem.
L. maritimus—As regards the flower this species
also resembles L. pratensis, and the stipules are
sagittate.
On the other hand, in L. palustris the stipules are
semi-sagittate. I have suggested that this may be
1 Avebury (Lubbock), Buds and Stipules.
I LEGUMINOS.E 173
explained by the winged stem, which, being so wide, is
uot entirely covered by the sheathing stipule. Conse-
quently if there were a lower limb on the outer side
it would be exposed. But though the stipule may
be correctly described as half-sagittate, it sometimes
shows a minute tooth where the other barb would have
been, indicating that it is descended from ancestors
which had a barb on each side.’ In LZ. pratensis and
L. maritimus, on the contrary, the petiole is round, the
wings lie one on each side and are fully covered by the
stipule of the preceding leaf.
L, sylvestris.—The flower is unsymmetrical. The
left honey gland and the passage leading to it are larger
than those on the right, and it is remarkable that when
bees bite through the flower to get at the honey, which
they often do, they always attack the left side. Either,
therefore, they have discovered the best place by biting
at first at random, or, which seems more probable,
having noticed the inequality when sucking the flowers
in the normal manner, make the opening on the left.
In either case the circumstance is very remarkable,
and Darwin regarded it as “the most remarkable case
of skill and judgment” on the part of the bees known
to him.’
L. Nissolia (Fig. 89) is another curious species. It
lives among grass in meadows and waste places, and
has lost altogether, not only the leaves, but also the
tendrils. Instead, however, of enlarged stipules, the
functions of the leaves are assumed by the leaf-stalks,
which are elongated, flattened, linear, ending in a fine
point, and, in fact, so like the leaves of the grasses
among which the plant lives that it is almost impossible
to distinguish it except when in flower. The stipules
are minute and very slender. For a weak plant grow-
ing among close grass a long linear leaf is, perhaps,
physically an advantage. Some of the flowers produce
seeds, and yet do not open. Sometimes the buds are
large, at others quite small. Though they are not true
1 Avebury (Lubbock), Buds and Stipules. 2 Forms of Flowers.
174 BRITISH FLOWERING PLANTS CHAP.
cleistogamic flowers, Darwin was disposed’ to regard
them as indicating the manner in which cleistogamy
may have originated.
ROSACEA
Of this great family we have in Britain seventeen
genera. Both calyx and corolla consist of separate
leaves, and the flowers are open, but in other respects
present great differences. They are generally large,
but sometimes quite small and greenish; often with
honey, secreted by a ring round the base of the calyx,
but sometimes without ; sometimes single, sometimes in
pairs, in close heads, in cymes, panicles, racemes,
corymbs, or spikes; mostly fertilised by insects, but
in some cases wind-flowers ; some are protandrous, some
protogynous ; some are considerable trees, some small
herbs. In many species the flowers. protect the pollen
by bending over in rain. The fruits present many
differences ; in some species a pome, in others a drupe,
a berry, or an achene. In many of the Rosacexe
belonging to various genera (Crategus, Geum, Pyrus,
Potentilla, etc.) the stipules are polymorphic.
Prunus
Of this genus we have four species: P. spinosa,
with the flowers single or in pairs; P. Cerasus and
P. Avium, with flowers in clusters, and P. Padus, in
axillary racemes. According to H. Miiller the flowers
are homogamous, but Kirchner says they are pro-
tandrous. Hach flower lasts seven to eight days. LP.
spinosa and P. Padus are protogynous. In P. spinosa
the young leaves are protected by woody spines.
P. Cerasus (Cherry).—In the wild cherry the fruit is
black. It seems probable that it is an advantage for
1 Forms of Flowers.
Il ROSACEAE 175
fruits which ripen when the leaves are still green to be
red, as this gives the greatest contrast. On the other
hand, red would not be conspicuous against faded leaves
which are brown, or even sometimes themselves reddish.
For such fruits, blue or black would be more advan-
tageous, and, as a matter of fact, many heath and moor
species have bluish or black fruit, as, for mstance, the
Bilberry, the closely allied Vaceiniun wuliginosum, or
the Black Bearberry. P. Cerasus keeps its leaves
longer in Southern Europe, and in Ceylon is evergreen.
The fruit of P. Padus (Bird Cherry) is also black.
SPIRZA
We have two species of this genus: in one, W.
Ulmaria, the leaves have a few large segments, and are
white underneath; in the second, S. Milipendula, they
have many small segments.
S. Ulmaria (Meadow-sweet).—The flowers are sweet-
scented, yellowish white, homogamous, and honeyless,
but a good deal visited by insects for the sake of the
pollen. The carpels are twisted, forming a spiral. Can
the object be to mimic small caterpillars, and thus
inveigle birds to carry them about? The seeds are
brown, oblong, and compressed laterally.
’
Dryas
D. octopetala is found in limestone and mountain
districts; it has large flowers with concealed honey.
The petals, as the name implies, are eight m number.
H. Miller describes the flowers as protogynous. When
the blossom opens the styles are mature; in a short
time the anthers commence to open, beginning with
the outer ones, so that at first insects touch the pistil
on one side, and the anthers on the other; thus cross-
fertilisation is almost sure to take place. If, however,
there are no insect visits, the styles bend outwards
toward the inner anthers, and the flower is self-fertilised ;
moreover, the Howers gradually bend over, so that the
176 BRITISH FLOWERING PLANTS CHAP.
stigmas come into the fall line of the pollen. The
carpels are numerous, and terminate in a long feathery
tail, which obviously serves to disseminate the seeds.
GEUM
We have two species, one ((7. rivale) with large
drooping dull-purplish flowers, and G. urbanwm, with
small upright yellow flowers. Both have honey. The
arrangement is very similar to that of the preceding
genus (Dryas).
G. urbanum is slightly protogynous. Besides the
complete flowers there are others, according to Schulz,
which are andromonecious and androdicecious. The
Fig. 121. Fig. 122. Fig. 123.
Figs. 121-124.—Geum urbanum. Fig. 121, young style ; Fig. 122, older ;
Fig. 128, still older; Fig. 124, ripe fruit.
carpels ave hairy, and terminate in a style which is
hairy in the middle and smooth at each end. Imme-
diately below the hairy tract a projection develops
(Figs. 122, 123), which gradually elongates and curves.
Finally, when the seed is ripe, the upper part of the style
detaches itself (Fig. 124), so that the fruit terminates in
a hook, which entangles itself in the hair of any passing
animal. It will be seen, however, from the arrangement
that the fruit cannot be torn away until it is ripe. In
other species the achene ends in a feathery tail as in
ra ROSACEX 177
Dryas. ‘The flower is said to produce honey more
abundantly in the North.
G. rivale.—The arrangement and history of the flower
are in essentials as in G. urbanwmn.
Rusvus
The species of this genus are richly endowed with
honey, secreted by a fleshy ring onthe receptacle below
the stamens. A more important botanical distinction is
in the ovary, which is superior or above the calyx and
corolla, while in the Rose it is inferior, the calyx and
corolla being above it. The carpels also become suc-
culent, forming a number of “drupelets” on a more or
less conical dry receptacle. The division into species
is more difficult even than in the Roses. Babington!
made forty-eight. In the most recent account, Moyle
Rogers’s Landbook of British Rubi (1900), 103 species
are recognised! Bentham and Hooker only accept
five. Of these two are herbaceous: one (&. saxatilzs)
having trifoliate leaves and small axillary flowers; the
other (2. Chamemorus, the Cloudberry) has simple
leaves and a large terminal solitary flower. Of the
other three, one (Jt. fruticosus, the Blackberry) has
3 or 5 leaflets and a black fruit, without bloom;
the second (R. cesius, the Dewberry) has glaucous
branches, and fruit covered with a bluish bloom. The
fifth is the Raspberry (22. Jde@us). The Blackberry is
especially variable.
R. fruticosus (Blackberry, Bramble).—The flowers
are large and widely open; the stamens, though
numerous, are not so close as to exclude even insects
with a short proboscis from access to the honey. The
outer anthers ripen first, and turn their open faces
upwards. The stigma ripens at the same time, so that
most insect visitors effect cross-fertilisation. Over 100
species of insects are recorded as visitors to the Black-
berry. In the late autumn many of the leaves present a
pale twining mark like a small serpent, and increasing in
1 Manual. 4th Edition.
N
178 BRITISH FLOWERING PLANTS CHAP.
width from one end to the other. In parts of England
it is, or used to be, believed that these are made by the
Devil, and that when a plant is so marked the fruit
must be left for him. They are, in fact, the mines
of a small moth. The branches form long sweeping
curves, and when the ends trail on the ground, roots are
developed. After this growth ceases they contract,
sometimes as much as 20 to 30 per cent, and thus
draw the tip of the branch down into the ground. The
older part of the original branch then often dies, while
the apex grows upwards and gives rise to a new plant.
R. Ideus (Raspberry).—According to Kerner, the
petals in this species remain more upright, thus squeez-
ing the stamens more closely together, the result of which
is that only insects with a sufficiently long proboscis
can reach the honey. Many are thus excluded, and only
about fifty are on record as visitors. The flower lasts
two days.
R. cesius (Dewberry).—According to Knuth, when
the flower opens the receptacle is flat, and neither the
anthers nor the.stigmas are ripe. The stamens arch
over the middle of the flower. The outer stamens open
first, and as they do so turn outwards towards the
petals. In the meanwhile the pistils are gradually
elongating, and eventually project above the inner
stamens. This arrangement evidently conduces to
cross - fertilisation; but the inner stamens gradually
grow up, and can hardly fail to touch the stigmas, so
that in the absence of insect visits the flower will almost
certainly fertilise itself.
R. saxatilis is, according to H. Miller, protogynous,
while R. Chamemorus is dicecious. The leaves are
adapted to snowy districts (see Viola palustris, p.
29). The moisture collects in the sunk nerves, and is
absorbed by certain glandular hairs.
FRAGARIA
It is remarkable that in four genera so nearly allied
as Rosa, Rubus, Fragaria, and Potentilla the fruit should
u ROSACEA 179
so greatly differ. In Rosa the carpels are enclosed in
the fleshy hollowed floral axis; in Rubus the carpels
become succulent, the convex floral axis being dry ; in
Fragaria the large convex receptacle is succulent, while
the ripened carpels are hard, and so closely surround,
that they are generally regarded as, the seeds; lastly,
in Potentilla there is nothing which in common parlance
could be termed a fruit, both receptacle and ripened
carpels remaining dry.
F. vesca (Strawberry).—The flowers are protogy-
nous, with concealed honey. As Darwin has pointed
out, the flowers are of three kinds: (1) female,
producing much fruit; (2) complete, which are not
so fertile; and (3) male, which, of course, give none.
Schulz has observed gynomoneecious on the same umbel,
and gynodicecious on different umbels, andromonecious
and androdicecious flowers. The flowers are visited by
beetles, flies, and bees, but in the absence of insect
visits they are capable of self-fertilisation. The Straw-
berry is one of the plants in which leaves growing in
sunshine and in shade differ considerably.
In Fragaria and Potentilla the sepals are stipulate ;
adjoining stipules unite to form, apparently, a set of
leaves alternating with the sepals, thus suggesting a
double calyx.
PoTENTILLA
Potentilla closely resembles Fragaria, with which
perhaps it should be united, but the receptacle is not
fleshy. The flowers are generally homogamous, but in
P. Comarum protandrous. There are nine British
species.
P. Comarum (Marsh Potentilla)—When the flower
opens, the stamens erect themselves and open gradually.
Some of the pollen falls on the stigmas, but has no
effect, as they are not mature. When the anthers have
dropped, the filaments of the stamens curve downwards
towards the petals, while the styles, on the contrary,
elongate and take their place. The receptacle makes
180 BRITISH FLOWERING PLANTS CHAP.
some approximation to that of Fragaria, as it is slightly
spongy, though not succulent.
P. Tormentilla.—This species, like Gewm urbanum,
is said’ to produce honey abundantly in Norway, but
not in Central France. In the North it is visited by
humble bees, but not in Germany or France.
P. anserina (Silver Weed) has the leaves silky white
on the under side, and sometimes, though less so, on
the upper as well. The flowers partly close at night
and in wet weather.
P. reptans has cleistogamous as well as the ordinary
flowers.
ALCHEMILLA
We have three species: one a small annual (A.
arvensis), the other two perennial; one (A. alpina) has
the leaves silvery below, in the other (A. vulgaris) they
are green on both sides. The calyx is double (as
described in Potentilla), and there are no petals. The
flowers are sometimes complete, but as a rule either
the stamens or the pistil are rudimentary. The anthers
open when it is fine, and shut again if it rains. The
honey is, as usual, secreted by a fleshy ring on the inner
side of the calyx, and forms a very thin layer, which
gives the flower a yellowish tinge.
A. vulgaris (Lady’s Mantle).—The leaves form a
small cup, which often contains a comparatively large
drop of rain or dew. The rain does not wet the
leaf, and only touches it at the base, from which it runs
into the small sunk nerves, and is thus retained in
place. <A tuft of hairs at the base of the leaf prevents
it from running off down the leaf-stalk. In the
mornings it is often icy cold, and perhaps deters cows
and sheep from eating the leaves.
SANGUISORBA
In this genus also petals are absent. It is represented.
in our flora by
1 Bonnier, Ann. Sct. Nat. ser. 6. viii. (1879).
II ROSACE.E 181
S. officinale (Great Burnet).—Honey is secreted as
usual. The four lobes of the calyx are deeply coloured
a rich dark brown. The florets are small, but 50 to
100 are united in an oval or cylindrical head. They
expand from below upwards, only one ring being open
at once, and are richly visited by insects, especially
flies and butterflies.
PoTERIUM
P. Sanguisorba (Salad Burnet), on the other hand,
has no honey. The flower-heads are greenish, smaller
and more globular. The florets are female at the
summit, complete in the centre, and male below. The
stamens are more numerous, and the pollen is carried by
wind, the anthers being exserted on long, slender,
pendulous filaments, which are white, yellowish, or red
in colour. The anthers are yellow or red. The stigmas
are numerous and elongated, so as more effectively
to catch the grains of pollen. This is mainly a wind-
flower ; still the flowers are occasionally visited by flies,
solitary wasps, and a few other insects.
The achenes are enclosed in a hollow development
of the receptacle, often termed the ‘‘ calyx tube.” There
is generally a single achene, but sometimes there are
three. It or they fill the receptacle, so that where three
are present they are more or less triangular. Each achene
contains a single seed. The receptacle is winged, and
no doubt serves for the dissemination of the seeds.
AGRIMONIA
A. Eupatoria (Agrimony).—There is a fleshy ring
at the base of the pistil which has all the appearance
of a nectary, but the presence of honey has not been
observed. The flowers open very early in the morn-
ing. The “calyx tube” is persistent, and is covered
with exquisite little hooks, which fix themselves into
the hair of any passing animal or into clothes, and
thus ensure the dispersal of the seeds. The flower
lasts three days. At first the stigmas are ripe, but
182 BRITISH FLOWERING PLANTS CHAP,
the anthers are not. In the second stage the anthers
are open, but turned away from the stigmas; finally,
in the third they bend over towards and _ fertilise
them, if they have not been already fertilised from
another flower.
Rosa
In this variable genus there are great differences of
opinion as to the limits of species. Bentham admits
five British species, while other botanists extend the
number to fifteen or twenty. I often wonder that the
older school of naturalists who regarded species as fixed,
aboriginal, and invariable, were not staggered by such
genera as Rosa, Rubus, or Hieracium, where the forms
are so various and so variable.
The Rose is much visited by insects for the sake of
the pollen, but does not produce honey. The numerous
stamens ripen at the same time as the pistil; but from
the convenient position of the latter, insects very fre-
quently alight upon it, and thus fertilise it with pollen
from other flowers, though self-fertilisation probably
often occurs. The carpels are numerous, one-seeded,
hairy, and embedded in the receptacle, which thus
forms a more or less bottle-shaped tube, open at the free
end, the walls of which become succulent when ripe,
forming the red “hips” which are go great an orna-
ment of our hedge-rows in autumn and winter. Roses
are well protected by numerous sharp curved prickles,
which in the climbing species are also useful as grapples.
In most cases of upright flowers with separate sepals,
the sepals are more or less similar. In the Rose the
differences are considerable, and have long been observed.
Mr. Landon has kindly called my attention to the
following Latin lines, which well describe them :—
Quinque sumus fratres, unus barbatus et alter,
Imberbesque duo, sum semiberbis ego.
The reason, I believe, is to be found in the arrangement of
the leaves in the bud. They overlap one another to some
u ROSACES 1838
extent. Two have both edges exposed, two have both
edges covered, while in the last one side is exposed and
one covered. In all cases the exposed edges are bearded.
The fruits do not fall, but remain attached to the
shrub. This is perhaps because they are arranged for
> © £3 Gd» 4d
Fig. 125. Fig. 126. Fig, 127, Fig. 128. Fig. 129. Fig. 130.
Fics. 125-130.—Scales of bud of Rose. Showing successively the Ist, 3rd, 4th,
5th, 6th, and 9th scale.
dispersal by birds. If they fell to the ground they
would be liable to be eaten by mice, etc. On the
branches, however, they are sufficiently protected by the
thorns and prickles.
If we examine a leaf-bud, say in December (Figs.
125-130), we shall find that
it consists of a number of
scales with three more or less
well-marked projections at the
apex. In this case the scale
itself represents the leaf-base,
while the stipules and upper
part of the leaf are indicated
by the three points. The
outermost scale is the shortest,
and they gradually increase
in length. After about ten
of such scales the little leaf-
blade becomes much larger,
and the leaf-base smaller in Fic. 131.—Expanding bud of Rose.
proportion. The expanding Stem bearing expanding lateral
bud is shown in Fig. 131. ee
: : revealing its axillary bud (d) ; five
One specles otf Rose, R. scales are shown, and two of the
berberidifolia, has leaves con- —_‘"S* leaves, Li’, Ll. — Sketched
sisting of a single leaflet only.
It is a native of the dry regions of Central Asia, and
probably would lose too much moisture if it had the
1 Buds and Stiles.
184 BRITISH FLOWERING PLANTS CHAP.
leaf surface of an ordinary Rose. The stipules also
have disappeared. The single leaf appears to represent
the terminal leaflet of an ordinary Rose-leaf.’
Pyrus
Protogynous plants, with half-concealed honey,
secreted by the base of the flower.
P. Malus (Apple).—The scent is especially strong
at night, and the flower is much visited by moths.
According to Waite,” self-fertilisation gives little fruit.
When the flower opens the stigmas are ripe. On the
second day the anthers begin to open, commencing from
the outer rows. The flower lasts five to six days.
P. communis (Pear).—The life-history of the Pear
flower is similar to that of the Apple, but the female
condition lasts two to four days, and the whole Hower
life seven to eight days. It is also nearly sterile to its
own pollen.
P. Aria (White Beam).—The under side of the
leaves is covered with a soft white cotton, and is often
turned upwards, so that the tree looks quite white.
The cottony down protects the stomata. The buds
stand upright, thus exposing a small surface to the sky,
and minimising the effect of cold. I have described
them at length in my Buds and Stipules, p. 140.
CraTEGUS
C. Oxyacantha (Hawthorn).—The flowers are proto-
gynous, with half-concealed honey secreted by a ring
at the base of the Hower. The scent is one of the
few which we consider pleasant, and which is also very
attractive to flies. The anthers do not begin to open
until the flower is one or two days old. The plant is
protected by modified branches which assume the form
of spines. On the lower part of long shoots a long
spine and a bud develop together, on the upper part a
bud only.
1 See Gardeners’ Chronicle, July 6, 1889.
* Waite, Pollination of Pear Flowers. Washington, 1894.
ul ROSACEE 185
The stipules on the leaves of the short lateral spurs
and those at the very base of the elongating shoots are
minute and tooth-like, or subulate, soon becoming brown
and falling early. Those on the upper part of the
elongating shoots vary from unilateral, falcate, serrated,
small but foliaceous organs, to large, half - cordate,
simply or doubly serrate, shortly stalked, foliaceous,
much - reticulated organs, with the principal nerves
radiating from the base of the lamina and passing into
the principal teeth. Thus there are at least three dis-
tinct types of stipules. These differences are probably
connected with the differences in the shoots. The latter
may be described as of two kinds, namely, those which
develop into more or less lengthy, leafy shoots, which
go to increase the height and breadth of the tree, and
those which form short lateral spurs. The latter are
very numerous, forming dense rosettes of leaves, and
produce clusters of flowers in profusion in adult bushes
and trees. Owing to the crowded state of their leaves
the bases of their petioles occupy the whole, or very
nearly the whole, of the surface of the short axis, thus
leaving little or no space for stipules. The lower or
euter leaves are very small, and entire or tridentate, or
trifid, with short petioles. Very often these have no
trace of stipules. The inner or upper leaves of these
rosettes are better developed, with elongated petioles, so
as to enable them to extend beyond and occupy the
space between the short ones. This is obviously a pro-
vision to expose every leaf to light. The stipules of
these longer-stalked leaves vary from mere points to
subulate or linear small brown organs, which, being
relatively functionless after the expansion of the leaves,
goon shrivel up and fall away.
At or near the base of the elongated leafy shoots
fairly well-developed leaves occasionally occur which
have no stipules, but as a rule the stipules in this
position are also well developed. As these shoots
elongate and become vigorous the internodes become
1 Avebury (Lubbock), On Buds and Stipules.
186 BRITISH FLOWERING PLANTS CHAP.
longer and the leaves and stipules larger. The latter,
indeed, become quite leafy, and supplement the area of
foliage. This is doubtless an advantage, as the leaves
themselves do not by any means utilise the area at their
disposal, as do those of the Lime, Beech, or Elm.
CoToNEASTER
C. vulgaris is a native of Europe and temperate Asia,
found wild in Britain only on the Great Orme. The
tiny pink flowers are homogamous or protogynous, with
concealed honey. ‘This species ascends to the Arctic
Circle, and high up in mountain ranges. The leaves
are typical of a cold wet district: small, ovate or
orbicular, entire, and glabrous on the upper surface, so
that wet runs off easily, while below they are covered
with a short dense cottony down, which protects the
stomata from wet during rain, and renders transpiration
possible as soon as the sun comes out again.
MESPILUS
M. germanica (the Medlar), a native of the Hast
Mediterranean area, has become naturalised in hedges
and thickets in Central and South England. The flowers
are homogamous, with half-concealed nectar. They are
remarkable for the great development of the sepals,
which are broad and leafy.
ONAGRACEA
The flowers are, with a few exceptions, regular, with
the parts in twos or fours, and an inferior ovary.
Eprtosium (Willow Herb)
We have ten species of this genus. One of them,
E. angustifolium, has the flowers irregular, the others
ul ONAGRACE 187
regular. Three have the stigma deeply four-lobed, one,
LE. hirsutum, with clasping leaves, while the other two
may be distinguished by the form of the leaves, which
in one, L. montanwm, are ovate or ovate-lanceolate, in
the other, E. parviflorum, are lanceolate. The flowers
also are small. Of the five species with a club-shaped
stigma, two have the stem marked with two or four
raised lines; E. tetragonwm has sessile leaves, while in
E. roseum they are shortly stalked. Of the three species
with a cylindrical stem, one, E. alpinum, is a small
Alpine species, not six inches high; &. alsinifoliwm has
ovate, EL. palustre lanceolate leaves. The flowers secrete
honey from the summit of the ovary. In wet weather
the long ovary bends so that the flowers turn downwards,
thus protecting the pollen from rain. The fruit is a
long narrow capsule, which splits open from above down-
wards both between the valves and also along the centre
of each, leaving the central axis with the seeds attached
to it. The seeds are very numerous, small, oblong,
brown, and with a tuft of long white silky hairs at the
upper end. ‘The hairs act as a parachute, and facilitate
the dispersal of the seeds by wind.
E. angustifolium (Rose-bay) has large purplish
flowers in conspicuous heads (Fig. 132), and is much
frequented by insects. The flowers,
as Sprengel pointed out, are so
strongly protandrous that self-
fertilisation is almost out of the
question. They open soon after
sunrise. The lower parts of the
filaments are flattened, and form a
hollow cone protecting the honey,
which lies between them and the
ovary. The space between the oS
two is arched over by hairs, which Fre. 182.—Lpilobinm angusti-
exclude rain while permitting the a
passage of the probosces of insects. When they have
shed their pollen the stamens turn outwards, while
the pistil grows up and the stigmas take their place.
188 BRITISH FLOWERING PLANTS OHAP.
Warming, however, as stated by Knuth, found the
specimens examined by him to be weakly protogynous,
and Schulz found the flowers in mountainous regions
less protandrous than those of the lowlands. Kerner
also found those examined by him less protandrous
than those of Sprengel, and capable of self-fertilisation
in the absence of insect visits.
E. parviflorum.—The stigmas are ripe when the
flower opens. Gradually the stamens elongate, and the
anthers open, so that self-fertilisation becomes possible.
The petals close up during the night, but open again the
following morning. Some of the anthers now project
beyond the stigma, and the pollen is
readily transported to other flowers.
While E. angustefolium has conspicu-
ous purplish-red flowers in long ter-
minal bunches or racemes, and is much
frequented by insects, this species (Fig.
133), on the contrary, has small soli-
tary flowers, and is seldom visited.
Now, to the former species the visits
Fic. 133. —Epilobium Of insects are necessary, since the
parviforim. Flower stamens ripen before the pistil, and
: the flower has consequently lost the
power of self-fertilisation. In £. parviflorum, on the
contrary, the stamens and pistil come to maturity at
the same time, and the flower can therefore fertilise
itself, It is, however, no doubt sometimes crossed by
the agency of insects; and, indeed, I am disposed to
believe that this is true of all the flowers which are
either coloured or sweet-scented. The plant is covered
with soft hairs.
E. montanum.—<According to Schulz the flowers of
this species and of E. rosewm are homogamous. The
stem is glabrous, or bears small woolly hairs.
E. hirsutum.—This species presents considerable differ-
ences according to locality. H. Miiller seems to have met
with homogamous flowers only 25-30 mm. in diameter.
Schulz describes three forms :—(1) Large flowers. These
ul ONAGRACEA 189
are markedly protandrous, with a long hanging pistil,
so that self-fertilisation is precluded. (2) Middle-
sized flowers, which are weakly protandrous or even
homogamous. The pistil is straight, and self-fertilisa-
tion is quite possible. (3) Small flowers. These are
homogamous, and regularly fertilise themselves. Female
flowers also sometimes occur, in which the anthers pro-
duce no pollen. The hairs are of two kinds—some long
and spreading, some glandular.
E. roseum is glabrous while young, afterwards
covered with woolly hairs, and towards the summit
with small spreading articulate hairs. The stigma is
sometimes slightly lobed. The stems are more or less
quadrangular, and the wings, besides strengthening the
stem, probably perform the same function as the rows
of hairs of other species in conducting moisture.
(EnorHERA (Evening Primrose)
Protandrous moth-flowers, with concealed honey.
A large genus, native of temperate North and South
America.
G. biennis.—Large pale-yellow flowers, which open
in the evening, and are then especially sweet-scented.
They are adapted to moths, but are also visited during
the day by some of the bees which have long probosces.
The nectar is protected by woolly hairs. The flowers
last two nights; the first evening the anthers open with
the flowers, but the lobes of the stigma do not open
until the morning. The petals are merely an advertise-
ment, and insects do not alight on them. The hairs are
tubercular at the base. This plant is a native of North
America, which has become established in various places
in this country as a garden escape. A Patagonian
species, Gi. odorata, has similarly become established
on the coasts of Somerset and at Plymouth. I have
described the peculiarly interesting cotyledons of this
and other genera of the family in my work On Seed-
lings, both in the original and in the popular edition
(International Science Series).
190 BRITISH FLOWERING PLANTS CHAP.
LupwIcia
L. palustris.—A rare plant, found in boggy pools in
Sussex and Hampshire. The minute flowers have no
petals.
CIRCA
In this genus the leaves are opposite, and the parts
of the flowers in twos. We have two species—one
hairy, C. lutetuana ; and one glabrous, C. alpina. In
both the capsule is pear-shaped, and covered with stiff
hooked hairs. The small white honeyed flowers are
borne in racemes. The stamens are at first some little
distance from the stigma, and at this stage the flower
is adapted for cross-fertilisation. In the absence of
insect. visits, which are not frequent, the stamen
gradually curls over and finally touches the stigma.
HALORAGE
MyriopHyLLUuM
We now come to an aquatic genus in which the
leaves are, as in so many water plants, divided into long
filaments. There are three British species. In one,
AL. spicatum, the bracts are shorter than the flowers;
in the second, M. verticillatum, they are longer; while
in AW. alterniflorum the bracts are longer than the
female, but shorter than the male flowers. The species
are more or less amphibious, and the water forms differ
considerably from specimens growing on land, especially
by the shortening of the internodes.
M. spicatum.—The flowers are in aerial spikes, with
small bracts; the upper flowers are male, the lower
female. They are wind-fertilised.
M. verticillatum.—This species lives in clear deep
water, and the flowers are all immersed; the bracts are
pinnate like the leaves.
II HALORAGE.E—LYTHRARIEX 191
Hippuris
The minute flowers are without petals. The leaves
are entire.
H. vulgaris (Mare’s Tail).—Grenier and Godron
mention ' a specimen in which the leaves were arranged
spirally instead of in whorls.
LYTHRARIEA
LyrHRuM
We have two British species—Z. Salicaria, with
upright stems and reddish-purple flowers; and L.
hyssoprfolia, small and decumbent, with minute petals.
L. Salicaria has three distinct forms of flower,
which were already recorded by
Vaucher, while their functions and
relations were first explained by
Darwin. He distinguished them
according to the length of their style,
as long-styled (Fig. 135), mid-styled
(Fig. 136), and short-styled (Fig.
137). In this species it is remark-
able that the seeds of the three forms
differ from one another, 100 of the
long-styled seeds being equal to 121
mid-styled or 142 short-styled. The
pollen grains also not only differ in
size, the long stamens having the
largest pollen grains, the middle-
sized stamens middle-sized pollen
grains, and the short stamens small Fic. 134. — Inflorescence
pollen grains, but also in colour, being = guthrun Satieurta
green in the longer stamens and yellow
in the shorter ones, while the filaments are pink in the
long stamens, uncoloured in the shorter ones. Darwin
1 Flore de France, vol. i.
192 BRITISH FLOWERING PLANTS CHAP.
also proved by experiment that this species does not set
its seeds if the visits of insects are prevented ; in a state
Fic. 135.—Long-styled flower of Lythrum Salicaria.
Fic, 136.—Mid-styled flower.
Fia. 1387.—Short-styled flower.
of nature, however, the plant is much frequented by bees,
humble bees, and flies, which always alight on the upper
side of the flowers, on the stamens and pistil.
u LYTHRARIE 193
It was also shown that perfect fertility can only be
obtained by fertilising each form with pollen from stamens
of the corresponding length. Thus the long-styled form
is naturally fertilised by pollen from the long stamens of
the two other forms; but 1t can be so, though imperfectly,
by its own two sets of stamens, and by the shorter
stamens of the two other forms. It can, therefore, be
fertilised, to use Darwin’s expression, “ legitimately ” in
two ways, and “‘illegitimately” in four ways. The
same is the case with the other two forms, so that
eighteen modes of union are possible, of which six are
natural or “legitimate,” twelve are “illegitimate” and
more or less sterile. This case is, therefore, indeed
most complex. The long-styled and short-styled forms
are almost sterile if ‘ illecitimately ” fertilised ; the mid-
styled produces about half as much seed as if “ legiti-
mately” fertilised. Darwin suggests’ that the tri-
morphous condition of this plant may be advantageous,
because if it were dimorphous only there would: be but
an equal chance in favour of any two plants being of
different forms, and therefore capable of self-fertilisation ;
whereas, being trimorphous, the chances are two to one.
In the Cowslip and Primrose, where large numbers of
plants grow together, this, he thinks, would not be so
material. However this may be, the stigma and the
two groups of stamens appear to correspond with the
three divisions of the body (viz. the head, thorax, and
abdomen) of the bee, Cilissa melanura, by which it is
almost exclusively fertilised.
The genus Lythrum is remarkable for the great
differences existing between different species. For
instance, DL. Greefferc, like L. Salicaria, is trimorphous;
while L. thymifolia is dimorphous, and L. hyssopifolia
is homomorphous.
The fruit is a capsule which opens along the centre
of each valve. The seeds are numerous, small, plano-
convex, yellowish, or testaceous, and nearly smooth.
They float in water. Cilissa melanura, as already
1 Journ. Linn. Soe. viii. (1864).
ce)
194 BRITISH FLOWERING PLANTS CHAP.
mentioned, devotes itself almost exclusively to L. Sali-
caria, which, however, is visited also by many other
insects. Knuth suggests that the green colour of the
anthers of the longest stamens, which, of course, are
‘most exposed, serves perhaps as a protection against
pollen-eating insects.
L. hyssopifolium.—This species is, according to Schulz,
protogynous. It is said by Vaucher, though Darwin
thinks erroneously, to be dimorphous.
PEPLIS
P. Portula (Water Purslane).—A small weak herb
erowing in moist places. The very minute flowers
sometimes have no petals.
CUCURBITACEA
Our only representative is the common Bryony
(Bryonia dioica), which climbs by means of tendrils.
Honey is concealed in the flowers. The plants are
dicecious, the female flowers only half as large as the
male, in which two pairs of the five stamens are grown
together; the fifth is free. The lower parts of the
calyx and corolla are grown together, and bear the
stamens, the bases of which completely cover the
stigma, leaving a passage, however, in the centre and
three at the sides which are protected by hairs. Lud-
wig records a case in which a female plant was fertilised
with pollen from a male growing at a distance of about
40 metres. One species of bee, Andrena florea, appears
to visit this species exclusively. It has been suggested
that the flower may have some special odour, very
attractive to this particular bee, but which we cannot
perceive. Struck by the great attraction which these,
to our eyes inconspicuous, flowers have for insects,
Knuth suspects that they may possess some attraction
not visible to our eye, and suggests that they may emit
II CUCURBITACE4—CRASSULACE.E 195
ultraviolet rays, which, as I have shown elsewhere,!
are visible to some insects. In support of this view
he finds that they act energetically on photographic
plates. The fruit is a globular berry with flat, nearly
orbicular seeds.
CRASS ULACEZL.
Generally succulent plants with numerous small
regular flowers, with usually 5 or sometimes more
sepals, petals, and carpels, and the same number of,
or twice as many, stamens. They generally have honey,
which is secreted by glands at the base of the ovary.
TILLZA
T. muscosa is probably self-fertilised.
CoTYLEDON
C. Umbilicus, Pennywort, so called from the thick,
round, peltate leaves. The flowers are protandrous.
The only insects recorded as visiting this species belong
to the genus Thrips. They do not probably, however,
serve to fertilise the flowers. The plants grow on almost
bare rocks and walls, especially on our western coasts.
SEDUM
We have nine species of this genus. Two have flat
broad leaves, one (S. Rhodiola) with 4 sepals and petals,
the other (S. Zelephiwm) with 5. The other species
have leaves as thick, or almost as thick, as they are broad.
Four have white or reddish flowers; of these, two have
ovoid or globular leaves, one of which (S. anglicum)
is glabrous, the other (S. dasyphyllum) with a few
glandular hairs on the calyx and pedicels; the other
two have oblong or cylindrical leaves; one (S. album)
is glabrous, the other (S. villoswm) is viscidly downy
1 Avebury (Lubbock), Ants, Bees, and Wasps.
196 BRITISH FLOWERING PLANTS CHAP,
Lastly, of the yellow-flowered species, one (S. rupestre)
is over 6 inches high, the other two not above 3 inches,
one (S. acre) bitter, the other (S. sexangulare) taste-
less. The fleshy leaves check transpiration, as the
surface is, of course, in a smaller proportion to the
volume; the succulent tissues also enable them to lay
in a store of water as a reserve in times of drought. In
some cases the character of the contained fluid is also
an impediment to transpiration; gummy, saline, and
resinous fluids evaporate much more slowly than pure
water.
It was in species of Sedum that Bohm in 1856
observed’ the movements of the chlorophyll grains
under the action of light. In diffused light the grains
are scattered, while in bright light they collect into
heaps. He did not, however, give details, and the
phenomenon is more clearly shown in Oxalis (p. 135)
and Lemna.
S$. Rhodiola is dicecious; according to Warming, in
Greenland tricecious.
S. acre-—The flowers are protandrous. The five
outer stamens, those opposite the sepals, first stand
upright and open their anthers. When the pollen is
shed they curl outwards and make way for the inner
series, which take up the same position. When these
also have shed their pollen, they in their turn curve
downwards and outwards, while the five carpels grow
up, and the small terminal stigmas occupy the same
central position. Self-fertilisation’ would thus be ex-
cluded. H. Miller, however, found in Westphalian
plants that the second series of stamens and the stigmas
ripened together. The bitterness, no doubt, as in other
cases, Serves as a protection.
8. Telephium.—In this species, on the other hand,
H. Miller found that both sets of stamens have shed
their pollen before the stigmas come to maturity.
8. album is strongly protandrous.
1 Sitzungsb. Akad. Wiss. Wien, xxii. (1856). See also Frank, Pringsh.
Jahrb. viii. (1872).
a CRASSULACE4!—RIBESIACE 197
8S. dasyphyllum.—This species is also said by some
authorities to be protandrous, but the stigmas are said
to ripen earlier in mountain districts, and, according to
Kerner, the anthers of the stamens opposite the sepals
open with the flower and fertilise their own stigmas.
Those of the series opposite the petals ripen later, and
as the stigmas are then withered, their pollen is, no
doubt, intended for cross-fertilisation.
8. villosum.—The flowers of this species are protected
by the stalks being clothed with adhesive glands.
SEMPERVIVUM
The leaves are succulent, serving for water-storage,
as in Sedum.
8. tectorum (House Leek).—The flowers are pro-
tandrous, but not so much so as to exclude self-
fertilisation.
RIBESIACEA
RIBES
There are four British species. One, the Gooseberry
(R. Grossularia), has prickly stems; 2. alpinum has
dicecious flowers and red fruit. In the last two the
flowers are complete; one (2. rubrum) has red, the
other (R. nigrum) black fruit. It is doubtful, however,
whether any of them except R. alpinum are really
native. The flowers are greenish-yellow, yellow, or red,
with more or less concealed honey.
R. alpinum.—The petals are very small. The calyx
forms an open shallow saucer, which secretes honey.
The flowers being dicecious, self-fertilisation is out of the
question. As usual, the male flowers are rather larger
than the female.
R. rubrum.—The flowers are homogamous and green-
ish-yellow. The calyx is less widely open than in the
preceding species. The anthers are so arranged that an
198 BRITISH FLOWERING PLANTS CHAP.
insect pressing its head to the flower touches them with
one side and the stigma with the other. It is a bee-
flower, but the flowers often hang in such a manner that
the pollen falls on to the stigma and fertilises it.
R. Grossularia (Gooseberry) is slightly protandrous.
The cup of the flower is somewhat deeper than in the
preceding species, and the honey is also protected by stiff
hairs on the pistil which reach across nearly to the
petals.
R. nigrum.—The flower is arranged like that of
R. rubrum, but the calyx is more bell-shaped, and
access to the honey is only possible to insects with
a proboscis. Insect visits, however, are not numerous,
and it is often, perhaps generally, self-fertilised.
SAXIFRAGACEZ
SAXIFRAGA
The flowers are white or yellow, often sprinkled with
purple, more rarely rose or blue. The outer wall of the
ovary secretes honey, which is generally quite exposed,
in consequence of which the flowers are richly visited
by insects. They are, as a rule, protandrous, but a few
species are protogynous. The fruit is an upright
capsule, and the seeds are jerked out by the wind.
S. Geum. — The stamens are arranged round the
flower, with the unripe pistil in the centre. After the
anthers have shed their pollen, they shrivel up, while
the stigmas separate and occupy the positions pre-
viously filled by the stamens.
S. oppositifolia agrees in essentials with S. Geum.
Engler describes the flowers as sometimes protogynous,
sometimes protandrous; Ekstam found them protan-
drous in Nova Zembla, while, according to Ricca, they
are homogamous ; according to H. Miiller on Piz Umbrail
and the Albula, to Warming in Greenland, and Lind-
ul SAXIFRAGACE.E 199
man in the Dovrefjeld, they are protogynous. In the
absence of insect visits they fertilise themselves.
8. stellaris——This species also is recorded in some
districts as protandrous, in others as homogamous, and
elsewhere again as protogynous.
S. tridactylites—According to Sprengel this species
is protandrous, while H. Miiller describes it as proto-
gynous. The leaves have sticky glandular hairs, which
often capture small insects. The glands are absorbent,
so that it is quite possible that the plant derives some
nourishment from them.
§. umbrosa (London Pride).—In this species also the
peduncles and petioles of the leaves bear a certain number
of glandular hairs, and the flowers are thus protected
against creeping insects.
CHRYSOSPLENIUM
The tlowers are greenish or golden-yellow, and incon-
spicuous, with exposed honey, which is secreted by a
band surrounding the base of the pistil. The leaves
surrounding the flowers are often golden yellow, thus
making the flowers more conspicuous. We have two
species, one with a triangular stem and alternate leaves,
the other with a quadrangular stem and opposite leaves.
These two conditions evidently depend on one another,
but which is the determining factor? Besides the com-
plete flowers, there are others with stamens only.
C. alternifolium.—The flowers are homogamous, but
apparently with a tendency in some places to become
protogynous. The flowers and surrounding leaves are
arranged on a plane, which renders them more con-
spicuous, and also more convenient for small insects.
Small snails, especially Succinea, also appear to assist
in the fertilisation.
C. oppositifolium.—The arrangement of the flowers
is similar, but they are protogynous.
200 BRITISH FLOWERING PLANTS CHAP.
PARNASSIA
White protandrous flowers, with half-concealed
honey.
P. palustris (Grass of Parnassus).—This species, as
its name denotes, inhabits wet and bogey places. It
has ten stamens, of which, however, five only bear
anthers, while the others secrete honey at the base, and
terminate in from eight to seventeen beautiful yellow
globular glands. These glands so closely resemble drops
of honey that it is difficult to believe they are perfectly
dry. They probably serve as sham drops of honey to
attract flies. There has been some difference of opinion
whether each of these “staminodes” represents a
stamen or a group of stamens. I can hardly doubt
that the former is the correct view. The five pollini-
ferous anthers ripen, not simultaneously, but successively,
and as each ripens it places itself right on the top of
the stigma, with its back to it, and the pollen is then
discharged from the anther on the side away from the
stigma, so that it is scarcely possible for any to fall on
it; and this is done by each of the five stamens in
succession,’ each taking a day to itself. When all five
have shed their pollen, on the sixth day the pistil takes
its turn. The flower smells of honey in bright sunshine,
and becomes scentless towards evening.
Parnassia offers another case in which, within the
limits of the species, the flowers are sometimes smaller
and the number of the parts diminished. In the Alps
the flowers are from 13-25 mm. in diameter, and
these small flowers often have only three stamens.
Knuth mentions that flowers from gathered buds
observed by him were often homogamous, confirming
the just remark by Sprengel, that it is not always safe to
conclude from cultivated specimens as to the behaviour
of plants in their natural homes. The seeds are very
minute, weighing only ‘00003 of a grain.
1 Bennett, How Flowers are Fertilised (1873).
H DROSERACE.E 201
DROSERACEA
Drosera (Sundew)
We have three species, which, however, do not seem
very well marked off from one another. The Common
Sundew (D. rotundifolia, Fig. 138) has the ends of
the leaves obovate or orbicular, as broad as long. In
D. anglica (Fig. 139) they are linear-spathulate, five or
more times longer than broad; but in D. longifolia the
leaves are almost intermediate in form. D. rotwnci-
folia and D. anglica produce cleistogamous flowers.
In the species hitherto described the relation between
the flowers and insects is one of mutual advantage.
The honey of the flowers affords
to the insects a rich and nutri-
tious food; and if the latter rob
the flowers of some of their pollen,
they make ample amends by carry-
ing a portion of the remainder
from one flower to another, and
thus conferring on the plant the
great advantage of cross-fertilisa-
tion. In Drosera on the contrary,
we find a very different state wos
of things, for the plant catches wUz,
and devours insects. This genus,
and the other plants which have
this remarkable habit, were the Fic. 138.— Drosera rotundi-
subject of an admirable memoir op eeee yam
by Sir Joseph Hooker, read before
the British Association,’ of a special work by Darwin,
and of many subsequent observations. The first observa-
tion of insect-eating plants was made about the year
1768 by our countryman Ellis, on Dionza, a North
American plant, the leaves of which have a joint in
the middle, and close over, kill, and digest any insect
which may alight on them. The plant has more
1 Nature, September 3, 1874.
202 BRITISH FLOWERING PLANTS cuap.
recently been studied by an American botanist, Mr.
Canby, who found, by feeding the leaves with small
pieces of beef, that ‘these were ‘completely dissolved and
absorbed ; the leaf opening again with a dry surface,
and ready for another meal, though with an appetite
somewhat jaded. Cheese disagreed with the leaves,
turning them black, and finally killing them.
In the case of Drosera the leaves are covered with
gland-bearing filaments or tentacles. Lach gland is
surrounded by a drop of viscid
secretion, which, glittering in
the sunshine, have given the
plant its poetical name of Sun-
dew. There are about 200 on
each leaf. If a small insect—
and the victims are mostly small
flies—alight on the leaf, it is
caught by the viscid secretion.
The gland is immediately excited
to moré active secretion, and the
stimulus gradually extends to
the whole leaf. The tentacles
also bend over towards the in-
sect, which is firmly held (Fig.
Fic. 139. — Drosera angtica. 140). The secretion becomes
Plant (reduced) with pistil more viscid, and the softer parts
, of the captive are dissolved and
digested. When all the nourishment has been ex-
tracted, the secretion dries up, the tentacles resume
their original position, the hard parts of the insect
are blown away, and the leaf is ready for another
meal. On one large leaf Darwin found the remains of
no less than thirteen insects. Mr. Francis Darwin has
found that plants fed on small bits of meat were more
vigorous than others which were kept without animal
food and left to depend on their roots alone.
The sensitiveness of the tentacles is marvellous.
Darwin found that a minute particle of a woman’s hair
weighing +s+5o of a grain produced a distinct move-
II DROSERACE 203
ment. Such a particle would have been entirely
imperceptible on the tip of the tongue, which is the
most sensitive part of our organisation. Of many
stimulants tried carbonate of ammonia was the most
energetic. A dose of pyyyoy of a grain given to a
gland produced a marked effect. On the other hand, it
is remarkable that though so sensitive the tentacles
do not move if struck by drops of rain, even if coming
down heavily. Inorganic sub-
stances again, such as bits of
glass, or sand, or organic sub-
stances not containing nourish-
ment, produce little effect, or if
the tentacles bend slightly over
them they seem soon to find
out their mistake.
It seems wonderful indeed
how such remarkable contriv-
ances can have originated.
Nevertheless some light appears
to be thrown on the problem if
we bear in mind that we find
every gradation. Many plants
produce a sticky secretion, Leaf enlarged, with the tenta-
which apparently seems only to. 6. guava sie teal ov
prevent creeping insects from .
ascending the plant and eating the leaves or robbing
the flowers of nectar. In others, as, for instance,
Saxifraga tridactylites and S. umbrosa, insects are
not only occasionally captured, but apparently sucked
of their juices. In Drosera, and, as we shall see,
in Pinguicula, the contrivances are more elaborate ;
and perhaps to this the great success of the genus in
the struggle for existence may be due, for there are
many species, spread almost over the whole continental
world.
D. anglica.—The leaves of this species stand erect,
and, as is usual in such cases, are not suddenly widened
at the end.
204 BRITISH FLOWERING PLANTS CHAP.
UMBELLIFERA
The Umbelliferee are generally herbaceous, and the
leaves are much subdivided. There are, however, some
exceptions. Hydrocotyle is a marsh plant growing on
wet mud or floating in water, and the leaves are round
like those of a small water-lily. Bupleurum also has
undivided leaves, and one South European species, the
only shrubby one in the family, has leathery leaves like
those of a Laurel. The fruits are sometimes winged,
as in Angelica ; sometimes covered with spines or hooks,
as in the Carrot, Anthriscus, or Sanicula.
The plants belonging to this group possess two
great advantages, namely, first, the association of the
numerous small flowers into com-
paratively large flat heads, by
which they are made much more
conspicuous ; and secondly, they
» all secrete honey in the centre
» of the flower on a flat disk (Fig.
142), which is thus accessible
to all insects, even those with
Z the shortest lips. This is an
2. advantage, as it effects a con-
‘ siderable saving of time, enabling
the insects to visit a given
number of flowers more rapidly,
/ . } and consequently rendering their
"i \j fertilisation more certain than
Fic. 141,—Wild Chervil_ (Chcero- if they stood singly. But though
‘phyllum sylvesire). Leaf and the order is so rich in genera
inflorescence (reduced) with and species, it is comparatively
uniform, and the divisions are for
the most part characterised by the form and structure
of the fruit. The flowers are generally small ; the petals,
5 in number, are inserted round a little fleshy disk ; the
stamens, also 5, alternate with the petals.
The self-fertilisation which, in small flowers such as
I UMBELLIFER 205
these, would otherwise naturally occur, is provided
against by the fact that the flowers are generally
protandrous, the stamens ripening before the pistil, and
the latter not being mature until the former have shed
their pollen, as, for instance, is shown in the following
enlarged figures of the Wild Chervil (Cherophyllum
sylvestve). Fig. 142 represents a floret in the earlier
(male) condition, showing three ripe anthers (a’) and
two still immature (a), while the stigmas have not yet
made their appearance; in Fig. 143 the same flower is
Fie. 142,—Wild Chervil in the first Fie. 143.—Wild Chervil in the second
(mule) state, (female) state.
a, immature anther ; a’, ripe anther ; «, nectary ; 0v, ovary ; p, petal; st, stigma.
represented in a more advanced condition, the stamens
having fallen off, and the stigmas (st) being now
mature.
In some cases flowers in both conditions may be
found in the same head or umbel; in others, as, for
instance, in Myrrhis, the flowers of one head are all
first in the male condition, and subsequently in that
with mature stigmas, none of them arriving at the
second stage until they have all passed through the
first.
It will be seen that in these florets the petals are
not symmetrical, the outer ones being considerably
larger than the others, and in many Umbellifers the
florets themselves, on the outer edge of the umbel, are
considerably larger than the inner ones. This dis-
tinction is carried still further in the Composite, where
also the florets are so closely packed together that the
whole flower-head is commonly, though of course
incorrectly, spoken of as a flower.
206 BRITISH FLOWERING PLANTS CHAP.
HyprocoryLe
Small white flowers with exposed honey, united in a
simple head or umbel.
H. vulgaris.—The anthers open one after the other,
but the stigmas are ripe before the last have shed their
pollen, so that the flower is capable of self-fertilisation.
The pollen is pale yellow, forming a pyramid or a double
pyramid about 25 w long and 18 » broad.
SANICULA
8. europea.—The flowers in different localities appear
to differ considerably. According to H. Miiller there
are 1-3 complete protandrous flowers in the centre of
the umbel, surrounded by 10-20 later-developing male
flowers. Schulz, on the contrary, found male flowers
in the centre of the umbels. Kerner and Francke
describe the complete flowers as protogynous, but
Kerner agrees with Miiller that the older flowers in the
middle of the umbels are complete. The stigmas are so
Jong that it is possible for them to touch the anthers
of neighbouring flowers. The flowers are principally
visited by small flies and beetles.
ASTRANTIA
White or reddish flowers with concealed honey. Of
this beautiful genus one species, A. major, a native of
Central and South Europe, has become naturalised in
woods in Herefordshire. Besides the complete flowers,
male flowers occur either on the same umbel (andromo-
neecious) or on different plants (androdiccious). The
bracts are white and shining like broad silvery plates,
reminding one very much of some of the simple and
pretty Norwegian peasant jewellery. Almost every head
contains a few outer complete and central male flowers,
which are somewhat later in coming to maturity.
According to Kerner the complete flowers are proto-
gynous, and may be fertilised by neighbouring male
flowers.
ul - UMBELLIFER& 207
ERyYNGIUM
Whitish or amethystine protandrous flowers with
concealed honey, which is secreted by a ten-rayed disk
at the base of the flower. The bracts are coloured, and
add considerably to the conspicuousness of the flowers.
The close flower-heads and stiff spiny leaves give the
plants some resemblance to a thistle, for which, indeed,
they are often taken. We have two species—one
common on our coasts — HL. maritimum, with the
scales of the receptacle three-lobed, and the leaves with
plaited and rounded lobes; the second, EL. campestre,
which is very local and not a true
native, has the leaves pinnately
divided, with pinnatifid lobes.
E. maritimum (Sea Holly).—
The spiny leaves and bracts form
an effective protection. The petals 1 2
(Fig. 144) are turned down in a Fic. 144.—1, Petal seen in
long lobe, which with the filaments fonts,» Petal seen from
close the opening of the flower, J
though they are easily pushed on one side by the pro-
boscis of an insect. The proboscis must, however, have
a length of 4 mm. to reach the honey.
E. campestre—The arrangement of the flower agrees
closely with that of the Sea Holly.
BuPpLeuRUM
This genus is somewhat peculiar, having entire leaves
with parallel veins, but the flowers and fruit resemble
those of other Umbellifers. The flowers are yellow.
We have four species. B. rotundifolium has pertfoliate
leaves, which perhaps prevent creeping insects from
obtaining access to the flowers; B. falcatum is a
perennial, with grass-like leaves. Of the other two,
B. tenvissimum has very minute bracts, while in B.
aristatum the bracts are longer than the flowers. The
flowers are protandrous. The leaves are adapted to
208 BRITISH FLOWERING PLANTS CHAP,
dry conditions. The cuticle is more or less thickened,
and there are often stomata on both sides.
In the remaining genera of this family the flowers
form a corymbose umbel, z.e. a head consisting of
several branches which start from the same point, and,
though of different lengths, reach the same height, so
that the flowers form a plane. They are generally white,
sometimes greenish, and in a few species yellow or
reddish. The honey is exposed.
ConIUM
C. maculatum (Hemlock).—This is a very typical
Umbellifer. The flowers are several hundred in an
umbel, protandrous, small, white, and conspicuous from
their numbers. The plant is about 3 feet high, with
much-divided leaves, which if crushed have a nauseous
scent, though the actual flowers have a sweet smell
of honey. The petals are turned over at the tip,
but not so much so as in Eryngium, and perhaps
with the object of protecting the honey till the
flower is mature. At the opening of the bud the
anthers are scarcely ripe, but they soon arrive at
maturity, and raise themselves so as to stand directly
over the still immature stigma. When each anther has
shed its pollen it turns outwards and another takes its
place. When they have all had their innings, and
generally not until all the pollen has fallen, the stigmas
themselves grow upwards and take their turn. The
honey being open to all, the flowers are visited by many
small insects.
Tittmann’ long ago remarked on the power pos-
sessed by plants of drawing themselves down under
the protection of the ground in winter by means
of the contraction of the roots. This is well shown
in several Umbelliferee, in some Composite, in Dipsacus,
Beta, etc. In this species, according to De Vries,’ it
amounts to as much as 8 per cent.
1 Flora, ii. (1819). 2 Bot. Zeitung, xxxvii. (1879),
ul UMBELLIFER. 209
PETROSELINUM
P. sativum (Parsley) occurs as a garden escape.
The flowers are greenish yellow, whereas
P. segetum, a native in Central and South England,
has white flowers.
TRINIA
T. vulgaris.—A rare plant, found on limestone rocks
in Devon and Somerset, has dicecious Howers ; the males
have narrower petals than the females.
APIUM
We have three species. A. nodzflorum has ovate or
lanceolate leaflets, while in A. inundatum they are
almost filiform, probably i in consequence of being sub-
merged. Both species have partial involucres of several
bracts. A. graveolens, on the contrary, has none.
A. nodifiorum.—According to Knuth this species is
markedly protandrous, and the secretion of honey ceases
when the anthers have shed their pollen, commencing
again when the stigmas reach maturity.
ALGOPODIUM
A. Podagraria (Goutweed).—According to Warnstorf
the umbels of the first order have complete flowers,
while those of the second have male flowers in the
centre and complete ones round the outside. Over a
hundred insects are recorded as visitors of this species,
which is a doubtful native occurring in waste places
near buildings or gardens.
CaRUM
Of this genus we have three species—C! tuberosum,
with tubers; C vertecillatwm, with leaves apparently
in whorls; and Ci Carw, the Caraway; the last not
native, but naturalised in waste places.
C. Caruii—According to Warnstorf, in some of the
flowers the anthers produce no pollen.
P
210 BRITISH FLOWERING PLANTS CHAP.
PIMPINELLA
We have two species—P. Saxifraga, which is
very common in pastures; and P. magna, which is less
frequent and larger, preferring mountainous and shady
places.
SIUM
This genus is represented by two species—S. lati-
folwwm, which has the umbels all terminal, and S.
angustifolium, in which many of them are lateral.
S. latifolium.—Some of the flowers are complete, some
male, and the arrangement seems to differ in different
localities. The flower-heads, which are at first upright,
gradually turn to the side, and in this position the
pollen of the upper flowers may fall on and fertilise the
lower ones. This happens in many Umbellifers.
CHNANTHE
We have four well-marked species. Two have long
linear leaves; one, Gi. fistulosa, with hollow, the other,
CE. pimpinelloides, with nearly solid stems. The other
two have broadly cuneate leaves, one, Gt. crocata, with
large terminal umbels, while the other, Gi. Phellan-
drium, has most of them opposite to the leaves.
(. fistulosa has andromoncecious, and also almost
homogamous complete flowers, which are generally cen-
tral. Some plants appear to produce male flowers only.
G. aquatica.—F lowers resembling those of the preced-
ing species.
AUTHUSA
#. Cynapium.—The flowers have been described by
Kerner and Schulz, who, as in so many other cases,
give quite different accounts. According to Schulz
the complete flowers are homogamous or slightly pro-
tandrous, while Kerner found them protogynous, It
is probable, therefore, that they differ in different
localities.
II UMBELLIFER.E 211
FenicuLum
F. vulgare (Fennel).—A tall glabrous herb with
finely divided leaves, and large umbels of small yellow
flowers ; it occurs on some of our southern sea-cliffs, but
is a doubtful native.
Mrum
M. athamanticum.—An Alpine plant found in Wales,
the North of England, and Scotland. It is, according
to Schulz, andromonecious ; the hermaphrodite flowers
being markedly protandrous.
CRITHMUM
C. maritimum (Samphire).—Like so many other
seaside plants, this has succulent leaves. The flowers
are markedly protandrous. According to Kirchner, the
pistil does not begin to develop till the anthers have
all shed their pollen.
ANGELICA
A. sylvestris.—In some of the flowers the anthers are
rudimentary.
PEUCEDANUM
We have three species. P. Ostruthiwm, which has
become naturalised in the North of England and Scot-
land, has broad leaves; the other two, narrow. Of
these, P. officinale, a very rare plant, has yellowish
flowers ; P. palustre, white flowers.
PastTInaca
P. sativa (Wild Parsnip) is easily identified by its
yellow flowers. The umbels of the first order, accord-
ing to Schulz, are hermaphrodite, with one or a few male
flowers in the centre; those of the second order are
hermaphrodite, sometimes with some male flowers in
the centre; those of higher orders contain more male
flowers. Warnstorf found no male flowers in the umbels
of the first order.
212 BRITISH FLOWERING PLANTS CHAP.
HERACLEUM
H. Sphondylium (Hoeweed).—This appears in some
localities to have complete flowers only. In others the
umbels of the second order are said to have male flowers
on the circumference, and those of higher orders to be
entirely male, or in some cases female. No less than
118 species of insects are on record as visitors of this
flower. In this respect it is pre-eminent. An allied
genus, Ferula, is supposed to have supplied Prometheus
with the rod or “ ferule” in which he brought down
fire from heaven.
SILER
S$. trilobum—Andromonecious, with protandrous
hermaphrodite flowers. The male flowers are numerous,
and occupy the centre of the umbels. The plant is not
anative of Britain, but has become naturalised at
Cherry Hinton, near Cambridge.
Daucus
D. Carota (Carrot).—The flowers are white; one or
a few in the centre, however, generally, but not always,
red. No satisfactory explanation of this has yet been
given. They do not appear to be of any functional
importance, and Darwin was disposed to regard them
“as a remnant of a former and ancient condition.” '
A somewhat similar case of the appearance of red
colour occurs in the ray florets of Yarrow and the
Daisy. Darwin’s suggestion of a primitive condition
in Carrot seems unlikely, as red is a rare colour in
Umbellifereez. The red colour would tend to increase
the attractiveness, but it is so small that this hardly
seems a sufficient explanation. The flowers vary con-
siderably in size, those at the circumference, and
especially the petals on the outside, being the largest.
Schulz describes in Mid-Germany two forms: the
commoner has complete and male flowers on the same
1 Forms of Flowers.
1 UMBELLIFER& 213
head, the latter occupying the centre. The second
form has greenish or reddish flowers; the umbels
have only female, or female and sexless flowers. The
anthers often contain normal pollen grains, but the
grains are often smaller and irregular in form; more-
over, the anthers rarely open, and even then remain in
the same position which they occupied in the bud.
Warnstorf found the umbels of the first order herma-
phrodite ; those of the second complete at the outside,
and with a few male flowers in the centre ; those of the
third all male. Here again, therefore, we find very
curious and as yet unexplained differences. The flower-
heads are upright during the day, but curve over at night,
thus protecting the flowers from rain and from too rapid
radiation. Irmisch long ago observed that after the
seedlings have made a certain amount of growth the
root contracts and draws the stem down under ground.
CHROPHYLLUM (Chervil)
We have three species. One, C. Anthriscus, has short
hispid fruit. Of the other two, one, Ci temulwm, has
the fruit ribbed ; in the other, C. sylvestre, it is smooth,
without ribs.
C. sylvestre (Figs. 141-143).—The flowers are andro-
moneecious, complete, and protandrous. The male
flowers are central. According, however, to Schroter,
all the flowers are complete and protandrous. The
honey is exposed, and the list of visitors very long.
C. temulum.—The arrangement of the flowers is as
in the preceding species.
ANTHRISCUS
A. vulgaris —According to Schulz the flowers are
homogamous, and fertilise themselves. They are not
much visited by insects. The fruits are covered with
short hooked bristles, and narrow at the top into a
short smooth beak.
214 BRITISH FLOWERING PLANTS CHAP,
ScANDIX
S. Pecten-Veneris (Venus’s Comb).—This prettily and
cleverly named species has andromoneecious, or homo-
gamous, or weakly protandrous, complete flowers. The
male flowers are generally central, but not always
present ; while the umbels of the third order are often
exclusively male. Before fertilisation the involucre
consists of five small, simple leaves. If fertilisation is
not effected they remain in this condition, but if even a
single flower of the umbel is fertilised they grow and
ramify considerably. The upper part of the ovary also
elongates rapidly, attaining a length of 2 inches.
When ripe the fruits spring open elastically.
PHYSOSPERMUM
P. cornubiense.—An extreme West of England species,
characterised by its bladdery fruit, whence its generic
name. It is an example of an element of the South-
west European flora subsisting under the mild climatic
conditions of the West of England. The Cornish heath,
Erica vagans, affords another example.
Myerruis
M. odorata.—A doubtful native. Most of the flowers
are complete and protandrous, but the later ones male
only.
CavcaLis
There are five British species. One, C. nodosa, has
the umbels opposite the leaves, and short fruit. In the
other four the umbels are terminal. Two have short
fruits not two lines long; in one, C. Anthriscus, the
general involucre has several bracts; in the other, C
arvensis, only one. Of the last two, one, C. latifolia,
has simple pinnate leaves; while in the other, C
daucoides, the leaves are twice or thrice pinnate.
C. daucoides.—According to Schulz, is andromon-
cecious, and also has protandrous complete flowers. The
male flowers are central. Kerner, however, describes
ra UMBELLIFERA.—ARALIACEE 215
the complete flowers as protogynous. It is not much
frequented by insects.
C. latifolia.—Andromoncecious, with complete flowers,
which are homogamous according to Kerner, proto-
gynous according to Schulz. A rare plant in cornfields
in the South of England, and not native.
C. Anthriscus.—Flowers generally white, but often
reddish. Schulz describes them as resembling those of
C. daucoides. The plant is covered with short appressed
hairs.
ARALIACEA
This family agrees with the Umbelliferee in many
respects, differing principally in the fruit, which forms
a berry, or berry-like “drupe.” The flowers are greenish,
protandrous, or homogamous, with free honey secreted
by a band surrounding the pistil.
HEDERA
H. Helix (Ivy).—A woody evergreen climber. The
main stems adhere to walls, trees, etc., by small modified
roots, which, unlike the ordinary ground roots, arise
along the length of the stem between the leaves. They
act solely as hold-fasts, and show a strong negative
response to the light, tending to grow away from it
into cracks or crannies of walls, bark, etc. The ivy,
like other green plants, derives its food from the air by
means of its leaves, and from the ground by means of
the ground roots, which arise only at the leaf insertions.
A plant cut off from connection with the ground withers.
The flowering branches project freely from their support,
and, instead of the typical three- to five-lobed “ivy”
leaves, have ovate leaves. They are so distinct that they
are often supposed by those who are not botanists to
belong to different plants. Other species with a similar
habit have two forms of leaves, as, for instance, Ficus
repens. The reason I believe to be as follows. It is
216 BRITISH FLOWERING PLANTS CHAP.
important to the leaves to secure as much light and
air as possible, and when growing on a flat surface the
ivy shape enables the leaves to fit into one another, and
to cover the whole surface. On the other hand, the
flowering branches grow up into the air. The leaves
are arranged round the stem, and under these condi-
tions an oval form is more suitable, as, for instance, is
also seen in the Black Poplar. The structure of the
leaf differs according to the amount of light to which it
is exposed, In the sun two layers of palisade cells are
developed under the upper epidermis, while in the shade
leaves the whole interior consists of rounded cells. The
difference is very like that which exists in the Dandelion
(see p. 250). The ivy is almost, if not quite, the last
of our plants to flower. The peduncles are covered with
stellate hairs. The five united carpels form a pistil
projecting about 1 mm. above the sepals. According to
Delpino the flowers are protandrous, while H. Miiller
and Kirchner describe them as homogamous. Honey is
abundant, and the flowers are very attractive to insects
—especially flies.) They appear to be sterile to their
own pollen. The fruit, which is set during the late
autumn, remains almost, if not quite, dormant during
the winter, and does not ripen until the following
spring.
LORANTHACEA
Shrubby or half-succulent evergreens, parasitic on
trees.
ViscuM
V. album (Mistletoe).—This interesting species is the
subject of many folklore tales. The traditionary connec-
tion with the Druids is more or less doubtful. Its
favourite tree appears to be the Black Poplar. It also
does well on the Apple, and some Conifers, as the Silver
Fir. It attains an age of forty years. The berry is
white, enclosing a single seed, surrounded by a very
Il ‘ LORANTHACEH—CORNACE 217
sticky pulp. The seed is carried by birds, and when
dropped adheres firmly to the bark, into which the
young plant drives its suckers, which ultimately become
thickened to wooden pegs. Unlike many other parasites,
the Mistletoe is partly green. This has been accounted for
by suggesting * that it only takes the ascending sap, while
the brown parasites make use of the descending, elabor-
ated sap, and consequently can dispense with ereen
leaves. This, however, is probably incorrect, for not
only does the Mistletoe root become firmly fixed in the
wood of its host, thereby tapping the stream of water
and dissolved substances rising from the roots, but also
develops secondary branches which make their way along
the bast, that is, the path of the descending sap. The
evergreen leaves well serve for the construction of carbo-
hydrate in the winter, when in most cases the host
plant will have shed its leaves. Hence the relation
between Mistletoe and host becomes one of symbiosis,
involving, that is, a certain mutual advantage.
The leaves have no palisade cells, the tissue between
the upper and lower epidermis being fairly uniform
throughout.
It is fertilised by insects (bees and flies), and is
therefore interesting as a species which is dependent on
both birds and insects.
CORNACEA
Cornus
We have two species—C! suecica, a low herb, with
4 petal-like bracts; and C. sanguinea, a shrub, ‘with-
out bracts. The flowers are homogamous, with free-
lying honey secreted by the base of the pistil.
C. sanguinea. —The anthers open inwards, and at
the same level as, but some little distance from, the
pistil; so that an insect visiting the flower is almost
sure to dust itself with pollen on one side, and to touch
1 Constantin, La Nature Tropicale.
218 BRITISH FLOWERING PLANTS CHAP.
the stigma with the other. Gradually, however, the
stamens rise and turn inwards, so that in the absence of
insect visits the flower would fertilise itself. The pollen
is large, rounded, and 63-75 » in diameter. The fruits
are black (see Wild Cherry, p. 175).
C. suecica.—The four alike red-veined bracts fulfil
the purpose of petals, and surround an umbel of about
twenty minute flowers. The true petals are minute,
purple, and reflexed, as are the sepals,
CAPRIFOLIACEA
This family presents great differences as regards
fertilisation. The Elder has no honey, and is visited
for the pollen; Adoxa and Viburnum have quite ex-
posed honey ; in Linnea it is accessible to insects even
with short probosces ; Symphoricarpus is a wasp flower;
Lonicera nigra is adapted to bees with a short proboscis ;
L. cerulea to humble bees; L. Periclymenum only to a
few of those with the longest proboscis, and to moths ;
and lastly, LZ. Caprifoliwm, with a tube almost an inch
long, only to hawkmoths.
ADOXA
Inconspicuous greenish flowers, with exposed nectar.
A. Moschatellina.—The flowers have a scent of musk,
as suggested by the specific name. The anthers stand
at the same level as the stigma. According to Kerner
the flowers are protogynous ; the anthers at first turned
from, and afterwards towards, the pistil.
SAMBUCUS
We have two species. S. EHbulus is a herb with
stipules, or lobes resembling stipules ; S. nigra, a small
tree without stipular lobes.
8. Ebulus (the Dwarf Elder, or Danewort) is supposed
to have been introduced by the Danes. The honey is
free-lying, secreted by the summit of the ovary.
1 CAPRIFOLIACE 219
8. nigra (Elder) has the flowers honeyless, sweet-
smelling, homogamous, and united in large corymbs,
which makes them very conspicuous. They are, how-
ever, not much visited by insects, and the anthers open
outwards, but the stigma comes in the fall line of the
pollen from at any rate one of the anthers. The flowers
are principally visited
by flies. The scales
protecting the bud are
petioles; the outer
ones are very small ;
the third pair often
terminate in more or
less rudimentary
leaves.
Fic. 145.—Lenticel from a branch of Sambucus
The bark of the nigra in the summer of the second year.
younger shoots 1s a e, epidermis ; 7, loosely arranged cork cells
‘ forming the lenticel; Zc, parenchyma of
good subj ect for the cortex ; pl, formative layer by the transverse
study of lenticels. division of the cells of which the lenticel is
Th ] t formed ; g, formative layer giving rise to the
ese are Oval Spots ordinary closely packed cork cells.
where the cork cells
are loosened and separated sufficiently to allow free
passage of air, as shown in the above figure (Fig. 145).
Lenticels replace the stomata of the young green shoots
fo)
as respiratory organs.
VIBURNUM
We have two very distinct species. V. Opulus has
three- to five-lobed glabrous leaves, and red berries; V.
Lantana, entire leaves, downy underneath, and purplish-
black berries. The honey is free-lying, or half concealed,
and V. Opulus has nectaries on the leaf-stalks.
V. Opulus (Guelder Rose) (Fig. 146).—This is the
wild form of the Guelder Rose. As in many of the
Umbelliferee the outer flowers are larger than the central
ones. In this species, indeed, they serve merely to make
the flower-head more conspicuous, for they have neither
stamens nor pistil, as Sprengel long ago observed. The
flowers are homogamous. They are visited by bees for
220 BRITISH FLOWERING PLANTS CHAP.
the pollen, while flies come principally to lick the layer
of honey. From the position of the flowers pollen must
often fall from one flower on to the stigma of another.
I was long puzzled as to the reason for the great
difference in the form of the leaves of our two species
of Viburnum, but it may perhaps be explained by the
following suggestions, which I brought forward in a
paper read before the Linnean Society in 1890, and
in my book On Buds and Stipules. V. Lantana has
Fie, 146.—Viburnum Opulus. Shoot, with flower and fruit.
leathery leaves, tomentose on the nerves, which, more-
over, are when young protected by a thick felt of stellate
hairs. V. Opulus, on the contrary, has more delicate
leaves, glabrous above, pubescent beneath. They are
protected in the bud by the lower leaves, which are.
leathery, and serve merely for this purpose. For facility
of packing.in the confined space of the bud they are
folded up, and hence the lobed form. They also present
curious stipules or stipuliform appendages, which fill up
and thus utilise a space at the base of the bud which
would otherwise be empty.? The leaf-stalks bear
one or more cups which secrete nectar. This is also
1 Journal Linnean Soc. (Bot.) xxviii.
2 This is described more fully in my Buds and Stipules, p. 40.
Il CAPRIFOLIACEH 221
perhaps connected with the tender delicate texture of
the leaves, and especially of the young leaves, which
afford a tempting food to many caterpillars and other
insects. The ants and wasps which are attracted by
the honey tend to keep them down, and thus to serve
as a bodyguard. Indeed,
it has appeared to me
that on specimens of V.
Opilus which are much
frequented by wasps and
ants the leaves are less }
eaten than in other cases (|
where they are not so ~
protected. It is said to
emit a peculiar odour in
the evening."
V. Lantana (Wayfar-
ing Tree) (Fig. 147).—In
addition to the differences
from JV. Opilus already
mentioned, the flowers of
i Lantana are all com- Fie, 147.— Viburnum Lantana. Shoot,
plete, the peripheral flowers with flower and young and ripe fruit.
are not much larger than the others, the quantity of
honey is less, and according to Schulz the flowers are
protogynous.
LonicERA
Honey is secreted at the surface of, or in a cup at,
the base of the corolla tube.
L. Periclymenum (Honeysuckle).—The first flowers
expand, and become strongly scented about seven o'clock
in the evening, and by eight most of them are open. The
buds stand more or less perpendicularly. The tube is
rather more than an inch in length, so that the honey is
only accessible to Lepidoptera. Soon after opening the
flowers turn downwards and become horizontal. The
flowers are homogamous, but in the first state of the
1 Rev. H. Friend, in Science Gossip, Sept. 1896.
222 BRITISH FLOWERING PLANTS CHAP.
flower, while the stamens project straight in front, the
pistil is turned somewhat downwards; moreover, it
projects beyond the anthers, so that self-fertilisation is
doubly precluded. The next day the appearance of the
flower is quite altered. If it has been, as usual, visited
by insects, the pollen is gone, and the stamens gradually
turn downwards, while the pistil rises and takes their
place. This change has generally taken place before the
evening (seven to eight). During the first night, there-
fore, an insect visitor would rub its breast against the
anthers, during the second against the stigma. Between
the two stages yet other changes take place. The tube
commences to arch itself, and the upper and under lip
to roll up, so that the flower becomes less conspicuous.
Nor is this all. The colour changes: having been white
internally and reddish outside, it becomes a clear
yellow. This change is completed before the second
evening, at which time, therefore, all the flowers of this
age are yellow. A change of colour takes place in several
other plants, as in Polemonium and Myosotis, and in a
Brazilian species of Lonicera there are even two changes,
so that the flower presents successively three different
colours. The advantage probably is that moths natu-
rally fly first to the more conspicuous flowers, thus
dusting themselves with pollen, and then passing on to
the others to deposit some of it on the stigma. But
this is not all. In the next stage the flowers become
darker, and finally dirty orange, the corolla rolls up still
more, and the scent ceases, so that the flower becomes less
conspicuous, and less and less attractive to insects. On
the other hand, Kerner and Warnstorf consider that in the
absence of insect visits the flowers fertilise themselves.
The production of honey is so considerable that the tube
is sometimes filled up half way. In such cases it is
accessible to humble bees with the longest probosces,
especially to Bombus hortorum. The feast is, however,
not arranged for them; there is no convenient alighting
stage, and they waste time in clumsy struggles to get
at the honey. The true friends are hawkmoths —
Ww CAPRIFOLIACEAE 223
especially Sphinx convolvuli and S. ligustri (the
Privet and Convolvulus hawkmoths). Some flies visit
the flowers for the sake of the pollen, but do not fertilise
them.
L, Caprifolium agrees in essentials with the preceding,
but the tube is even longer, reaching 30 mm., so that
the honey is effectually reserved for hawkmoths—and
even of them, only those with the longest probosces.
Kerner describes the flowers as weakly protogynous,
H. Miiller as homogamous. The flower is first rose
outside and white within, and subsequently yellow. Its
life continues for three days. The uppermost leaves
are united and form a cup round the stem, which,
according to Kerner, forms an unclimbable barrier and
prevents creeping insects from reaching the flower and
robbing it of its honey."
L. Xylosteum.— Homogamous. The tube is only
3-4 mm. in length. This species affords an instance of
synanthy, or greater or less union of two or more
flowers. The two flowers of the cyme are united for
about half their length; the two red berries are, how-
ever, nearly distinct. In L. alpigena, which is not
found in Pvitain, the union is nearly complete in
the flower, while in the globose berry the distinction
between the two ovaries of which it is made up has
been completely lost.”
The two last species are not native, but have
become naturalised in some of our southern and eastern
counties.
LINN 2A
Homogamous flowers with concealed honey, which
is secreted between the bases of the shorter stamens.
L. borealis.—The honey is protected by the hanging
position of the flowers. The petals are also lined with
hairs, which perhaps serve to exclude both rain and
small creeping insects. The pistil projects considerably
1 We find a similar provision in Chlora.
2 See Arber in Journ. Linn. Soc. (Botany) xxxv.
224 BRITISH FLOWERING PLANTS CHAP.
beyond the stamens, so that insects are almost sure to
touch it before reaching the anthers. This delicate
little plant is sometimes glabrous, sometimes covered
with fine glandular hairs, which are specially developed
on two bracts which stand immediately below, and
almost close over the fruit, thus probably assisting in
its dissemination. The plant was named by Gronovius
in honour of Linnzeus; a spray is generally introduced
in portraits of the creat naturalist.
RUBIACEA
A large world-wide order which is represented in
Britain by the tribe
STELLATE
The tribe is so named because the leaves appear to
be in whorls. There are, however, in reality only two
leaves at each node with buds in their axils. These
are opposite one another. The others are stipules, and
have no buds in their axils. Where there are six leaflets,
these correspond to two leaf-blades and their four
stipules. Where there are only four leaflets, this is
considered to be due to a coalescence of stipules by
pairs, as occurs also in the case of the Hop.
SHERARDIA
Honey is secreted by the fleshy base of the pistil, and
concealed in a short narrow tube.
S. arvensis is gynodicecious. The complete flowers
are slightly protandrous and rather larger than the
female. Kirehner, however, describes the flowers as
homogamous. In any case the flower is self- fertile.
Knuth observes that from the narrowness of the tube
Sherardia would appear to be especially adapted to
small butterflies. As a matter of fact, however, I do
not find that any are recorded as visiting it. It seems
i RUBIACEA 225
to be chiefly frequented by flies. The calyx teeth
enlarge after flowering, and the fruit is covered with
bristles, which probably assist in dissemination.
ASPERULA
We have two species—A. cynanchica, with glabrous,
and A. odorata, with hispid, fruit.
A. cynanchica (Squinancy-wort).—The flowers secrete
a rich supply of honey. H. Miiller describes two forms
—one with smooth, white, rather blunt petals, while in
the other the petals are rough, pointed, and with three
red lines. The pollen easily drops from the anthers on
to the stigma.
A. odorata (Woodruff).—The flowers are larger, but
resemble those of A. cynanchica. They are very sweet.
The leaves are extremely sensitive to light, and while
healthy green in the shadow of a thick wood, soon turn
sickly yellow if the trees are cut down and the plant
is exposed to the full sunlight. They are larger and
more delicate than those of most of their allies, no doubt
from living in localities which are shady and moist.
(See Dentaria, p. 80, and Petasites, Butter-bur, p. 236.)
GALIUM
The small flowers have free-lying honey. Insects
probably carry the pollen from flower to flower very
often on their feet. The anthers and stigma are, how-
ever, so close that no doubt the flowers frequently
fertilise themselves. We have ten or eleven species.
G. Aparine (Cleavers), takes its common name from
the recurved hooks on the angles of the slender four-
sided stem, by means of which the plant clings, and is
able to scramble over other vegetation. The leaves are
also hispid, and similar hooked bristles occur on the
rather large fruit and aid in its distribution.
G. Cruciata.—According to Darwin the flowers are
andromoneecious ; the lower ones male, the upper com-
plete. Schulz, however, gives a different account. He
found the earlier flowers of each shoot complete, the
Q
226 BRITISH FLOWERING PLANTS CHAP,
later ones male; the complete ones were generally
protandrous. The plant is covered with long white
spreading hairs. The specific name recalls the leaf
arrangement, four in a whorl, crosswise.
G. Mollugo.—At first the stamens stand upright,
and the anthers are covered all round with pollen,
while the two stigmas are close together, though
mature. Gradually the stamens turn outwards, and
eventually bend quite out of the flower, while the two
stigmas separate.
G. saxatile agrees with G. Mollugo as regards the
flowers, and so does G. verum, the common Lady’s
Bedstraw. The last-named is glabrous or pubescent.
In some localities the flowers are said to vary con-
siderably in size, while Knuth found them on the North
Friesian islands all approximately of the same size.
VALERIANACEA
In this order honey is secreted in a cup or spur of
the corolla,
VALERIANA
The flowers have 3 stamens, and the calyx forms a
feathery pappus in the fruit.
We have three species—one, V. dioica, is dicecious ;
V. pyrenaica has large cordate, the other, V. officinalis,
pinnate, leaves.
V. officinalis. —The flowers are protandrous. As
honey guides there are five purple lines, which gradually
fade. The honey is protected by some hairs on the
inner side of the corolla tube. In the first stage the
stamens, with open anthers, project above the corolla;
in the second the three stigmas. The anthers develop
one after the other.
V. dioica.—Sprengel long ago pointed out that as
the male flowers were larger than the female, insects are
likely to visit them first. According to Kerner the
II VALERIANACEA 227
female flowers open before the male. In some cases,
though rarely, complete flowers occur.
V. pyrenaica.—A native of the South of France and
Spain which has become naturalised in plantations. The
flowers resemble those of V. officinalis.
CENTRANTHUS
Tube of the corolla spurred. 1 stamen.
C. ruber.—The corolla tube is divided into two un-
equal parts by a thin membrane: the smaller contains
the pistil; the larger is produced into a spur, but is so
narrow that the honey is only accessible to Lepidoptera.
The stamen is connate with the corolla, and only
becomes free at the base of the lobe; when the flower
opens it projects. When the anther has shed its pollen
the pistil elongates and takes its place. According to
Knuth, self-fertilisation is therefore excluded, but the
stamen gradually curls over so much that the anther
might often fertilise a neighbouring flower. It is a
Central and South European species often grown in
gardens, which has become naturalised, especially in the
_ South of England.
VALERIANELLA
Homogamous or protogynous flowers with concealed
honey. ‘There are 3 stamens, but the calyx is not
pappose.
We have four species, which are most easily dis-
tinguished by the fruits. They consist of three cells,
but only one has a seed in it, the other two remain
empty. A more or less similar arrangement occurs in
other plants, and perhaps serves a useful purpose by
reducing the specific gravity of the fruit and thus
enabling it to be more easily carried by wind. In some
of the foreign species the fruits are provided with hooks.
In V. discoidea they are winged. The germinating
seedling of V. coronata’ (Fig. 148) shows an interesting
contrivance for fixing the fruit to the soil and thus
1 Avebury (Lubbock), On Seedlings.
228 BRITISH FLOWERING PLANTS CHAP.
enabling the cotyledons to make their escape. The
embryo swells up and the radicle usually bursts through
the side of the fruit beneath the calyx limbs; it then
pierces the latter, entering by the outer
face, and pushing on through both sides,
enters the ground, thus pinning the
fruit to the soil, while the cotyledons
are pulled out in a comparatively short
time into the light.
In V. olitoria the fruit is laterally
compressed. The chamber containing
the seed is in the middle, with the two
empty chambers on one side and a
corky mass on the other.
In V. carinata the fruit is not flat-
tened laterally, but compressed rather
from front to back, so as to be almost
boat-shaped.
In V. auricula the two hollow cells
are much larger than that containing
the seed.
Ege Tay Sontag ot Lastly, in V. dentata the hollow
natn ~ 4 Cells are smaller than the fertile one,
aud each lies in a separate projection
of the fruit wall, which is also produced at the two
ends.
DIPSACEA
Each floret is surrounded by an involucel; they are
rendered conspicuous by being collected into a head.
Our species are protandrous. Honey is secreted by
the upper part of the ovary, and concealed in the tube
of the corolla.
Dipsacus
Stiff bristles prevent insects from walking on the
flower-heads, so that they must touch the anthers and
stigmas with their heads rather than with their feet.
ul DIPSACEA 229
We have two species, or forms—D. sylvestris, with
ovoid heads, and very prickly; and D. pilosus, with
globular heads, and very hairy.
D. sylvestris—One of the stigmas is generally
atrophied. H. Miiller suggests that as the tube of the
corolla is narrow, if both stigmas were retained there
would be no room for the proboscis of the bee, and that
fertilisation being secured, a second stigma is un-
necessary. The leaves are sessile and broadly connate
at the base, forming a water-collecting cup round the
stem, which effectually prevents creeping insects from
reaching the flowers. The water thus collected is also
probably useful as affording the plant a supply in dry
weather. The Fuller’s Teazel, in which the scales of
the receptacle terminate in hooks, is sometimes regarded
as a variety of D. sylvestris, sometimes as a separate
species, D. Fullonum.
ScABIOSA
We have three species. One, S. swecisa, has entire
leaves. In the other two the leaves are divided; one,
S. Columbaria, has the florets five-lobed, the other, S.
arvensis, four-lobed.
S. arvensis—When the flower opens the stamens
project 4-5 mm. above the corolla, and the anthers open
one after the other, so that this stage lasts several days.
When they have all shed their pollen they shrink up.
The pistil now elongates, and the ripe stigmas take up
the position previously occupied by the anthers. The
florets open from the circumference towards the centre,
but the central florets have all shed their pollen before
the stigmas of the outer ones are ripe; so that not only
each floret, but the whole head, is at first male, and sub-
sequently female. Self-fertilisation is therefore excluded ;
but this is immaterial as the flowers are so richly visited
by insects—something over 100 species are recorded.
Some plants also have female flowers, especially early in
the season. In Kent, Darwin found the female flowers
much less numerous than the others. According to
230 BRITISH FLOWERING PLANTS CHAP.
Willis, on the contrary, in Cambridgeshire they are
more numerous. The plant bears hairs of three
kinds—(1) long and simple; (2) long and seated on a
dark gland; (3) short ones, sometimes very numerous.
S. succisa (Devil's Bit).—Fifty to eighty deep-blue
florets are united in one hemispherical head. The corolla
has generally 4, but sometimes 5 lobes, of which the
outer one is larger than the rest. The life-history of the
flower resembles that of S. arvensis. Some plants have
flowers in which the stamens are more or less atrophied,
and which are smaller than the complete ones. These
appear to be much more numerous in some places than
in others; near Homburg Magnus estimated them at
10 per cent, Schulz in Brunswick and Halle at 30
per cent. Turner’ describes the plant as trimorphous
-—with hermaphrodite, and two female forms, one
with a straight and the other with a bent style. The
flower-heads are much visited by insects. The stem is
pubescent.
8. Columbaria.—The heads contain 70-80 pale
purplish florets. The life-history, which is similar to
that of the two preceding species, was well described by
Sprengel. The outer florets are half again as large as
those of the next and inner rows. Plants with female
Hower-heads appear to be less common than in the
preceding species. The insects recorded as visitors are
much less numerous. When young the flower-heads
turn over at night, thus protecting the florets from rain
and cold. The stem is clothed, especially on the upper
part, with downward-pointing hairs.
COMPOSITA
The Composit agree with the Dipsaces in having
flower-heads composed of a large number of florets.
The stamens which are 5, or rarely 4, in number,
1 Nature, xl. (1889).
u COMPOSITA 231
are united in a tube. The flower-head is surrounded
by an involucre, consisting of more or less numerous
bracts. It serves in some cases to support the florets ;
if these are taken away from the flower-head, say of a
Thistle or a Centaurea, the involucre contracts and
closes together, showing how closely it compresses the
florets. In other cases, as in Carlina, it contributes
much to the conspicuousness of the flower-head. The
calyx is absent, or represented either by a narrow ring
or by a pappus, often of long feathery hairs. The
corolla is tubular, with a four- or five-toothed border. The
ovary is inferior, with a filiform style, divided at the
top into two short branches bearing the stigmas. Honey
is secreted at the base of the style. Hildebrand has
pointed out that while the small disk flowers fade, as
usual, when fertilised, the ray flowers remain fresh until
all the florets of the disk are impregnated, clearly show-
ing their relation to the flower-head as a whole. This
is the most extensive and widely distributed family of
plants. There are over 10,000
known species. We have in Wf
Britain no less than 40 genera.
It is hardly necessary to say
that what we call a “flower”
in, say, a Daisy is really a com-
bination of many small flowers
or florets. In many the heads
close up in wet weather, thus
protecting the pollen and stigma,
as, for instance, in Hieracium,
Bellis, and Carlina. It is said
that when once closed, even if
the sun comes out again they will
not reopen till the next morning. Fic. 149.—Chrysanthemum Par-
We may take Chrysanthemum — erin with elagel es
Parthenium (Fever-few) (Fig.
149) as a type of the order. It has been well described
by Ogle.’ The flower-heads consist of an outer row of
1 Pop. Sci. Rev. April 1870.
232 BRITISH FLOWERING PLANTS _ CHAP.
female florets, in which the tubular corolla terminates on
the outer side in a white leaf or ray, which is useful in
making the flower conspicuous. The inner florets are
also tubular, but are small, yellow, and without a ray.
Each of these florets has stamens as well as a pistil.
The anthers are united at their sides so as to form a
closed tube, within which the pistil lies. They ripen
before the pistil, and open on their inner sides, so that
the pollen is discharged into the upper end of the tube
above the head of the pistil. When the flower opens
the pollen is already ripe, and fills the upper part of the
stamen tube. A floret in this condition is represented
in Fig. 150. The style, however, continues to elongate,
and at length pushes the pollen against the upper end
of the tube, which gives way, and thus the pollen is
forced out of the tube, as shown in Fig. 151. The style
itself terminates in two branches, which at first are
pressed closely to one another, and each of which termi-
nates in a brush of hairs (Fig. 152). As the style elon-
gates, this brush of hairs sweeps the pollen cleanly out
of the tube, and it is then removed by insects. When
the pistil has attained its full length, the two branches
open and curve downwards, so as to expose the stig-
matic surfaces (Fig. 152, st) which had previously been
pressed closely to one another, and thus protected from
the action of the pollen. From this arrangement it is
obvious that any insect alighting on the flower-head
would dust its under side with the pollen of the younger
flowers, which then could not fail to be brought into
contact with the stigmatic surfaces of the older ones.
As the expansion of the flowers begins at the outside,
and thence extends to the centre, it is plain that the
pollen of any given floret cannot be used to fertilise one
situated on its inner side. Consequently, if the outer
row of florets produced pollen, it would in the great
majority of cases be wasted. I have, however, already
mentioned that these florets do not produce pollen,
while the saving thus effected enables them to produce
a larger corolla. It is also interesting to observe that
i COMPOSITE 233
in these outer flowers the branches of the pistil do not
possess the terminal brush of hairs, which in the absence
of pollen would be useless.
When the fruits are ripe the involucres press strongly
inwards. If the fruits are removed it will be found that
the bracts quickly close in. On the other hand, when
it is dry they open out and thus allow the fruits to
escape. ‘This is well seen in Centaurea. The dispersal
i .
|
isl
Fras. 150-152.—Chrysanthemum Parthenium. Successive stages in the life of the
flower. a, anthers ; st, stigmas,
of the fruits has been specially studied by Hilde-
brand.’ In some there is no special provision, but
they are small and easily carried by the wind. In
many cases they are surmounted by a ring of simple or
plumose hairs, or flat scales. In Dahlia the floral bracts
or palez are long, membranous, and attached to the fruit,
thus forming a wing; in Melampodium the corolla is
persistent, and serves the same purpose. In other cases
(Bidens, Lappa) they are covered with hooks, or are sticky,
and attach themselves to animals. In one genus (Wulffia)
1 “ Ueber die Verbreitungsmittel der Compositen-friichte,” Bot, Zeit, xxx. (1872).
234 BRITISH FLOWERING PLANTS CHAP.
they are fleshy. In Silybum marianum the involucre
contracts, compressing the achenes more and more until
at last they detach themselves and are scattered in all
directions. The common Calendula (Marigold) of our
gardens is a very interesting case. Three devices for
dispersal are united in each head. The outer achenes
(Fig. 153) are narrow, and bent into a curve forming
three parts of a circle, and well adapted to hang on to
Side view.
Front view.
wy
win Ee) @®
Hooked form. Winged form. Grub-like form.
Fig. 153. Fig. 154. Fig. 155.
Fies. 153-155.—Seeds of Calendula officinalis, showing various forms.
the hair of any passing animal. Then follow a certain
number which are puffed out with wide wings (Fig.
154), and are evidently intended for dispersal by wind.
Towards the centre the achenes are smaller, and much
resemble small green or brown caterpillars (Fig. 155).
These, it has been suggested, are picked up by birds,
and then dropped when they discover their mistake.
Between the extreme types there are many intermediate
forms.
re COMPOSITA 235
EUPATORIUM
Flower-heads of few florets. Protandrous. The
branches of the stigma are as long as the flower-tubes,
and for three-quarters of their length clothed with hair.
E. cannabinum (Hemp Agrimony).—The plant is
so named from the form of the leaves. There are
generally only about 5 florets to a head. They are of a
reddish purple, and as the flower-heads themselves are
numerous and in compact terminal corymbs, they are
very conspicuous in spite of the small size of the indi-
vidual florets. The corolla tube has a length of
45 mm., of which 24 form a tube and the upper 2 are
expanded into a bell. The anther tube does not pro-
ject beyond the bell of the corolla. The anthers open
on the inner side, and the pollen fills the upper part of
the tube. When the flower opens the upper part of the
branches of the pistil elongate and carry up the pollen
on their hairy surface. The lower parts constituting
the stigma are still in the corolla. In the second stage
of the flower the papillary part of the stigma also pro-
trudes and is ready for fertilisation. The long pollen-
covered hairy branches of the stigma must often serve
to fertilise neighbouring florets.
TUSSILAGO
T. Farfara (Coltsfoot) has the flower-heads solitary
and yellow; while in 7. Petasites they form a com-
pound raceme, and are white or pinkish. The flower
was well described by Sprengel. It is moneecious.
The ray flowers are female; those of the disk, male ;
both being yellow. The pistil of the ray flowers
- has a pollen brush, which would appear to be use-
less, and in most Composites is not developed in the
female flowers. The male flowers are about 40, the
female about 300 in number. The male flowers only
produce honey. The flower-heads close up at night
and in bad weather. Burkill’ remarks that the female
1 Journal of Botany, 1897.
236 BRITISH FLOWERING PLANTS CHAP.
flowers do not fade as soon as they are fertilised, but
retain their clear colour until the male flowers, which
do not open till several days after the female, have shed
their pollen. The flowers are succeeded by the soft
white pappus. The plant is perennial, developing its
flowers early in the spring, and later the leaves, which
are often very large. It spreads widely by means of
burrowing stolons. The stem is somewhat woolly.
The stomata are on the under side of the leaves, and
are protected by a loose white cottony wool.
T. Petasites (Butter-bur).—In this species the male
and female flowers are, as a rule, on different plants.
There are sometimes, however, a few female florets on
the male and a few male florets on the female plant.
The male has smaller flower-heads and a looser panicle.
The male flowers are tubular below and expand into a
bell above. They secrete honey. They have a pistil,
which is necessary to brush out the pollen, but which
has no stigma. The female flowers are tubular and
honeyless. They have not a trace of stamens, and the
outer sides of the stigmas have some short hairs which,
however, can hardly be said to amount toa brush.
The stem is somewhat woolly. The leaves are char-
acteristic, and perhaps our most remarkable example,
of those adapted to situations in which the supply of
water is considerable, the air moist, and the light not
too strong. They are very large, sometimes almost a
yard across, flat, smooth, delicate, and glabrous. As,
moreover, they grow where leaves are abundant the
plants have comparatively little to fear from browsing
quadrupeds. In dry arid regions such as the Riviera
such leaves would not last a day. To the same type
belong those of Dentaria (p. 80), Orobus, Paris,
Lunaria, Mercurialis perennis (Dog’s Mercury), Arum
(Lords and Ladies), Impatiens (Balsam).
The Butter-bur is often separated as a distinct
genus, Petasites, when it is known as Petasites vulgaris.
nl COMPOSITAE 237
ASTER
The ray flowers in a single row, female; sometimes
absent. We have two species—A. T'ripolium, with ray
flowers; A. Linosyris, without.
A. Tripolium (Sea Aster) is common in salt marshes
along our coasts. As in so many shore plants, the
plant is glabrous and the leaves are succulent. The
ray florets number 20-30, are purplish violet, and
female ; the disk florets are yellow, with stamens and
pistil. The disk florets are tubular below and _bell-
shaped above. In the first stage the anther tube pro-
jects, and the pollen is pushed out by the brush of the
pistil. The lobes of the corolla are horizontal. In the
second the anther tube has retired into the cup of the
flower, the lobes of the corolla are upright, and the
stigmas protrude, exposing the stigmatic surface.
A. Linosyris has no ligulate ray flowers. The life-his-
tory of the florets is much the same as in A. Tripoliwm.
ERIGERON
Ray flowers in several rows, female, narrow or almost
filiform. Disk flowers often but few, complete. The
pistil of the female flowers is without a terminal brush,
which would be useless in the absence of pollen. We
have two species—. acre, which is annual or biennial,
and £. alpinum, which is perennial. ££. canadense,
which has thoroughly established itself, differs from the
other two in having the outer florets filiform.
E. alpinum is gynomonecious. According to H.
Miiller there are two forms of female flowers—in the
one the ray is conspicuous, in the other it is absent; so
that there are three kinds of flowers in each head. The
complete flowers also produce honey. According to
Kerner the stigmas of the female flowers are mature
some days before the pollen of the complete flowers in
the same head.
E. acris (Fleabane).—The life-history of the flower
resembles that of E. alpinum.
238 BRITISH FLOWERING PLANTS CHAP.
SoLIDAGO
8. Virgaurea (Golden Rod).—The flowers are gyno-
moncecious and freely visited by insects, and the pollen
also may easily drop from the stamens of the upper
flowers on to the pistil of the lower ones.
INULA
Ray flowers in a single row, female; disk flowers
complete. We have five species. Elecampane (L
Helenium) has large flowers, and only occurs here
and there, if indeed it is truly native. Two species
have the rays much longer than the involucre: one,
I. crithmoides, is succulent and glabrous; the other,
I. dysenterica, is downy. Of the last two, I. Pulicaria
is annual, J. Conyza perennial.
I. Helenium.—The leaves are nearly glabrous above ;
white and cottony below.
I. dysenterica is gynomoncecious.—The heads contain
about 100 ray and 600 disk flowers. The leaves are
rough above, more or less downy or cottony under-
neath.
I. Conyza is a downy plant with the under sides of
the leaves soft and cottony.
I. crithmoides, a seaside plant, is glabrous, with
succulent leaves.
I, Pulicaria.—Like J. dysenterica, but smaller, with
short ray florets, less woolly leaves, and a foetid smell.
BELLIS
The ray flowers are in a single row, are female, and
do not have the pollen brush, which is present in the
disk flowers. On the other hand, the stigmatic papille
are rather larger.
B. perennis (Daisy) is gynomonecious.—The flower-
heads vary somewhat in size. After fertilisation the
stigmas draw back into the bell of the flower. The
flowers close at sunset, whence the name, and also in wet
u COMPOSIT 239
weather. The tips of the petals are coloured red with
anthocyanin on the side which is turned towards the
ground when the head is open, and towards the sky when
it is closed (see ante, p. 212). The leaves are closely
applied to the ground, and, as in so many similar cases,
are broad. The result is that no seedlings can grow up
under them, and the plant is very injurious in meadows
and lawns. The fruits have no pappus. It has
occurred to me whether, as they would fall on the flat
plane of the leaves, the wind carries them a sufficient
distance. The plant is generally clothed with white
jointed hairs.
CHRYSANTHEMUM
We have four species. C. segetum is yellow, the other
three are white. Of these C! Leucanthemum has the leaves
toothed, while in C. Partheniwm and C. inodorum they
are pinnate; in the former the flower-heads are in
corymbs, in the latter they are terminal, and the lobes
of the leaves are narrow or filiform.
I took this genus (see p. 231) as typical of the
order, and need not therefore repeat the description of
C. Parthenvwm (Fever-few), which has been already
given.
C. Leucanthemum (the Oxe-eye Daisy) is sometimes
glabrous, sometimes downy ; C. Parthenium is pubescent.
C. segetum (Corn Marigold).—The upper side of the
corolla lobes of both disk and ray flowers is covered
with microscopic papille. The plant is glabrous.
C. inodorum.—The receptacle gradually rises in the
middle, becoming convex or hemispherical, though not
so much so as in Matricaria. Kerner suggests that
the advantage of this is to bring the stigmas of the
outer florets into the fall line of the pollen of the
inner ones. This species, and still more the next,
closely resembles Anthemzs Cotula. That species is
protected by a very bitter taste, and these two benefit
perhaps by resembling it so closely. The plant is
glabrous.
240 BRITISH FLOWERING PLANTS CHAP.
MatTRICARIA
M. Chamomilla (Wild Chamomile).—The receptacle,
as just mentioned, becomes considerably lengthened.
The plant can hardly be distinguished from A. Cotula,
except by the absence of scales between the florets. It
is glabrous. The achenes secrete mucus, which helps
to fix them to the ground and to ensure a definite
position for the seedling.
ANTHEMIS
This genus closely resembles the two preceding, but
is distinguished by the curious character that it has a
scale between each two florets.
There are four British species—three with white
flowers, and one, A. tinctoria, with yellow. In A.
Cotula the ray florets have no stigma; A. arvensis has
the scales narrow and pointed; while in A. nobilis they
are oblong and obtuse.
A. Cotula.—As already mentioned, this species has a
disagreeable taste and smell, which probably serve to
protect it from browsing quadrupeds. The receptacle
is conical from the commencement. The ray florets
have neither stamens nor pistils. They are only for
show. The plant is generally glabrous.
A. nobilis (Chamomile) is downy and aromatic.
A. arvensis has minute silky hairs. A. tinctoria is
more downy than the other species. It is not a native,
but occurs on ballast heaps and in similar places.
ACHILLEA
The flowers are gynomoneecious.
A. Millefolium (Milfoil or Yarrow). — This species
differs from our only other Achillea in having the leaves
much divided, while in A. Ptarmica they are linear
and serrated. The flower-heads are numerous, small,
often over 100 in number, and collected into a dense
terminal corymb. Each flower-head comprises about
20 disk florets, surrounded by generally 5 ray florets.
I COMPOSIT 241
The ray itself is broad and short. The list of insect
visitors is very long. H. Miiller observed over 120,
and others have been added since. The plant is some-
times glabrous, sometimes densely covered with white
woolly hairs.
A. Ptarmica.—The flower-heads are larger than those
of A. Millefoliwm, but not so numerous. They appear
to be especially attractive to bees of the genus Prosopis.
The plant is nearly glabrous.
Diortis
D. maritima.—The plant is covered with a dense
white cottony wool. It is a native of the shores of
the Mediterranean and sandy shores in our eastern and
southern counties, but very rare in this country. The
hairs are no doubt a provision corresponding to the hot,
dry climate.
TaNACETUM
The flowers are all tubular, or if the outer ones are
ligulate, they are scarcely any longer than the others.
T. vulgare (Tansy ).—Flower-heads in a large corymh,
which is very conspicuous in spite of the small size of
the individual florets. It is evident that in a plant
so arranged ray flowers are unnecessary, and indeed,
except at the edge of the corymb, the rays would be
inconvenient. It is a nearly glabrous plant, found in
waste places, but probably not a true native.
ARTEMISIA
Wind- or pollen-flowers. The florets are small, and
combined in small heads. The branches are easily
swayed by the wind. There are four British species.
Two have the leaf-segments narrow linear, while in the
other two they are broader. Of the former, A. maritima
has the stem and leaves cottony white, while in A. cam-
pestris they are green or reddish. Of the two latter, A.
Absinthium (Absinth), has the leaves silky and whitish
on both sides, while in A. vulgaris they are green above.
R
242 BRITISH FLOWERING PLANTS CHAP.
GNAPHALIUM
Wind-flowers, with small flower-heads. Ray florets
female, filiform, in several rows. Disk flowers com-
plete, tubular. Achenes with a silky pappus. There
are four British species. The name of the genus recalls
the woolly habit of the plants. Edelweiss belongs to
a closely allied genus, Leontopodium. G. supinum is
typical in this respect (see p. 28).
SENECIO
Ray flowers female, sometimes wanting ; disk flowers
complete. Achenes with silky pappus. We have eleven
species. The genus is very large, and widely distributed.
S. vulgaris (Groundsel).—The florets are almost
always all tubular; there are 60-80 in a head. The
honey is abundant, but from the smallness of the
flower-heads insect visits are not numerous. Bateson
has experimented with this species, and found that
seeds which were the result of cross-fertilisation pro-
duced more vigorous plants than those resulting from
self-fertilisation. The plant is annual with us, but
becomes perennial in Alpine districts (see Cardamine
hirsuta, p. 79). It is glabrous, or with a little
cottony wool. The sides of the achenes have short
appressed hairs, as also have those of S. sylvaticus.
These hairs secrete a mucus, which serves to attach
the achenes to damp soil.
S. viscosus—This is one of the species in which the
access of creeping insects is precluded by the presence
of a sticky secretion. The plant is covered with a short,
viscous, unpleasantly smelling down. The achenes are
glabrous.
S. Jacobea (Ragwort).—This species is perennial.
It has an unpleasant odour. The flower-heads are large,
showy, and much visited by insects. The plant is
glabrous, or with a loose woolly down. The achenes of
the disk have short hairs, those of the ray are glabrous.
This is also the case with those of S. aquaticus.
II COMPOSITE 243
S. erucefolius has the habit of S. Jacobea, but is
more pubescent. The achenes are all equally hairy.
S. squalidus.—A Southern European species which
has become naturalised on old walls at Oxford and
elsewhere. The achenes all bear silky hairs.
S. paludosus.—A native of the Fens in the eastern
counties. It has glabrous achenes.
S. saracenicus.—A South European plant which has
become naturalised by river-sides and in moist meadows.
The achenes are glabrous.
8. palustris—Native in the Fens district, but very
rare. The achenes are glabrous, with strong ribs.
S. campestris occurs on dry banks and chalk downs
in York, Lincoln, and southwards. The achenes are
downy, with faint ribs.
DoronicuM
Disk flowers complete. Ray flowers female, without
any pollen brush on the stigma. Two species occur
in Britain, naturalised in plantations. Sometimes
glabrous, sometimes hairy, and generally glandular
towards the summit.
D. Pardalianches.—The ray flowers have rudiments
of stamens, and are as richly supplied with honey as the
disk flowers. A native of Central and Southern Europe.
BrpEns
Ray flowers sometimes absent ; when present, with-
out either stamens or pistil. The achenes terminate in
a few (2-5) stiff awns, covered with reflexed prickles.
The generic name was suggested by the two stiff awns
of some species. We have two species: one, B. cernua,
with undivided leaves, while in B. tripartita they are
deeply cut into 3-5 segments. They grow in watery
places, and are both nearly glabrous.
B. cernua.—The ray florets are sometimes wanting.
The achenes have 2-3, rarely 4 awns.
244 BRITISH FLOWERING PLANTS CHAP,
XANTHIUM
The male and female florets are in different heads
on the same plant. The female flowers open some time
before the males. The males are in several rows; the
females in pairs. The involucre is covered with hooked
hairs, which very effectively secure the dispersal of the
achenes.
X. strumarium.—Though generally included in our
English lists, this is not a true native.
ARCTIUM
A. Lappa (Burdock).—The achenes are large, with a
short pappus of stiff hairs, but the dispersal 1s perhaps
more effectively secured by the strong hooks at the ends
of the involucral leaves. The leaves are green above,
more or less covered with loose cottony wool beneath.
SERRATULA
§. tinctoria.— Gynodiccious, with, according to
Kirchner, intermediate forms. The hairs of the pappus
are simple and unequal. This is one of the genera in
which there are scales between the florets. Sir J. E.
Smith pointed out that the seeds of the female are larger
than those of the hermaphrodite form.
SAUSSUREA
This genus is closely allied to Serratula, but the
hairs of the pappus, at least the inner ones, are feathery,
and the anthers have hair-like appendages at their lower
ends. ‘The florets are all tubular and complete.
8. alpina.—The florets are protandrous. The plant
is covered with loose cottony hairs. It is an Alpine
species, found in North Wales, the Lake district, the
Highlands, and Donegal.
Carpuus (Thistle)
Florets tubular, complete, with scales. Achenes
with a pappus, which is sometimes simple, sometimes
Il COMPOSIT 245
feathery. The thistles are more or less effectively pro-
tected by the spiny leaves and flower-heads. There are
eleven British species. Several of them hybridise freely.
The species with a feathery pappus are often placed
under another genus, Cnicus.
C. acanthoides——In this species the leaf surface is
supplemented by green wings which run down from the
base of the leaves. Similar wings occur in C. nutans,
C. pycnocephalus, C. lanceolatus, C. palustris, and
C. arvensis.
CaRLINA
Receptacle with scales. Florets all tubular and
complete. The white inner bracts take the place of the
ray florets and make the flower-heads very conspicuous ;
they also seem to protect the florets, as they close over
in bad weather and at night. The outer ones are very
prickly, the inner ones smooth and shining.
C. vulgaris is the only British species. The leaves
are green above, cottony below.
ONOPORDON
Receptacle with scales. Florets tubular, complete.
0. Acanthium.— The filaments are sensitive. The
plant is covered with a loose cottony wool. This is the
so-called Scotch thistle, and, though not a Scotch plant,
has been adopted by heralds as the special emblem of
that country.
In most Composites the pollen is pushed out of the
anther tube by the growth of the pistil, as already
described (p. 232). In Onopordon and Centaurea a
different plan is adopted. The filaments of the stamens
are sensitive; they protect the pollen, but if touched
by an insect, rapidly contract, carrying down, of course,
the anthers with them, and as the stigma is stationary
the pollen is squeezed out. This arrangement is
perhaps connected with the fact that in Onopordon the
heads are unable to close up.
246 BRITISH FLOWERING PLANTS CHAP.
CENTAUREA
Herbs, sometimes spiny. Receptacle with scales.
The bracts are often curiously and beautifully fringed.
The outer row of florets is generally without stamens
or pistil. The disk flowers are complete. Achenes
glabrous, generally with a pappus of short hairs. The
pollen-brush is not situated at the summit of the
stigmas, but forms a ring round the pistil just below
where it bifurcates. When the flower opens, the pollen
has already been shed into the hollow space between
the pistil and the hood formed by the anther-heads.
It is not, as in most Composites, pushed up by the
growing pistil, but the stamens are sensitive, as in the
previous genus, and when touched by the proboscis of an
insect they contract, thus exposing the pollen. This
interesting process can easily be seen if the stamens are
gently touched by a hair. The sensitive part appears
to be that covered by the hairs. If the stamen be
touched above or below the hairs no movement takes
place. Eventually the stigmas open and curl over, so
that if insect visits are delayed the flower can hardly
fail to fertilise itself. We have six species. Two are
prickly, one, C. Caleitrapa, with purple, the other,
C. solstitialis, with yellow florets. Of the other four,
two have the involucral bracts ending in small teeth ;
one, C. Cyanus, is bright blue; the other, C. aspera, is
purple. The last two have the involucral bracts with
a broad black or brown fringed border, one, C. Scabiosa,
with deeply pinnatifid leaves, while in C! negra they are
nearly entire or toothed. The stamens contract to from
one-tenth to one-fifth of their length. They take about
ten minutes to return to their original state. They are
very elastic, and can be stretched to double their usual
length, contracting again to their former size when the
force is removed. The contraction appears to affect
the whole parenchyma, but not the spiral vessels, which
consequently are waved. The tension, however, must
1 Haberlandt, Sinnesorgane im Pflanzenreiche.
ul COMPOSITA 247
he different in different parts of the tissue, for if a stamen
is cut vertically it at once rolls up. When the pistil is
full grown, and the stigmas open, the stamens lose their
power of contraction.!
C. nigra (Knapweed).—According to Knuth ray
flowers are always wanting; in England they occur,
though not generally, yet not infrequently. Hairs are
few and small; the leaves are rather cottony underneath.
C. Scabiosa.—A stouter plant than the preceding,
which, however, it much resembles. The flower-heads
always have an outer row of longer, sterile flowers.
C. Cyanus (Corn-flower).—A corn-field weed. It is
covered with a loose cottony down.
C. Calcitrapa.—A rare plant, found in dry waste places
in the South of England. It is sometimes covered with
loose cottony down ; as is also C. solstitialis, a rare plant,
found in fields in the East and South of England, but not
native; it is a native of the Mediterranean area which
has become widely naturalised.
TRAGOPOGON
The leaves are long and grass-like. Achenes narrowed
at the top into a long beak, and bearing a pappus of
feathery hairs. We have one species, 7. pratensis,
with yellow florets. 2 porrifolius, which has purple
florets, occasionally occurs as an ‘‘escape.”
T. pratensis (Goat’s-beard, John-go-to-bed-at-noon).
—The heads contain 20-50 golden-yellow florets. They
close in wet weather, and about noon, whence the name.
At Upsala, according to Linneeus, they open at 3 to 5 in
the morning and close as early as 8 to 10. The plant is
glabrous.
HELMINTHIA
Characterised by the outer bracts, which are leafy
and broadly cordate. The achenes are narrowed into a
short beak.
1 Colin. ‘‘ Ueber contractile Gewebe im Pflanzenreiche,” Jahresb. Schlesischen
Ges. 1861.
248 BRITISH FLOWERING PLANTS CHAP.
H. echioides—The plant is covered with stiff, bristly,
often hooked hairs.
Picris
Achenes not beaked, with a whitish pappus.
P. hieracioides.—The plant is covered with short, stiff,
generally hooked hairs.
Lrontopon (Hawkbit)
Achenes tapering into a short beak. Hairs of
pappus feathery. We have three species: in one,
L. hirtus, the achenes of the outer row have a pappus of
very short simple hairs; in the other two all the achenes
have a feathery pappus—one, L. hispidus, is hairy, the
other, L. autwmnalis, glabrous.
L. autumnalis—The heads contain from 50 to 80
florets. They are much visited by insects. The plant
is glabrous or with a few stiff hairs.
L. hispidus—The plant has short, stiff, erect hairs,
often forked or stellate at the top.
L, hirtus.—This is often regarded as a separate
genus—Thrincia—and with some reason. It is an
interesting example of a plant with two kinds of fruit.
The achenes of the outer row of florets are curved, taper
slightly at the top, and have a short scaly pappus.
Those of the other florets are long, striate, and rugose,
tapering at the top, and have a pappus of long brown
feathery hairs. These could be easily carried away by
the wind, while the former could grow close at home.
The plant is glabrous, or hispid with forked hairs.
Hypocueris
A few, but by no means all the florets, have palez,
or flat membranous outgrowths of the receptacle, repre-
senting the floral bracts. We have three species: one,
HI. maculata, has the involucre hairy; of the other
two, H. radicata has achenes ending in a slender beak,
while in H. glabra they have no beak.
H. maculata.—According to Linneus, at Upsala the
II COMPOSIT 249
flowers open at 6 a.m. and close between 4 and 5; while
at Innsbruck, Kerner found them opening about 7 to 8
and closing at 6 to 7. The plant is scabrous and hairy.
H. glabra, on the other hand, is glabrous; while
H. radicata has the leaves rough, with stiff hairs.
Lactrvuca (Lettuce)
There are but few florets in each flower-head. The
achenes taper into a slender beak, and have a pappus of
many white silky simple hairs. There are four British
species: ZL. muralis has the beak shorter than the
achene, and leaves on long stalks; in L. virosa and
L. Scariola the beak is about as long as the achene; in
LL. saligna, twice as long.
L. Scariola.—The plant is glabrous, but with a few
stiff bristles or prickles on the edges and midribs of the
leaves in the lower part of the plant, and on the stem.
This is a shade-loving species, and the leaves are very
delicate. While most English plants have the leaves
so arranged as to receive a maximum of light, in this
species they change their position so as to avoid it.
In the morning and evening, when it is faint, they are
ranged perpendicularly to it, 2.e. east and west. When,
however, the sun becomes strong they turn themselves
north and south, so as to receive as little light as possible.
For the same reason they are horizontal in the shade,
more or less perpendicular in sunshine. The involucral
scales ase smooth, tense, and full of a sticky juice. The
investing membrane is so delicate that it is pierced by
the claws of insects, such as ants, which thus become
smeared by the sticky j juice. The result is that they do
not attempt to reach the flowers. It is a rare plant in
waste places in some of our southern and eastern counties.
L. virosa, a commoner plant, is closely allied to the
above, but is never generally scabrous.
Soncuus (Sowthistle)
Achenes not beaked; pappus sessile, of numerous
simple hairs; leaves clasping the stem at the base.
e
250 BRITISH FLOWERING PLANTS OHAP.
There are four British species: one, S. alpinus, with blue,
the others with yellow flowers; of these S. oleraceus
is annual, the other two perennial; one, S. palustris,
has the auricles of the leaves narrow and acute; the
other, S. arvensis, short and broad.
S. arvensis is a “Sunflower,” turning round so as
to face the light. The flower-heads and peduncles are
hispid with black or brown glandular hairs. The stem is
hispid and glandular above, glabrous below.
S. palustris —A marsh plant in our eastern counties,
and now almost extinct. It is glabrous, as is also
S. oleraceus, a weed of almost world-wide distribution.
S. alpinus, is found on Alpine rocks in the North
of Scotland. It has the panicle hispid with jointed
glandular hairs ; the leaves are glabrous.
Taraxacum (Dandelion)
Bracts of the involucre in two sets: outer ones
imbricated’; inner row, equal, erect.
T. officinale—A glabrous plant, taking its common
name from the teeth of the leaves. These are very
large in some cases, and pointing backwards, while in
Fig. 156, Fig. 157. Fig. 158.
Fic, 156.—Section of part of a leaf of Dandelion grown in shade.
Fic. 157.—Section of part of a leaf grown in diffused light.
Fig. 158.—Section of part of a leaf grown in sunshine.
other plants, especially in shady places and rich soil, the
leaves are often almost entire. The flower-heads close
at night and in wet weather. At Upsala, according to
Linneeus, they open at 5-6 in the morning, and close
between 8 and 10; at Innsbruck, according to Kerner,
they open between 6 and 7, and close between 2 and 3.
*
II COMPOSIT 4 251
Each flower-head consists of 200-300 florets. The list
of insect visitors is a long one, extending to considerably
over 100 species. The pollen presents several crystalline
forms in the same anther. Self-fertilisation, in the
absence of insect visits, is ensured by the same means
as described under Centaurea. In the last stage of the
flower the stigmas bend over among the collecting hairs
at the end of the style. This is one of the plants in
which the structure of leaves grown in the sun differs
considerably from those in shade. Fig. 156 represents a
section of a leaf grown in shade, Fig. 157 represents a
section of a leaf grown in diffused light, Fig. 158 a
corresponding section of a leaf grown in sunshine. The
last is the thickest, and has two rows of palisade cells in
the upper part.
CREPIS
The pappus is very white. We have six British
species, all with yellow flowers. Two have slender beaks
to the achenes: in one, C. taraxaczfolia, all the achenes
have a long slender beak; in the other, C. faetida, the
achenes of the outer row are only short-beaked. Of the
other four, two have the lower leaves pinnatifid ; one,
C. virens, with the outer bracts of the involucre narrow
linear, while in the other, C. biennis, they are oblong
linear, with a whitish edge. The last two have mostly
oblong leaves, coarsely toothed or entire; one, C. palu-
dosa, with about 10, the other, Ci hieracioides, with
about 20 ribs to the achenes.
C. virens is a nearly glabrous annual, while
C. biennis—as the name implies, a biennial—is more
or less hispid.
C. foetida is also hairy. The interior of the bracts of
the involucre bears appressed hairs.
C. paludosa—erowing in damp places—is, as we
might expect, glabrous. The access of creeping insects
to the flowers is prevented by glandular hairs on the
bracts of the involucre.
C. hieracioides is glabrous or slightly hairy.
252 BRITISH FLOWERING PLANTS CHAP.
Hirracitum (Hawkweed)
Pappus of simple hairs. This is one of those genera
which are undergoing rapid change. The forms run
into one another, and no two botanists are agreed as to
the species.
Bentham and Hooker accept seven principal forms as
regards Britain.
H. Pilosella (Mouse-ear Hawkweed).—There are
about 50 florets toa head. According to Linneus, in fine
weather it is open from 7 to 3. The flowers are much
visited by insects. The leaves have a few long stiff
- hairs above, and are protected underneath by a white
felt of stellate hairs (see Cerastiwm alpinum, p. 28).
In very dry weather the leaf rolls up, so that the white
felt comes uppermost and protects the whole leaf.
H. alpinum is shaggy, with woolly, glandular, and
stellate hairs, as in so many mountain plants. It is a
rare plant in Britain, occurring in North Wales, the
North of England, and Scotland. It is regarded by
some as an Alpine variety of H. murorum.
H. murorum.—The stem is glabrous, or with long
white woolly hairs on the lower part, getting more dense
towards the base. The leaves are slightly hairy above,
glaucous green below. Grenier and Godron give a some-
what different account. They describe the leaves as
‘couvertes sur les deux faces ou au moins sur l’inférieure
de longs poils mous, sans poils étoilés ”; and the stem as
“plus ou moins pubescente ou herissée munie vers le
haut de poils glanduleux qui manquent quelquefois, un
peu rameuse, rarement naine et uniflore.”}
H. anglicum—Sometimes glabrous, sometimes with
long white, and other, glandular, hairs.
H. umbellatum.—The leaves are glabrous, or hairy
underneath ; the stems have long loose hairs, especially
towards the base.
H. boreale is more hairy than the last.
H. prenanthoides.—The involucres and peduncles bear
1 Flore de Franee, vol. ii.
Il COMPOSIT.E—-CAMPANULACE.E 253
short down, and black glandular hairs. The leaves are
glabrous above, glaucous and pubescent below. The
stem is sometimes glabrous, sometimes slightly hairy.
CIcHORIUM
C. Intybus (Chicory).—A stiff woody perennial, with
sessile, lateral, and terminal, blue flower-heads. The
achenes are crowned with a ring of minute erect scales.
The stem is hispid, the leaves are more or less hairy,
especially above. According to Linnzeus, the flowers at
Upsala open at 5 and close at 10; at Innsbruck, accord-
ing to Kerner, they are open from 6-7 to 2-3.
ARNOSERIS
The achenes are crowned by a minute raised border.
A. pusilla is found in dry pastures and fields on the
east side of Britain. Watson regarded it as a colonist.
The plant is nearly or quite glabrous.
LAMPSANA
Achenes without any pappus or border.
L. communis (Nipplewort).—The flower-heads are
small and inconspicuous. According to Kerner, they
are open from 6-7 to 10-11, but keep closed in bad
weather. According to Warnstorf, at New Ruppin
they are open from 6-7 to 3-4. The stem is nearly
glabrous, with a few stiff hairs below.
CAMPANULACEA
The Campanulaceee’ are protandrous, and secrete
honey. In many species (Campanula glomerata, Trach-
elium, rotundifoliwm, etc.) the flowers are hanging ; in
others (C. patula) they are upright by day, but pendent
at night and in wet weather; while in a third series (C.
1 A good account of the family is given by Kirchner, Vurtemb. Naturwiss.
Jahreshefte, 1897.
254 BRITISH FLOWERING PLANTS CHAP,
glomerata, ete.), which have short stalks, and cannot
therefore turn over, the flowers themselves close. In
the absence of insect visits the greater number are
capable of fertilising themselves; the pollen reaching
the stigmas partly through the folding of the corolla,
partly by the rolling back of the stigmas themselves.
LoBELIA
The corolla is irregular, open on the upper side.
The pollen is shed into the anther-tube, as in Com-
posite, and is swept out by the brush of the stigma.
We have two species—one, L. Dortmanna, an aquatic
plant with drooping flowers; the other, Z. wrens, a
heath plant with erect flowers. They do not seem to
be much visited by insects, but have not been carefully
watched.
In ZL. wrens the stem is angular, and the plant
puberulent. It is a South-west European species, which
finds its northern limit of distribution in the West of
England. .
L. Dortmanna is aquatic and glabrous. The leaves
are doubly fistular; that is to say, they are divided into
two longitudinal tubes.
J ASIONE
Corolla regular, deeply divided into five narrow
lobes. The anthers form a tube into which the pollen
is shed.
J. montana (Sheep’s-bit).—This species has been well
described by Sprengel. The heads consist of 100-200
pale-blue florets. It is one of the flowers most richly
visited by insects, being, indeed, surpassed only by a
few Umbellifers and Composites. The association of
the florets into heads, the convenient position and rich
supply of nectar, and the arrangement of the flower, all
contribute to this result, and about 150 species of insect
visitors are on record, of which over 50 are bees, 30
butterflies and hawkmoths, and 30 flies. Perhaps in
consequence, the power of self-fertilisation is apparently
II CAMPANULACE 255
almost lost. The plant is sometimes, though rarely,
glabrous, sometimes clothed with simple, sometimes
with long, stiff hairs.
PuytEeuma (Rampion)
The anthers shed their pollen in the bud, as in the
Composite, but the tube into which it is received is not
enclosed by the anthers themselves, but by the lobes of
the corolla. The upper part of the pistil also resembles
that of the Composite, in being provided with a brush,
and terminating in two branches. It acts in the same
manner, first sweeping out the pollen, after whicli the
two branches diverge, and thus expose the stigmas.
They are long enough eventually to reach some of the
neighbouring florets, and thus in the absence of insect
visitors the flower fertilises itself. There are two British
species : one, P. orbicwlare, has rounded, the other, P.
spicatum, oblong, and finally cylindrical, heads.
P. spicatum.—Flower-heads with about 100 florets,
pale blue or yellowish white, with green tips. The plant
is glabrous or pubescent. It is found, in this country,
only in Eastern Sussex.
P, orbiculare—Flower-heads, with 15-30 florets, deep
blue. A native of the chalk downs in our south-eastern
counties.
Campanuta (Bell-flower)
The corolla is regular, or nearly so, and bell-shaped,
as the name denotes. The lower parts of the filaments
are swollen and cover the honey; the anthers are dis-
tinct; the styles 2, 3, or 5. The flowers are especially
adapted for bees. The life-history of the flower falls
into four periods. Even before the opening the anthers
shed their pollen on to the hairy pistil, against which they
are pressed by the folded corolla (Fig. 159). This is the
first stage. Soon after the flowers open, the anthers and
upper part of the filaments shrivel up; the lower portions,
however, swell, and form a covering for the honey. The
hairs on the pistil gradually draw themselves in, thus
256 BRITISH FLOWERING PLANTS CHAP.
exposing the pollen, which is gradually carried off by
the insects visiting the flowers for the sake of the nectar
(Fig. 160). This is the second stage. When the hairs
are all withdrawn the stigmas open out, and are ready
to receive pollen (Fig. 161). This is the third stage.
Fourthly and finally, in the absence of insect visits the
stigmas bend over and dust themselves with any pollen
which may be remaining on the pillar of the pistil.
The fruit is a three-celled capsule. The seed
capsules are in some species erect, in others hanging.
The former open at the apex, the hanging ones at
Fig. 159, Fig. 160. Fig. 161.
Fics. 159-161.—Campanula medium. Fig. 159, section of bud ; Fig. 160, section of
flower in first (male) condition ; Fig. 161, section of flower in second (female)
condition. wu, anthers ; ca, calyx ; co, corolla ; /, filaments of stamens ; p, style
with stigmas ; yo, pollen.
the base. Thus in both cases the opening is at the
actual upper part of the capsule. I have suggested
that the object is to provide for the dispersal of the
seeds. The result is, that they do not fall directly
out of the capsules, but remain in them until on some
windy day the capsules are swung backwards and for-
wards, and eventually scatter the seeds. In the hanging
capsules the method by which the valves at the base
open is very peculiar. In C. mediwm, for instance, the
inner face is very much thickened and lignified. The
thickened portion is ovate, and drawn out into a long,
acuminate neck, extending up into the capsule; the
broader end is at the base of the capsule, and corresponds
Mt CAMPANULACEE 257
to the outline of the valve. Along the centre is a
shallow groove. At maturity this process becomes
convex on the inner face, and deeply concave on the
outer, breaking away from the rest of the capsule, while
at the same time the thin edges turn outwards. The
seeds are of large size for the genus, oblong, often
broader at the opposite end from the hilum, biconvex,
and frequently surrounded at the edges by a narrow,
thin margin, especially when not over well filled. The
testa is bright reddish brown, polished, smooth, and
shining.
C. rotundifolia (Harebell). —The rounded radical
leaves (see Viola palustris, p. 29), from which this
beautiful plant has received its name, are generally
withered before the flowers open. The upper leaves are
narrow. The plant is glabrous or pubescent.
C. rapunculoides.—The flowers are borne in long ter-
minal racemes. The capsules are hanging, but small
doors open near the base, and therefore at the upper
part, through which the seeds are jerked during wind.
They close if it rains, and open again when the sun
comes out. The plant is glabrous or pubescent.
C. Trachelium has the flowers in clusters. According
to Kerner, at Innsbruck the flower is open from 6-7 in
the morning to 6-7 at night. On the Brenner the flowers
are white. The leaves are scabrous, with short hairs;
the stem hispid.
C. Rapunculus.— The flowers are in long terminal
racemes. The plant is hairy and rather rough; rarely
glabrous.
C. glomerata.—The flowers are sessile, in compact
clusters. The plant is glabrous or pubescent.
C. latifolia (Giant Campanula).—The blue or white
flowers are solitary in the axils of the upper leaves.
They were well described long ago by Pontedera.’ The
capsule is hanging.
C. patula is pubescent. The flowers are in a spread-
ing panicle, more open than in the other species. They
1 Anthologia, 1720.
8
258 BRITISH FLOWERING PLANTS CHAP.
are upright in sunny weather, pendulous at night and
when it rains.
SPECULARIA
Remarkable for the long triangular ovary. Flowers
sessile. Corolla blue, very open.
S$. hybrida.—A corn-field weed, chiefly in the eastern
counties. The flowers are protandrous. The style is
clothed with hairs, on which the pollen is deposited. It
is used by insects as an alighting stage, and they can
hardly fail to carry off some of the pollen. Every even-
ing the corolla folds up longitudinally, and the five pro-
jecting angles also dust themselves. The three stigmas
open out when mature, and insects coming from another
flower deposit pollen on them. When the flower folds
up at night they come in contact with the pollen on the
projecting ridges of the corolla.
WAHLENBERGIA
The pistil secretes a viscid fluid, to which the pollen
adheres.
W. hederacea.—A graceful, prostrate plant, glabrous,
with delicate ivy-shaped leaves. The flowers are on long
stalks, and pale blue, with darker veins. The filaments
widen gradually downwards, and after the anthers have
shrivelled up the broad base remains as a protection to
the honey. A South-western European plant, found in
bogs and damp woods in our southern and especially in
the western counties.
ERICACE.X
Stamens sometimes equal in number to, but generally
twice as many as, the divisions of the calyx or corolla;
cells of ovary as many, sometimes apparently twice as
many. Fruit a capsule or berry. Flowers, as a rule,
with honey.
ul ERICACEA 259
ANDROMEDA
A. polifolia is a small glabrous bog plant, seldom
above 6 inches high. The leaves are evergreen, glaucous
below, and with their edges rolled up—a_ provision
found in many plants growing in peat bogs in cold
climates. The air is often saturated with moisture for
weeks, and the summers are short. If the stomata or
breathing pores, which are on the under side of the
leaves, were liable to be clogged with moisture, it might
often happen that, even when the sun appeared, it would
take so long to free the passages that dew and rain
might come on again before they were open. Under
these circumstances it is of great importance to protect
the stomata, and one way in which this is effected is by
rolling the leaves. We find this arrangement in some
of the Silenes, Heaths (see p. 27), in Azalea, Cranberry
(Vaccinium Oxycoccos), Crowberry (Empetrum) (see
Fig. 11, p. 28), Ledum, some Willows, and some of the
grasses associated with them. Certain grasses have the
leaves flat in fine weather, but are able to roll them
up if it is wet.
LoIsELEuRIA (Azalea)
L. procumbens is a low trailing moorland shrub, found
in the Scotch mountains, with evergreen leaves rolled
back at the edges. The small rose-coloured flowers are
borne in terminal clusters. The anthers open inwards
and surround the pistil, so that insects dust themselves
on one side with pollen, and touch the stigma with
the other. Gradually, however, they bend over towards
and fertilise the stigma.
VaAccINIUM
Honey is secreted by a ridge on the ovary. The
anthers have lateral appendages. We have four species.
Two are deciduous, with black or bluish berries; of these
V. Myrtillus has toothed, V. uliginosum entire leaves.
The other two are evergreen, with red berries ; one, V.
260 BRITISH FLOWERING PLANTS CHAP,
Vitis-Idea, with a bell-shaped, the other, V. Oxycoccos,
with a spreading corolla. The pollen is dry and pulveru-
lent. The anthers are provided with appendages as in
Erica, and also have an orifice at the tip, but the pollen
is prevented from falling by the anthers being applied
against the pistil—not, as in Erica, against one another.
When the ring of anthers is dislocated by the bee the
pollen falls on the insect.
V. Myrtillus (Bilberry or Whortleberry).—The stems
are glabrous, angular, green, and supplement the leaves
as organs of carbon-assimilation. The flowers, which
hang down, are a pale greenish white, rich in honey,
supplied by a ridge which surrounds the base of the
ovary. The corolla is swollen at the base and con-
tracted at the summit so as to leave a comparatively
narrow entrance. ‘The stigma projects a little, but
the anthers remain in the bell. This is the favourite
flower of Vespa rufa.’ The berries are nearly black,
which probably is more conspicuous against the sur-
rounding vegetation than red would be.
V. uliginosum.—A smaller plant, but more woody,
and with nearly cylindrical branches. The flowers are
smaller, but redder and more conspicuous. They are also
more open, and therefore accessible to a larger number
of insects. The berries are nearly black. The plant
is common in the Highlands and our northern counties.
V. Vitis-Idea (Cowberry).—The stems are glabrous,
procumbent, and straggling. The flowers are in terminal
drooping racemes. ‘The corolla is white or a pale flesh
colour, with spreading, but not reflexed, lobes. The
filaments are hairy. The anthers are elongated, and
almost as long as the filaments. According to Warming
the flowers are protogynous, and in some cases the
pistil is wanting. On the under sides of the leaves
are small depressions, each of which is nearly filled by
a club-shaped structure composed of thin-walled cells.
These absorb the water which collects in the little pits.
See also Viola palustris (p. 29).
1 Evans, Entomologists’ Monthly Mag. 1903,
II ERICACEE 261
V. Oxycoccos (Cranberry).—The procumbent stem is
much more slender than in the other species. The
leaves are lanceolate, evergreen, glaucous below, and
with the edges rolled back. The flowers are on long
slender peduncles; the corolla is red with reflexed lobes,
exposing the stamens, which are widened, and thus form
a tube protecting the honey. Their whole outer side is
rough with short hairs, but those on the edges are
longer and so interlocked that no insect can get at the
honey through them, but must push its proboscis between
the anthers. No insect visitors have yet been recorded,
but some bees are very early risers, and work short
hours, so that they may easily be missed. The flowers,
moreover, are long-lived, lasting, according to Sprengel,
no less than eighteen days.
ARCTOSTAPHYLOS
A. Uva-Ursi (Bearberry).— The flowers are 4-6
together, in compact terminal drooping racemes. The
honey does not remain on the nec-
tary, but runs into ten cups at the
base of the corolla. It is prevented
from running down any further by
the hairs on the outer side of the
stamens and the inner side of the
corolla. The stamens (Fig. 162) are
narrow at the base, then expand
suddenly, forming a closed ring round , ;
the ovary, then again diminish into a ee ae
cylindrical filament. At the base of — Uyst seen from the
the anther are two long tail-like ““ *~” ul
appendages. Hive bees and humble bees seem alone to
be able to reach the honey. The fruit is red. The
leaves are shining, evergreen, obovate or oblong.
A. alpina (Fig. 163).—This is, strictly speaking,
a Northern, not an Alpine species. The flowers are
generally 2-3, in compact terminal drooping racemes.
The appendages of the anthers are much smaller, and
in Greenland are said to be altogether wanting.
262 BRITISH FLOWERING PLANTS CHAP.
The fruit is black, which is probably more conspicuous
among the brown leaves of autumn. The leaves,
which are ciliated, are thin,
strongly veined, and toothed at
the top. It occurs in Britain only
on Ben Nevis and the northern
Highlands,
Erica
The parts of the flower are in
Fic, 163.—Section of fower OUTS ‘The fruit is a capsule with
of Arctostaphylos alpina. 4 cells, opening with either 4 or 8
x7. d, anther; 7, nec-
tary; p p, lobes of the valves. :
corolla; s, sepal; st, E. Tetralix (Cross-leaved Heath)
Ee Pee is pubescent. The leaves are in
fours, the edges are fringed with long and often glandular
hairs. The flower is in the
form of a bell (Fig. 164),
which hangs with its mouth
downwards, and is almost
closed by the pistil, and
stigma (st), which represents
Fic. 165.—Stamen of Krica Tetratlix.
a, anther; f, filament ; pr, appendages
of anther.
the clapper. The stamens
are 8 in number, and each
terminates in 2 cells, which
_ diverge slightly, and have at
Fia. 164.—Section of flower of Erica :
Tetraliz, aa, anthers; f f, base their lower end an oval open-
of filaments ; p, style ; pr, append- ing (Fig. 165). But though
spe chanDers Seana this opening is at the lower
end of the anther cells the pollen cannot fall out,
II ERICACEE 263
because each cell, just where the opening is situated,
rests against the next anther cell, and the series of
anthers thus form a circle surrounding the pistil and
not far from the centre of the bell. Each anther cell
also sends.out a long process (p7), which thus form a
series of spokes standing out from the circle of anthers.
Under these circumstances, a bee endeavouring to suck
the honey from the nectary cannot fail, firstly, to bring
its head in contact with the viscid stigma (Fig. 164, st),
and thus to deposit upon it any pollen derived from a
previous visit; and, secondly, in thrusting its proboscis
up the bell it inevitably comes in contact with one of
the processes (p7), which then acts like a lever and dis-
locates the whole chain of anther cells, when a shower
of pollen falls on to its head.
E. cinerea (our Common Heath).—The arrangement
of the flower agrees with that of HL. Tetralix; the leaves
are, however, glabrous, and in whorls of three.
E. carnea.—In this species—which is a native of
Ireland, but not of Great Britain—the plant is ren-
dered additionally conspicuous by the redness of the
stem. The anthers have no processes, and project a
little beyond the corolla. The style is still longer, so
that insects visiting the flower must touch the stigma
first, and then the anthers. It cannot fertilise itself,
as the stigma is not widened out, but is, as it were,
cut sharp off. The pollen grains are united in fours.
From the narrowness of the entrance H. Miiller looks
on this as a butterfly flower. The bright red colour
also points in this direction. He found it, in fact,
almost exclusively visited by Vanessa cardw. The
flower-buds are fully formed in the summer for the suc-
ceeding year.
CALLUNA
Calluna vulgaris (Ling).—This species was formerly
described as a species of Erica, but is now regarded,
and, as it seems to me, correctly, as a distinct genus.
264 BRITISH FLOWERING PLANTS CHAP.
The corolla is small, and the red colour is due to
the calyx, which has four small bracts at the base.
The appendages of the anthers are covered with rough
hairs. The leaves are glabrous, and somewhat concave
below. It is a Northern and Alpine species, especially
adapted to resist cold (see p. 27). The leaves are, as a
rule, closely appressed to the stem, but in shady places
diverge from it so as to receive more light.
Pyrota (Wintergreen)
Low herbs, sometimes rather woody; some with,
others without, honey. We have five species. One,
P. uniflora, has a single flower, the others several. P.
secunda has small flowers in a one-sided raceme, and
pointed leaves. In P. rotundifolia the style is much
longer than the corolla and curved; in P. intermedia
it is longer and straight; in P. minor it is not longer
than the corolla. The pollen grains remain coherent in
fours. This fact, which we have noted in other species,
is simply the persistence of an earlier stage of develop-
ment. The pollen grains are formed by division of a
mother cell into four as a result of successive bipartition.
In so-called powdery pollen the separation of the daughter
pollen grains is complete, but not infrequently they
remain aggregated in the original tetrad.
P. secunda.—The flowers are protogynous, and
crowded on a one-sided spike; the petals are greenish
white. This species may be taken as typical of the
genus. Honey is secreted at the base of the corolla.
The anthers open near the base, which, however, is
brought upwards by a curvature of the stamens. The
anthers are kept in this position, with the pore
upwards, by the petals, but when an insect pushes
into the flower and presses back one of the petals, the
anther at once drops down, and some of the pollen
falls out.
P. uniflora.—The flowers are large, but honeyless ;
the general arrangement is as in P. secunda. The
II ERICACEE 265
pores of the anthers are produced into short tubes
(Fig. 166). The pistil at first stands out so that it
is well beyond the stamens, but the flower gradually
curves down so that the stig- .
mas come within the fall line
of the pollen. The leaves form
little saucers, thus probably
retaining a store of water as a
provision for dry weather. The
seeds are very minute.
P. minor.—The flowers are
homogamous, drooping, and
borne in a short loose raceme Fic, 166.—Pyrola uniflora. Section
on an erect peduncle 4-9 inches feito eo anther
high. The sepals and petals “"™ "eS" PO™
are broad and rounded, the latter concave, closing over
the stamens. There is no honey, but the five lobes of
the stigma secrete a sticky fluid which is licked up by
insects.
P. rotundifolia has larger and sweet-scented flowers,
but without honey ; homogamous according to Knuth,
protandrous according to Warnstorf. Knuth mentions
that in a peat-moss near Kiel he had the opportunity of
watching many specimens of this plant intermixed with
Parnassia palustris. The flowers of the latter, though
smaller, were much visited by insects, while the former
were quite neglected.
P. media.—The pistil is at first upright, but finally
bends over, and, as some of the pollen generally falls
into the saucer-shaped petal below, is able to fertilise
itself.
MonoTRoPa
Homogamous flowers, with concealed honey.
M. Hypopitys.—This curious plant is 6 or 8 inches
high, with a few flowers in a terminal raceme. It is
of a pale brownish or dingy yellow colour, and lives
in woods. The roots are short and fleshy. They are
embedded in humus, and enveloped in a thick mantle
266 BRITISH FLOWERING PLANTS CHAP.
of fungus mycelium, by means of which the plant is
able to feed on the nutritive matter in the humus.
It is a case, therefore, of a flowering plant living at the
expense of a fungus, reversing the usual rule. Prob-
ably, however, the fungus also derives some advantage
from its association with the Monotropa. The terminal
flower is in fives, the rest are in fours; the former,
according to Kirchner, having 10, the others 8 nec-
taries at the base of the ovary, which project into
corresponding hollows in the corolla. The anthers open
transversely. The style is hairy, which tends to pre-
vent the pollen from reaching the stigma of the same
flower.
PRIMULACEA
The flowers in this beautiful family offer considerable
variety in their arrangement. The corolla, indeed, is in
all cases the invitation to the feast. Some, however,
are merely pollen flowers, though the majority secrete
honey. Samolus has a “sham” nectary. In some
species the honey is accessible to bees with a short
proboscis, in others only to those with a long one, while
there are some—Primula farinosa, for instance—which
are adapted to Lepidoptera. Many species of Primula
and Hottonia are dimorphous. The flowers of some
species are upright and apparently unprotected, but the
mouth is narrow, so that rain-drops cannot enter, but
roll off the surface.
PRIMULA
Honey is secreted by tho base of the ovary. The
capsule dehisces by ten valves. The outer epidermis is
passive ; the cells within are lignified and contract on dry-
ing, while the inner epidermis forms the layer of resistance
(Fig. 167). At the lines of fissure the inner epidermis
only is lignified, while elsewhere this is the case with
the whole of the inner tissue. We have four species.
rt PRIMULACEA 267
Three are yellow-flowered : the Primrose, with peduncles
one-flowered and apparently radical; and the Cowslip and
Oxlip, in which the peduncles bear an umbel of several
flowers. The limb of the corolla in the Cowslip is small
and concave, in the Oxlip broad and flat. These three
were considered by Linnzus and Bentham as varieties
of one species. Lastly, P. farinosa is pale lilac, and
is covered in parts with a white meal. All four are
dimorphous; that is to say, if a number of specimens
are examined it will be found that about half of them
have the stigma at: the top of the tube, and the stamens
half-way down (as is shown in Fig. 168); while the other
o
Pr)
One
Fic. 167.— Primula elatior. Section through the wall ofa capsule. e, external epiderm ;
i, internal epiderm, partly lignified ; J, line of dehiscence ; », parenchyma.
half have, on the contrary, the stamens at the top of the
tube, and the stigma half-way down (as shown in Fig.
169). Corresponding differences occur in Polyanthus and
Auricula. They have long been known to gardeners, and
even to school children, by whom the two forms are dis-
tinguished as “ pin-eyed ” and “‘thrum-eyed.” As already
mentioned, plants which present these differences are
known as heteromorphous (in opposition to those which
are homomorphous, or have only one kind of flower).
Heteromorphous species with two forms are called
dimorphous; those with three, trimorphous. Sprengel
himself had noticed a case of dimorphism in Hottonia,
and shrewdly observed that there was probably some
reason for it, but was unable to suggest any explana-
tion. In Lythrum the existence of different forms had
268 BRITISH FLOWERING PLANTS oar,
been observed by Vaucher in 1841, and in the genus
Oxalis by Jacquin, who regarded them as indicative of
different species ; but it was reserved for the genius and
perseverance of Charles Darwin to explain’ the signifi-
cance of this curious phenomenon, and the important
part it plays in the economy of the flower. Now that
it has been pointed out, it is sufficiently obvious.
An insect thrusting its proboscis down a Primrose
of the long-styled form (Fig. 168) would dust its pro-
boscis at a part which, when it visited a short-styled
flower (Fig. 169), would come just opposite the head of
Fig. 168. Fig. 169.
Fic. 168.—Primula farinosa. Long-styled form and pollen.
Fic. 169.—Short-styled form and pollen,”
v, anthers ; ca, calyx ; co, corolla ; st, stigma. Pollen x 250.
the pistil, and could not fail to deposit some of the
pollen on the stigma. Conversely, an insect visiting a
short-styled plant would dust its proboscis at a part
further from the tip, which, when the insect sub-
sequently visited a long-styled flower, would again
come just opposite the head of the pistil. Hence we
see by this beautiful arrangement, insects must carry
the pollen of the long-styled form to the short-styled,
and vice versa.
There are other points in which the two forms differ
from one another; for instance, the stigma of the long-
styled form is globular and rough, while that of the
short-styled is smoother and somewhat depressed. The
pollen of the two forms (Figs. 168 and 169) is also dis-
1 Journ. Linn. Soc. (Bot.) vi. (1862).
Il PRIMULACEAS 269
similar, that of the long-styled being considerably
smaller than the other—+,% 5 of an inch in diameter
against +944, or nearly in the proportion of three to
two—a difference the importance of which is probably
due to the fact that each grain has to give rise to a
tube which penetrates the whole length of the style,
from the stigma to the base of the flower ; and the tube
which penetrates the long-styled pistil must therefore
be nearly twice as long as in the other. Darwin
showed that much more seed is set if pollen from the
one form be placed on the pistil of the other than if the
flower be fertilised by pollen of the same form, even
when taken from a different plant. Nay, what is most
remarkable, such unions in Primula are more sterile
than crosses between some nearly allied though dis-
tinct species of plants. Darwin’s explanation has
been generally accepted by botanists. It has, how-
ever, been questioned by the late Mr. E. Bell in a
special work (The Primrose and Darwinism, by a
Field Naturalist), and again in a paper “On the
Pollination of the Primrose,” in Nature Notes for
April. This paper has a pathetic interest, as the
author, who had been for some time in bad health,
died before it was published. Mr. Bell scarcely appre-
ciated, I think, the cases of insect visits which are on
record, and the fact that while Darwin attributed the
fertilisation to night-flying moths, most of the obser-
vations have been made by day. The length of the
pistil varies very much both in the Cowslip and the
Primrose, and both sometimes produce equal-styled
varieties.
P. veris (Cowslip) is visited by humble bees and
solitary bees in the day, and by moths at night.
P, vulgaris (Primrose) is rarely visited by the larger
humble bees, and not often by the smaller ones. It
appears to be mainly fertilised by moths, but is some-
times visited by Bombus hortorum.
P. farinosa.—In the Alps this species is visited
principally by butterflies ; in lower districts by humble
270 BRITISH FLOWERING PLANTS CHAP.
bees. The leaves are glabrous above; the under side is
covered by a waxy secretion, which protects the stomata
from being clogged by rain or dew.
H. Miller gives the following list of insect visitors
—twelve in number:—Coleoptera: Omalium florale,
numerous, creeping about in the flowers. Diptera:
Bombylius discolor, numerous; B. major, rarer, and
probably not often getting to the honey. Hymen-
optera: Bees: Anthrena gwynana, female, frequent on
the short-styled flowers ; Anthophora pilipes, both male
and female, very numerous; the hive bee, sucking busily ;
Bombus confusus, female; B. hortorum, female, very
numerous; B. lapidarius, female; B. silvarwm, female ;
B. terrestris, robbing the flower of its honey after biting
through the corolla; Osmia rufa, male.
Horronta
This genus resembles Primula in the position of
the honey, and in being dimorphous. It is sometimes
cleistogamous.
H. palustris (Water Violet).—As in so many other
water plants the leaves are cut up into numerous narrow
linear lobes. That the plant was originally terrestrial is
indicated by the aerial flowers. The observations made
by Darwin on Primula were repeated and confirmed as
regards Hottonia by John Scott and subsequently by
H. Miiller.
CYCLAMEN
C. europeum.—The flowers produce no honey, but it
is supposed that insects pierce the delicate tissues inside
the tlower and thus obtain a sweet sap. The flowers
are pendent, and being smooth and slippery, Kerner
has suggested that creeping insects are unable to get
round the lip, but slip off and fall down. The flowers
are protandrous, and the pollen is at first sticky, but
gradually becomes dry and pulverulent. The anthers
open at the apex. When the flowers first open, the
flower-stalk is bent nearly at a right angle, so that as
rt PRIMULACEA 271
it opens, the pollen which drops, and which from its
stickiness is but little, falls (Fig. 170) clear of the pistil.
Gradually the stalk bends downwards (Fig. 171), moving
about 10 per cent a day, and finally (Fig. 172) hangs
almost perpendicularly, so
that the pollen, which has
now become dry and_ pul-
verulent, drops on to the
stigma. The leaves are glab- _/
rous and oval, but in the
species or variety known as
Ci hederefolium they are
ivy-leaf in form. No ex-
planation of the difference, so
far as I know, has been sug-
gested. The flower is said to
last ten days. When the
flower is fertilised the stem
contracts into a spiral, and
carries the fruit down to, and
even into, the ground. The
seeds gradually ripen during
the winter, while the lower
part of the stalk rots away, the
upper portion remaining as a
hook attached to the capsule
and facilitating its dispersal.
LysIMAcHIa
Fias. 170-172.— Cyclamen europeeum.
The parts of the flower are Fic. 170.—Position of flower as it.
: opens,
generally in fives, but SOME- Fig, 171.—Position of flower when
times in sixes. The flowers, as _ fully open.
me ‘ Fic. 172.—Final position of flower.
m the preceding genus, are a, flower-stalk ; 6, cone formed
honeyless We have four by the anthers ; c, fall line of
‘ i the pollen.
species. Two have erect
stems: LZ. vulgaris, with short terminal panicles; and
L. thyrsiflora, with flowers in axillary racemes. The
other two are trailing plants: one, L. Nummularia,
with large flowers and broad calyx segments; the
272 BRITISH FLOWERING PLANTS CHAP,
other, Z. nemorum, with small rotate flowers and
narrow calyx segments.
L. vulgaris appears to be in special relation with
one species of bee—Macropis labiata. This insect does
not appear to exist where L. vulgaris does not occur.
Besides the usual large flowers there are other smaller
ones, slightly modified, so as to favour self-fertilisation.
The stem is sub-quadrangular, and the leaves pubescent
below, with black spots.
L, Nummularia (Moneywort).—From the structure
of the flower the pollen must often fall on the stigma,
but, according to Darwin, it has little effect, and Kerner
refers to the species as self-sterile. The plant is gla-
brous, with a quadrangular stem.
L. thyrsiflora has protogynous flowers.
TRIENTALIS
The parts of the flower are generally in sevens,
which is a very unusual number. There is no honey,
but a juicy fleshy ring surrounding the ovary, and,
bearing the stamens, is probably pierced by the insects
for the sake of the sweet juice. This and other similar
cases seem to indicate the manner in which honey may
have been gradually evolved.
T. europea is generally protogynous, but the plants
observed by Schulz in the Riesengebirge were homo-
gamous, or very slightly protogynous. Whien the
anthers open, an insect visiting the flower would touch
them on one side and the stigma on the other. The
pistil somewhat elongates while the flower is open, so
that eventualiy the stigma is raised a little above
the anthers. Finally, the flower closes, pressing the
anthers against the stigma, and thus, it would seem,
ensuring self-fertilisation.
GLAUX
A small decumbent seaside plant, without any
corolla, the function of which is taken over by the
reddish calyx. Honey is secreted, though only in small
I" PRIMULACEE 273
quantity, by the base of the flower. The single species,
G. marituma, is widely spread in the temperate parts
of the northern hemisphere.
ANAGALLIS
Creeping herbs. The flowers are homogamous and
without honey. The capsule opens transversely by a
circular fissure across the middle. Along the line of
dehiscence the cells are elongated transversely (Fig.
173, c), and are but slightly attached, while above and
below they present irregular outlines, which tend to
keep them together. We have two species: one
perennial, with a campanulate pale-pink corolla, A.
tenella; the other annual, with a rotate deep-red, pink,
blue, or white corolla, A. arvensis. The seeds are dark
brown, biconvex, flattened on the dorsal aspect by
pressure against the wall of the pericarp, and covered
with obtuse, broad-based teeth, which give them the
appearance of being deeply pitted.
A. arvensis—The flower is open from about 9 a.M. to
3 P.M., and it is interesting from this point of view that
the only insect visitor yet
recorded (Halictus morio) “er 0)
belongs to a genus which also N ve ‘i
goes to rest early. When ae
the corolla closes, the stigma Da es
would probably come in =<
contact with the anthers 2S
Moreover, the corolla drops <=
early, and in slipping over » a.
the pistil can hardly fail to ee, Cc
dust the stigma with pollen. ) v | =
The blue form, which, though \ IX i
rarer with us, is equall
common in the South of Fic. 173.—Anagallis arvensis. Wall
? i of the capsule. cc, elongated cells
Europe, is often considered, along the line of dehiscence,
pe,
as, for instance, by Bentham
and Hooker, to be merely a variety. Clos, however,
finds that the two are infertile together, in which
T
274 BRITISH FLOWERING PLANTS CHAP.
case they must no doubt be regarded as distinct
species. The plant is glabrous, with a quadrangular
stem; the leaves bear black dots. The stem has water
furrows, which start from the intervals between the
leaves.
A. tenella.—Here the pistil projects beyond the
anthers, so that self-fertilisation seems unlikely. The
tube of the flower is almost filled by the woolly hairs
of the stamens. The stem is quadrangular and glabrous.
CENTUNCULUS
The capsules open transversely, as in Anagallis.
C. minimus.—The flowers, according to Kerner, are
only open between 10 and 11. In the island of Fohr,
Knuth found them to be cleistogamous. The plant is
glabrous.
SaMOLUS
The capsule opens in five valves.
S. Valerandii—aA glabrous plant growing in Britain,
generally near the sea. The ovary has a ring at the
base which resembles a nectary, but apparently secretes
no honey. The anthers are at the same height as the
stigma, and open inwards, so that the flower can easily
fertilise itself.
LENTIBULARIACE
Corolla two-lipped. Stamens 2.
UrricuLaria (Bladderwort).
Calyx deeply two-lobed. Corolla spurred. Capsule
globular, opening in two valves. Our species of the
genus are all floating plants, without roots, and with
leaves divided into “capillary branches, bearing little
bladders or utricles, whence the name. As in so many
I LENTIBULARIACE 275
aquatic plants, the flowers rise above the water, an
Fic. 174.— Utricularia vulgaris. a, flower seen from the side ; }, flower seen from
the front ; c, ovary and pistil ; d, stamen ; e, part of leaf showing a bladder.
Fie, 175.— Utricularia vulgaris. 1, The flower, natural size. The dotted line shows
the position which the spur takes on the downward pressure of the under lip. 2,
Stamens and pistil shortly before the opening of the bud, viewed from under-
neath. 3, The same, viewed from the side. 4, The same, viewed from above.
5, The same, from a newly opened bud, viewed from the side. The lobe of
the stigma is bent downwards. 6, The same, viewed from underneath. 7, The
same, viewed from above. 8-10, The pistil, after an outward irritation upon the
lobe of the stigma, and after the withdrawal of the corolla, in consequence of
which the stigma lobe, unimpeded by the corolla, has strongly turned itself
upwards.
indication of their originally aerial condition. We have
276 BRITISH FLOWERING PLANTS CHAP.
three species: U. intermedia is distinguished by the
bladders being on separate branches; in U. vulgaris
the spur is conical; in U. minor it is very short.
They are said to be fly flowers, the entrance of the
corolla being too narrow for bees. It is seldom that
flies show sufficient intelligence to avail themselves
of a flower so complicated. The remarkable bladders,
from which the genus derives its name, have been speci-
ally studied by Cohn’ and Darwin.* Darwin worked
mainly with U. neglecta. The bladders, he says, “ are
supported on short foot-stalks. When fully grown they
are nearly one-tenth of an inch (2°54 mm.) in length.
Fic. 176.— Utricularia vulgaris. Bladder much enlarged. ¢, collar indistinctly seen
through the walls ; e, entrance; d, a small Crustacean (Chydorus) which has
been captured.
They are translucent, of a green colour, and the walls
are formed of two layers of cells. The exterior cells are
polygonal and rather large; but at many of the points
where the angles meet, there are smaller rounded cells.”
The interior is lined with a serried mass of absorbent
processes, in groups of four, two long and two short.
The general form is shown in Fig. 176. The lower side
is nearly straight, the upper much arched, and terminates
in some long processes, two of which are larger than
the rest and branched, giving the whole organ a curious
resemblance to a Daphnia. At the angle is an entrance
1 Cohn, ‘‘ Ueber d. function der Blasen von Aldrovanda u. Utricularia,” Beitr.
Biol. Pflanzen, i. Heft 3 (1875).
2 Darwin, Insectivorous Plants.
u LENTIBULARIACEE 277
closed by a flap (Fig. 177, 178, c), which plays freely on
arim or collar. This flap i is easily pressed inwards, but
then springs back into place. Minute fresh-water Cras-
tacea and insects seem to have a singular fascination for
entering, and once
in, as they cannot
open the flap from
inside, they are
doomed. Darwin
found in one
bladder as many
as ten minute
Crustacea. The
walls of the en-
trance (Fig. 177,
a) are slightly
contracted in
the centre like
{though not so
much as) an hour-
glass; and the
flap (6), shown by
the dotted line,
being nearly semi-
circular, can open
inwards, but not
outwards.
U. vulgaris.—
The arrangement
of the flower in Fi. 177.—Utricularia vulgaris, Opening of bladder,
seen in front; much enlarged. «, wall of opening ;
some respects re- b, outline of the flap ; c, opening.
sembles that of
Antirrhinum (Snapdragon). The two lips of the
corolla completely close the flower. The upper lip is
simple: the lower consists of three parts (Fig. 175, 1)
—(1) the spur which contains the honey; (2) the
arched prominence which abuts against the upper lip
and closes the flower; and (3) the lateral projecting
lobes. These serve as an alighting stage for the
278 BRITISH FLOWERING PLANTS CHAP.
fly, the weight of which presses down the lower lip,
and thus opens the way to the honey. As in Antir-
rhinum the pistils and stamens lie close underneath the
upper lip. The pistil consists of two lobes—an upper
one, quite short and pointed ; and a lower one, which is
longer, spathulate, and bears the stigma on its upper
surface (Fig. 175). The stigma projects beyond the
anthers, so that it is first touched by any entering
insect. The anthers open downwards, so that the
head of the insect necessarily touches them and takes
up a fresh supply of pollen. The stigmatic surface, as
already mentioned, is on the upper side of the stigma,
and lies, therefore, against the upper lip of the corolla.
Fic. 178.— Utricularia vulgaris. Mouth of bladder, seen sideways. a, antenna;
2, strengthened margin of fore-court ; ¢, flap.
When the flower opens, however, it turns downwards
(Fig. 175) so as to touch the head of any insect visitor.
It is, moreover, sensitive, and as soon as it is touched it
rises again, and resumes its original position, so that the
retreating insect cannot dust it with any of its own
pollen. ‘The edge of the stigma is furnished with a row
of hairs, which, according to Heinsius,’ serve to brush
the pollen from the head of the visitor. The pollen
grains lend themselves to this, being provided with
several longitudinal ridges. The visitors appear to be
especially flies belonging to the family Syrphide.
The flowers of U. minor and U. intermedia are formed
on the same general plan.
In autumn most of the plant decays away, but the
1 Bot. Juarb. iv. (1892).
II LENTIBULARIACEZ 279
terminal part grows into a compact bud, and thus
passes the winter.
PinGuicuta (Butterwort).
The corolla is spurred as in Utricularia, but with
a broad open mouth. There are three British species :
P. vulgaris, with violet-purple, P. alpina and P.
lusitanica, with yellow flowers. In P. alpina the spur
is very short, and nearly straight, while in P. lusitanica
it is longer and curved. The plant grows in damp
places. “It bears on an average eight, rather thick,
oblong, light green leaves, having scarcely any foot-
stalk. A full-sized leaf is about 1$ inch in length and
2 inch in breadth. The young central leaves are deeply
concave, and project upwards; the older ones towards
the outside are flat or convex, and lie close to the
ground, forming a rosette from 8 to 4 inches in diameter.
The margins of the leaves are incurved (Figs. 179,
180). Their upper surfaces are thickly covered with
two sets of glandular hairs, differing in the size of
the glands and in the length of their pedicels (Fig. 181).
The larger glands have a circular outline as seen from
above, and are of moderate thickness ; they are divided
by radiating partitions into sixteen cells, containing
light-green homogeneous fluid.”* The glands secrete
a colourless fluid which is so viscid that Darwin was
able to draw out a thread to a length of no less
than 18 inches. It has been calculated that an
ordinary rosette of leaves bears about 500,000 of such
glands. Any small insect alighting on the leaves is
thus caught: the edge curves over, which appears to
be an advantage in two ways, partly in preventing the
victim from being blown away, and partly by pushing
it slightly towards the centre of the leaf, where there
are more glands. Seeds, small fruits, pollen, etc., are
also caught. Thirty-two leaves examined by Darwin
had 142 insects adhering to them, or rather more than
four each.
1 Darwin, Jnsectivorous Plants.
280 BRITISH FLOWERING PLANTS CHAP.
P. vulgaris.—As regards arrangement the flowers of
Pinguicula differ from those of Utricularia principally
in being adapted to small bees, in being open, and in
not having a sensitive stigma. The latter is in the present
genus pushed back by the retreating head of the bee.
Fics. 179, 180.—Transverse section through the leaf of a Butterwort (Pinguicula
alpina). Fig. 179, nat. size. Fig. 180, x 50.
P. alpina.—This species has protogynous flowers, and
is mainly visited by flies, which creep into the flower
until their head reaches the base of the spur. In almost
all cases the presence of a spur or a tube in flowers
indicates that of honey. P.
alpina, however, is said to
be honeyless, but the inner
side of the spur is clothed with
glandular juicy hairs the con-
tents of which are very attractive
Fic. 181,—Piece of the epidermis of to insects. As the flower is oa
a leat of Butterwort, showing togynous, the flies necessarily
the two Kinds of Gund sessile effect cross-fertilisation, carry-
ing the pollen from older flowers
to those more recently opened. The bristles give
an easy entrance, but are supposed to make the with-
drawal of the head more gradual, and in other cases
prevent it altogether, the fly being thus treacherously
captured. Thus P. alpina is doubly an insect-capturing
plant.
II AQUIFOLIACEA 281
AQUIFOLIACEA
ILEx
Parts of the flower in fours. Calyx sometimes with 5
teeth. Flowers often subdicecious ; with exposed honey.
I. Aquifolium (Holly). — Generally dicecious. The
male flowers possess the rudiment of a pistil. The
female flowers are larger than the male. The honey is
but sparing. As in so many small trees, the dispersal
of the seed is due to the fruit being attractive to birds ;
and the ripeness is indicated by the colour.
The leaves are spiny, glossy, and twisted. The teeth
are a protection against browsing quadrupeds. It is
interesting that the upper ones which are out of reach
tend to lose their spines, and old trees are often almost
entirely without them. As Southey well said,—
Below, a circling fence, its leaves are seen
Wrinkled and keen ;
No grazing cattle through their prickly round
Can reach to wound ;
But as they grow where nothing is to fear,
Smooth and unarm’d the pointless leaves appear.
Some evergreen oaks also when young have prickly
leaves. The leaves are also protected by a thick cuticle,
and their generally tough, leathery character enables them
to withstand conditions of dryness and cold which would
be fatal if they were less well-protected. The glossiness
is perhaps an advantage in throwing off snow, which
might otherwise accumulate and break down the branches.
Other evergreens—the Common Laurel, Portugal Laurel,
Ivy, Pines, etc.—also have the leaves glossy. The twisted
character of the leaves has the effect of presenting spines
in every direction. We find a similar character in the
leaves of many thistles. I have sometimes thought also
that the absence of flat surfaces is another protection
against snow. ‘The stipules are black, and reduced to
minute points. They are now perhaps functionless, the
rudiments of once larger organs.
282 BRITISH FLOWERING PLANTS CHAP.
OLEACEZ
The flowers are small, but rendered conspicuous by
association. The honey is at the base of the corolla
tube. Fraxinus is wind-fertilised.
FRAXINUS
Flower polygamous. Corolla 2—4-fid or wanting.
Fruit, as in so many other high trees, provided with a
wing, which assists in the dispersal by wind.
F. excelsior (Ash).—The leaves, as in so many other
plants with large leaves, are divided into leaflets. This
renders them less liable to be injured by hail or wind.
The leaf-stalk has a deep groove on
the upper side, with openings oppo-
site the leaflets, and in it the rain
which falls on the leaves is retained
for some time. There are special
hairs by which the moisture is said
to be absorbed. The fruits, com-
monly called keys, are thin, flat,
and an inch and a half long. The
flowers come out early, before the
leaves. This is generally the case
ng Pe Nis 188. with wind-flowers, and is an ad-
Fic. 182.—Fraxinus excel-
sior, Samara with halt Vantage, as the leaves do not get
removed and the seed in the way of the pollen. Some
pulled out. Nat. size.
wo, aborted ovules; ch, Of the flowers are complete, some
chalaza i Jr tmicle; p& have rudimentary stamens, others
placental axis ; ra, raphe. ‘ jae :
Fig. 183, — Longitudinal &@ Yudimentary pistil, and inter-
Chalazes embryo; ¢ Mediate forms occasionally occur,
funicle; p, endosperm; indicating that the transition is not
ii ae yet fully accomplished. Schulz has
observed that the same tree, and even the same branch,
differs in these respects in different years. They are
protogynous, the stigma being ripe two to four days
before the anthers. The anthers when ripe arrange
themselves so as to open on the upper side. The ovary,
WI OLEACEA 283
as characteristic of the order, is 2-celled with 2 ovules in
each chamber. During development of the fruit, how-
ever, three ovules become atrophied, and the samara is
one-seeded. The septum between the ovary chambers
becomes separated, and bears as on a long funicle the
three atrophied ovules and the perfect seed (Fig. 182).
The bud-scales are modified leaf-stalks, and gener-
ally show more or less rudimentary leaflets at the tip.
The outer scales are thick, and rather furry on the
inner side. The second pair are furry on the outer side,
and especially on the edges. The third pair still more
so. The outer scales are not dead, like those of so
many trees, but increase more or less in size. They
are olive green, so dark as to be almost black. Tennyson,
in The Gardener's Daughter, describes Juliet’s hair
as-—
More black than ash-buds in the front of March.
The dark colour is due to a layer of black, more or less
angular bodies, which are flattened hairs, containing a
dark resinous secretion, and do not increase in size or
number. As the scale grows they are, therefore, carried
further and further apart, and occupying a smaller
relative portion of the surface, the general colour
becomes lighter and greener.
Licustrum (Privet)
Flowers homogamous, with concealed honey, in
compact panicles.
L. vulgare.—The honey is at the base of the tube,
which is about 3 mm. in length. The corolla has
generally 4, but sometimes 5 lobes. The stamens
are generally 2, but sometimes 3. The anthers open
widely ; their position also varies. Sometimes they are
far apart, so that an insect would touch the stigma on
one side and an anther on the other; sometimes they
incline over the stigma, so that the flower would
fertilise itself. The flowers are visited by various
butterflies, bees, flies, and beetles. As in Ash, the
284 BRITISH FLOWERING PLANTS CHAP.
ovary contains 4 ovules, whereas the fruit contains
only one or two seeds. In the Privet, however, the
pericarp becomes fleshy, forming a berry.
APOCYNACEA
Chiefly a tropical family of trees or shrubs, with a
milky juice, and opposite leaves. We have only one
genus.
Vinca (Periwinkle)
Homogamous flowers, with concealed honey, secreted
at the base of the ovary. We have two species: Vinca
major, which has become naturalised in copses and
hedges, with broad leaves, large flowers, and a fringed
calyx; and V. minor, a doubtful native, with narrower
leaves, smaller flowers, and the calyx quite glabrous.
V. minor.—The curious structure of this flower
(Figs. 184-186) was described independently by Darwin
and Delpino. The flower forms a tube 11 mm. in
length. The honey is secreted by two yellow nectaries
at the base of the ovary, and is protected from rain
by a number of hairs at the opening of the corolla.
The stamens are attached to about the middle of the
tube, are bent like a knee, and the anthers, which
are hairy, lie over the stigma. The stigma is conical,
expanding upwards, and terminating in a curious flat
plate. The edges of this are sticky and constitute
the stigma, while the upper surface is hairy. The
pollen is shed into the space above the stigma,
which, however, it cannot reach on account of the
brush of hairs. Insects are able to force their heads
into the upper part of the tube, so that a proboscis
8 mm. long is able to reach the honey. It becomes
smeared by the sticky secretion, and on being with-
drawn some of the pollen adheres to it and consequently
is carried to another flower and deposited on the stigma.
Il APOCYNACEZ—GENTIANACE 285
Bees and some flies, especially Bombylius discolor, are
frequent visitors.
wtiper ne ke
NW Wage tu
‘i es Gna
Fig, 184. Fig. 185. Fig. 186.
Fic. 184.—Vinca minor. Flower after the removal of the front part of the
corolla, x 2.
Fic. 185.—Pistil. x 3.
Fic. 186.—Stamen. x 3.
a, ovary ; &, yellow honey-gland ; ¢, style; «, stamens bent in the form of a
knee ; e, anther opening towards the inside ; g, flat plate at the summit of the
style supplied with sticky stuff round the edge, and whose under edge acts as
stigma ; h, hairy connective of anther ; &, the brush of hair which sits on the top
of the style, and receives the pollen which comes out of the anthers ; », pollen.
V. major.—The structure of the flower agrees with
that of V. minor; but the tube is 15-16 mm. long, and
it requires a proboscis 11 mm. in length to reach the
honey.*
GENTIANACEA
The leaves are opposite. Chlora and Erythrea have
quadrangular stems, as also have some Gentians.
1 See Baillon, Bull. Soc. Linn., Paris, 1882.
286 BRITISH FLOWERING PLANTS CHAP.
CICENDIA
Parts of the flower in fours. There are two British
species: C! filaformas, with broad, the other, C. pusilla,
with linear, calyx teeth.
ERYTHRZA
Parts of the flower in fives. There is no honey, but
the flower is sweet and juicy, and it would appear that
insects pierce the tissue and suck out the sap. They
only open in fine weather, and close again if it rains.
E. Centaurium.— A variable species, the forms of
which are regarded by some botanists as distinct species,
while others consider them to be mere varieties. The
flowers are homogamous, but the stamens and pistil at
first bend away from, afterwards, however, approaching,
one another. Wilson’ found them to be heterostylic,
with corresponding differences in the pollen. This has
been confirmed by Loew. German botanists have not
altogether accepted this view, though they found that
the pistil varies in length. According to Kerner, the
life of the flower lasts five days. They open, according
to Warnstorf, from 5-7 a.M., and begin to close about
mid-day.
GENTIANA
Blue, yellow, or red flowers, with the parts in fours
or fives. They have honey secreted at the base of the
ovary and of the corolla, and from the length of the
tube generally accessible to humble bees and Lepi-
doptera only. In many Gentians the leaves are so
arranged as to hold water, retaining it for some time,
during which it can be absorbed by special club-shaped
hairs. Some species are protected from browsing quad-
rupeds by a bitter sap. The stamens are adnate to the
corolla, projecting in the form of ridges, and thus divide
the hollow of the flower into four or five separate tubes.
G. Pneumonanthe.— The flowers are protandrous.
They close at night and in wet weather. The
1 Nature, xviii. (Sept. 5, 1878).
ro GENTIANACE 287
corolla-tube is 25-30 mm. long, and 8-10 wide at
the mouth. Beneath the middle the tube suddenly
narrows, as the filaments of the stamens are soldered
to the corolla. To this point a bee can enter, and
touches with its head the pollen in young flowers, the
stigma in older ones. In this stage the stigma projects
above the anthers. Gradually, however, the tube
elongates, and brings the anthers to the level of the
stigma, so that in the absence of insect visits the flower
fertilises itself.
G. verna.—This species is fertilised principally by
butterflies.
G. nivalis.—This species appears to be generally self-
fertilised. The flowers open and close rapidly—occa-
sionally, according to Kerner, several times in an hour.
G. Amarella—The flower-tube is 16-18 mm. in
length, but is 6 mm. wide, so that humble bees, by
which the flowers are principally visited; can push their
heads some 6 mm. down. At the entrance to the tube
are a number of hairs, which exclude unwelcome visitors,
especially flies, and, in combination with the contraction
of the flower, also serve to exclude rain. The anthers
open upwards and at the same time as the flower. The
two stigmas project somewhat farther, so that an
approaching insect must almost inevitably, in the first
instance, touch the stigma, and then dust itself with
pollen.
G. campestris. —This species differs from the preceding
in having 4 sepals and 4 corolla-lobes. Two of the
sepals are wider than, and overlap the others. In some
districts it is said to be slightly protogynous, in others
protandrous. It appears also to differ in these respects
somewhat according to the season. In bad weather the
flowers are said to be cleistogamous. In Norway the
stigmas are at the same level as the anthers, or even
lower; in the Alps, according to H. Miiller, they
project beyond the anthers, but finally bend over to
them and so fertilise themselves. They are visited by
humble bees and butterflies. An interesting point
288 BRITISH FLOWERING PLANTS CHAP.
about the species is that while it is annual in the plains,
in Alpine districts it becomes biennial.*
Cutora (Yellow-wort)
The calyx and corolla are eight-lobed. The flowers
produce no honey.
C. perfoliata.— The flowers close at night. The
leaves are glabrous and connate, forming a smooth
collar round the stem, which creeping insects cannot
get over.
MenyantHes (Buckbean)
Honey secreted by the base of the ovary. Flowers
generally dimorphous.
M. trifoliata.—The upper surface of the corolla is
clothed with beautiful white filaments. According to
Knuth these render the flower more conspicuous, and
also serve as a protection against rain and unwelcome
Fig. 187. Fig. 188.
Fic. 187.—Menyanthes trifoliata. Short-styled form, after the removal of the front
part of the corolla and front stamens (nat. size).
Fic. 188.—long-styled form (as before).
po, pollen from the stamens of each form (x 70); s, papille of the stigma of
the two forms (x 4).
intruders. I am not satisfied that this is a suflicient
explanation. This curious and beautiful flower is
dimorphous in some places and not in others. Sprengel
knew only the homomorphous form. Warming in
West Greenland plants found the stamens and pistil of
1 Grisebach, Die Vegetation der Erde.
tt GENTIANACEA—POLEMONIACE 289
equal length. Knuth, near Kiel, and other observers,
found two forms, one long-styled and one short-styled,
as in Primula. In England also they are dimorphous.
As in Primula, the papillee of the stigma (Figs. 187, 188)
and the pollen of the two forms differ in size. The
flowers are very little visited by insects—at least by day.
LIMNANTHEMUM
Dimorphous flowers, with concealed honey, secreted
by five nectaries between the roots of the stamens.
L. nymphzoides.—This is a floating water plant, well
named from its resemblance to a water-lily. Flies are
much attracted to the flowers by a sap which exudes
from the cells of the corolla. The entrance to the
flower-tube is occupied by numerous filaments. The
pistil of the long-styled is about one and a half times as
long as that of the short-styled form. The bud forms
under water, the flower emerges as it opens, and after
it fades the stalk turns down again and the seed
matures below the surface. This is a most unusual
arrangement. When ripe the seed rises ; it is lenticular,
the surface is smooth, and not wetted by water, so that
it floats and is carried about by currents; the edge,
moreover, bears a row of stiff roughened hairs, which
no doubt sometimes attach themselves to animals—
perhaps, also, they tend, in conjunction with the lens-
like form, to make the seed float.
POLEMONIACHAE
PoOLEMONIUM
Protandrous flowers, with concealed honey, which is
secreted at the base of the ovary. The filaments of the
stamens are dilated into hairy scales.
P. caruleum.—A glabrous or slightly pubescent
plant, the flowers of which are united in a beautiful
terminal corymb or panicle. The access to the honey
U
290 BRITISH FLOWERING PLANTS CHAP,
is concealed by the woolly hairs on the inner side of the
corolla, and the dilated filaments of the stamens. When
the bud opens, the anthers are ripe, but not the stigmas,
which, moreover, project considerably. Self-fertilisation
is therefore at first excluded, but eventually the flower
bends over, and the stigmas come within the fall line of
the pollen (see Pyrola, p. 265).
In Nova Zembla, according to Ekstam, the plant is
protogynous. The flowers bend over in wet weather.
The capsule is upright, and at maturity it ruptures along
the middle of the dissepiments, so that the outer cell-walls
break away from the central axis. The seeds thus lie
in a cup, and are jerked out by the wind. They are
dark brown, elliptical, convex on the back, flattened on
the ventral aspect, and more or less finely rugose.
CONVOLVULACEA
ConVOLVULUS
Flowers brightly coloured and adapted to various
insects ; generally only open for a single day. Corolla
plaited in the bud, and rolling inwards when it fades.
Honey secreted at the base of the ovary. Many of the
exotic species have extrafloral nectaries. As in other
climbers, the growing part of the shoot revolves or
“circumnutates” from right to left (ze. against the
course of the sun), and in this species makes a revolution
in about two hours. Other plants move more rapidly.
The vine revolves in about an hour, Cobea scandens
{a member of the preceding order) in only twenty-five
minutes. We have three species of Convolvulus. C.
arvensis has small, the other two have large bracts, and
are sometimes separated as the genus Calystegia; C.
sepium has the leaves angular at the base, and the
corolla white; while in C’ Soldanella the leaves are
rounded, and, as in so many other seaside plants, fleshy,
and the corolla pink.
II CONVOLVULACEA: 291
C. arvensis (Bindweed).—The leaves are ovate-
sagittate; the flowers are sweetly scented, and open
from about 7 a.M. to 10 p.m., closing at night and in
bad weather. Honey is secreted by the base of the
ovary, and the swollen bases of the five stamens (which
are adnate to the corolla) leave only five narrow entrances
to it. The filaments are woven together by short stiff
projections at their edges, so that an insect cannot
insert its proboscis between them. The anthers open
outwards, and the stigmas project beyond them, and
must therefore be first touched by any visiting insect.
The flowers, as in so many cases, present numerous
differences. In Belgium, MacLeod found four forms :
(1) that above described; (2) one with larger flowers,
the corolla surrounded by a red band; (8) a form with
small flowers; (4) a female form, with shortened
stamens and rudimentary anthers. After flowering
the ovary curves downwards and thus protects itself.
The flowers are often infested by a spider, Thomisus
onustus, which seizes the unsuspecting insects which
come for the honey. The plant is sometimes glabrous,
sometimes hairy.
C. Soldanella.—The general arrangement of the flower
agrees with that of C. arvensis. The relative lengths
of the stamens and pistil vary considerably. Besides
the complete plants, MacLeod found at Blankenberge
some that were gynodiccious. It is a plant of sandy
sea-shores; its slender root-stock helping to bind the sand.
C. sepium.—This species has no scent, but in other
respects the arrangement of the flower is much the same
as in Cl arvensis. On moonlight nights, however, it
remains open. Though sometimes visited by other
insects, it is especially adapted to the Convolvulus
hawkmoth, and seldom sets its seeds where that insect
does not occur. The ovary does not curve downwards
after the flowering—perhaps, as Dutrochet long ago
suggested,’ because it is sufficiently protected by the
large bracts. The plant is glabrous.
1 Recherches Anatomiques, ete.
292 BRITISH FLOWERING PLANTS CHAP.
Cuscuta (Dodder)
This curious genus is annual, leafless, and parasitic,
with thread-like, delicate, pinkish, twining stems, bearing
clusters of small homogamous flowers, with concealed
honey, which is secreted by the base of the ovary. They
are often cleistogamous. The seeds germinate in the
soil, developing a slender root and thread-like stem, but
no cotyledons. When, as a result of its cireumnuta-
tion, the stem has come in contact with its future host,
it curls round it like a tendril and develops suckers,
which penetrate to the vascular tissue of the host-
plant. The root then withers, and the Dodder is
henceforth a parasite. There are three British species.
In C. europea and C. Epilinum the corolla-lobes are
short and broad—the latter grows only on flax, and is
not a true native; in C. Epithymum the corolla-lobes
are spreading and pointed.
C. Epithymum.—This species grows on heath, thyme,
and other small shrubs. The flower parts are generally
in fives, but sometimes in fours, threes or even twos.
The honey is protected by small scales growing from the
inside of the corolla. The stigma and anthers ripen
simultaneously, and an insect would naturally touch the
stigma on one side and the anthers on the other.
C. europea resembles C. Epithymum in the general
arrangement, but is larger.
BORAGINEA
Generally rough, with coarse hairs. Nectar is gener-
ally secreted at the base of the ovary, and often protected
by scales at the summit of the corolla-tube. The flowers
are especially adapted for and visited by hees, and are
often bent in a manner well adapted to suit the proboscis.
Blue is the predominant colour.
II BORAGINE 293
EcHIUM
E. vulgare (Viper’s Bugloss) has generally protandrous
flowers. The honey is abundant. From the size and
bright colour of the flowers, and their association in a
long one-sided inflorescence, they are very conspicuous,
and much visited by insects, nearly 100 species being on
record. The lower parts of the filaments are soldered
to the corolla-tube, and where they detach themselves
the tube suddenly enlarges, so that even the largest
humble bee can conveniently insert its head and
thorax. Four of the stamens lie along the under side of
the flower ; one, on the contrary, is separate, and divides
the tube into two parts. The anthers open with the
flower, and turn the pollen upwards. When the flower
opens, the pistil is somewhat shorter than the corolla-tube,
but it soon elongates and projects beyond the stamens.
This is one of the flowers which changes colour ;’ from
reddish purple they become bright blue. Besides these
complete flowers, plants occur with smaller flowers, in
which the stamens are short and the anthers without
pollen. Intermediate forms also occur. The plant is effec-
tively protected by stiff, spreading, almost prickly leaves.
E. violaceum, which occurs in Cornwall, is of interest
from its geographical distribution. It belongs to that
Southern European element, examples of which oceur in
our flora only in the West of England.
PULMONARIA
Nectar secreted by the base of the ovary, and pro-
tected by hairs on the inside of the corolla. Corolla-
tube straight.
P. officinalis is a European species, rare in Britain,
where it has become naturalised in woods and copses in
the South of Scotland and England. The flowers, which
are borne in a terminal forked cyme, are first red, then
blue-violet; they are dimorphous; the tube is 10-12 mm.
long, but as it is large enough at the summit to admit
1 See p. 84.
294 BRITISH FLOWERING PLANTS cmar.
the head of a bee, the honey is accessible to insects with
a proboscis 8 mm. in length. As in other cases, the
pollen of the short-styled is larger than that of the long-
styled form.’ From the size of the flowers, the bright-
ness of the colours, the early season at which they open,
and the abundance of honey, they are richly visited by
insects, especially by bees and butterflies. Hildebrand
has shown” that the long-styled flowers are utterly
sterile to their own pollen, and even to pollen from
other plants of the same form. The short-styled flowers,
on the contrary, under such circumstances produce some
seed, though only about half as much as they do if
properly fertilised. The plant is covered with spread-
ing hairs.
MERTENSIA
This genus is glabrous, which is unusual in the
present family, but frequent among maritime plants.
M. maritima.—A Northern and Arctic plant found
on our sea-shores in Wales, North England, and Scot-
land.
LITHOSPERMUM
Nectar secreted by the base of the ovary, and concealed
at the base of the corolla-tube. Generally humble bee
flowers. We have three species : two have white or pale
yellow flowers; one, L. arvense, is annual, with wrinkled
nuts; the other, L. officinale, perennial, with smooth
nuts; the third, L. purpureo-ceruleum, has bright blue
flowers. The name is derived from the extreme hard-
ness of the nuts (AiOos, stone, and o7épya, seed).
L, arvense.—Flowers small and white, or on the
Continent sometimes blue. The nectar is protected by
hairs in the upper part of the corolla-tube. The anthers
open inwards and even before the flower, though the
flowers examined by Kerner were slightly protogynous.
The pistil ends in two short lobes, beneath which is a
ring of papille, which are at the level of the anthers,
1 See p. 288, 2 Bot. Zeit, xxiii. (1865).
ul BORAGINEE 295
and with them fill the corolla-tube. To arrive at the
honey an insect must therefore press its proboscis be-
tween the anthers and the stigmas. The leaves are
rough with appressed hairs.
L. purpureo-ceruleum.— The arrangement of the
flower resembles that of the preceding species. The
colouring curiously repeats that of Pulmonaria, being
first purple and then blue. The plant is pubescent.
L. officinale—The leaves are rough, green above,
pale below.
Myosortis
Flowers in one-sided cymes, generally blue, homo-
gamous, with concealed honey. Corolla-tube straight.
Nuts attached by the narrow end. There are five
British species: M. palustris has the calyx with short
teeth and appressed hairs; in the other four the calyx
has long teeth and spreading or hooked hairs. M. syl-
vatica and M. arvensis have the pedicels longer than
the calyx, the first being perennial with rather large
flowers, the second annual with small ones. The last
two have the pedicels less than a line long—WM. collina,
with blue flowers; MZ. versicolor, with flowers first
yellow, then blue, and finally violet.
M. sylvatica.— The anthers are contained in the
corolla-tube a little above the stigma, but open at the
same time as the latter is ripe. They open inwards, so
that an insect touches the stigma on one side and dusts
itself with pollen on the other. At first the flower is
horizontal, but it gradually becomes upright, so that
the anthers are just over the stigma, and in the absence
of insect visits the flower is almost sure to fertilise itself.
The leaves are pubescent.
M. versicolor.—This is another case in which the
flower changes colour. When it opens it is of a clear
yellow colour, and the pistil projects beyond the anthers,
so that it is adapted for cross-fertilisation. Gradually,
however, the colour changes to blue; the corolla elon-
gates, carrying the anthers, which are attached to it,
296 BRITISH FLOWERING PLANTS CHAP,
up to the level of the stigma, so that in the absence of
insects it fertilises itself. The leaves are bright green,
with spreading hairs. Fig. 189 represents a flower of
M. versicolor when just
opened. It will be ob-
served that the pistil pro-
jects above the corolla and
stamens, so that it must
be touched first by any
insect alighting on the
flower. Gradually, how-
Fig. 189. Fig, 190, ever, the corolla elongates,
Fic. 189.—A©yosotis versicolor. Young Carrying up the stamens
flower. 7 ; ;
Fic. 190.—Older flower ; much enlarged. with It, until at length
a, anther; ca, calyx; co, corolla; 2, they come opposite the
nectary ; ov, ovary ; st, stigma. stigma, as shown in Fig.
190. Thus, if the flower has not already been fertilised
by insects, it is almost sure to fertilise itself.
ANCHUSA
Homogamous bee flowers. Corolla-tube straight, with
honey at the base. Nuts attached by the broad end.
Two species occur in Britain, but both are rare, and
have presumably been introduced by human agency.
A, officinalis has terminal forked spikes, A. semper-
verens short axillary spikes.
A. officinalis—The corolla is at first violet, then deep
blue. The entrance to the tube is guarded by five hairy,
closely fitting scales. Immediately below them is the
stigma, and about the middle of the tube are the
anthers, so that visiting insects touch the stigma first
and then the anthers. The corolla eventually detaches
itself and falls off, carrying some of the pollen with it,
and thus, in the absence of insects, fertilising the stigma.
In some places, besides the usual complete flowers,
others occur in which the stamens are rudimentary.
The flowers differ also in size and in the exact position
of the stamens, which, according to Schulz and Warming,
rei BORAGINES 297
are sometimes at the same level with, sometimes even
below, the stigma. In that figured by Bentham the
anthers are at the summit of the tube. The flowers are
much visited by bees, and sometimes by butterflies and
moths. The stem is rough with stiff downward -point-
ing, and the leaves with spreading, hairs.
A. sempervirens.— According to Loew, the anthers
and stigma are at the same height. The nuts have a
small convex appendage on the inner side of the hase.
The plant is rough.
Lycopsis
Resembles Anchusa, but the tube is bent.
L. arvensis (Bugloss).—The arrangement of the flower
agrees closely with that of the common form of Anchusa
officinalis. The plant is rough.
Borago (Borage)
Flowers protandrous, in loose forked cymes. Corolla
rotate. Tube short, closed by scales at the mouth.
Filaments forked. Nectar secreted by the base of the
ovary, and concealed in a short tube formed by the bases
of the stamens.
B. officinalis—F lowers drooping, sky-blue. Anthers
nearly black, forming a cone round the stigma, and
opening gradually from the tip to the base. Hach anther
is said to contain 60,000 pollen grains. They are
smooth, dry, and pulverulent, and fall into the conical
space round the pistil. The stamen has
a prolongation (Fig. 191) which touches,
or almost touches, the wall of the corolla-
tube. The arrangement, therefore, some-
what resembles that in the hanging
flowers of the Heath. An insect in search
of honey must press its proboscis between 191. anther
two of the stamens, thus dislocating the — of Borage; en-
anther-tube, when some of the pollen '8**
drops on to it, and is thus carried to another flower.
Gradually the pistil elongates and the stigmas ripen.
298 BRITISH FLOWERING PLANTS CHAP.
If any pollen is left some might easily fall on it, but,
according to Darwin, the flowers are not very suscep-
tible to their own pollen. They are principally visited
by bees, and Darwin says by more than in the case of
any other plant he knew. The plant is rough, with
stiff hairs on tubercles. It is not a native, but occurs
in waste ground near dwellings.
Sympuytum (Comfrey)
Flowers homogamous. Corolla tubular, enlarged
above the middle. Nectar secreted by the base of the
ovary. According to Kerner, the flowers gradually bend
down, so that the stigma comes into the fall line of the
pollen. There are two British species—S. officinale,
with decurrent leaves ; S. tuberosum, with leaves not, or
only very slightly, decurrent.
S. officinale—The corolla is white or purple-violet.
The arrangement of the stamens resembles that of
Borage, but the flower-tube is longer—14 mm. The
upper swollen part, however, occupies 6 mm., but a
proboscis 11 mm. in length is required to reach the
honey, because when the tube contracts the entrance is
still further protected by five triangular scales and by
the stamens. Bombus terrestris and other humble
bees, however, often bite through the corolla, and thus
rob the flower of its honey. The leaves are rough, with
short scattered hairs, and longer ones on the ribs.
8. tuberosum is less roughly hairy than the preceding.
It is not found in the South of England.
ASPERUGO
The calyx enlarges after the flower fades, and becomes
flattened and veined. The flowers are homogamous,
with nectar secreted by the base of the ovary.
A. procumbens.—The flowers are small and blue.
The plant is rough, with- hooked hairs turned down-
wards. It is not common in Britain, but is occasionally
found in waste places.
"I BORAGINEAZ—SOLANACE 299
CYNOGLOSSUM
Flowers in one-sided cymes. Corolla-tube short,
with scales at the mouth closing the aperture, and
forming a roof to the chamber containing the honey,
stamens, and pistil. The dispersal of the nuts is
ensured by the presence of numerous short hooked
prickles. There are two British species: C. officinale,
with soft appressed hairs, and C. montanum, with rough
scattered hairs.
C. officinale.—Corolla dullish purple. The stamens
are longer than the pistil. The leaves are soft, with
fine appressed down.
C. montanum.—The leaves are thin, semi-transparent,
glabrous above, rough below, with scattered hairs on
tubercles. The stem bears soft spreading hairs.
SOLANACEA
DaTURA
Homogamous moth-flowers. Nectar secreted by the
base of the ovary. Not indigenous, but sometimes
found wild in Britain.
D. Stramonium (Thorn-apple).—The pure white
flower has a strong smell of musk, which is specially
strong at night; it opens about seven in the evening,
and, according to:Kerner, only lasts one day. In bad
weather the corolla folds up and closes. The tube has
a length of about 60 mm. The stamens are attached to
the corolla by their centres, but the sides widen out, so
that they touch one another, and leave five narrow tubes
leading down to the honey. The stigma is about at the
same height as the anthers. It is a North American
plant, which has become widely introduced in the Old
World.
300 BRITISH FLOWERING PLANTS CHAP.
HyoscyaMvus
Homogamous humble bee flowers. Nectar secreted
by the base of the ovary. The capsule is enclosed in
the enlarged persistent calyx. The seeds are jerked out
by the wind.
H. niger (Henbane).—The plant is hairy and viscid,
with a nauseous smell. The corolla is dingy yellow with
purplish veins. The stamens are hairy. The stigma
rises above the anthers at first, but gradually the corolla-
tube grows, bringing them up to the level of the stigma,
and thus, in the absence of insect visits, facilitating
self-fertilisation. According to Ludwig, the terminal
flowers are cleistogamous. The seeds are numerous,
compressed, dirty gray or pale brown, moderately deeply
pitted all over, and divided into roundish or oblong
areas by more or less conspicuously toothed ridges.
SoLANUM
There is no honey. The anthers, which are almost
sessile, form a cone round the pistil, and each opens by
a pore at the end. Fruit, a berry. We have two species :
S. Dulcamara, a climber; S. negrum, erect.
§. Dulcamara (Bitter-sweet).—The flowers are blue,
with violet veins and yellow anthers. The base is
bluish black, and so shiny that it looks as if covered by
a film of liquid. At the base of the corolla-lobes are
greenish knobs which surround the flower in a ring, and
also look as if covered with fluid, so that H. Miiller
calls them sham nectaries. Flies have, in fact, been seen
exploring the flower, evidently expecting to find nectar.
Delpino, however, refers the plant to the same type as
Borage, and regards it as a bee flower. Hoffer has
suggested that the juicy greenish knobs are pierced and
sucked by the insects. The fruit is a berry, pulpy and red
when ripe. The seeds are somewhat reniform, tapering
to one end, white, cartilaginous, and smooth to the naked
eye, but in reality very finely, though deeply, pitted
and rugose. It is probable that birds scatter the seeds
rt SOLANACEA:—OROBANCHACE.E 301
while eating the juicy pulp. Moreover, if swallowed
they would probably not be digested. The leaves have
short appressed hairs, and are sometimes woolly.
8. nigrum.-—This species on the Continent has the
stems covered with short appressed hairs; with us they
are generally glabrous or nearly so. The flowers close
at night. They are smal] and white, sometimes with a
blue spot at the end of each corolla-lobe.
ATROPA
Protogynous humble bee flowers. Nectar secreted
by the base of the ovary.
A. Belladonna (Deadly Nightshade).—The corolla
is a pale purplish blue. Knuth, however, describes it
as brownish red above, dingy yellowish green below.
As regards size and form, the flower is adapted to
middle-sized humble bees. The nectar is protected by
stiff hairs on the stamens. The pistil projects some
distance beyond the anthers. When the flower opens
the stigma is mature, but the anthers are still closed.
The filaments are bent below the anthers. Finally,
the latter burst open and become covered with
pollen ; the filaments also elongate somewhat, but still
remain bent and overtopped by the stigma. The stem
is finely glandular at the summit.
Below each leaf, and on the same side of the stem,
is a smaller one. This seems to fill up the interval.
The arrangement is peculiar, and is supposed to be due
to displacement, the leaf-stalk being connate with the
following shoot, and thus seeming to arise from it.
OROBANCHACEA®
Parasitic plants, brown or purplish, never green.
The parts of the flower in twos or fours; flowers some-
times with, sometimes without, nectar.
302 BRITISH FLOWERING PLANTS CHAP,
OROBANCHE (Broomrape)
We have seven species. The embryo shows no
differentiation into root and stem, and has no cotyle-
dons. It is a delicate simple filament, and the end
which corresponds to the shoot remains in the seed.
The other end works its way down into the earth in a
spiral line. If it does not meet with a suitable host it
soon dies, and indeed the vast majority perish. The
seeds, however, are very numerous. If the rootlet
finds a suitable host it adheres to it and thickens, the
upper part perishing. The thickened part drives pegs
into the root to which it has attached itself, sucks out
sap, and forms a bud which grows into a short, thick,
strong stem. The plant also throws out rootlets, which
probably derive a certain amount of nourishment from
the soil.
0. caryophyllacea.—The flowers are homogamous ;
sweet-smelling, and with nectar. The corolla-tube is
somewhat bent, gradually widening to the middle; the
underlip is trifid and thrown into folds, which so much
diminish the width of the tube that insects are almost
certain to touch the anthers and stigma. The latter
projects beyond the stamens. The four anthers are
grown together at the sides, and each chamber is pro-
vided with a long stiff horn directed downwards. If
these are shaken by an insect the dry pulverulent pollen
falls on its head or proboscis. The flower does not
fertilise itself The plant is parasitic on species of
Galium, Rubus, etc.
O. elatior.—The flowers are scentless and without
nectar. The stigma at first projects beyond the anthers,
which, however, gradually grow up to it, so that self-
fertilisation is possible. The stem is glandular-pubescent.
The plant, which is parasitic on Centawrea Scabiosa, is
rare, and found chiefly in the eastern counties.
O. ramosa.—Pale straw colour. The arrangement
of the flower resembles that of O. elatior. According
to Kirchner and Warnstorf, it is slightly protogynous.
rt OROBANCHACEA. 303
The stem is covered with glandular hairs. The plant
is parasitic on Hemp, and is occasionally found in
Britain, but not native.
LaTHRAA
Parasitic on the roots of trees. Protogynous humble
bee flowers. Nectar secreted by a gland on the under
side of the ovary.
L. Squamaria(Toothwort).—The plant is flesh-coloured
or slightly bluish, with red or purple streaks. The
flowermg stems and the rhizome bear scales, those
underground thick and fleshy. The flowers are in a
one-sided spike, which is at
first bent and does not
become straight until the
uppermost flower is ready to
open. The stigma then pro-
jects beyond the flower-tube,
within which lie the still
unripe anthers, so that, as
the honey is abundant and Ps
humble bees assiduously visit Fis. 192. Fig. 198.
the flowers, cross-fertilisation TOP Tee ok Mh pideraround
is effectively provided for, Fic. 193.—Longitudinal section through
For a short time after the ™*™*
anthers open the stigma remains fresh, yellow, and
capable of impregnation. Soon, however, it dries and
shrivels up. The dry pollen falls from the anthers, but is
supported by a thick brush of hairs. If, however, the
short points of the anthers are pressed aside by the pro-
boscis of the bee the pollen drops out on to the insect’s
head. In the meanwhile the corolla-tube lengthens
and eventually covers the stigma. The stamens also
elongate, and project at last beyond the tube; the dry
pollen is carried away by the wind, and as the plants
generally grow in patches, some must occasionally
reach the stigmas of younger flowers. The underground
scales resemble those on the stem in outline. At
first sight they seem to be squarely mounted on a short
304 BRITISH FLOWERING PLANTS CHAP.
foot-stalk. In reality they are folded back on them-
selves, and what seems to be the lower is really part
of the upper surface, so that the true lower surface
is very small and not visible in the usual positions of
the leaf (Figs. 192-194). In the thickness of the leaf
are from 5 to 18, generally about 10 chambers, which
have irregularly undulating outlines. The interior of the
LT TTS TO TT ee TTT TT et
Ha (ast TTT fo ,
SOMOS So
CORES
CS
HD
ee T
Fic. 194.—Longitudinal section through a leaf of Lathrea, x 60.
cavities bears two forms of glands (Fig. 195). The first
are in the form of a little head, consisting of two cells
ona short stalk. In the other the cells of the head form a
flattened dome. Both kinds of cells emit delicate proto-
plasmic filaments exactly like those of Rhizopoda (Fig.
196). When any small animals penetrate into the
chambers the projecting cells begin to emit filaments
which entangle and capture them, and by degrees suck
out all that can be digested, leaving only the claws,
hairs, and other hard parts. Several naturalists have
ret OROBANCHACEA:—SCROPHULARIACE: 305
expressed their surprise that so many animalcules should
enter these traps and those of Utricularia, etc., but we
x eae eae SE = sa
Fic. 195.—Piece of the wall of a cavity. Fic. 196.—Plasmic threads radiating from
x 200. the cells of the little heads. x 540.
must remember that they press into any small crevice
in search of food and shelter.’
SCROPHULARIACEA
The prevailing colours are yellow and red. In many
species they are different in different localities. The
flowers generally secrete nectar at the base of the ovary,
or in Pentstemon at the base of the stamens. Most of
the Verbascums, however, are without nectar. Some
species have opposite and some alternate leaves. The
latter have round stems. Among the former the stems of
some species of Scrophularia, Rhinanthus, Melampyrum,
Veronica, and Mimulus have quadrangular stems.
Verpascum (Mullein)
The flowers are yellow, white, or (rarely) purple.
They are in some species rendered more conspicuous by
the brightly coloured stamens. Most species have a
thick covering of woolly, sometimes branched hairs.
These probably serve three purposes. Firstly, they
protect the plant from grazing quadrupeds: they
would be unpleasant in the mouth, and probably in-
jurious in the stomach. Secondly, they prevent the
access of creeping insects; and thirdly, they prevent
too rapid transpiration.
1 See also Praeger, Open-air Studies in Botany, p. 32.
/ x
306 BRITISH FLOWERING PLANTS CHAP.
We have six species. V. Thapsus may be recognised
at once by its decurrent leaves ; two are nearly glabrous
or slightly glandular-hairy—V. Blattarva, with pedicels
mostly longer, V. virgatwm shorter, than the calyx.
Of the other three, V. nigrum
has the leaves cordate, the others
narrow at the base; of these, V.
Lychnatis has white flowers; V.
pulverulentum, yellow.
Crosses are not infrequent in
this genus. Gaertner found that
taking the produce of V. Lych-
nitis with pollen of its own
species as 100 seeds, when ferti-
lised with pollen from V. phena-
ceum it produced 90 seeds, with
that of V. negrum 68, of V. Blat-
taria 62. On the other hand,
the ovary is quite sterile to
pollen of the same flower.’
Kerner calls attention to the beautiful manner in
which the rain is collected and carried down to the
roots. The upper part of the leaves hangs downwards,
and consequently the rain drops off at the tip. But as
the leaves are shorter the higher their position on the
stem, the drops fall on that part of a lower leaf which
shelves towards the stem. Thus all the rain-water
received by the plant is eventually conducted to the
tap-root.
V. Thapsus.—Two of the stamens are longer than the
other three, which have hairy filaments. The leaves
have stomata on both sides, and a hairy covering which
it is impossible to wet. The whole plant is tomentose.
V. Blattaria.—The flowers are homogamous, gener-
ally yellow, but sometimes white. According to Kerner
the corolla secretes nectar, but this is denied by
Kirchner. The pistil projects beyond the anthers.
Eventually the corolla drops off and slips down the
1 Darwin, Forms of Flowers.
Fic. 197.—Verbascum nigrum.
8 SCROPHULARIACEE: 307
pistil, hanging to it, however, for some time. As the
stamens are inserted on the corolla, the result of this is
that the anthers are almost sure to touch the stigma,
and thus, in the absence of insect visits, to fertilise the
flower. The leaves are glabrous and shining.
V. nigrum.—The filaments are clothed with bright
purple hairs. The flowers are homogamous ; they secrete
nectar, but very sparingly. The uppermost stamen is
the shortest, the two lowest are the longest. The
anthers open outwards. The pistil is somewhat shorter
than the lowest stamens, but generally bent a little
downwards, so that an insect visiting the flower would
generally touch it first. According to Gaertner, con-
firmed by Darwin, the plant is absolutely sterile to its
own pollen. The leaves are pubescent above, tomentose
below. The seeds are brown, subquadrate, obtuse at
both ends, with wavy longitudinal and transverse
ridges, between which are deep oblong pits. They are
light, and readily adhere to any surface with which they
come into contact.
V. Lychnitis—The flowers are homogamous, white,
or sometimes pale yellow, without nectar. The stamens
are clothed with yellowish, somewhat clubbed hairs.
The pistil projects rather beyond the stamens. This
species is also sterile to its own pollen. The leaves are
pubescent above, shortly tomentose below.
ANTIRRHINUM (Snapdragon)
Homogamous bee and humble bee flowers. The
upper and under lip close the corolla-tube, but the latter
opens by a spring. Nectar is secreted by the base of
the ovary. The stamens lie along the upper lip; they
are in pairs, the anthers of the two longer ones lying in
front of the others. The anthers deposit their pollen on
the back of the bee. We have two species—A. majus
is perennial, with large flowers; A. Orontiwm annual,
with small ones.
A. majus.—This .is especially a humble bee flower.
The corolla is purple, rarely white, with yellow gums.
308 BRITISH FLOWERING PLANTS CHAP.
The lower lip has two projections which fit into hollows
in the upper lip. It completely closes the entrance,
and excludes small insects. Humble bees, however, are
able to press it down and creep into the corolla, which
they nearly fill, so that their back presses against the
open anthers. Bombus terrestris, however, and B.
lucorum bite through the base of the corolla, and
thus rob the flower of its nectar. The hive bee, accord-
ing to Douglas,’ also pierces the corolla for the nectar ;
but if only in search of pollen, presses down the door
and collects pollen without actually entering. He
does not suggest any reason, but is it not possible that
if she once entered she might be unable to get out
again? According to Darwin, the red form is self-
sterile, the white variety less so. The flowers are some-
times “ peloric,” that is, depart from the characteristic
irregular form, becoming regular. The seeds are black
or dark brown, oblong ovoid, with high longitudinal
ridges. The plant is glabrous, but with the upper part
of the stem pubescent and slightly glandular. It is not
a native, but occurs as an alien on old walls.
A. Orontium.—The flowers are much smaller, red or
(seldom) white. The arrangement of the flower re-
sembles that of A. majus. They are visited by the
hive bee as well as by humble bees. The plant is
nearly glabrous, or with long spreading glandular hairs.
LINARIA
This genus differs from Antirrhinum chiefly in having
the corolla produced into a spur. There are seven
British species. The effect of the habit of the plant
on the form of the leaf is well shown in this genus.
Five species are erect, with upright linear leaves; three
trailing, with ovate, orbicular, or ivy-shaped leaves.
L. vulgaris (Toadflax).—The flowers are large in a
terminal panicle, yellow with an orange palate. The
tight closing of the lips and the length of the spur debar
all insects excepting bees with a long proboscis from
1 Entom. Month. Mag. Nov. 1886.
1 SCROPHULARIACEAR 309
access to the honey. For such insects, however, the
flower is admirably arranged. When they have opened
the door they find on each side of the lower lip a band
or ribbon of close orange-coloured hairs, between which
is a clear space leading directly to the honey. The fruit
is a capsule. The cells of the outer wall are thickened,
and contract more than the inner layer. The result is
that the walls curve outwards, thus opening the upper
end of the capsule. The seeds are jerked out by the
wind; they are brown or black, somewhat rounded in
form, with a notch at the base, laterally compressed,
winged, and finely reticulate. The plant is glabrous,
pubescent and glandular above. In some cases there
are traces of the posterior stamen.
L. minor.—The arrangement is much the same as in
the last species, but the parts are smaller, and no doubt
adapted to smaller insects. They are not, however,
much visited.
L. supina has glaucous and glabrous yellow flowers,
but the plant is pubescent-glandular above.
L. spuria has a trailing stem, with leaves orbicular
or nearly so. The upper lip is purplish brown, the lower
lip yellowish. Some of the lower flowers are cleisto-
gamous, and these are said to be more numerous in
shade. The stem has two sorts of hairs, long and soft,
and short and glandular.
L. Cymbalaria also has the stem trailing. The leaves
are ivy-shaped ; the flowers lilac with a yellowish palate.
They stand up in the sunlight, but when they fade the
flower-stalk turns down and inserts the growing seed-
pod, if possible, into some hole or crevice. The seeds
are globular and longitudinally ridged. The plant is
quite glabrous. Like Antirrhinum majus, it is not a
native, but an alien found on old walls.
L. Elatine—A corn-field weed, the short stem bearing
long prostrate slender branches; hairy as in L. spuria.
L. repens—A rare plant, but occasionally found in
waste places. It is quite glabrous, and is a perennial
with many slender creeping stems.
310 BRITISH FLOWERING PLANTS CHAP.
SCROPHULABIA
Protogynous wasp flowers. Nectar secreted by a
ring at the base of the open corolla. Cleistogamous
flowers also occur. There are four British species. Two
have the leaves glabrous; in two they are downy. Of
the former, S. aquatica has the stem four-winged; in
S. nodosa it is four-angled, but not winged. Of the
downy-leaved species, S. Scorodonia has purple flowers,
S. vernalis yellow. One of the stamens is barren, and
usually forms a scale under the upper lip. The reason
or use of this peculiar arrangement is not known.
8. nodosa (Figwort).—The flowers are small (Fig.
198) and generally reddish brown, which seems to be a
favourite colour with wasps. The tube of the corolla is
a pale greenish purple. The
flower has a scent, pleasant no
doubt to wasps, but disagreeable
to us. In the first stage of the
flower, which lasts two days, the
stigma projects, and the anthers
are not ripe; in the second,
which also lasts two days, they
open and expose the pollen. The
stigma and anthers lie on the
lower side of the flower, and the
upper (fifth) stamen being use-
less, the anther is not developed,
but forms a widened end to the
§ stamen. This, however, is so
well formed that I cannot help
suspecting it has some function
which has not yet been observed. The style, after ferti-
lisation, gradually curves down.’ In bee flowers the
lower blossoms generally open first, and bees begin below
and work their way up. Wasps, on the contrary, begin
at the top. The flowers open irregularly, but the general
result is that the younger flowers are fertilised with
TT. W. Fulton ‘On Scrophularia,” Trans. Bot. Soc. Edinb. xvi. (1886).
G
} Clinard
Fie. 198.—Serophularia nodosa.
ul SCROPHULARIACE 311
pollen brought from older flowers of another stock.
In America also, wasps are the special visitors of this
species. There appear, however, to be remarkable
differences. Knuth, like Sprengel and other observers,
found the flowers in Holstein to be, at first, specially
attractive to wasps. Later in the season, however,
they were neglected by wasps, and much visited
by bees. Robertson, in Illinois, confirms this, but
adds that the wasps gradually returned. It may be
possible that these differences might be explained if we
knew what other plants were in flower at the same time.
Knuth remarks that the brown of the corolla and
the yellow anthers closely reproduce the colouring of
the wasps. Epipactis latifolia, which is also a dingy
purple, is almost the only other British plant which is
visited by wasps. The plant is glabrous.
S. aquatica—The flower agrees in the main points
with that of S. nodosa. The stem is distinctly winged,
and the plant is glabrous.
S. Scorodonia, on the other hand, is pubescent, or
sometimes hairy. It is a native of the West of England
and Kerry.
S. vernalis.—A bee flower with a sweet smell. There
is no barren stamen. The anthers all project beyond
the corolla-tube. The plant is glandular-pubescent. It
is a rare plant, occasionally found in waste places, but is
not native.
MiImv.Lvs
Homogamous bee flowers with a sensitive stigma.
M. luteus. — A native of North America, now
thoroughly naturalised in Britain. The pistil lies over
the stamens, and the bee first touches the stigma. This
has two sensitive lips which close over the pollen like
a forceps. If none is enclosed they reopen, ready for
another chance.
' According to Edgeworth, M. moschatus has two
kinds of pollen. The seeds are brown, very minute,
biconvex and oblong or elliptical.
312 BRITISH FLOWERING PLANTS CHAP,
LIMOSELLA
A small floating annual.
L. aquatica.—According to Kerner, if the small pink
flowers are submerged they become cleistogamous.
DIGITALIS
(Foxglove, z.c. Folksglove or Fairy’s-glove)
Protandrous humble bee flowers, with nectar secreted
by a ring surrounding the base of the ovary.
D. purpurea.—Beautiful purple flowers in, as Bentham
well says, “a long stately raceme.” The flowers hang
downwards, and are thus protected against rain. The
posterior sepal is small, a step towards its complete
suppression in the next genus (Veronica). The in-
terior of the corolla is lined with hairs, which Kirchner
regards as intended to prevent the entrance of small
creeping insects. Knuth doubts this, and suggests that
they perhaps rather serve to give a foothold to the
friendly visitors. May they not be useful for both pur-
poses? The size of the flower is well adapted to that
of humble bees. The anthers and stigma are not spread
out round the circumference of the corolla, but are
arranged together on the upper side. The fifth stigma,
which was fully developed and useful in Verbascum,
and has lost its anther in some species of Scrophularia,
in this and the following genera of the family has en-
tirely disappeared. The pistil lies along the centre of
the upper lip between the anthers, which are in two pairs,
one in front of the other, so that they must be touched
by the back of an insect entering the flower. The
anthers of the two longer stamens open first, then those
of the shorter ones, after which the two stigma lobes
open. If humble bees are abundant the pollen may be
removed before the stigmas are ripe; if any pollen
remains the flower might easily fertilise itself. Accord-
ing to Darwin, however, it is self-sterile. The anthers
(Figs. 199-201) are at first horizontal, but as they ripen
1 SCROPHULARIACES 3138
they become vertical, so as to be more closely in the
centre of the flower. According to Kerner the life of
the flower lasts six days. Ludwig found on some of
the plants examined by
him small female flowers
with rudimentary stamens.
The capsule is upright.
The reddish brown seeds
are thrown out by the
wind; they are small,
numerous, oblong, and
variously compressed. The
plant is covered with
fine spreading hairs. The
fruit normally splits along Fig. 199. Fig. 200. Fig. 201,
the septa. The lignified Fic. 199.— Digitalis purpurea. Section of
layer of the inner epi- flower, showing the anthers unripe and
3 z horizontal.
dermis 18 composed of Fic. 200.—The same, more advanced. The
a upper anthers vertical, the lower as
horizontal fibres, and the j2P
sub - epidermal layer of Fic. 201.—The same, still more advanced.
: : : : All the anthers ripe and vertical.
isodiametric cells, which
contract more than those of the epidermis, and thus
open the fruit.
VERONICA
Flowers generally blue or white, with nectar, specially
adapted to flies, which gather up, as it were, the two
stamens under the body to act as a support while
they sip the honey. Other stamens would, under the
circumstances, only be in the way. The calyx is 5 or
4 cleft, the lobe representing the posterior lobe being
suppressed. The corolla is deeply 4-cleft, two of the
lobes being united. There are sixteen British species.
The fruit is a capsule. The seeds fall into two series.
In some species they are smooth, flattened, and winged.
This is the case, as a rule, in species living in or close
to water. To this series belong V. Beccabunga, V.
Anagallis, V. scutellata, and among land species V.
serpyllifolia, V. Chamedrys, V. montana, V. officinalis,
314 BRITISH FLOWERING PLANTS CHAP.
V. arvensis, and V. triphyllos. In the second the seeds
are hollowed out on the ventral side and wrinkled, as in V.
Buxbaumi, V. agrestis, V. polita, and V. hederefolva.
V. Chamedrys.—This species is remarkable for having
the hairs collected in two rows running down the stem
from between each pair of leaves. The flowers are
homogamous and adapted to flies.
They are blue, or sometimes
smaller and pinkish, with darker
lines, and are collected into showy
racemes. ‘The nectar is protected
by hairs. The pistil projects
straight from the flower, while
the two stamens diverge on each
side. The lower lobe of the
corolla forms a convenient alight-
ing stage for insects, which must
inevitably touch the stigma. The
fly clasps the stamens and presses
the anthers against its body, dusting itself with pollen,
some of which it would probably deposit on the stigma
of the next flower visited. The stamens become thinner
towards the base, and thus yield more easily to the
pressure of the insect. According to Kerner, the flowers
open from 5 to 6 a.m. and close from 5 to 6 P.M.
V. montana.—The arrangement resembles that of
V. Chamedrys. The plant 1s softly hairy.
V. officinalis——The flowers are small, nearly sessile,
blue with darker lines, or sometimes pale pink. The
stamens are even thinner at the base than in the pre-
ceding species. The general arrangement is as in V.
Chamedrys. Stapley found some of the flowers pro-
tandrous. On the other hand, Kirchner found those
near Stuttgart distinctly protogynous, and Warnstorf
says the same of those at Ruppin. The plant is hairy.
It seems probable that some plants have entire leaves,
in order to facilitate the removal of rain and dew; while
others have the edges toothed when the object is to
retain moisture. The teeth seem to be an advantage
Fia.202.— Veronica Chamedrys.
ul SCROPHULARIACEA 315
in snowy districts, as they serve to retain small reserves
of comparatively warm air; while the absence of teeth
is an advantage in rainy districts, because the wet runs
more quickly off a smooth edge. Jungner tested’ the
effect of this form on leaves of V. officenalis. In this
species the same plant has some entire leaves, some
with toothed edges. He chose some smooth and some
toothed, and surrounded them by a freezing mixture. The
former froze soonest, and melted after the toothed ones.
V. serpyllifolia—The flowers are small, pale blue or
white, sometimes protandrous, at others homogamous
or protogynous. The leaves are glabrous, the stem
finely pubescent.
V. arvensis,—A variable plant ; covered with jointed
hairs, arranged on the lower part of the stem in two rows.
V. agrestis has a pale blue or white corolla, and is
pubescent, as is also V. hederefolia.
V. spicata.—The flowers are protogynous, blue, or
sometimes pale pink, in a dense terminal spike. They
open from below, and the undermost are in fruit while
the upper ones are still in the bud, so that a spike may
show in descending order—buds, flowers in the female
state, in the male state, flowers faded, and at the base
young fruit. H. Miller, however, found some plants
protogynous, others protandrous. He also found some
in which the pistil was rudimentary. The plant is
pubescent, and generally slightly glandular.
V. saxatilis has homogamous flowers, rather large,
and bright blue.
V. alpina, a rare plant, found in the highest Scotch
Alps, has flowers homogamous or slightly protogynous,
small and blue. The plant is glandular-pubescent in
the upper part.
V. scutellata, not a very common plant, found in
bogs and on edges of ditches, is glabrous or glandular-
pubescent.
V. Buxbaumii, a field species, with large bright-blue
flowers, is pubescent, but not glandular.
1 “Klima und Blatt in der Regio Alpina,” Flora, lxxix (1894).
316 BRITISH FLOWERING PLANTS CHAP.
V. verna has a small deep-blue corolla, with darker
lines, and small stamens not narrowed at the base. The
flowers are homogamous. The stem is hairy, and glan-
dular above.
V. Beccabunga (Brooklime) is a glabrous succulent
plant, found on margins of brooks and ditches. The
flowers are protogynous, and a deep sky-blue. The
specific name comes from an old German word meaning
‘brook-loving.”
V. Anagallis is also a glabrous succulent plant, found
in watery places. The sepals are glabrous or slightly
glandular. The small corolla is pale lilac or white.
We now come to a series of parasitic or semi-
parasitic genera.
Ruinantuvs (Yellow Rattle)
This is a semi-parasitic plant, which attaches itself
by means of suckers to the roots of grasses. The
suckers are comparatively large, and often surround
more than half of the root attacked. They are homo-
gaimous, humble bee, or in some cases butterfly, flowers.
The general arrangement of the flower agrees with that
of Euphrasia, but is on a larger scale. The calyx is
swollen, not so much, in Knuth’s opinion, to protect
the flower from being bitten into by humble bees, as to
give the wind more purchase, so that the winged seeds
may be thrown out with more force.
R. Crista-galli—The corolla is yellow, with beautiful
violet teeth, and the tube 9-10 mm. in length. Hach
anther is opposite the corresponding one on the other
side of the flower, and the two are connected by matted
hairs, thus enclosing a space into which the pollen is
shed. The filaments of the stamens are waved, leaving
a space between them through which the bee thrusts
its proboscis, and thus separating the anthers sets free
the pollen. The stigma projects beyond the corolla.
According to H. Miiller, the Alpine form R. hirsutus is
adapted both to butterflies and humble bees. Close to
II SCROPHULARIACE.E 317
the extremity of the flower is a small orifice, suited to
the narrow proboscis of a butterfly, and nearer the
middle a second and larger one, for that of a humble bee.
The corolla gradually elongates, and thus carries the
anthers up to the stigma, so that in the absence of
insect visits the flower fertilises itself. This is more
especially the case in certain flowers which are smaller
than the others, thus presenting a first stage in the
direction of cleistogamy. The stem is quadrangular, and
bears narrow opposite leaves. The capsule included in
the bladdery calyx-tube suggests a rattle, whence the
popular name of the plant—Yellow Rattle.
BartTsia
Semi-parasitic herbs. Flowers homogamous or pro-
togynous, adapted to humble bees, and containing nectar
secreted by the under part of the ovary. There are
three British species: B. viscosa, with yellow flowers ;
B. Odontites, with flowers in panicled spikes, and pink ;
and B. alpina, with dull purple flowers in simple
short spikes.
B. alpina.—The flowers are slightly protogynous. The
mode of fertilisation in some respects resembles that of
Melampyrum pratense, but the position of the stigma
and anthers that of Rhinanthus Crista-gallz. When the
flower opens the corolla-tube has a length of 12-16 mm.,
and the pistil projects beyond it. Gradually the tube
elongates to 19-20 mm., while the pistil remains almost
stationary, so that the anthers are carried close to the
stigma. After the stigma has shrivelled up the dry
pollen may still be carried by the wind in small clouds,
and may serve to fertilise another flower. This species
not only derives some nourishment from the earth and
some parasitically from other plants, but it also puts the
animal kingdom under contribution and is insectivorous.
The subterranean winter buds bear scales which leave
recesses between them (Figs. 203, 204). These bear
glands of two kinds (Fig. 205) somewhat resembling
those of Lathreea (p. 303), and probably with the same
318 BRITISH FLOWERING PLANTS CHAP,
function. It is a glandular-pubescent sub-Alpine plant,
found in the North of England and Scotland. The
Fig. 203. Fig. 204, Fig. 205.
Fic. 208.—Bartsia alpina. Subterranean bud. Nat. size.
Fic. 204.—Cross section through part of this bud. x 60.
Fic. 205.—The margin of a bud scale in section. x 200,
leaves are typical of plants growing in cold, wet regions
(see Cerastuum alpinum, p. 28).
B. Odontites—The flower forms a tube 4-5 mm.
long, at the base of which is the honey, while the
entrance is protected
against rain by the four
hairy anthers. These lie
close together ; but im-
mediately below them
the filaments of the
stamens separate, so as to
leave a space (Fig. 206,.e)
through which bees can
insert their proboscis and
Fig. 206. Fig. 207.
Fic. 206.—Bartsia Odontites. Flower with thus each the honey.
short pistil, In doing so they natur-
Fic. 207.—Flower with long pistil. ally dust themselves with
e, entrance to flower ; st, stigma.
pollen, some of which
they transfer to the stigma (Figs. 206, 207, st) of the
next flower they may visit. In warm and sunny places,
where insect visits are numerous, the stigma projects
well above the anthers (Fig. 207); in cold and shaded
places, where insects are comparatively few, it scarcely
projects beyond the anthers.
II SCROPHULARIACEZ 319
MeLampyrum (Cow-wheat)
Flowers unsymmetrical, with nectar secreted by a gland
at one side of the ovary. Semi-parasitic like Bartsia and
Rhinanthus. The suckers resemble those of Rhinan-
thus, with which it also agrees in the general arrange-
ment of the flower. The conspicuousness of the flowers
is in some species enhanced by the presence of coloured
bracts. There are four British species. Two have
yellow flowers; one, JZ. pratense, with the upper bracts
toothed at the base, while in the other, MZ sylvaticum,
they are entire.. The other two species have yellow
flowers variegated with purple; one, M. cristatum, has
the bracts finely toothed, while in M. arvense they
have long slender teeth.
M. pratense.—The corolla-tube has a length of 14-
15 mm., but as humble bees can press their head a short
way into the entrance a proboscis 10-11 mm. long is
sufficient to reach the nectar. This, however, excludes
the hive bee and Bombus terrestris, which often bite
through the corolla and thus rob the flower of its nectar.
The flowers are horizontal, and the stigma hangs over
the entrance. Inside the tube the anthers touch at
their edges and thus form a pollen-box. At their lower
ends are projecting teeth, which are pressed on one side
by the bee, thus unlocking the box and setting free the
pollen. In the absence of insects the filaments gradually
become flaccid, in consequence of which the anthers
separate, and as in the meanwhile the style has bent
downwards, some of the pollen
generally drops on the stigma. () ()
In most flowers the secretion of
nectar ceases when the flower 1!
fades, Melampyrum, however, ™s. 208—1, Beed of Molem
: pyrum ; 2, chrysalis of
is an exception, and the reason Formica fusca.
is interesting. The result of the
continued secretion of nectar is that the plants are
visited by ants (Formica fusca). The seeds of Melampy-
rum (Fig. 208) curiously mimic the chrysalis of a common
320 BRITISH FLOWERING PLANTS CHAP.
ant (F. fusca). They resemble it in size and colour
and in the possession of a black spot at one end. Asa
rule, our English ants take no notice of seeds. But, as
I have proved by actual experiment, they take up and
carry off the seeds of Melampyrum, mistaking them
apparently for the chrysalises, which they so much
resemble." The stem is quadrangular, pubescent, or
nearly glabrous; the leaves, as throughout the genus,
being narrow and opposite. It bears two rows of hairs ;
the lateral horizontal branches have one row on the lower
side.
M. arvense.—The general arrangement resembles
that of M. pratense, but the tube of the corolla is bent
in a manner which makes it peculiarly convenient for
the proboscis of a humble bee. The lower lip is also
slightly bent, so that, as in Antirrhinum, it closes the
orifice and excludes small creeping insects. The plant
is covered with short stiff hairs.
M. cristatum.— This species differs in colour in
different districts. In the Southern Tyrol the bracts
are pale yellow; in Lower Austria and Hungary, red.
The plant is pubescent, especially near the summit. It
is a rare British plant, occurring in fields and copses in
our eastern counties.
M. sylvaticum is also rare, occurring in sub-Alpine
woods in the North of England and Scotland. The
leaves are glabrous or finely puberulent.
PEDICULARIS (Lousewort)
Semi- parasitic annual or perennial herbs with
homogamous, or rarely protogynous, flowers. Nectar
secreted by a ridge at the base of the ovary. The
general arrangement of the flowers is as in the preceding
genera. There are two British species. P. palustris is
erect, and the calyx has 2 broad jagged lobes. P.
sylvatica is prostrate, and the calyx has 4 or 5 lobes
or teeth.
1 Ants, Bees, and Wasps. Lundstrém (Pflanzen-Biol. Studien) has inde-
pendently made the same suggestion.
II SCROPHULARIACE.E ool
P. sylvatica.—This curious flower is unsymmetrical
and compressed laterally. The corolla-tube is 10-14
mm. in length. The under lip falls from right to left,
so that the» right half is 2-8 mm. higher than the left.
The tube is contracted about 1 mm. below the opening
and then expands again, so that it consists of a very
short and a longer lower part connected by a very narrow
passage. The stigma projects slightly, as usual. The
anthers are arranged so as to form a pollen-box, and
the lower edges are fringed with long hairs which direct
the pollen on to the bee. The edges of the upper lip of
the corolla are rolled back, and the inner edge is armed
with projecting teeth. The plant is glabrous.
P. palustris.—The corolla-tube is rather shorter than
in the last species, and the anthers have not the lower
fringe of long hairs, which H. Miller suggests are not
in this case required, because the anthers are so close to
the bee’s head that the pollen needs no guidance. The
plant is an annual, and glabrous or sparingly hairy.
Evupurasia (Eye-bright)
This genus is semi-parasitic on the roots of grasses.
The suckers are tiny little nodules which only just pene-
trate into the root of the host. Huphrasia is an annual,
and Kerner makes the interesting suggestion’ that the
useful substances existing in the green leaves of the
Eye-bright may, before it withers, be transferred to the
host plant. If so, then it would be unjust to Euphrasia
to call it a parasite, for the two plants would be mutu-
ally beneficial, as occurs in other cases (see p. 217).
Dichogamous, ‘generally protogynous bee flowers, with
concealed nectar, secreted by the lower part of the
ovary. This is one of the genera with reference to the
species of which there has been much difference of
opinion. Bentham and Hooker consider that there is
probably but one in the northern hemisphere. Wett-
stein, in a recent memoir,’ makes about fifty, fourteen
1 Nat. Hist. of Plants, vol. i.
2 Monographie der Gattung Euphrasia, Leipzig, 1896.
Y
322 BRITISH FLOWERING PLANTS CHAP,
of which, according to Mr. Frederick Townsend, occur in
Britain.’ No doubt the plants vary wonderfully in the
size and form of the leaves, in the size, colour, and
arrangement of the flowers, and if one district or country
is considered alone they may be divided into well-marked
forms. I have, however, examined the plant in France
and Switzerland as well as in England, and believe that
if we take a sufficiently large area, such as Western
Europe, intermediate forms can be found between all
the varieties, so that I cannot but accept, at any rate
provisionally, the view of the two great English
botanists whom I have quoted.
E. officinalis.—H. Miller distinguishes two principal
forms : one with large flowers adapted for cross-fertilisa-
tion, one with smaller ones for spontaneous self-fertilisa-
Fic. 209. — Euphrasia officinalis. Fic. 210.—Luphrasia officinalis. Partial sec-
Shoot, with flower, pistil, and tion of flower, enlarged. a, anthers; ca,
fruit ; enlarged. calyx, uncut; co, corolla; 7, filaments of
stamens ; s, stigma.
tion. The upper lip (Fig. 210) protects the anthers
and nectar from rain. The ripe stigma projects from
the flower even before it opens. The corolla gradually
elongates so as eventually to reach the stigma, thus
bringing the anthers close to it. In this respect, how-
1 Monograph of the British species of Euphrasia, Jowrnal of Botany, 1897.
See also Babington, Manual of British Botany, ed. ix., H. and J. Groves, 1904.
1 SCROPHULARIACEZ—LABIATA 323
ever, there are several differences, and Schulz describes
no less than seven forms of the flower. In any case,
however, when the anthers first open they are behind
the stigma. The stamens are 4 in number, so that
there are 8 anthers (Fig. 210). The lower chambers
of the-upper or outer anthers coalesce with the upper
chambers of the inner or lower anthers, and the two
upper are firmly connected. The lower surface of each
anther has a stiff pointed process. The two lower
points are distinctly longer than the upper ones and
project into the mouth of the flower, while the upper
ones end in a brush of hairs which prevent the pollen
from being scattered at the sides, so that they are sure
to be touched by the bee, which thus dislocates them,
the result of which is that some of the pollen drops on
to it. The plant is pubescent, and more or less glan-
dular, especially near the summit.
LABIATA
Herbs, or rarely shrubs, with quadrangular stems
and opposite leaves. Flowers generally protandrous.
Corolla tubular, generally forming two lips. Stamens,
probably for the reason already suggested (see p. 313),
4 or sometimes 2. Nectar secreted at the base of
the ovary. Fruit enclosed in the persistent calyx,
separating into 4 one-seeded, seed-like nuts. The
upper lip of the corolla protects the anthers and stigma,
and the lower lip forms a convenient alighting stage for
insects. The corolla-tube often assumes the curve con-
venient for the proboscis of a humble bee. The flowers
often vary in size, sometimes even on the same plant.
Sometimes there are two distinct forms, sometimes two
1 T have attempted to show (Brit. Assoc. Cambridge, 1904) that it is an
advantage for herbs with opposite leaves to have quadrangular stems, and that
the two generally go together.
324 BRITISH FLOWERING PLANTS CHAP.
extremes with intermediate gradations. Many species
have female as well as complete flowers, generally on
special, but sometimes, though rarely, on the same
plants. The female flowers are always smaller than the
others, though they vary considerably in size. The
nectar is generally protected from rain by hairs. The
capsules are generally upright, and the nutlets are
jerked out by the wind or by passing animals. Ina
few genera the flower is nearly regular.
Mentua (Mint)
Complete flowers, protandrous, generally less numer-
ous than the smaller female ones. Some species dimor-
phous. Calyx regular or slightly two-lipped. Corolla
nearly regular. Stamens equal and erect.
M. arvensis.—The corolla is lined with hairs which
protect the nectar ; the leaves are glabrous or hairy.
M. aquatica includes a number of varieties and
forms, some of which are more or less glabrous, others.
more or less hairy.
M. rotundifolia has cut leaves, hairy above, tomen-
tose below, with branched hairs.
M. Pulegium (Pennyroyal).—With us it is nearly
glabrous, but in the hot dry regions in the South of
Europe it develops a thick covering of hair as a pro-
tection against too rapid transpiration.
Tuymvs (Thyme)
In this genus the corolla is two-lipped, but not very
markedly so.
T. Serpyllum.—The stamens and pistil project freely
from the flower. Besides the complete there are small
female flowers. In these, indeed, stamens occur, but
without fertile anthers. The filaments vary greatly
in length. Delpino found the plants near Florence
trimorphic—hermaphrodite, female, and male. Darwin,
however, in spite of careful search, never found any male
flowers in this country. The leaves are flat, ciliated at
Ir LABIATAE 325
the base, sometimes glabrous, sometimes hairy; the
stems bear reflexed hairs.
OriGaNuM (Marjoram)
Protandyrous. Besides the complete there are often
small female flowers.
0. vulgare.—The corolla-tube of the complete flowers
is 7 mm. long, of the female 4-5 mm. long. The small
female flowers open some eight days before the others.
The leaves are hairy underneath ; the stem bears soft
hairs.
Lamium (Dead-nettle)
We now come to the typical Labiates in which the
corolla is distinctly two-lipped. I take Lamium as a
type, because it is very characteristic, very common, and
known to every one. They are red, white, or yellow
homogamous bee or humble bee flowers, with nectar
secreted at the base of the ovary, and protected by a
ring of hairs round the corolla. We have five species.
Two are annual: ZL. amplexicaule, with the bracts
sessile and orbicular; while in L. purpureum they are
stalked and ovate. Of the three perennial species, one,
L. maculatum, has red flowers; one, L. Galeobdolon,
yellow ; and the third, LZ. album, white.
L. album (Fig. 211).—In few flowers is the use of
the various arrangements more clearly and beautifully
shown. The honey occupies the lower contracted
portion of the tube, and is protected from the rain by
the arched upper lip and by a rim of hairs. Above the
narrower lower portion the tube expands, and throws
out a broad lip (Fig. 213, m), which serves as an
alighting place for large bees, while the length of the
narrow tube prevents the smaller species from obtain-
ing access to the honey, which would be injurious to
the flower, as it would remove the source of attraction
for the bees, without effecting the object in view. At
the base of the tube, moreover, at the point marked
ca (Fig. 213), there is a ring of hairs which prevents
326 BRITISH FLOWERING PLANTS CHAP.
small insects from creeping down the tube and so
getting at the honey. Lamium, in fact, like so many
of our other wild flowers, is especially adapted for
humble bees. They alight on the lower lip, which
projects at the side, so as to afford them a leverage, by
means of which they may press the proboscis down the
tube to the honey; while, on the other hand, the
arched upper lip, in its size, form, and position, is
admirably adapted not only as a protection against rain,
Fig. 211, Fig, 212. Fig. 213.
Fig. 211.—Lamium album. White Dead-nettle.
Fig, 212.—Flower magnified.
Fic. 218.--Section of flower magnified. «, anthers; ca, calyx; co, corolla;
m, lower lip of corolla ; st, stigmas.
but also to prevent the anthers (aa) and pistil (st)
from yielding too easily to the pressure of the insect,
and thus to ensure that it should press the pollen, which
it has brought from other flowers, against the pistil.
The stamens do not form a ring round the pistil, as is so
usual. On the contrary, one stamen is absent or rudi-
mentary, while the other four lie along the outer arch of
the flower, on each side of the pistil. They are not of
equal length, but one pair is shorter than the other ; the
inner pair in some species, the outer pair in others, being
the longest. Now, why is this? Probably, as Dr.
TT LABIAT.E 327
Ogle has suggested, because if the anthers had lain side
by side they would have formed a too broad surface,
and the pollen would have adhered to parts of the bee’s
head which do not come in contact with the stigma,
and would therefore have been wasted; perhaps also
partly, as he suggests, because it would have been
deposited on the eyes of the bees, and might have so
greatly inconvenienced them as to deter them from
visiting the flower. Dr. Ogle’s opinion is strengthened
by the fact that there are some species, as, for instance,
the Foxglove, in which, as shown in Figs. 199-201, the
anthers are transverse when immature, but become
longitudinal as they ripen.
But to return to the Dead-nettle. From the position
of the stigma, which hangs down below the anthers
(Fig. 213, st), the bee comes in contact with the former
before touching the latter, and consequently generally
deposits upon the stigma pollen from another flower.
The small processes (m) on each side of the lower lip
are the rudiments of the lateral petals with which
the ancestors of Lamium were provided. Thus, then,
we see how every part of this flower is either—like
the size and shape of the arched upper lip, the relative
position of the pistil and anthers, the length and narrow-
ness of the tube, the size and position of the lower lip,
the ring of hairs, and the honey—adapted to ensure
the transference, by bees, of pollen from one flower
to another, or, like the minute lateral points (m),
an inheritance from more highly developed organs of
ancestors. If we compare Lamium with other flowers
we shall see how great a saving is effected by this
beautiful adaptation. The stamens are reduced to 4,
the stigma almost to a point. How great a contrast to
the Pines and their clouds of pollen, or even to such
a flower as that of Nymphzea, where the visits ‘of insects
are secured, but the transference of the pollen to the
stigma is, so to say, accidental. Yet the fertilisation of
Lamium is not less effectually secured than in either of
these.
328 BRITISH FLOWERING PLANTS CHAP.
The Dead-nettle is so called because in the form
of the leaf and in general habit the plant so closely
resembles young plants of the Stinging-nettle, although
the two species belong to very different families. How
close the similarity is may be seen by the following
illustration taken from a photograph. The plants on
the right are true Stinging-nettles ; those on the left are
the white Dead-nettle, one of which is in flower. So
close was the resemblance that after getting the photo-
graph I went back to the spot on which they were
growing to assure myself that there was no mistake. It
cannot be doubted that
the true Nettle is pro-
tected by its power of
stinging; and that
being so, it is scarcely
less clear that the Dead-
nettle must be protected
by its likeness to the
other. Moreover,
though I was fortunate
* Siero. in lighting on so good
Fig. 214.—Group of Dead-nettles and an illustration as that
Stinging-nettles. shew tH the figure,
just when I had an opportunity of photographing
it, still every one must have observed that the two
species are very commonly found growing together.
Assuming that the ancestor of the Dead-nettle had
leaves possessing a faint resemblance to those of the true
Nettle, those in which the likeness was greatest would
have the best chance of survival and consequently of
ripening seeds. There would be a tendency, therefore,
according to the well-known principles of Darwin, to a
closer and closer resemblance. Jam disposed to suggest
whether these resemblances may not serve as a protec-
tion, not only from browsing quadrupeds, but also from
leaf-eating insects. On this part of the subject we have
as yet, however, I think, no sufficient observations on
record.
I LABIAT.E 329
L, maculatum.—The corolla-tube is rather longer
than in L. album—15-17 mm.,—so that it is adapted
to bees with a somewhat longer proboscis. As they can
press their head into the tube, 10-12 mm. is sufficient.
The leaves are hairy or pubescent; the stem hairy or
olabrous.
L, purpureum.—In this species, on the contrary, the
flower-tube is shorter—10-11 mm.,—and a proboscis
6-7 mm. long is sufficient. The leaves are hairy.
L. amplexicaule.—The length of the tube is about the
same as in the preceding. The ring of hairs is wanting
—perhaps being unnecessary, as the flower closes in wet
weather, and is, indeed, often cleistogamous. In the
latter flowers there are no petals; and the anthers do
not open, but the pollen tubes pierce the walls and reach
the stigma. The leaves are pubescent.
L. Galeobdolon.—The corolla-tube is 8 mm. in length,
and yellow. This difference of colour in the three
perennial species—red, white, and yellow—is perhaps of
use in enabling the bees easily to distinouish them.
The leaves are hairy.
CALAMINTHA
Protandrous bee or humble-bee flowers. The two
upper teeth of the calyx are more or less connected at
the base into an upper lip. There are three British
species: one, C. Acinos, annual; the other two peren-
nial—C. officinalis many-flowered, the other, C. Clino-
podium, with few flowers in close cymes.
C. Acinos.—The corolla is a little longer than the
calyx. The stem bears reflexed hairs.
C. Clinopodium.—The complete flowers, according to
Miiller, fall into two distinct forms—(1) large-flowered,
protandrous; (2) small-flowered, almost homogamous.
The leaves are more or less hairy.
NEPETA
The upper or central stamens project beyond the
outer ones (Fig. 215), while in most Labiates the reverse
330 BRITISH FLOWERING PLANTS CHAP.
is the case (Fig. 216). Some species are adapted to
butterflies. We have two species: N. Glechoma, creep-
ing; NV. Cataria, upright.
N. Cataria (Catmint).—The flowers are pale blue or
nearly white. The stigma sometimes projects beyond
the anthers, and at others is on a level’ with them;
but this does not lead to self-fertilisation, as the plant
is distinctly protandrous. The
complete flowers are 7-8 mm.
long. There are also female
flowers 5-6 mm. long. These
are generally on the same
plants as the complete ones.
A pubescent species, rare in
England, and found as an
introduction in Scotland.
Fig. 215, Fig, 216. N. Glechoma (Ground Ivy).
a .. ~The flowers are blue-violet,
jagram to show arrange
ment of stamens in Nepeta. rarely white or rose, with purple
Mia, 216. Diagram to show position and white spots. The corolla-
tube is lined on its lower side
with stiff hairs ; in the large complete flowers it is 13-16
mm. in length. That of the small female flowers is
only 64-8 mm. long. Willis, in Cambridgeshire, found
one year at the beginning of the flowering time 86
per cent female, towards the end 24 per cent; another
year 50 per cent and 28 per cent. A polymorphous
plant, glabrous or hairy. In summer it sends out
creeping runners, from which the flowering shoots rise
in the following spring.
VW
PRuNneELLA or BRUNELLA
Calyx distinctly two-lipped. The stamens have a
process or lobe beyond the anthers. The processes on
the longer stamens are much longer than those on the
shorter ones.
P. vulgaris.—Besides the complete flowers, there are
smaller ones with more or less rudimentary stamens. In
Belgium, MacLeod found cleistogamous flowers.
II LABIAT.E 38361
SCUTELLARIA
We have two species: S. galericulata, blue, and
S. minor, pink.
S. galericulata (Fig. 217).—The flower is protan-
drous. The upper lip is three-lobed and laterally com-
pressed, so as to leave a small orifice (Fig. 218, «),
which it has been suggested by Kirchner’ is especially
adapted to butterflies; while the larger one between
4 &
Fig. 217. Fig. 218,
Fic. 217.—Scutellaria galericulata. Side view of flower.
Fic. 218.—Front view. uu, entrance for butterflies ; 6, entrance for humble
bees.
the upper and under lip is used by bees. According
to Warnstorf the longer stamens have only one anther
chamber. Besides the complete flowers, there are
others with rudimentary anthers, which are sometimes
on the same, sometimes on distinct plants. When the
corolla has faded the calyx closes tightly over the
ovary, forming the helmet-shaped hood, and protecting
the young seeds.
S. minor has the habit of the former species, but is a
smaller, slenderer plant, with much smaller pale pink-
purple flowers.
LEonuRvus
Protandrous or homogamous bee flowers repre-
sented by
L. Cardiaca, a pubescent plant now established,
though rare, in this country.
1 Neue Beobachtungen tiber d. Bestdéubungs - Hinrichtungen einheimischer
Pflanzen. Stuggart, 1886.
332 BRITISH FLOWERING PLANTS CHAP.
MELITTIS
Protandrous. Adapted to humble bees and moths.
M. Melissophyllum.—In some districts the corolla is
white, in others pale purple, in others red or white with
purple spots. The flowers are very sweet. The corolla-
tube is 25-35 mm. in length and sometimes half filled
with nectar. It varies in colour in different countries,
being white in Southern Tyrol, purplish white in Lower
Austria and Hungary.
Marrvusium (Horehound)
M. vulgare.—The ten teeth of the calyx curve back,
forming hooks, which facilitate the scattermg of the
nutlets. The plant bears long soft hairs.
Sracuys (Woundwort)
8. sylvatica has protandrous flowers. The corolla-
tube, 11 mm. long, is often filled with nectar to a depth
of 2-3 mm.
8. palustris is also protandrous. The corolla-tube is
7-9 mm. long. The anthers of the outer stamens are
open first and lie in front of the others. After shedding
their pollen they turn outwards, while the inner stamens
elongate and their anthers open at the same place.
Then the pistil elongates and the stigma presses itself
between the anthers. The leaves are finely hairy. The
stem bears reflexed hairs on the edges.
8. arvensis is homogamous. According to Kirchner
there is very little, if any nectar. The corolla-tube is
only 4 mm. in length.
S. annua, an alien which has become established
in corn-fields in Kent, has homogamous flowers. The
corolla-tube is 8-10 mm. in length. The leaves are
glabrous or slightly hairy.
S. germanica.—Besides the complete flowers this
species has others in which the stamens are rudimentary.
These are often on special plants. The plant is covered
with a white tomentum.
ret LABIAT.E 333
GALEOPSIS
Homogamous or slightly protandrous bee flowers.
Kerner describes the anthers as boxes closed with a lid
which is pushed open by the humble bees, though only
by those which correspond to the size of the flower.
These only, therefore, are dusted by the pollen. There
are three British species. One, G. Tetrahat, has long stiff
hairs, and the stem swollen at each node. Of the other
two, G. Ladanum has purple, G. ochroleuca yellow
flowers ; the leaves bear soft hairs.
G. Tetrahit.—The corolla-tube varies between 11 and
17 mm. in length; but the upper part is widened, so
that for small humble bees a proboscis of 12 mm. is
sufficient. Besides the complete there are small female
flowers, which seem to be more frequent in the south
than in the north. The two forms sometimes occur on
the same plant. The stem bears rough jointed hairs.
Briquet in his Monograph of Galeopsis says :—
“Les renflements sont des portions d’entre-noeud
différenciées en organes spéciaux, sur lesquels se localise
l’action du géotropisme, et de l’héliotropisme, et qui, dans
les mouvements effectués par |’axe sous l’influence de ces
forces, jouent le rdle de charniere, tandis que les entre-
neeuds proprement dits ne jouent qu’un réle passif.
Une expérience tres simple suffit pour constater
cette localisation. Couchons, dans les mémes conditions
de température et de lumiere, une tige de G. Ladanum
et une tige de G. Tetrahit dans du sable humide. Au
bout de quelque jours, les deux tiges se sont relevées et
méme completement érigées; mais tandis que chez le
G. Ladanwm \a courbure affecte les entre-nceuds tout
entiers, on constate que le G. Tetrahit sest érigé unique-
ment sur ses renflements qui sont fortement courtes, et
que les entre-nceuds sont restés droits.” ?
And further on he adds :—
“Le réle des renflements se revele comme étant d’une
utilité incontestable pour la plante dans une quantité de
1 J, Briquet, Monographie du Genre Galcopsis, p. 74.
334 BRITISH FLOWERING PLANTS CHAP.
cas. Nous avons d’abord celui dans lequel les pieds sont
couchés par le vent ou par une cause accidentelle de ce
genre; on constate que dans immense majorité des cas
sous l’action du géotropisme, les tiges s’érigent avec une
grande rapidité et rattrapent ainsi en fort peu de temps
les dommages que leur a causés la tempéte. Dans les
haies et les taillis, que les Galeopsis du groupe des
Tetrahit affectionnent, la sensibilité phototropique fait
rapidement prendre aux tiges qui se courbent sur leurs
renflements une position favorable a loptimum d’éclai-
rage.”
BETonIca
Protandrous to homogamous bee flowers.
B. officinalis (Wood Betony).—The corolla is 7 mm.
in length, and is not widened at the mouth, perhaps
because a tube of this length is accessible to all the
humble bees.
BaLLota
Protandrous bee flowers.
B. nigra.—The corolla-tube has a length of about 7
mm., and is slightly widened at the mouth, so that the
nectar is accessible to a proboscis 6 mm. long. The
flower is protandrous, and if not carried away by
insects the pollen falls on to the lip of the corolla.
Finally the pistil elongates, and the stigma touches the
lip, taking up some of the pollen. The leaves are
hairy.
AJUGA
Nectar protected by a ring of hairs. The upper lip
of the corolla is very short, but the anthers and stigma
are protected by the bract of the flower above. There
are three British species. One, A. Chamepitys, has
yellow flowers, with much-divided leaves ; the other two
blue or ash-coloured, with nearly entire leaves; one, A.
reptans, is glabrous or nearly so, with creeping scions ;
the other, A. pyramidalis, very hairy, and without
creeping scons.
II LABIATAE 335
A. reptans (Bugle).—The flower is generally homo-
gamous ; sometimes, however, the anthers open a little
before the stigma is ripe, while at others the reverse
happens. MacLeod, in Belgium, found a distinctly
protandrous form with large flowers. The stem is
alternately hairy on two faces, and glabrous on the
other two. In this species, as in many others, the
leaves are coloured red, especially on their under sides,
by anthocyanin. The use of the pigment seems to be
to turn the light- into heat-rays. The object of the
lower side being coloured is apparently that some of
the light would otherwise pass through the leaf and be
lost to the plant. It is found especially in plants
which grow in shady places, in Alpine plants, water
plants, and many sea-weeds, especially those found at
greater depths and not exposed at the ebb-tide. There
are other cases in which the anthocyanin is on the upper
surface. Here it probably serves as a screen, and pro-
tects the plants against too intense illumination by
turning part of the light into heat. This view seems
strongly supported by some of King’s experiments. For
instance, he placed some chlorophyll in intense sunshine,
part, however, protected by a screen of anthocyanin
extracted from Beetroot. The part so sheltered remained
green, the rest was decomposed by the light. It is also
borne out by the frequent presence of the red colouring-
matter in young leaves in which the delicate epidermis
forms an inadequate protection from strong light.
A. pyramidalis has the stem hairy all round, and
very hairy leaves.
A. Chamepitys.—The leaves are deeply divided into
three lobes. It is a southern form, and I have found it
on the Riviera growing with Huphorbia Cyparissias,
which it so much resembled that I could not but think
it was a case of mimicry. The Euphorbia is protected
by its acrid sap, and the similarity may be a distinct
advantage to the present species, which itself has an
unpleasant taste. The leaves are rather viscous; the
stem is hairy all round.
336 BRITISH FLOWERING PLANTS CHAP.
TEUCRIUM
Protandrous bee flowers. The upper lip is apparently
absent, as in Ajuga. We have four species. 7.
Scordium and T. Botrys have axillary flowers. In the
other two they are in terminal one-sided spikes; 7.
Scorodonia has pale yellow, T. Chamedrys red flowers.
When the flower opens the anthers stand out at the
orifice ; afterwards they bend up, and their place is
taken by the stigma.
T. Scorodonia (Wood Sage).—The corolla-tube is
9-10 mm. long, sometimes nearly half filled with nectar.
When the lower flowers of a raceme have reached the
second (female)
condition (Fig.
220), the upper
ones are still male
(Fig. 219), so that
a bee first visits
female _—_ flowers,
and then dusts
PP itself with pollen,
which it probably
Fig. 219. Fig. 220. : A
Fie. 219.—Teuerium Scorodonia. Flower in the first carries Qe ane
state, with anthers erect. Enlarged. other plant. The
Fic. 220.—Flower in the second state, with recurved
anthers and exposed stigmas,
plant is pubes-
cent.
T. Chamedrys.—According to H. Miiller the pistil
is only as long as the shorter stamens, while according
to Schulz it exceeds the longer ones. The leaves are
pubescent ; the stem hairy. It is not a British plant,
but found, rarely, as a garden escape on old walls.
Lycopus
In this genus the stamens are reduced to two. The
complete flowers are protandrous ; there are also smaller
ones which are female. The corolla-tube is only
3-4 mm. long, and the nectar is therefore accessible
even to insects with a very short proboscis.
It is represented in our flora by L. europeus, a
Ir LABIATE 337
glabrous or slightly pubescent plant; found in ditches or
on river banks, with small bluish-white flowers.
We now come to a genus which presents us with
one of the most remarkable pieces of mechanism to be
found in the whole vegetable kingdom.
SALVIA
Two of the stamens are rudimentary or absent. In
the other two the halves of the anthers, instead of
being close together, are united by a more or less long
connective (Fig. 224), and one half produces little or
no pollen. In several of the species the access of creep-
ing insects is precluded by the presence of glutinous
hairs. There are two British Species: one, S. pratensis,
with a large flower and leaves mostly radical; the
other, S. Verbenaca, with a leafy stem and small
flowers.
I take S. officinalis, the common garden Sage, as an
example, because it is accessible to any one. The
flowers were well described by Sprengel, and more
recently by Hildebrand and Ogle.’ Fig. 221 represents
a young flower of S. officinalis in which the stamens
(a) are mature, but not the stigma (p), which, more-
over, from its position is untouched by bees visiting
the flower, as shown in Fig. 222. The anthers,
as they shed their pollen, gradually shrivel up;
while, on the other hand, the pistil increases in lenoth
and curves downwards until it assumes the position
shown in Fig. 223, st, where, as is evident, it must
come in contact with a bee visiting the flower, and
would touch just that part of the back on which pollen
would be deposited by a younger flower. In this
manner self-fertilisation is effectually provided against.
The general form of the flower is very similar to that
of other Labiates. We find that, as generally, the corolla
has the lower lip adapted as an alighting board for
insects, while the arched upper lip covers and protects
1 Pop, Sct. Rev. July 1869.
Z
338 BRITISH FLOWERING PLANTS CHAP.
the stamens and pistils. In S. officinalis, however, the
back of the upper lip shows an arch at the part x, and
the front portion of the lip, containing the stamens, is
loftier than in Lamium, and does not therefore come in
contact with the back of the bee (Fig. 222). This is
evidently correlated with the difference in the stamens
Fig. 223. Fig. 224. Fig, 225.
- Fig, 221-225.—Salvia officinalis. Fig. 221, section of a young flower; Fig. 222,
flower visited by a bee; Fig, 223, older flower; Fig. 224, stamens in their
natural position; Fig. 225, stamens when moved by a bee. All enlarged.
u, sterile, a’, fertile half of anther; f, filament of functional stamen; 7’,
position of aborted stamen ; m, connective ; p, pistil; st, stigmas; w, arch of
corolla.
(Fig. 221), two of which (f’) are minute and rudi-
mentary, while in the other pair the two anther cells
(aa’) are separated by a long connective. Moreover,
the lower anther cells (a @) contain very little pollen;
sometimes, indeed, none at all. This portion of the
stamen, as shown in Fig. 223, hangs down and
partially stops up the mouth of the ccrolla-tube.
II LABIAT.B 339
When, however, a bee thrusts its head into the tube in
search of the honey, this part of the stamen is pushed
into the arch (Fig. 222, x), the connectives of the two
large stamens revolve on their axis, and consequently
the fertile anther cells (a’) are brought down on to the
back of the bee, as shown in Fig. 225.
In this country we have only two species of Salvia,
but the foreign species are numerous, and differ con-
siderably in their mechanism for fertilisation. For
instance, in S. verticellata’ the arrangement is quite
different. The lower anther is rudimentary. The
connective does not move, but the hood is connected
with the tube of the corolla by a narrow part which
acts asa hinge. The flower is much smaller, and the
bee dusts itself with pollen by pressing back the
movable hood. In fact, in this species it is the hood
of the corolla, and not the anther, which is movable.
Connected with this change in the structure of the
stamen is an alteration in the position of the pistil.
If it occupied the usual position it would impede, if not
prevent, the raising of the hood. At first it lies close
to the lower lip, which it about equals in length.
Gradually, however, it elongates, projects beyond the
corolla, and generally raises itself a little, so that it can
scarcely fail to touch the head of the bee. Besides the
large complete flowers, some species have plants with
small female flowers.
S. Verbenaca.—This is our common species. The
flowers are small. There are also cleistogamous flowers.
S. pratensis.—A very rare British plant, found in
dry fields in a few of our southern counties. The
pericarp is thick, crustaceous, deep brown, not shining,
and the epidermis is rugulose. When placed i in water
it emits long colourless filaments, which are at first
spirally coiled, but gradually open out.
In S. Horminum these mucilaginous threads attain a
considerable relative length, and for some time wriggle
about like small worms.
1 Hildebrand, Pringsh. Jahrb. vol. iv. (1865-66).
340 BRITISH FLOWERING PLANTS CHAP.
VERBENACEA
Verzena (Vervain)
Homogamous bee flowers. Nectar secreted by the
base of the ovary, and protected by a ring of hairs.
V. officinalis is the only representative of the
family in the British flora. The flowers are small, but
are rendered less inconspicuous by being collected into
a long slender spike. The corolla-tube is 3-4 mm.
long. The lower half is turned upwards, the upper
outwards, thus protecting the stigma, anthers, and
nectar. The stem is quadrangular, and bears opposite
leaves.
PLUMBAGINACEA
The flowers are small, but conspicuous by association.
Calyx and corolla tubular ; nectar secreted by the base
of the flower.
Armertia (Thrift)
Small red or sometimes white flowers collected in
a terminal globular head. The calyx has a petal-like
border.
A. vulgaris—The flowers are sweet-scented. The
calyx is 5 mm. long, the upper part thin, violet, and
supported by five ribs ending in short teeth. The corolla-
tube is lined with hairs which protect the nectar.
When the flower opens the five stigmas are in the centre
surrounded by the anthers, which are over the honey.
Subsequently they change places, the stigmas moving
outwards, the anthers approaching the centre of the
flower. Finally the stigmas wind spirally, and touch
the anthers. The membranous calyx serves as a
parachute for the dispersal of the seed. This species
has two well-chosen haunts—mountains and the seaside.
Il PLUMBAGINACEE:—PLANTAGINEZ 341
Sratice (Sea Lavender)
Flowers in a dichotomous or trichotomous panicle.
Nectar secreted by the base of the flower. The calyx
is membranous above and coloured, as in Armeria. We
have three species. One, S. Limonium, has leaves
several inches long; in the other two they are short ;
in S. awriculefolia all the branches are flowering; the
other has a number of short barren branches.
S. Limonium is protandrous. Some of the flowers
have rudimentary anthers. A glabrous plant found on
muddy shores round England and the South of Scotland.
S. auriculefolia is a Southern European plant, found
in Britain as far north as Lincoln on the east and
Wigtown on the west.
S. reticulata occurs in salt- marshes in Norfolk,
Suffolk, and Cambridge.
PLANTAGINEZ
Parts of the flower in fours. As a rule protogynous
wind flowers, with long movable stamens, and the
stigmas feathery, which, of course, increases their chance
of receiving some of the pollen. They are also long-
lived.
PLantTaGo
Flowers in heads or spikes; complete. The anthers
are somewhat conspicuous, and the plants are sometimes
visited by insects for the sake of their pollen. This is
especially the case with P. media. The filaments of
the stamens are long and thin, so that they are easily
shaken by the wind. The orifice of the anthers is small,
so that the pollen only comes out if they are some-
what violently shaken. They open when it is fine, and
close again if it rains. The anthers open on the side
turned to the sky, and it takes a couple of days to
342 BRITISH FLOWERING PLANTS CHAP,
disperse the pollen.’ As in many other wind flowers
the pollen is dry and dusty, but the bees moisten it
with honey from their proboscis, which makes it easy to
collect. The Plantains illustrate the difference between
broad leaves, which tend to be horizontal, and narrow
ones, which tend to be vertical.
Thus P. media (Fig. 226) has
broad leaves, which lie flat on the
ground, and P. lanceolata has
narrow ones, which point upwards
(see also Drosera, p. 203). The
seeds secrete a mucilaginous adhe-
sivesubstance, which exudesfreely
as soon as they are moistened,
and serves to fasten them if they
meet with damp earth. We have
five species. One, P. maritima,
has narrow linear leaves; one,
P. Coronopus, deeply toothed or
pinnatifid leaves; in the other
three they are broad and entire. P. lanceolata has
short round heads; the last two, slender spikes; P.
major with reddish brown, yellowish, or white, P.
media with pink or purple anthers.
P. major.—Anthers reddish brown, but according to
Ludwig sometimes yellow, greenish yellow, or white.
The plant is glabrous or bears appressed hairs. The
seeds are small, faintly rugose, somewhat flat, and
covered by a layer of mucilage.
P. media.—Anthers pink or purple. This species
forms a passage from a wind flower to an insect flower.
The long flexible filaments and feathery stigma are
characteristic of a wind flower; while the violet anthers
and the scent serve to attract insects. Some flowers
have anthers only, and others only the pistil. These
also are sometimes moncecious, sometimes dicecious, so
that there are five forms of flower. The plant is
covered with short hairs.
Fig. 226.—Plantayo media.
1 Kerner, Natural History of Plants, vol. ii.
II PLANTAGINEA—CHENOPODIACE 343
P. lanceolata.—This species also presents female as
well as complete flowers. It is visited by hive bees,
which moisten the anthers with honey, then force them
open, and collect as much of the pollen as they can.
The plant is glabrous, or, in the maritime variety, with
appressed hairs. The seeds are comparatively large,
shining, smooth, with a deep furrow on one side; they
have a thin layer of mucilage.
P. maritima has glabrous leaves. The peduncles bear
an appressed pubescence. The seeds are like those of
P. lanceolata.
P. Coronopus.—This species grows in sandy situa-
tions, generally near the sea. The lobes of the leaves
are so arranged that the rosette offers a smooth surface,
over which the sand blows, and on which it finds no
ledge or hollows in which it might accumulate. The
seeds are small, with narrow white expansions at each
end, and covered with a layer of mucilage.
LITTORELLA
This genus differs from Plantago in the flowers being
few and moncecious.
L. lacustris.—This is a small plant, 1} to 3 inches
high, and grows in shallow ponds. It often goes some
years without flowering, till a dry summer comes, when
the water contracts and the ground is laid dry. The
stamens are sometimes 4 inch long. The plant is
glabrous or minutely hairy.
CHENOPODIACEA
The flowers are inconspicuous, and appear to be
generally self-fertilised. Perhaps the pollen is carried
by creeping insects. Sprengel regarded them as wind
flowers, and no doubt this may sometimes be the case,
but they do not present the special characteristics of
wind-fertilised flowers.
344 BRITISH FLOWERING PLANTS CHAP.
SALICORNIA
Leafless herbs, with cylindrical succulent jointed
stems; found in salt-marshes. The minute bisexual
flowers are sunk in pits at the nodes, and contain no
honey.
S. herbacea and S. radicans occur in Britain, the
latter only south of Yorkshire.
Sausoia (Saltwort)
This genus is represented by §. Kali, another succu-
lent maritime species. It is homogamous or proto-
gynous. The plant is glabrous or with rough hairs.
The leaves are fleshy, and somewhat awl-shaped.
CHENopopium (Goosefoot)
Generally protogynous wind flowers ; without nectav.
Some, however, have nectar. Though insect visits are
few and far between, it must be remembered that the
flowers are very numerous and long-lived.
C. Vulvaria (Stinking Goosefoot).— This species,
according to Kirchner, produces nectar. The very un-
pleasant smell is perhaps a protection against browsing
quadrupeds. Kirchner describes it as distinctly proto-
gynous, but Hildebrand found it protandrous in his
neighbourhood. The plant is covered with powdery
dust-like hairs.
C. album.— More or less mealy white, from the
numerous small globular hairs. The flowers are proto-
gynous. In this species also Kirchner found nectar.
The young leaves rise vertically at night. The stem
has alternate bands of white and green.
C. rubrum is a glabrous shining plant, the stem
having alternate bands of green and white or red.
C. glaucum.—In this species the leaves are green
above, white, glaucous, and mealy below.
C. polyspermum.—Leaves entire and scentless.
C. hybridum.— Maple-leaved Goosefoot; with a heavy
odour.
ra CHENOPODIACEE 345
C. murale, a nearly glabrous plant, found in waste
places near houses. The leaves are mealy when young.
C. Bonus-Henricus (Good King Henry).—Stem with
bands of green and red, papillose, as is also the under
face of the succulent triangular leaves.
C. urbicum.—The stem has alternate bands of green
and white.
Beta (Beet)
B. maritima.—A glabrous plant with fleshy shining
leaves, and small protandrous flowers in clusters of two
or three. This is the origin of the Beetroot and
Mangel Wurzel.
ATRIPLEX (Orache)
According to Bentham,’ “the flowers are small and
numerous, clustered in axillary spikes or terminal
panicles as in Goosefoot, but always of two kinds; in
some, which are usually males only, the perianth is
regular and 5-cleft, as in Goosefoot, with 5 stamens ;
in the females the perianth consists of two flat segments
(or rather, bracts replacing the real perianth), either
free or more or less united at the edges, enclosing the
ovary. After flowering this false perianth enlarges, is
often toothed at the edge, and covered with wart-like
excrescences. Seeds usually vertical. In some species
there are also a few regular female real perianths, which
ripen without enlarging, and contain a horizontal seed,
as in Goosefoot.” The species, of which we have five,
are found on shores and in waste places. The plants
are generally more or less covered with mealy hairs.
A. hortensis—The fruit is an utricle, much com-
pressed, and concave on the sides, one-celled, one-seeded.
It is enclosed in two orbicular, or nearly orbicular,
bracts, which are connate at the base, aurescent, and
probably serve to disperse the seeds. The seeds are of
two kinds. Some are small and black, with a rather
thick, crustaceous, smooth, and shining coat; the others
are larger, brown, and more orbicular, with a thin,
1 Handbook of the British Flora, vol. ii.
346 BRITISH FLOWERING PLANTS CHAP.
membranous, smooth, but not shining coat. They are
mixed indiscriminately on the panicle. The large brown
ones germinate much more quickly than the small black
ones, which would seem, under natural conditions, to be
more adapted to remain in a resting condition in the
ground during the winter and germinate in spring. If
such is the case they would enable the plant to exist in
a colder climate than the large ones would.’ The plant
occurs in Britain as a garden escape.
POLYGONACEA
In this family also the flowers are small, but contain
nectar, and are often conspicuous by association. They
generally contain both anthers and pistil. Many species
are dimorphous.
Rumex (Dock)
The British species are all perennials. The flowers
are generally reddish. The parts of the flower are in
threes. The Sorrels have hastate leaves. The true
Docks are generally distinguished by the form of the
perianth segments and the tubercles on them. The
function of these tubercles is not known, nor has any
suggestion been offered as to why some species (Lf.
aqueticus) should have none; others (R. crispus and
Ft. sanguineus), one on one at least of the perianth seg-
ments, while f. conglomeratus, as a rule, has one on
each segment.
R. crispus.— The leaves are much waved or crisped
at the edges. The flowers are protandrous, and the
pollen is wind-borne. Some are complete, some are
male, some female; these last are generally small.
R. obtusifolius.—Kirchner describes the flowers of this
species as resembling those of R. crispus. Kerner, how-
ever, found those examined by him to be protogynous.
1 Avebury (Lubbock), On Seedlings, vol. ii.
I POLYGONACEA 347
R. sanguineus. — Schulz describes this species as
slightly protandrous; Kerner as protogynous. Some
flowers have no pistil; these may be on the same or on
special plants. The perianth bears only one tubercle,
which is bright red, and on the midrib of the upper-
most segment round the drooping fruit.
R. conglomeratus.—In this species there are two
tubercles.
R. maritimus is a local British plant. The flowers
are homogamous.
R. Acetosella.—According to Lindman the flowers
early in the season are protogynous, the later ones
homogamous. Besides the complete, there are some
female dicecious flowers.
PoLyGonuM
The species differ much in habit. Nectar is
secreted in some cases. Some species have cleisto-
gamous flowers.
P. Bistorta (Bistort).—The flowers are protandrous.
Though small they are brightly coloured, and being col-
lected into a long spike are fairly conspicuous, and being
well supplied with nectar are much visited by insects.
The nectar is secreted by eight glands at the base of the
stamens. According to Schulz, besides the complete
there are also female flowers, which are more numerous
on the mountains than in the plains. The spike is
composed of small two-flowered groups—one flower
complete, the other male with a small style and rudi-
mentary ovary. The complete flowers open first, and are
protandrous. Gradually the anthers fall off, the styles
elongate, and the plant is adapted for fertilisation by
pollen from another flower. In the absence of insect
visits the anthers often touch their own stigmas.
P. viviparum.— The length and relations of the
stamens and pistil differ considerably in different
districts. The plant does not set its seed easily, and is
principally increased by bulbils, into which the lower
and sometimes all the flowers are modified.
348 BRITISH FLOWERING PLANTS CHAP.
P. amphibium.—This species secretes honey by five
orange-yellow glands at the base of the ovary. The
flowers are dimorphous; some with a long pistil and
short stamens, others with long stamens and a short
pistil. There are also female flowers. The plant grows
sometimes on land and sometimes in water. And here
we find also another interesting adaptation. The land
form is more or less hairy, while plants growing in water
are entirely glabrous. One form changes into the other
if the plant is moved from dry land into water or
vice versa.
P. Hydropiper.—The flowers are small and without
nectar. Of the eight stamens two are generally rudi-
mentary. Some of the flowers in this and the following
species are cleistogamous, especially those which receive
little light. The plant is protected from browsing
quadrupeds by a bitter juice, whence the name.
P. minus is very near the preceding. It has no
bitter flavour, but is probably protected by its great
similarity to P. Hydropiwper. Bentham regards it as a
mere variety.
P. Aviculare (Knot-grass).—A creeping plant with
small green, white, or purple flowers which have no
scent or honey. Five of the eight stamens bend out-
wards towards the corolla; the other three towards the
stigma, which, as they are at the same level, and ripe
at the same time, they can scarcely fail to fertilise.
The young leaves rise up vertically at night.
P. Fagopyrum (Buckwheat).—This is an Asiatic
species, but familiar to us as being so often cultivated.
The flowers are markedly dimorphous. According to
Richer they are quite sterile when self-pollinated, or
with pollen from flowers of the same form on the same
plant. They are very slightly fertile after cross-pol-
lination between flowers of the same form on distinct
plants. They are, on the contrary, highly fertile after
cross-pollination between flowers of different form on
distinct plants."
1 Comptes Rendus, cxxxviii. (1904).
I THY MELZACEXZ—ELAAGNACEH 349
P. Convolvulus.—This species much resembles a
Convolvulus in habit. Though the secretion of nectar
is slight, the flowers are occasionally visited by bees.
The stem is angular.
THYMELAACEA
DaPHNE
Homogamous flowers with nectar secreted by the
base of the ovary. In species which have the corolla-
tube short the flowers are fertilised mainly by flies ;
when it is longer, by bees ; and the longest, by butter-
flies. There are 8 stamens, inserted in the upper part
of the corolla-tube.
We have two species only—D. Mezerewm, which is
deciduous, with red berries, and D. Laureola (Spurge
Laurel), which is evergreen, with black ones.
D. Mezereum.—The flowers are sweet-scented, well
supplied with nectar, and much visited by insects.
Ludwig considered the flower to be sterile to its own
pollen; Schulz, however, came to the opposite con-
clusion. Perhaps, as Ludwig suggests, this is one of
the cases where plants differ in different localities ; or
perhaps different plants are differently constituted in
this respect. Some of the flowers have no anthers.
ELHZAGNACEA
Dicecious wind flowers.
HiprorpH&
H. rhamnoides (Sea Buckthorn).—The leaves of this
species are the food of a special hawkmoth, the large
caterpillars of which have orange patches curiously
350 BRITISH FLOWERING PLANTS CHAP.
resembling the fruits in size and colour. This does
much to render them inconspicuous. The leaves are
grey, with red scales on the under side.
SANTALACEA
THESIUM
Homogamous flowers. Nectar secreted at the base
of the flower. The anthers remain open some time; in
wet weather, or if moistened, they close rapidly—accord-
ing to Kerner, in 7. alpinum in about half a minute.’
T. linophyllum.—A glabrous green woody perennial,
6-8 inches high. Generally dispersed over Europe,
but in England only found on some of our south-eastern
downs. It is semi-parasitic, and derives some, at least,
of its nourishment from the roots of other plants. The
suckers are little white knobs on the sides of the roots.
ARISTOLOCHIACEA
Protogynous trap flowers secreting nectar .at the
base of the flower.
ASARUM
A. europeum.—The flowers are greenish brown, about
half an inch long on a short recurved stalk, and on the
ground or often concealed among dead leaves. They
have ascent resembling camphor. The flower-tube ends
in three long pointed lobes; these are at first curled
over so that the entrance to the flower is formed by
three narrow slits. The stigmas are 6 in number, and
ripe when the flower opens. The stamens are 12, in
two rows, and end in a long point. As the flower hangs
down the pollen may easily drop on the stigmas. The
1 Nat. Hist. of Plants, vol. ii.
II ARISTOLOCHIACE4—EUPHORBIACE.E 351
insect visitors are principally small flies. A Southern
European plant found in several English counties, but
regarded by Watson as a denizen.
EUPHORBIACEZ
EUPHORBIA
The plants are protected by a milky acrid juice.
The flowers secrete nectar, which lies quite exposed.
The apparent flowers are really flower-heads. The cup-
shaped involucre has 4 or 5 rounded or moon-shaped
glands, which secrete a thin covering of nectar. It
contains 10-15 stamens, each of which is jointed,
showing that it represents a stalk bearing a flower
which is reduced to a single stamen,’ and in the centre
is a single female flower consisting of a 3-celled ovary
and 3 styles, each terminating in 2 stigmas. The
flower-head is protogynous. The flowers are occa-
sionally visited by bees and wasps, but fertilisation is
almost exclusively due to flies. According to Kerner
the anthers close in wet weather. The seeds differ con-
siderably. Some are smooth (E£. hyberna, E. Paralias,
E. amygdaloides); some pitted (EF. Peplus, E. pep-
loides, E. Helioscopia, E. segetalis); some wrinkled
(E. exigua, E. Lathyris); others dotted, or tubercular.
The capsule, as a rule, opens both loculicidally and
septicidally, so that each valve consists of one half of
a carpel.
Mercurtiatis (Dog’s Mercury)
Wind flowers ; generally dicecious.
We have two species—one annual, the other peren-
nial. In both, male flowers sometimes, though rarely,
occur on the female plants. There are only two carpels.
The outer skin of the fruit of WM annua,’ which is.
1 An interesting confirmation of this view is afforded by a foreign genus,
Anthostema, which has a distinct perianth.
2 Leclere du Sablon, Ann. Set. Nat. xviii. (1884).
352 BRITISH FLOWERING PLANTS CHAP.
formed of soft parenchyma, has no part in the opening
of the valves. The inner lignified layer, according to
Le Clere du Sablon, is composed of three divisions,
each of one layer of cells. The internal epidermis
consists of fibres at an angle of 45° to the axis of the
fruit ; then comes a layer elongated radially, and finally
one of cells at right angles to those of the epidermis.
The result of this is that the valves open outwards.
The structure of M. perennis is very similar, but the
rows of cells are more numerous.
M. perennis.—The dust-like pollen is conveyed to
the stigmas by the wind; and the stigmas are said
to be capable of fertilisation at least two days before
the pollen is ripe. The leaves, which are glabrous or
hairy, are opposite, and provided with stipules. They
thus form a sort of cup which holds the rain. In it is
a rounded ridge, with a row of hairs. This is readily
wetted and probably absorbs moisture.
M. annua.—Like the preceding, this species is dice-
cious. But female plants cultivated in pots by them-
selves have long been known to give fertile seeds. This
result is so unusual and.so remarkable that it has been
suggested either that there may have been one or two
male flowers which had been overlooked or that a few
grains of pollen might have come from a distance.
Ramisch, however, and subsequently Kerner, have grown
female plants in districts where the plant does not
occur wild, and yet they set fertile seeds. The plant is
glabrous. Like so many other weeds of cultivation it
is annual. According to Kerner it throws its seeds.
Buxus (Box)
Moncecious wind flowers, with free-lying nectar in
both sexes.
B. sempervirens.—The Box flowers early, and is
sometimes visited by bees for its pollen, the more so, no
doubt, as there are not then many other plants in
flower. The male and female flowers are associated in
the same cluster, the former below, and the latter
II EUPHORBIACE.E—-EMPETRACEA& 353
above. The former have one bract, the latter three.
The clusters are slightly protogynous. The pollen, like
that of wind flowers generally, is dry and dusty, but
the hive bee, having separated the pollen from the
anther, moistens it with nectar from its mouth, and
then brushes it on to its hind legs. The leaves are
evergreen, and well protected against extremes of
temperature and drought. The epidermis is thick, the
stomata are sunk, and there are no less than four rows
of palisade cells. The polished surface, which occurs
in several other evergreen species, is perhaps a provision
to throw off snow.
EMPETRACEA
Empetrum (Crowberry)
Generally dicecious. Warming and Knuth consider
them as wind flowers. Lindman regards them as
fertilised by insects, especially flies. They have nectar,
but very little.
O}
USO NAR ISeatucaa,
SS A
Fic. 227.—Transverse section of leaf of Empetrum. Much enlarged. a, upper
epidermis ; 0, lower epidermis ; s, stoma.
E. nigrum.—The male flowers are rose, the female
purple. The pistil is short, with 6-9 diverging black
shining stigmas. Besides the dicecious, Lindman found
some protandrous complete flowers.
The leaves are evergreen and conform to the heath
2A
854 BRITISH FLOWERING PLANTS CHAP.
type (Fig. 227, also p. 28). The upper face is protected
by a strong smooth cuticle ; the stomata are on the under
face, and communicate with an almost closed chamber
formed by the rolling back of the leaf margins. This
arrangement serves to check excessive loss of water in
the exposed situations in which the plant is found, and
also prevents clogging of the stomata by the dew or rain
which is deposited on the upper face only, and owing to
the smooth surface is got rid of as quickly as possible.
CALLITRICHINE
Aquatic floating herbs.
CALLITRICHE
Inconspicuous moncecious protogynous flowers. The
pollen is probably in some cases carried by insects, in
others by wind, and sometimes by water.
Fic, 228.—Male flower, consisting of Fic, 229.—Female flower, consisting of
one stamen subtended by a pair of a 4-lobed ovary with 2 styles ; bracts
bracts, v. as in male, v.
C. aquatica.—The pollen grains, as in some other
aquatic plants, have no outer coat (extine). They are
lighter than water, and thus may easily be carried to
the female flowers. :
IL CERATOPHYLLACE.E—URTICACEE 355
CERATOPHYLLACEA
As in so many submerged plants the leaves are
divided into many linear divisions (see p. 25). The
flowers are moneecious. The plants float freely, having
no roots.
C. demersum.—The flowers are sessile; male and female
in different whorls, the female generally below. The
males are the more numerous, containing 12-20 anthers,
and produce much pollen. The female flowers consist
of an ovoid ovary with a filiform sticky pistil. Ludwig?
points out that though several marine phanerogams
flower under water, this is the only European fresh-
water species which does so. He has, however, over-
looked Najas, four speeies of which occur in European
fresh waters. The anthers terminate in two points,
and contain a tannin-like substance which Ludwig
suggests protects them from water snails. They also
contain air chambers, so that they float on the surface
of the water. When they ripen they slightly contract,
squeezing the pollen into the water, which it equals in
specific gravity. The diffusion of the pollen is increased
by the peculiar movements of the plant itself, which
were first noticed by Rodier.* Sometimes in seven
hours an angle of 120° is passed through. The pollen
is so plentiful that some of it is almost sure to come in
contact with the sticky stigmas.
URTICACEA
Leaves rough and often stinging. Flowers unisexual.
Urtica
Wind flowers. Male with 4-lobed perianth and
4 stamens. Female perianth with 2 lobes, or if 4, the
1 “*Siisswasserflora,” in Zacharias, Tier- wu. Phlanzenwelt d. Siisswassers, i.
2 Comptes Rendus, lxxxiv. (1877).
356 BRITISH FLOWERING PLANTS CHAP.
2 inner ones larger than the outer. There are three
British species. U. dioica, the Common Nettle, is
perennial; the other two annual; one U. wrens, with
the flowers in nearly sessile short clusters; the other,
Fig. 230. Fig. 231. Fig. 282.
Fic. 230.—Urtica dioica. Vertical section
through part of the leaf of a Stinging-
nettle, showing two hairs, from the lower
one of which the head has been broken.
x 35.
Fic. 231.—Top of hair more magnified, entire.
x 150. ad, line of fracture.
Fig. 232.—Top of hair more magnified, after
removal of the head. x 150.
U. pilulifera, with the
male flowers in loose
spikes, the female in
stalked globular heads.
U. urens and U. pilu-
lifera are moncecious,
with stinging hairs.
U. dioica (Common
Stinging-nettle) is gener-
ally dicecious. The plant
is protected by stinging
hairs (Fig. 230). These
point forwards, so that
the plant may safely be
grasped from below, as
they are merely com-
pressed. If, however,
taken from above, they
are sure to run into the
skin. Hach hair sits on
a cushion of delicate
tissue, contains an acid
fluid, and terminates in
a small rounded head set
on at an angle. The
silicified tissue at the
base of the head is very
thin, and breaks through
with the slightest touch.
As the fracture is oblique (Fig. 231, a b) the point is very
sharp, so that it easily penetrates into the flesh. Our
British Nettles can make themselves very unpleasant,
but some of the foreign species produce serious results.
Borscow' has described the movements of the proto-
1 Bull. Acad. Sci. St. Pétersburg, xii, (1868).
II URTICACE 357
plasm in the stinging hairs. He found that it was
repelled by red light, and attracted by blue. No
doubt, however, the protoplasm would react differently
in different species. The filaments bearing the anthers
are coiled in the bud and suddenly spring up at the
moment the anthers open, thus ejecting the pollen in
little puffs. This happens on bright summer mornings
as soon as they are touched by the sun, and the
cannonade lasts about half an hour.
PaRIETARIA (Pellitory)
There are three forms of flower—complete, male, and
female. Male flowers as in the Nettle. Female, with a
tubular or campanulate four-lobed perianth and a brush-
like stigma. The complete flowers are protogynous.
P. officinalis is the only British species. The stamens
explode as in Urtica. The name is
derived from the habit of the plant to
grow on old walls. The stem and
leaves are pubescent, with curled hairs.
Humutvs (Hop)
Dicecious wind flowers. A climber.
H. Lupulus.—The stigmas of the
female flowers are ripe at least two
days before the anthers of the male
plants open. The orifice of the anther
is small, so that the pollen is gradually
scattered. The stipules (Fig. 233) are
interesting: they are connate, but the
two which have joined belong to oppo-
site leaves. This explains the deep
notch at the end. The leaves are
smooth above and rough below. The Pe ie aan
upper part of the shoot, as in other — sommate stipules in
climbers, revolves in a circle or ellipse,
the object being to find some support up which to
climb. The direction is always towards the right,
and on an average a revolution takes 2 hours and
358 BRITISH FLOWERING PLANTS CHAP.
8 minutes." The surface is covered with hairs, shaped
like an anvil with a broad top. These climbing hooks
help to attach it to its support. The persistent bracts
serve as parachutes to disperse the seeds.
ULMACE
Uimvus (Elm)
Flowers generally complete, protogynous, with long-
lived stigmas. Pollen carried by the wind. Perianth
of 4-6 lobes and as many stamens (Fig.
234), According to Kerner the filaments
double their length very shortly before the
opening of the anthers. These close in
wet weather. The fruit, as in the case of
that of so many other trees, is thin, flat,
and easily carried by wind. We have
two species. The Wych Elm (U. mon-
tana) has the fruit slightly, the other,
Fie. 234.—Flower the Common Elm (U. campestris), deeply
of the im. Eu notched. There are, however, consider-
arged. a Ds fl
able differences of opinion as to the
number of species, and U. campestris may perhaps
represent a group of allied forms rather than a single
species. The hairs are sometimes poisonous.
The buds of the Common Elm (U. campestris) are
covered and protected by scales, each of which repre-
sents a pair of stipules.” This is shown by the position
and arrangement of the scales. The leaves are in two
ranks, as in the Beech. Hence, as there are two stipules
to each leaf, it follows that if each scale corresponded
to a stipule they must be in four ranks, as, in fact,
they are in the Beech (Fig. 253). Those of the Elm,
however (Fig. 285), are in two rows, showing that
1 Darwin, Climbing Plants.
2 Avebury (Lubbock), Buds and Stipules, p. 144.
1 ULMACE.E 359
each consists of two connate stipules. This is further
suggested by the fact that they are sometimes bifid at
the summit, as shown in Fig. 244. The young leaf,
moreover, is situated, not between two scales, as in the
Beech, but within and opposite the middle of the often
bifid scale. The outer four stipular scales are coriaceous,
dark brown, brittle, and more or less ciliate towards
the apex. Owing to their being connate, however, the
single piece occupies the central position of the leaf, the
Fig. 235. Fig. 936. Fig. 987, Fig. 288. Fig. 289. Fig, 240. Fig. 241. Fig. 242.
Fig. 243, Fig, 244. Fig. 245. Fig. 246. Fig. 247. Fig, 248.
Fic. 235.—Elm. Terminal bud, showing seven scales.
Fic. 236.—The first scale. Fic. 237.—The second scale.
Fic. 238.—The third scale. Fic. 239,—The fourth scale.
Fic. 240.—The fifth scale. Fic. 241.—The sixth scale.
Fig. 242.—The seventh scale. Fic. 243.—The eighth scale.
Fic. 244.—The ninth scale, showing fusion, which is unusual.
Fig. 245.—Members at the tenth node. vv. st, outer stipule, with a portion removed
to show the leaf, 7, which comes next in order ; 7. st, inner stipule.
Fias. 246-248.—Members at nodes 11 to 13. 0. st, outer stipule ; 7, leaf;
t, st, inner stipule. All are separated to show outline.
blade of which, if present, would be between them.
These four scales do not elongate in spring, being
practically dead; they often split at the apex into four
or five teeth. In Figs. 236-248 I have given an
analysis of a terminal bud.
Though the Elm flowers so freely the seeds seldom
ripen. Mr. Boulger states’ that this is the case also on
the continent of Europe and in Asia.
1 Familiar Trees.
360 BRITISH FLOWERING PLANTS CHAP.
AMENTACEA
This order comprises many of our forest trees—the
Oak, Beech, Hornbeam, Birch, Poplars, Willows, ete.
The flowers are generally monecious or dicecious; they
generally precede the leaves. Perianth none, or forming
a mere border to the ovary. In some the fruits are
winged (Birch), or carried on winged bracts (Horn-
beam), or the seeds are provided with silky hairs (Willow,
Poplar), and dispersed by the wind, an arrangement
especially suitable in the case of trees ; in others (Beech,
Spanish Chestnut, Hazel, Oak) they are carried by
animals. In several, for instance in the Hornbeam, Birch,
Hazel, Willow, etc., as in the case of the Lime (ante,
p- 31), the bud situated apparently at the end of the
branchlets is in reality axillary, as is shown by the
presence of a terminal scar, due to the fall of the true
terminal bud. The genera here included in Amentaceze
are separated in recent systems of classification under
the orders Myricaceee (Myrica), Corylacez (Alnus,
Betula, Corylus, Carpinus), Fagaceze (Fagus, Quercus,
Castanea), Salicaceze (Salix, Populus).
In my Flowers, Fruits, and Leaves I have devoted
some space to the consideration of the arrangement and
forms of the leaves in this family, and it will perhaps
be more convenient to consider them here as a group
than under the separate species. In the first place, let
us consider the size of the leaf. On what does this
depend? In herbs we very often see that the leaves
decrease towards the end of the shoot, while in trees
the leaves, though not identical, are much more uni-
form in size. If we take a twig of Hornbeam, we
shall find that the six terminal leaves have together
an area of about 14 square inches, and the section
of the twig has a diameter of ‘06 of an inch. In
the Beech the leaves are rather larger, six of them
having an area of perhaps 18 inches, and correspond-
ing with this greater leaf-surface we find that the
II AMENTACEE 361
twig is somewhat stouter, say 09 of an inch. Follow-
ing this up, we shall find that, ceteris paribus, the
size of the leaf has relation to the thickness of the
stem.
Of course, however, this is only approximate. Other
things have to be taken into consideration. Strength,
for instance, is an important element. If, for example,
we compare the Beech and Hornbeam with the Lime
(p. 81), the general plane of the leaves is again that of
Fic. 249.—Beech. Fie. 250.—Spanish Chestnut.
the branch (Fig. 249); but the leaves themselves are
ovate in form, and smaller, being only from 2 to 3 inches
in length. On the other hand, the distance between
the nodes is also smaller, being, say, 14 inch against
something less than 2 inches. The diminution in length
of the internode is not, indeed, exactly in proportion to
that of the leaf, but, on the other hand, the leaf does
not make so wide an angle with the stem. To this
position is probably due the difference of form. The
outline of the basal half of the leaf fits neatly to the
branch, that of the upper half follows the edge of the
leaf beyond, and the form of the inner edge being thus
determined decides the outer one also. But it may be
362 BRITISH FLOWERING PLANTS CHAP.
said that the Spanish Chestnut (Castanea sativa,
Fig. 250) also has alternate leaves in a plane parallel
to that of the branch, and with internodes of very
nearly the same length as the Beech. That is true;
but, on the other hand, the terminal branches of the
Spanish Chestnut are stouter in proportion. Thus,
immediately below the sixth leaf, the Chestnut stalk
may be ‘15 of an inch in thickness, that of the Beech
not more than half as much. Consequently, the Chest-
nut could, of course, supposing the strength of the
wood to be equal, bear a greater weight of leaf; but,
the width of the leaf being determined by the distance
between the nodes, the leaf is, so to say, compelled to
draw itself out. Moreover, not only do the leaves on
a single twig thus admirably fit in with one another,
but they are also adapted to the ramification of the
twigs themselves. Fig. 249 shows a bough of Beech
seen from above, and it will be observed that the form
of the leaves is such that, while but little space is lost,
there is scarcely any overlapping. ach fits in perfectly
with the rest.
The form of the Oak leaf is so familiar that it does
not strike us as anything peculiar, and comparatively
few of us, perhaps, have ever asked why it should be as it
is; and yet it is peculiar, unlike that of any of our forest
trees, and those of the evergreen Oaks so abundant in
hotter countries. In botanical phraseology it is “ decidu-
ous, oblong-oblanceolate, or oblong-elliptical, sinuated,
with blunt lobes extending not more than half-way
down to the midrib.” The sinus between the lobes is
generally rounded off at the bottom. Again, though I
have not seen this mentioned in the botanical works
which I have consulted, they are rarely symmetrical,
the lobes of the two sides not corresponding. The three
points, then, which give the Oak leaf its peculiar form
are—
1. The deep rounded sinuses.
2. The want of symmetry of the two sides.
3. The obovate or oblanceolate outline.
I AMENTACE.E 3638
The explanation which I have suggested is as follows:
—The leaves of the evergreen Oak are entire, and
small in comparison with those of the English Oak.
During the winter and early spring they are protected
‘by a series of brown scales, inside which they lie, form-
ing the familiar buds, which are both small and short
in proportion to the size of the leaves themselves.
In cooler and moister regions, on the contrary, there
is, as we know, a tendency for leaves to become
larger and deciduous. These influences do not, how-
ever, affect the outer scales, which remain as before,
without any increase of size. But as the leaves have
increased in size and the buds have not, the leaves
can no longer retain their original arrangement in
the bud. Te, for instance, we compare ” the buds
of the Oak and of the Beech, we see that while
the leaf of the Oak is longer than that of the Beech,
the bud of the Oak (Fig. 271) is, on the contrary,
shorter than that of the Beech (Fig. 253). Under
these circumstances, what must happen? ‘The leaf
grows and becomes longer than the bud; it is therefore
necessarily bent into a curve. But an entire leaf, if
thus thrown into a curve, would necessarily fall into
folds, the number being determined by the number of
ribs or veins. For such folds, however, there would be
no room within the narrow limits of a bud, or rather,
perhaps, they would be inconvenient because they
would leave more or less empty spaces. This may be
rendered more clear by taking a piece of cloth or paper,
folding it up, and then throwing it into a curve. It
will then necessarily fall into one or more folds. If it
were strengthened, as an Oak leaf is, by three or four
side ribs, there would be a fold between each two ribs.
As a matter of fact, however, from the absence of space
the membrane where the fold would be is not actually
developed. We may imitate this by removing them.
If this be done, the result will be the formation of
sinuses, rounded at the base, closely resembling those
so characteristic of the Oak leaf. These sinuses are due,
364 BRITISH FLOWERING PLANTS CHAP,
then, as I believe, to the curvature of the leaf, owing to
the shortness of the bud in comparison with the length
of the leaf. The young leaf is not only curved, it is
wrapped round the interior leaves. The result of this
is that one side of the leaf is folded within the other;
the one therefore has more space than the other. The
two sides of the leaf are, in fact, differently situated,
and this, I believe, accounts for the second point—
namely, the want of symmetry. The obovate form is
an advantage in consequence of the way the leaves
diverge from the stalk. JI think, then, that the
explanation I have suggested accounts for all these
points, and beautifully explains the peculiar form as-
sumed by the leaf.
The arrangement of the seeds is also very interesting.
Fig. 252 is a diagram of a Nut with the parts somewhat
separated from one another so as to show the relations
more clearly. The micropyle (m) is at the apex of
the seed.’ The ovule, however, is not straight and
orthotropous, which would be, or at any rate seem
to be, the simplest arrangement. Quite the contrary,
for we find a long placental axis (pl), which extends to
the apex of the Nut, and from which starts a raphe (7),
which returns about half-way back again to the place
where the true attachment or chalaza (ch) is situated.
I have in vain endeavoured to discover or imagine any
circumstances which would render this complex arrange-
ment specially adapted to present conditions. It would
seem as if it would be simpler, and give Nature less
trouble, if the ovule sat directly with its base on the
stalk, thus doing away with both the placental axis
(pl) and the raphe (7).
This view is strengthened by the fact that such an
arrangement has actually been nearly attained by the
Oak. The ovule in this genus is theoretically ana-
tropous, but the placental axis and the raphe are both
greatly shortened (Fig. 251), so that the distance
which the nourishment has to traverse is much less,
1 Avebury (Lubbock), On Seedlings, ii.
Ir AMENTACE.E 365
though the actual place of attachment remains the
same. The Oak, in fact, seems to have appreciated
the difficulties of the situation, and to have in great
measure neutralised them. Is it fanciful to imagine
that some ages hence the Oak may be practically
orthotropous ?
But why should these species be anatropous if it is
an advantage to be orthotropous? On this question
some light is thrown by the fact that while one seed
only comes to maturity, the ovary contains originally
Fig, 251.—Fruit and seed of Oak. Fia. 252.—Fruit and seed of Nut. Nat.
u, placental axis; ch, chalaza; size. ch, chalaza; m, mycropyle; 0,
m, wicropyle ; v, abortive ovule. abortive ovule ; pd, placental axis; 7,
raphe.
several cells, each with one or two ovules, though none
of the others comes to anything. They can, however,
easily be seen, either at the apex of the seed, as in the
Nut (Fig. 252) and Beech (Fagus), or, as in the Oak
(Fig. 251), near the base. Their presence appears to
indicate that these species are descended from ancestors
the fruit of which was composed of several cells, each
with more than one seed—a state of things, therefore,
very unlike the present, and in which the anatropous con-
dition would be an advantage. If this view be correct,
the structure of the fruit in the Nut, Beech, and others
becomes peculiarly interesting, because it represents a
case in which the present arrangements are not those in
all respects most convenient to the plant, and renders it
probable that the same explanation may apply to other
cases of difficulty.
366 BRITISH FLOWERING PLANTS CHAP.
Myrica
Shrubs. Generally dicecious. The catkins hang
down, thus protecting the pollen from wet.
M. Gale (Sweet Gale or Bog Myrtle)—The flowers
are sometimes complete, but the stamens and pistils are
generally on separate plants. Hach male flower has
4 stamens. The pollen is pulverulent, and when it
falls is held by the scales of the catkins until it is
shaken by the wind. The leaves are glabrous or slightly
hairy.
Aunvs (Alder)
Generally moncecious, but sometimes also with com-
plete flowers. Pollen wind-borne.
A. glutinosa. —The male catkins are cylindrical; the
female, ovoid.’ According to Kirchner the plants are
protandrous, according to Kerner protogynous, while
Macleod, in Belgium, found the male and female flowers
appearing simultaneously. The petioles and under sides
of the leaves are hairy. The young leaves are also
protected by being sticky, whence the name.
Facus (Beech)
Moneecious protogynous wind flowers in globular
catkins; the male pendulous, with 8-12 stamens, the
female almost sessile. Nuts generally 2, enclosed in a
hard prickly involucre, composed of the combined inner
and outer bract-scales of the catkin. When they are
ripe the involucre opens. The nuts are larger than those
of the Hornbeam, and are intended to be carried by
squirrels and other animals. Hence they differ from
the fruit of the Hornbeam, which the Beech so much
resembles—first, in the absence of a wing, which would
be useless ; ‘secondly, in having a less hard coat; and
thirdly, in being larger.
The bud of the Beech is very complex.’ It is elon-
gated, spindle-shaped, in winter half to three-quarters of
1 Avebury (Lubbock), Buds and Stipules.
ul AMENTACE.E 367
an inch in length; on the outside are four closely imbri-
cating rows of stipules, arranged apparently in opposite
decussate pairs (Fig. 253). 1 say apparently, because,
as the leaves are alternate, it is possible that each pair of
these stipules are really alternate, though so compressed
as to appear to be opposite. The first pair (Fig. 254) are
small, triangular, and pointed. The five following are
also triangular, each rather larger than the preceding and
more convolute, till they almost enclose the upper part
of the bud. The lower ones are brown and coriaceous ;
the upper membranous, and furnished with numerous
straight, longitudinal, parallel slender veins running
from the base to the apex. The covered parts are
white, the exposed brown. The upper ones are fringed
with long, recurved, silvery or satiny hairs. They are
sometimes a brilliant pink or rose colour after expansion,
but less often than those of the Hornbeam. The fifth
and sixth pairs (Fig. 255) are ciliate with short hairs,
and rolled round a considerable part of the bud. The
seventh pair are half as long as the bud, but other-
wise like the sixth; the eighth pair, two-thirds as long
as the bud; the ninth, nearly as long as the bud, with
silky hairs directed downwards, and the outer one of
the two distinctly overlaps the inner. The tenth pair
are as long as the bud, and each is convolute, so as to
cover nine-tenths of the bud, or even more. The
eleventh pair (Fig. 256) are similar, and almost meet
at their edges. These eleven pairs of stipules show no
traces of a leaf. Fig. 258 represents a bud after the
removal of the first eleven pairs of stipules. About the
twelfth pair there is a material change; they (Fig. 259)
are smaller, and between them is a leaf-blade; this is.
about one-third as long as its stipules, concave on the
inner face, and plicate along the course of the ascending
lateral nerves. The thirteenth pair of stipules (Fig. 260)
are rather narrower, especially at the base. The leaf is
about half as long as the stipules. The fourteenth pair
(Fig. 261) are much smaller, thinner, narrower, and
unequal, the inner one being the smaller. The leaf
368 BRITISH FLOWERING PLANTS CHAP,
AA
Fig. 254.
\\
INO. _X
Fig. 259.
Fic. 253.—The Beech. Winter bud.
Fic. 254.—First or lowest pair of stipules.
Fig. 255.—Sixth pair of stipules, overlapping at the corners.
Fic. 256.—Eleventh pair of stipules, showing how one is rolled within
the other ; 7, position where the leaf should be, though it is yet
absent.
Fia. 257.—Diagrammatic transverse section of the stipules, showing the
extent to which they overlap.
Fia, 258.—The bud after eleven pairs of stipules have been removed ;
Z, the first leaf ; s¢ s¢, the twelfth pair of stipules; ee, the edges of the outer
one of the twelfth pair.
. 259.—st st, the twelfth pair of stipules flattened out ; Z, the first leaf belonging
to the same.
260.—s¢ st, the thirteenth pair of stipules ; 7, the second leaf.
. 261.—-st st, the fourteenth pair of stipules ; 2, the third leaf.
262,—st, the only stipule of the fifteenth pair discernible in this bud ; J, the
fourth leaf.
. 263.—No stipule discernible in the bud examined ; J, the fifth and last leaf dis-
cernible, occupying the centre of the bud.
. 264.—Junction of the wood of two seasons’ growth ; sc. st, scars of the outer
eleven pairs of stipules that covered the winter bud and which were unaccom-
panied by leaves,
u AMENTACE 369
is three-fourths as long as its stipules. The leaf (Mig.
262) belonging to the fifteenth pair is longer and more
bulky than the stipule. The next leaf (Fig. 263) is
large, deeply concave, or rolled into a cylinder occupy-
ing the centre of the bud, and densely covered with
silky hairs on both surfaces, but particularly on the
back, as are all the others.
The above description may be regarded as giving
the average composition of the winter or resting bud of
the Beech. Larger buds have a greater number of
leaves and stipules; smaller buds, fewer. Strong shoots
on vigorous young trees have more leaves, though the
inner ones are small or but slightly developed in
winter.
The buds gradually elongate. Before unfolding,
they turn slightly upwards, but afterwards bend down.
The long, narrow, pale-brown or straw-coloured stipules
are thrown off when the leaves expand, and sometimes
quite colour the ground under the tree. If the branch
is examined, the scars where the stipules were inserted
may be seen forming rings (Figs. 264) round the base
of each annual shoot. The shoot elongates consider-
ably between the leaves, but not between the leaf-
less stipules, so that the stipular rings remain close
together; they are very persistent, and can be traced
for twenty-five years or more.
The Beech is one of the most interesting cases of the
difference of structure of leaves in sunshine and in
shade. They have been carefully studied by Stahl.’
The leaf consists of an upper epidermis, of one or more
layers of palisade cells, of a layer or layers of spongy
parenchyma, and a lower epidermis. Fig. 265 represents
a transverse section of a leaf grown in sunshine. ‘There
are two layers of long palisade cells. Fig. 266 repre-
sents a similar section of a leaf grown in shade. There
is only one layer of palisade cells, which, moreover, are
broader and much shorter. The parenchyma is also
much reduced in thickness. The leaf is more delicate,
1 Jenaischer Zeitschr. f. Naturwiss, xvi. (1882-83).
2B
370
BRITISH FLOWERING PLANTS CHAP.
larger, and thinner, being 0°22 mm. in thickness against
0°35 mm.
( bp
CANTATA
Onercek 4 Lene ||
ely Magee sla
ab
Fic. 265.—Transverse section of a Beech leaf grown in sunshine.
Pp, palisade layers ; x, spongy parenchyma.
Much enlarged.
M. de Lamartiere gives the following measurements
as showing the contrast between leaves exposed to the
sun and those growing in shade :—
|
MIcROMETRIC DIVISIONS, EACH CORRESPONDIN
TO aeoo OF A MILLIMETRE.
Oak. BEECH. !
at |
Tn sunlight.| In shade. | In sunlight.| In shade.
Upper epidermis 3 2 ar 2
First layer of palisade 12 7 10 | 5
Second si 5 0 6 0
Spongy tissue 12 9 9 6
Lower epidermis 2 Q Z4 2
Total 34 20 | 300 15
It is a remarkable fact that the roots of many trees
are covered by an evenly
Cae eee.
r LA? vty ryan j woven generally thin, but
‘ uO" is ities in some cases compara-
Fic. 266.—Transverse section of a Beech
leaf grown in shade, p, palisade layer ;
s, spongy parenchyma.
tively thick layer (Fig.
267), of mycelial filaments
known as a mycorhiza.
This is not only no injury,
but a positive benefit to the tree. There is, indeed,
II AMENTACE.E
some reason to doubt whether it could live without the
assistance of the fungus. At any
rate, attempts to rear seedlings of
Beech and Fir in nutrient solu
tions have failed; and it seems
fairly well established that the
roots of the Beech and of many
other trees suck up moisture and
nutriment by help of the my-
celium; and, on the other hand,
the mycelium, no doubt, is nour-
ished by taking toll of the sap of
Fig. 268.
Fic. 268.—Buds of Spanish
Chestnut.
the Beech. To what
species of fungus the
mycelium belongs has Fic. 267.—Tip of the root of a
J Beech with closely adher-
not y et been ascer- eut mycelial mantle.
tained.
The cupule forms a single chamber sur-
rounded by four or five valves which open at
their upper ends. ‘The walls are composed of
two distinct layers of woody cells. Those of
the inner layer are elongated vertically, those
of the outer are isodiametric. They therefore
contract more, and thus open the valves.
Castanea (Spanish Chestnut)
The erect catkins, which flower
when the tree is in full leaf, bear
a few groups of female flowers at
the base, and the male flowers
above. Each female group con-
sists of 38 towers, the whole
enveloped, as in Beech, by a
cupule, formed from the four brac-
i nat. size. teoles. In the fruit the cupule
Fig. 269.
His ts ean scale de- fonms a spiny envelope around
the three nuts.
The Eating or Spanish Chestnut (Castanea sativa)
has been cultivated in England since the Roman period.
372
BRITISH FLOWERING PLANTS CHAP,
The scales which protect the bud of Castanea are connate
stipules. This is indicated by the indentation at the
apex (Fig. 269), and the bud at the base.
Monececious.
Quercus (Oak)
Male flowers in slender pendulous
catkins, with 6-12 stamens; female flowers solitary or
Fia. 270.—Shoot of
Oak. Nat. size.
by a gall-insect. The cotyledons are
subterranean, and the first few leaves
are small scales.
advantage, as enabling the stem to
grow longer and thus carry up the first
foliaceous leaves above the surround-
ing herbage.
clustered. Pollen wind-borne. Accord-
ing to Kerner the trees are protogynous.
Q. Robur.—Two forms are often re-
garded as distinct species—(1) Q. Robt,
var. pedunculata, which has the leaves
sessile or shortly stalked, and the fruits
above the middle of a peduncle from
1 to 5 or 6 inches long; and (2) Q.
Robur, var. sessiliflora, with leaves on
foot-stalks half an inch to one inch
long, and fruits either sessile or on
a peduncle rarely attaming an inch in
length.
The leaves are pubescent when young,
but afterwards glabrous. There are said
to be about 500
species of insects
which live on the
Oak, in which con-
nection we may men-
tion the familiar Oak-
apples, the result of
an irritation set up
This is probably an
F Fic. 271.—Oak bud. x6.
The same reduction
of the first few leaves to scales occurs in several other
1 AMENTACEA 373
plants which have large seeds and subterranean coty-
ledons.
The buds of the Oak! (Quercus pedunculata) (Figs.
270, 271) are even more complicated than those already
described. They are a rich brown, and make a beautiful
contrast with the greyish-black of the stems. They are
ik aa es ALO
Fig, 272. Fig. 273. Fig. 274. Fig. 275. Fig, 276. Fig. 277. Fig. 278. Fig. 279. Fig. 280.
Fig. 281. Fig. to. Fig, 283, Ig. 284. Fig. 285. Fig. 286. Fig. 287.
st YA
(J) | i
Fig. 288. Fig. 289. Fig. 290. Fig. 201. Fig. 202.
Fias. 272-285.—Quercus pedunculata. Pairs of stipules forming the scales of the
winter bud, sketched in the first week of May ; some of them had small lateral
buds between them, but no leaf; the bud had resumed growth, was oblong, and
16°56 mm. in length. x2.
Figs. 286-292.—Stipules which had elongated when growth was resumed in spring.
x 2. st st, stipules ; J, leaf, conduplicate in bud, but not likely to attain any
great size if it had been allowed to develop.
short and conical, and the colour, together with the
arrangement of the scales, gives them a curious similarity
to a miniature cone of a Pine. The buds differ con-
siderably in size, but are comparatively short, broadest
above the base but somewhat below the middle, covered
with dry brown stipules arranged in five imbricating
rows. The buds are slightly pentangular, each of the
five angles being made up of one stipule from each of
two contiguous and successive pairs. The pentangular
" Avebury (Lubbock), Duds and Stipules.
374 BRITISH FLOWERING PLANTS CHAP.
character of the bud is due to the leaves being on the
two-fifths plan of arrangement. The centres of the
stipules correspond with the angles, while the leaves lie
in the middle of the flat surfaces. Figs. 272-292 show
the succession of bud scales, of which, as will be seen,
there are some forty before the first leaf is produced.
For the form of the leaf, see ante, p. 362.
The three genera Fagus, Castanea, and Quercus
S
have in the female flower three united carpels, forming
ine
Fic, 298.—Young female flower of Fic. 294.—The same, cut lengthwise. Two
1
'
‘
1
Oak enveloped by an involucre of of the ovary chambers have been opened
scales, s, from which protrude by the section, exposing one ovule in
the three stigmas. Much enlarged. each.
a three-chambered ovary, with two ovules in each
chamber. The fruit is, however, one-seeded, as five of
the six ovules do not form a seed. These genera are
often placed in a separate order—Fagacese—from the
following four, in which the pistil contains only two
carpels, and which comprise the order Corylacez.
The cup surrounding the base of the acorn is formed
from the union of a number of scales borne on the floral
axis below the flower (Figs. 293, 294).
Beruua (Birch)
Flowers moneecious and protogynous. The pollen
is wind-borne. The male and female catkins are not
simple spikes, but compound inflorescences, each bract
on the main axis subtending a group of three flowers.
The fruits are surrounded by a scarious wing, and rest,
I AMENTACE 375
in groups of three, on the scales of the cone-like fruit.
Each of the hardened cone-scales is formed by the union
of the three bracts which subtend the group of female
flowers (see Figs. 295, 296). We have two species—the
Common Birch, a tree with pointed leaves (B. alba) ;
and B. nana, a shrub with small orbicular leaves (see
Viola palustris, p. 28). The colouring is rich and
varied: the stems white and black, boughs coppery,
6
SK 4
B
Fic. 295.—Cone-scale of Birch, Fig. 296.—Diagram of a three-flowered group
formed by union of the bract from the female catkin of Birch. .A, posi-
B, and the pair of bracteoles, tion of axis of catkin ; B, bract subtending
da, 6. Much enlarged. See the group of flowers; a, 5, bracteoles ;
next figure. 1, median ; 2 and 38, lateral flowers.
twigs purple, and leaves green or gold according to
the variety and the season of year. The pleasant
smell of Russian leather is said to be given by an oil
distilled from the Common Birch.
Carpinus (Hornbeam)
Monecious wind flowers; males with about 12
stamens. The fruit is small, one-seeded, and very hard,
attached to a long, leafy, unequally three-lobed bract,
so that it is easily carried by wind.
C. Betulus.—A group of two flowers is borne in the
axil of each bract of the female catkin (Vigs. 297, 298).
This group of two is comparable with the three-flowered
group in Birch, the central flower being suppressed.
The main bract B, subtending the group, plays no part
in the formation of the cupule : the pair of three-lobed
376 BRITISH FLOWERING PLANTS CHAP.
wings, each with its fruit shown in Fig. 297, is homologous
with a single cone-scale with its three-winged fruits in
Birch. The bracteoles a’, b’ are undeveloped in Birch.
The leaves are pubescent below, on the nerves. The
stem is somewhat flattened, and has a considerable
Fig. 297. Fig. 298.
Fic. 297.—Pair of fruits of Hornbeam. u, 0, a’, b’, bracteoles forming the wing ;
J, fruit. Somewhat enlarged.
Fic. 298.—Diagram of a pair of female flowers of Hornbeam. 4, position of
axis of catkin; B, bract subtending the pair of flowers; a,b, a’, 6’, bracteoles
enveloping each flower ; p, rudimentary perianth ; /, pistil of two carpels.
tendency to form buttresses. Bentham describes it as
a small tree, but it often attains a considerable size. It
is the most characteristic tree in Epping Forest, where,
however, owing to exercise of ancient lopping rights,
the individuals are generally much distorted.
Cory us (Hazel)
C. Avellana.—In this species some individuals are
protandrous, and others protogynous. These, therefore,
would naturally fertilise one anether. The same arrange-
ment also occurs in the Walnut (Juglans). The floral
arrangement is the same as in Hornbeam (see Fig. 298),
but the bracts a, a’, b’, and b, a’, b’, instead of forming
a three-lobed wing, unite to form the characteristic
cupule.
In the male flower the half-anthers in each stamen
are distinct, giving the appearance of 8 stamens.
IL AMENTACEAL 377
They are placed on a three-lobed scale formed by the
union of the main bract B and the pair of secondary
Fig. 299. Fig. 300.
Fic. 299.—Pair of fruits of Hazel, each in its involucre.
Fic. 300.—Plan of arrangement of a male flower of Hazel. A, position of axis of
eatkin ; L, bract subtending the flower ; u, 5, bracteoles.
bracts a, b. Compared with the arrangement in the
female catkin, we may regard the single male flowers as
Fie. 301.—Corylus Avellana, Female Fic, 302.—Corylus Avellana. Male
flower. flower
representing the lost median flower in the female group ;
in the male the lateral flowers are undeveloped.
The leaves are pubescent below.
Satix (Willow)
A vast genus, particularly in the north. The flowers
are dicecious, with half-concealed nectar, which is so
abundant that the trees are much visited by insects.
The’ flowers are very variable. The stipules are per-
sistent or deciduous, and vary much in form. The
arrangement of the leaves of the Willow is very in-
structive. They are in spiral whorls, and so shaped
378 BRITISH FLOWERING PLANTS CHAP.
that each whorl occupies the whole circtimference. For
instance, S. herbacea has a whorl of 3 nearly circular
leaves; S. Caprea, with broad leaves, 5 in a whorl; S.
pentandra, with lanceolate foliage, and 8, and S. incana,
with 13 linear leaves arranged in 5 spirals. In several
species the ascent of ants and other unwelcome visitors
is prevented by a waxlike, smooth, and slippery secretion
which they cannot scale. The seeds have a tuft of long
white silky hairs which enable the wind or water to carry
them about, and when at length they fall on damp earth
serve to fasten them to it. The nectary bears in many
cases a single large water-gland at the end, through
which the nectar exudes.
I have described the buds of the Willow and Poplar
in my Buds and Stipules. It is curious that in some
species the young leaves are convolute, while in others
they are “equitant.” The more the genus is studied
the more dificult, I might say the more impossible, does
it become to divide it into well-marked species. The
difficulty is increased by the facts that the male and
female flowers are on different trees, which are often
dissimilar, and that the leaves and flowers are out at
different seasons of the year, and also by the readiness
with which the species hybridise.
S. viminalis—The stomata on the under side of the
leaf are protected by silky hairs. The young stem is
hairy, afterwards glabrous.
S. Caprea.—In this case the stomata are protected
by short crisp, but not silky, down. The leaves are
glabrous and shining above, tomentose below. The
stems are at first tomentose, afterwards glabrous.
8. pentandra.—lIn this species stipules are sometimes
present, sometimes absent.
S. herbacea.—The leaves of this species, which, like
the two following, is an Alpine and Arctic form, are
typical “‘ snow-leaves” (see Viola palustris, p. 28).
S. reticulata.—This species also has rounded leaves,
but the edges are entire. It is possible that this differ-
ence is due to the prevalence of rain rather than of
I AMENTACE.E 379
snow. The advantage of a toothed edge in snowy
regions has been already indicated. On the other hand,
teeth would retain moisture, and in wet regions, there-
fore, an entire edge tapering to the stalk is an advantage,
because it carries off the moisture more rapidly. (See
also Cerastium alpinum, p. 28.)
8. lanata.— This is also an Arctic and Alpine species.
The stomata are protected by thick, soft, silky wool.
This not only serves to prevent the stomata from be-
coming clogged, but also keeps a layer of comparatively
warm air, thus protecting the leaf from extreme cold.
Porutvs (Poplar)
Dicecious, and, as a rule, wind flowers; they are,
however, visited by bees for the sake of the pollen.
We have three species. In P. alba the under side of
the leaves is white, while in the other two both sides
are green. P. tremula (Aspen) has orbi-
cular or rhomboidal leaves with large
teeth. In P. nigra (Black Poplar)
the leaves are ovate triangular, tapering
to a point, and with small teeth. It is
not a true native. The seeds have a
tuft of silky hairs which serve the same
purposes as in the Willows. While in
most species the stipules are caducous,
or fall with the leaf, those of the ter-
minal leaf in the Poplar are persistent,
and assist in protecting the bud during
winter. In P. alba and P. ee ea Cie al
the young shoots are downy, the female bean ees
catkins dense, the bracteal scales fringed _ stipules (st) belong-
with hairs, and the stamens 4-12 in ins to#leaf of last
number. On the other hand, the leaves
of P. alba ave white and cottony underneath ; those of
P. tremula silky or smooth.
P. tremula (Aspen).—The leaves are green and
glabrous underneath. There are two kinds. Those
on the upper part of the tree have long petioles,
380 BRITISH FLOWERING PLANTS ONAP.
and rounded blades with somewhat sinuate mar-
gins. Those on the radical shoots have shorter
stalks and subtriangular lamine; and the whole leaf
is so arranged that the rain falling on it runs down
towards the petiole. Here are two small cups which
catch and hold it. The cells lining the cups have thin
walls, and secrete a resinous substance which swells up
when moistened. The thin-walled cells then absorb the
moisture, but in dry weather are protected by the
resinous varnish.
The medizval explanation of the tremulousness of
the leaves was the touching legend that the Cross was
made of Aspen wood, and that the tree shivered ever
afterwards at the recollection. It has been suggested
that the movement helps to pump up the sap. Herbert
Spencer suggested that in all cases the movement of
leaves and branches by the wind was of use in this way,
but the object of the tremulousness of the leaves in
Poplars does not seem to be as yet clearly explained.
It is due to the insertion of the blade on the vertically
flattened leaf-stalk, as on a knife-edge.
P. nigra (Black Poplar).—The leaves are orbicular
or rhomboidal, and rather coarsely toothed. They are
ciliate, and silky on the under side when young, after-
wards glabrous. The female catkins are lax, with scales
nearly smooth ; the male flowers have 12-20 stamens.
In most trees the stomata are situated mainly, if not
entirely, on the under side of the leaves. In the Black
Poplar, on the contrary, they are nearly as numerous on
one side of the leaves as on the other. Now, why is
this? If we compare the leaves of the Black and White
Poplar, we shall be at once struck by the fact that,
though these species are so nearly allied, the leaves are
very different. In the White Poplar the upper and
under sides are very unlike both in colour and texture,
the under side being thickly clothed with cottony hairs.
In the Black Poplar the upper and under surfaces
are—which is not frequent—very similar in colour and
texture. The petioles or leaf-stalks, again, are unlike
I AMENTACE.E— CONIFER 381
those of P. nigra, presenting the peculiarity of being
much fattened at the end towards the leaf. The
effect of the unusual structure of the petiole is that the
leaf, instead of being horizontal, as in P. alba and most
trees, hangs vertically; and this, again,
explains the similarity of the two sur-
faces, because the result is that both
surfaces are placed under nearly
similar conditions as regards light and
air, Again, it will be observed that
if we attempt to arrange the leaves of
the Black Poplar on one plane, they
generally overlap one another; the
extent is larger than can be displayed
without their interfering with one
another. In foliage arranged like
that, for instance, of the Beech, Elm,
Sycamore, or, in fact, of most of our
trees, this would involve a certain Fic. ae Poplar
amount of waste; but in the Black ee
Poplar, as Fig. 304 shows, the leaves, when hung in their
natural position, are quite detached from one another.
Another peculiarity of the Black Poplar is that it
not only sheds its leaves, but also some of the twigs or
small branches. That these are thrown off, and not
merely broken, is clear, because they are thickened at
the base. It is said to have been only introduced into
England in 1758.
CONIFER
Wind flowers. The quantity of pollen is very con-
siderable, and may be seen falling from the trees in
yellow clouds. The grains are sometimes lightened by
the presence of two air-sacs. The flowers are sometimes
red in colour. This is perhaps a protection against
cold. The seeds of the Pines and Firs are generally
382 BRITISH FLOWERING PLANTS CHAP.
winged and dispersed by wind. The berries of the
Juniper are globular and of a dark purple blue; the
seeds of the Yew are imbedded in a pulpy cup of a
brilliant scarlet. Both are, no doubt, carried by birds.
The young cone makes its appearance, and the
pollen is shed in the spring. The pollen is long-lived,
and the development of the seed very slow. The pollen
of Pinus remains dormant, or rather completing its
development, for more than a year, and the ovule is not
fertilised till the following July, more than twenty
months after its commencement. The same occurs also
in the Juniper. Two embryos start from each fertilised
egg, so that several may be developed together in the
early stages. Only one, however, comes ultimately to
maturity. The cones open in dry weather, often at con-
siderable intervals, so that the seeds are dispersed by
the wind in various directions. A cone placed in a glass
of water will soon become tightly closed.
The leaves are round (Pinus monophylla), semi-
circular, or triangular. Some are much longer than
others. Why is this? I puzzled over it for some
time. The governing consideration is, I believe, to
secure a suitable amount of leaf surface. They are
all evergreen, but in some cases the leaves of one
year fall soon after those of the next are developed.
In others they are longer lived. In the Scotch Pine
they last three or even four years; in the Norway Fir
eight or ten; in the Pinsapo even as many as sixteen
to eighteen. Now, speaking roughly, and having regard
also to thestoutness of the terminal shoots, it will be found
that the shorter leaves have longer lives, and vice versa.
The longest-lived leaves amongst the Coniferee which I
know are those of Lbzes Pinsapo, which last some eigh-
teen or twenty years. Those of Welwitschia, a member
of the order Gnetacez, however, are said to reach even
acentury. This remarkable genus’ is represented by a
single species inhabiting the desert country in south-
west tropical Africa. It has a short thick stem like a
1 Described by Sir J. Hooker in Trans. Linn. Soc. xxiv. (1868).
II CONIFER.E 383
huge wooden radish, and bears only one pair of long
ribbon leaves a yard or more in length.
The cotyledons are long and narrow, varying in
number from two to nearly twenty ; when numerous they
seem to form a tuft. The Conifers are a very ancient
group, dating back to the later Palaeozoic periods.
PINUS
This genus includes those Abietinese in which both
shoots and leaves are dimorphic ; or, as regards the leaves,
polymorphic.’ There are about seventy species, spread
mainly over the north temperate region, and nearly
equally divided between the New and the Old World.
The extension shoots grow rapidly, and during the
season more or less continuously, and are elongated.
The lateral shoots are either elongate or short and thick,
forming “spurs.” These are axillary shoots, which
grow slowly and are soon arrested in their growth, so
that they do not materially lengthen between the
nodes, and probably serve as store-places for reserve
food or for water. They are surrounded by bud scales.
There are three principal forms of leaves: the cotyledons;
the primordial leaves, which are often mere scales ; and
the adult leaves, which are sometimes single (P. mono-
phylla), but generally arranged in tufts of two, three,
or five (rarely more), on the ends of the spurs. The
number in a tuft is, as a rule, constant in each species.
P. sylvestris (Scotch Pine).—The leaves are borne
in pairs on the dwarf shoots. The seeds have a wing,
formed by the separation of a layer from the upper
face of the mature cone scale. The pollen grains,
which are carried by the wind, are lightened by having
a hemispherical bladder at each end. The upper
side of each stamen is saucer-shaped, and, as the
stamens are one over the other, when the anther opens
the pollen falls into the saucer of the stamen below,
where it remains till it is jerked out by the next gust
of wind. The quantity of pollen produced by Pine
1 Masters, ‘‘A General View of the Genus Pinus,” Jowrn. Linn. Soc. (Bot.)
xxxv. (1904).
3884 BRITISH FLOWERING PLANTS CHAP.
trees is amazing. It is formed in the spring, remains
dormant in the mouth of the ovule
‘i all through the summer, autumn,
K and winter, and rouses itself to
fe * fertilise the ovule in the following
a A spring. The fruits open under the
¢) 7; influence of dry winds, which carry
j } a 3 off and scatter the winged seeds.
The bud' is covered by brown
elongated scales, which are spirally
arranged on the axis, and represent
the primary leaves. They rest on
a pedestal or base (Figs. 305, 306),
which in the winter is green, and
from which they are easily stripped
—
7
JS
ay al
Bets wen
ype
-_ nnn
SoS
ieee y pire >
DoS n eres
a : off, leaving a whitish scar. The bud
-, may be divided into three parts (Fig.
307). The lower, which occupies
oe from one-fifth to one-tenth of the
length, is somewhat narrower than
the rest (sc’). No needles are de-
veloped on this part of the bud.
Fic. 305.—Pinus sylvestris.
Fragment of terminal bud
represeuting seven tiers of
scales of the winter bua,
x6. se, three scales with
their fringed inembranous
margin, the rest have been
removed ; 0, persistent
bases of scales ; 72, buds of
secondary leaves in the
axils of the primary.
The middle portion (sc) is the
longest, and, when the brown por-
tion of. the primary leaves has been
stripped off, has, from their spiral
arrangement, very much the appear-
ance of an elongated cone. At the
base of each pedestal is a small axillary bud, bearing
the secondary leaves or needles in pairs (Fig. 305, J).
At the apex are the terminal (¢b”) and lateral buds (/b)
for next year.
The brown terminal part of the O
primary leaves is thrown off in spring,
and these secondary leaves form the ra. 306.—Pinus sylves-
needles. The brown primary leaves ‘i , A detached
are thicker towards the centre, and thin _
off towards the edges. They consist of diverging fibres
1 Avebury (Lubbock), On Buds and Stipules.
II CONIFERAL
connected by a thin membrane.
385
Towards the edges the
fibres turn suddenly backwards, and are frayed at the
edges, forming an interlacing tissue
which helps to strengthen the bud
(Fig. 305, sc). These scales are very
numerous. Some of the outer ones
are truncate (Fig. 308). These are
followed by a few that are tri-
angular -subulate and acuminate.
Succeeding scales pass quickly from
triangular to decidedly subulate
forms, which are more or less revol-
ute at the tip. They are followed
by a few more which are linear, with
a subulate base, and revolute at the
tip. These scales with revolute tips
are followed by a dense mass of
others which are subulate-linear,
acuminate, straight, and closely
appressed to the bud. If a large
terminal bud (Fig. 308, ¢) is taken,
and the scales removed, it will be
seen that the bud includes the whole
axis.
Fic. 307.—Pinus sylvestris.
Terminal Lud. ¢, point
of insertion of a female
cone; ¢, base of pair
of ueedles; 7b, lateral
bud ; se, bases of primary
leaf scales which have
been removed, revealing
the axillary foliage-leaf
buds ; sc’, lower portion
of bud in which no
needles are developed ;
tb, extreme base of ter-
minal bud; ¢b’, ter-
minal bud of next year.
of the plan of growth for the two
succeeding years (Fig. 307).
The scales themselves are the
primary leaves of next summet’s
shoot; and their obovate per-
sistent bases constitute the per-
sistent scales upon the primary
In the axils of these per-
sistent portions, which are green
Fic, 308.—Apex of branch. in winter, we find the axillary
x2. t, terminal bud; «a,
axillary buds at the base
buds which go to form the second-
of the terminal; 7, base ary shoots upon the resumption of
of pair af secondary leaves
or needles.
growth in spring. In those buds con-
taining male catkins, the latter are
equivalent to axillary shoots, and occupy the lower
portion of the axis of the bud; while the perfect leaves
2¢
386 BRITISH FLOWERING PLANTS CHAP.
are similarly accommodated, but higher up the axis of
the large resting winter bud.
Picza
P. excelsa (Spruce or Norway Fir).—Commonly
planted in Britain, but not native. In this species
the true bud scales are inserted on a “ common ringlike
wall of tissue investing the base of the bud; when the
bud bursts, this ring separates off below, and the whole
mass of scales is carried up on the elongating bud, like
a cap.”* There are about twenty species, all in the
north temperate region. This is well named excelsa, as
it is said to be the loftiest of European trees, reaching
a height of 150, or even 180 feet. The cones contain
from 300 to 350 seeds. After fertilisation they become
pendent, and in the following spring the scales open,
the seeds drop out and are wafted away by the wind,
after which the rest of the cone drops off whole, and
does not break up like that of the Silver Fir.
The winter buds (Fig. 309) vary greatly in size,
those at the apex and immediately beneath it being
strongest ou the leading branches; they are also the
first to resume growth m the spring. All are covered
with numerous scales, which consist of modified leaves.
The actual number of scales varies greatly, according to
the size of the bud. The accompanying figures would
represent buds and scales about the middle of April,
after growth has recommenced. The outer scales are
the most coriaceous, and elongate slightly or not at
all; the inner ones are transparent and membranous,
elongating considerably in spring. The true leaf (Fig.
310) consists of a lamina, which becomes disarticulated,
when about to fall, from a short persistent portion or
pedestal surmounting a basal portion which is decurrent
upon the axis. Fig. 311 shows a small, slightly modi-
fied leaf—a form which occurs but sparingly. The
basal portion of the bud is covered with broad, tri-
angular, acuminate scales (Figs. 312, 313), with a more
1 Marshall Ward, Trees, pt. i.
I CONIFER 387
or less evident midrib, which seem to consist of the
whole leaf modified. These are followed by a few
oblong obtuse, or subacute scales (Figs. 314, 315) which
4
Fig. 309, Fig. 310. Fig. 311. Fig. 312.
Fig. 318. Fig. 314. Fig. 315. Fig, 316. Fig. 317. Fig. 318.
Fic, 309.—Apical and two lateral buds. p. 2, pedestals of leaves after the green
portion has been removed.
Fic. 310.—Normal and perfect leaf. 7, leaf: p, pedestal ; b, basal portion decurrent
upon the axis,
Fig, 311.—Slightly modified small leaf. J, leaf; and 6, pedestal and base merged
in one another,
Fias. 312, 313.—Leaves now modified to triangular acuminate scales with a midrib,
Figs. 314, 315.—Succeeding forms of scales.
Figs. 316-318.—Inner scales after they have elongated, about the middle of April.
Z, J, in Figs. 316, 317, would seem to represent the lamina, surmounting elongated
pedestals ; the same portion in Fig. 318 is hooded over the apex of the bud ;
the lower portions are membranous and transparent.
are still coriaceous; the inner ones elongate slightly
in spring." .
The innermost scales (Figs. 316-318) are as long
1 Avebury, On Buds and Stipules.
388 BRITISH FLOWERING PLANTS CHAP.
as the bud, or nearly so; but after the resumption of
growth they soon extend beyond the coriaceous ones,
keeping pace for a time with the elongated axis, and
completely enclosing the young true leaves. These inner
scales elongate chiefly in the lower portion, which seems
to correspond to the pedestal. They are, on the whole,
more or less spatulate, but vary in form, and the apical
portion may be regarded as corresponding to the lamina,
because there is generally a trace of a joint or articula-
tion. This apical portion is slightly more coriaceous
and browner than the long and very membranous lower
portion. Some of the inner scales are more or less
evidently trifid (Fig. 317) or tridentate, the lateral
lobes appearing to correspond to the shoulders seen
below the pedestal of the normal and perfect leaf. The
innermost scales (Fig. 318) are suddenly widened at the
apex, forming a hood or cap rolled round the apex of
the bud, and completely covering and protecting the
young leaves. The stomata are arranged in two series
on the under side of the leaf, and are protected by a
waxy secretion, which gives rise to two white stripes.
The seeds take two seasons to ripen.
The “‘ witches’ brooms’ which sometimes appear on
Silver Firs are caused by the growth of a fungus,
Aeidium elatinum.
JUNIPERUS (Juniper)
J. communis.—In this species also the stomata are
arranged in two series and protected by a waxy secre-
tion, so that the leaves have two white stripes on the
upper surface. The leaves are linear, spreading and
ending in a stiff point. In hot dry countries many
species have scale-like leaves closely appressed to the
stem, and partly covered by other leaves, which
diminishes the transpiring surface. That the narrow
spreading leaves are the original form is shown by the
fact that in the species with scale-like appressed leaves
the seedlings have linear spreading ones, and only
5
afterwards produce the other form. In some species,
" CONIFERZ—TYPHACEA 389
J. chinensis, for instanee, the two tendencies are so
nearly balanced, that while the general form is broad
and appressed, some branches or twigs, generally in the
lower and shaded parts of the tree, bear narrow spread-
ing leaves.
The tube of the pollen grain branches, and fertilises
several egg cells. This is very unusual.
Botanists variously estimate from twenty-five to
fifty species, mainly in the Mediterranean region and
the North Atlantic Islands.
Taxus (Yew)
There are six to eight species, all in the north
temperate zone. The name is said to be derived from
a Celtic word Jw = green.
T. baccata.— When the anthers open the pollen falls
into a sort of pocket, where it lies quietly till there is
some wind, when it is thrown out. Generally it is
dicecious, but occasionally male and female flowers occur
on the same tree, and even on the same branch.’
MONOCOTYLEDONS
TYPHACEA
TypHa (Bulrush)
Monecious wind flowers. We have two species. In
one, Z. latifolia (Reed-mace), often called Bulrush,
the flowers are in an almost continuous spike; in
the smaller species, 7. angustifolia, there is a distinct
interval between the upper (male) and lower (female)
flowers. The minute one-seeded fruits are raised on a
long thread-like stalk which bears long silky hairs,
ensuring the ready dispersal of the fruit by the wind.
The ‘ Bulrushes” in which Moses was concealed
1 Lowe, The Yew Trees of Great Britain.
390 BRITISH FLOWERING PLANTS CHAP.
were probably the Papyrus (Papyrus antiquorum a
member of the Cyperaceze), which would be plentiful in
the river Nile.
SPARGANIUM
Protogynous, moncecious wind flowers, in globular
heads. We have three species. One, S. ramosum, has
the inflorescence branched; in the other two it is
simple—one, S. simplex, has short, the other, S.
minimum, long styles.
AROIDEZ
ARUM
Moneecious, protogynous fly-trap flowers. The spike
is half concealed in the large leaf or spathe, only the
purplish or yellow club-shaped top ap-
pearing. The spike supports a number
of pistils (Fig. 319, ») near the base, and
of anthers (a) somewhat higher. Now
in this case nothing would at first sight
seem easier or more natural than that
the pollen from the anthers should fall
on, and fertilise, the pistils. This, how-
ever, is not what occurs. The stigmas
mature before the anthers, and by the
time the pollen is shed, have become
incapable of fertilisation. It is impos-
sible, therefore, that the plant should
fertilise itself. Nor can the pollen he
carried by wind. When it is shed it
Bro. 309 Diseram” drops to the bottom of the tube, where
fe edeense et aes so effectually sheltered that nothing
ens phets short of a hurricane could dislodge it;
and although Arum is common enough,
still the chances against any of the pollen so dislodged
being blown into the tube of another plant would be
immense.
I AROIDEZ 391
. As, however, in Aristolochia, so also in Arum, small
flies, especially those belonging to the genus Psychoda,
attracted by the showy central spadix, the peculiar
smell, the prospect of honey, and perhaps of shelter,
enter the tube while the stigmas are mature, and find
themselves imprisoned by the fringe of hairs (Fig. 319, h),
which, while permitting their entrance, prevent them
from returning. After a while, however, the period of
maturity of the stigmas is over, and each secretes a
drop of honey, thus repaying the insects for their
captivity. The anthers then ripen and shed their
pollen, which falls on and adheres to the insects. Then
the hairs gradually shrivel up and set the insects free,
which carry the pollen with them, so that those which
then visit another plant can hardly fail to deposit some
of it on the stigmas. Often more than a hundred small
flies will be found, and in one case Knuth counted no
less than 4000 in a single Arum.
Another explanation of the floral mechanism in Arum
maculatum has recently been suggested by Father
..Gerard.'| He considers that the honey secreted by the
stigmas has a stupefying effect on the insects, which are
killed and ultimately digested in the interior of the spathe.
The insectivorous habit is deduced from the presence
of dried remains of flies on the walls of the cavity.
Schnetzler’ had previously claimed a similar insectivo-
rous habit for Arwm erinitum. Self-pollination is not,
he thinks, precluded in A. maculatum, some of the
stigmas being still functional when the anthers dehisce.
The Aroids are mainly tropical. As regards the
leaves, see Dentaria (p. 80) and Petasites (p. 236).
A. italicum appears to be the plant of our flora in
which the temperature relatively to that of the atmo-
sphere rises highest. The evolution of heat which
accompanies the vigorous activity of vital processes
connected with flowering, was noticed in this species by
Lamarck, and quantitative experiments have been made
1 Journ. Bot. August 1905.
°” dann. and Mag. Nat. Hist. Ser. 5, iv. 1879, p. 399.
392 BRITISH FLOWERING PLANTS CHAP.
by various workers in plant physiology.’ Kerner records
that when the outside air was 15° C. the interior of the
spathe rose to 40° or even 44°.
Acorus (Sweet Flag)
Protogynous, complete flowers forming a spike.
Perianth consisting of 6 short scales, with 6 stamens.
A. Calamus.—The spike contains many hundred
flowers. It never, however, produces ripe fruit in
Europe, though it does so in Asia. It is probable that
this is due to the absence of the proper insects for
fertilisation. Ludwig, on the other hand, accounts for
it by suggesting that all our European plants are
descended from a specimen brought from the east by
Clusius. Bentham, however, regards it as native in
some of our eastern counties.
LEMNACEZ?
Small floating plants of remarkably simple structure,
consisting of repeatedly branching so-called “ fronds,”
which show no distinction of stem and leaf. In Wolffia
there are no roots, or vascular tissue, the plant consist-
ing of little greea cellular cushions. The flowers, which
are very rare, appear in a fissure at the edge of the
shoot. They are reduced to a small spathe-like bract
enclosing one or two stamens, and a pistil (Fig. 320).
Lemna (Duckweed)
We have four species. L. polyrhiza has the roots
in clusters. In the other three they are single. L.
tiisulca has the fronds very thin, oblong, or narrowed
at one end. In the other two they.are broadly ovate,
in L. minor nearly flat, in L. gibba very thick and
convex underneath. ZL. trisulea is submerged, the
others float on the surface of the water.
1 Vines, Physiology of Plants, p. 304.
* Hegelmaier, Die Lemnaceen. Leipzig, 1868.
II LEMNACE 393
L. minor is protogynous. The anthers, however,
are ripe before the stigma has faded.
Ludwig * believes that the pollen is
carried by thesmall insects which are so
abundant on the surface of still waters.
The structure of the pollen, which is
covered with small projections, favours
this view. The plant generally in-
creases by division of the fronds, but
when it blossoms a number of flowers "zener iisutes much
generally come out at once. This — svlarged. «anther;
flowering in pulses occurs in other 77°” ?*™
species in which the pollen is carried by wind or water.
We have seen in the case of some preceding species
that the leaves are arranged, and shaped, with reference
to the supply of light and air. In this respect the
transparent fronds of Lemna are very instructive, not
indeed as regards their form or position, but with refer-
ence to the ee of the ae eae
aa ca) a aap es
mar
ie
Fig. 321. Fig. 322. Fig. 323.
Fics. 321-323.— Position of the chlorophyll granules in the cells of the ivy-leaved
Lemna (Lemna trisulea). Fig. 321, in darkness; Fig. 322, in diffused light ;
Fig. 323, in direct sunlight.
In the dark (Fig. 321) the granules of chlorophyll
arrange themselves on the side and inner walls of the
cells ; in direct sunlight, on the side walls (Fig. 323), so
as to receive as little of the light as possible; while in
diffused light (Fig. 322) they are placed so as to receive
the maximum amount of light.’
Wolffia arrhiza, which occurs in ponds in the Home
Counties, is the smallest, known flowering plant; the
shoots are only 5 inch long.
1 Susswasserflora. 2 See ante, p. 138, Oxalis.
394 BRITISH FLOWERING PLANTS CHAP.
NAIADACEA
Floating or submerged plants, with very simple
flowers. Pollen without extine.
ZostERA (Sea-grass)
Marine grass-like herbs, with flowers enclosed in a
sheath near the base of the leaves, and always submerged.
The pollen forms long slender thread-like tubes, the
so-called confervoid pollen from its resemblance to an
algal filament. The thin hair-like styles are exserted
from the spathe to catch the pollen. We have two
species—Z. marina with ribbed seeds, common in
muddy and sandy estuaries, and Z. nana with smooth
seeds, a much smaller and rare plant.
Nagas
Small submerged herbs growing in fresh or brackish
water, with a slender stem and small opposite leaves
with a narrow blade and basal sheath. The flowers are
unisexual. The male flower consists of an anther, closely
surrounded by a thin membranous sac-like perianth. The
pollen is spherical or oblong. The female flower is a
more or less ellipsoidal ovary, produced into a narrow
style with usually three stigmas.
We have two species, both very local. N. marina
is dicecious, and NV. flexilis moncecious.
N. marina is almost world-wide; but in Britain
oceurs only in one or two localities in the Norfolk
Broads, though in prehistoric times it was more widely
distributed.
N. flexilis is a North American species which has
been found in several localities in Ireland, Scotland, and
on the Continent.
Mr. Clement Reid’s discovery of fossil seeds in recent
beds indicates that these species were once more
generally distributed in Britain, and also the presence
of two other species—N. minor, which is now
widely spread in Europe and Asia, and N. graminea,
u NATADACE.E 395
common in the tropics of the old world, and finding its
present northern limit in the Mediterranean area.’
ZANNICHELLIA
Z. palustris (Horned Pondweed) is more or less
common in fresh or brackish water, in temperate and
tropical regions all over the world. The plants are sub-
merged. ‘The long-stalked male flowers consist merely
of one or two stamens; the female, of single free or
shortly-stalked carpels, collected in groups of four or
fewer, and surrounded by a cup-like or entire spathe.
The pollen is spherical.
Ruppia
R. maritima is widely distributed in salt and brackish
water in the temperate and tropical zones. The simple
hermaphrodite flowers are enclosed in the broad swollen
sheaths of the two uppermost foliage leaves up to the
time of flowering, but are then raised to the surface
by elongation of the peduncle, which lengthens still
further after fertilisation, and often becomes spirally
coiled. The pollen is bow-shaped and floated by the
water to the stigmas.
PotaMocETon (Pondweed)
Protogynous wind flowers. Parts of the flower in
fours. The flowers are borne in spikes which rise
above the water. Some botanists make fifty species,
of which no less than twenty-one are British. Others,
however, reduce the number considerably ; Bentham
reduces ours to nine—probably too low an estimate.
In P. erispus shoots with short leaves quite unlike
the usual form are developed in autumn at the ends
of some of the branches, detach themselves from the
mother plant, sink to the bottom, and root in the
mud.
P. natans.—This species affords a good illustration
of the way in which the chlorophyll grains adapt
1 Rendle, ‘‘ British Species of Najas,” in Journal of Botany, 1900.
396 BRITISH FLOWERING PLANTS CHAP,
themselves to changes in the intensity of light by
altering their shape. Figs.
324, 326 are two palisade cells,
seen in section in Figs. 325,
327. In diffused light the
grains are hemispherical or
even somewhat contracted at
the base. In sunshine they
flatten themselves out, and
thus receive less light.’
A
Fig. 324. Fig. 326. ALISMACEA
Perianth of 6 segments;
stamens 6, 9, or indefinite;
ovary with 3, 6, or many
carpels.
Fig. 825. Fig. 827.
Fic. 324.— Palisade cell of Potamo- Butomus (Flowering Rush)
pace Re ae ged UGB Nectar abundant, secreted
Fic. 326.—A similar palisade cell by the base of the ovary.
Pg baa B. umbellatus.—The flowers
1G. 327.—Section of same.
are large, rose-coloured, often
20-30 in an umbel, and about an inch in diameter, with
6 perianth leaves, 9 stamens, and 6 carpels. According
to Sprengel the anthers all shed their pollen before the
stigma is ripe, so that self-fertilisation is impossible.
On the other hand, H. Miiller says that the anthers are
still covered with pollen when the stigma is ripe.
Schulz near Halle found the anthers and stigma ripe
simultaneously. In the plants examined by Knuth the
six anthers which alternate with the segments of the
perianth ripen first and shed their pollen. Then the
other three anthers open, and soon after the stigmas are
ripe. These are all such good observers that the plants
probably differ in different localities or seasons.
1 See also Oxalis, Lemna, Fagus.
i ALISMACE 397
SAGITTARTIA
Moneecious pollen flowers without nectar.
S. sagittifolia (Arrowhead).—There are three kinds
of leaves. Those which are submerged are ribbon-
shaped ; the swimming ones, heart-shaped ; those which
rise into the air, arrow-shaped. The submerged leaves
are very thin, and, as Frank has shown,’ the chlorophyll
grains arrange themselves in the cell according to the
light, almost as in Lemna (see ante, p. 393). Moreover,
they are somewhat flat, and with the same object alter
their angle according to circumstances. The seeds are
shining, and are not wetted by water; the result is
that they float on the surface and are dispersed by
currents.
ALISMA
White or reddish flowers with half-concealed nectar,
secreted by a ring at the base of the stamens. There
are three British species. A. Plantago has numerous
flowers in a loose panicle. The other two have few
flowers. A. ranunculordes is an erect or creeping plant ;
A, natans floats.
A. Plantago.—The flowers are homogamous; the
anthers open outwards. They are principally visited
by flies.
A. ranunculoides.—The secretion of nectar is less
abundant.
A. natans—A delicate floating plant very rare in
Britain. Owing to its difference in habit it has been
regarded by some botanists as a distinct genus, Hlisma.
DAMASONIUM
D. stellatum (Star-fruit).—So called from the spread-
ing fruits. It is a Western Mediterranean plant, which
is sometimes found in gravelly ditches and pools in the
South of England.
1 Pringsheim’s Jahrbucher, 1872.
398 BRITISH FLOWERING PLANTS CHAP.
TRIGLOCHIN
Perianth of 6 nearly equal segments. Stamens 6;
carpels 3 or 6. Protogynous wind flowers. There
are two British species—T. palustre with 3, T. mari-
timum with 6 carpels. The stigmas precede in maturity
the anthers by two or three days. Underneath each
stamen is a deeply concave perianth leaf, into the
hollow of which, when the anther opens, the pollen
falls. There it rests till the wind rises and it is thrown
out. As in so many other wind flowers, the stigma is
brush-like. The fruits are sharply pointed, diverging,
and turned downwards, being attached by their sum-
mits to a stiff erect axis, so that they are easily brushed
off by, and run into the fur or skin of, any passing
animal,
HYDROCHARIDEX
ELODEA
Tricecious water plants.
E. canadensis (Water-thyme).—This is a Canadian
plant. It was introduced into Ireland about 1836,
appearing in England in 1841, and became so well
established as often to choke canals and streams. This
rapid propagation was a purely vegetative one of the
female plant. In Britain the male has only been
found near Edinburgh.
Hyprocwaris (Frogbit)
Dicecious plant, with half-concealed honey.
H. Morsus-rane.—The petals have a nectar scale at
the base. The plant has no fixed roots, but floats loose
on the water. The flowers rarely produce seeds; the
plant throws off short shoots, which sink to the bottom,
but rise again and develop in the following spring.
II HYDROCHARIDEA.—ORUHIDACEX 399
Srratiores (Water Soldier)
Dicecious, with half-concealed honey.
S. aloides.—The plant is protected from aquatic
animals by sharp teeth along the edges of the leaf. The
male flowers have about 12 fertile stamens, and 15-30
others which serve as honey glands. The female flowers
have similar honey glands. It is said that in Northern
Europe there are no male flowers, while in Holstein
they are not infrequent. The increase is even with us
mainly by offshoots. During the winter the plant
remains at the bottom of the water. In spring it rises
to the surface, producing fresh leaves, flowers, and
floating roots. After flowering it again sinks. The
seeds ripen in safety, and young plants are also pro-
duced at the end of long stalks which spring from
between the leaves. Towards the end of August the
plant rises a second time, and is at first surrounded
by the young ones. The connecting stalks, however,
die and decay, thus setting them free. Finally they all
descend to the bottom for the winter.
ORCHIDACEZ
This is one of the largest, most varied, most interest-
ing, and most beautiful families in our whole flora. The
homologies of the flowers were first pointed out in
1831 by our great botanist, Robert Brown.’ The
perianth consists of two whorls of 3 leaves; those of
the outer whorl and two of the inner often form a sort
of hood protecting the inner parts of the flower. The
other petal is known as the labellum, and forms an
alighting stage for insects. This petal would normally
be uppermost, but the ovary is generally twisted, so that
it becomes a lower lip. The stamens (represented only
by the anthers) are normally 3, reduced, however, to 1,
1 Trans. Linn. Soc. xvi.
400 BRITISH FLOWERING PLANTS CHAP.
or rarely 2. There are also normally 3 stigmas, the
upper and central one of which is modified into a re-
markable organ known as the rostellum (Figs. 328, 331).
The anther and stigmas are borne in close proximity
on a prolongation of the floral axis known as the
column. The stigma is sticky. The pollen is generally
Upper or posterior sepal.
A
Upper } Upper
petal. petal.
8
Rd
weO
@
g Ont
Lower Oo Lower
sepal, sepal,
i
Labellum.
Fic. 328.—Section of the flower of an Orchid. SS, stigmas; Sv, stigma modified
into the rostellum ; .A,, fertile anther of the outer whorl; A», dA3, anthers of
the same whorl sometimes present in the form of barren outgrowths (stamin-
odes) of the column (as in Orchis), but generally absent ; a, a, rudimentary
anthers of the inner whorl fertile in Cypripedium, generally forming staminodial
outgrowths of the column ; us, third anther of the same whorl, normally sup-
pressed, but occasionally present in abnormal flowers.
united by elastic threads, and forms one or two oblong
or globular pollen masses. The flowers as a rule pro-
duce nectar, often contained in a spur.t In some cases
(Orchis) the nectar does not transude, but the tissue
must be bored to obtain the sweet juice. The flowers
are very long-lived. Those of our wild orchids are said
to retain their beauty often for a month, and some
foreign ones for twice or even nearly three times as
1 In one species, Angraecum sesquipedale, of Madagascar, the spur reaches a
length of 18 inches.
1 ORCHIDACE 401
long. Some foreign species have more than one kind of
flower. The above diagram (Fig. 328) illustrates the
structure of an orchid flower. The seeds are numerous,
and very minute.
In some species the ovules are undeveloped or very
rudimentary when the plant is in flower. According to
Hildebrand,’ in Dendrobium the formation of the ovules
has not yet commenced, even the placentz are not
fully developed, and it is not till four months after the
deposition of the pollen that the formation of the embryo
begins.
ORCHIS
Of this genus we have ten species, of which Orchis
mascula (Karly Purple Orchis, Fig. 329) is perhaps the
commonest, and I have therefore taken it as the type.
It occurs in Southern and Central Europe as far as South
Scandinavia. It is sometimes,
but not always, scented. The
leaves are spotted and broad.
The flowers vary from pinkish
purple to flesh-colour, sometimes
pale or even white. They form
a loose spike 3 to 6 inches long.
Fig. 330 represents the side view
of a flower from which all the
petals and sepals have been re-
moved, except the lip (/), half of
which has been cut away, as
well as the upper portion of the
near side of the nectary (7). The
pollen forms two masses (Figs. Z/~\ \\
331, a, and 332), each attached Fic, 329.—Orchis mascula.
to a tapering stalk, which gives
the whole an elongated pear-like form, and is attached
to a round sticky disk (Fig. 332, d), which lies loosely
in a cup-shaped envelope, the rostellum (7). This
envelope is at first continuous, but the slightest touch
1 “© On the Impregnation in Orchids,” dnn. of Nat. Hist. xii. (1863).
2D
402 BRITISH FLOWERING PLANTS CHAP.
causes it to rupture transversely, and thus to expose the
two viscid balls (dd). Now suppose an insect visiting
this flower: it alights on the lip (/), and pushing its
Ploboscis down the spur it can hardly fail to bring
Fic. 330.—Orcais mascula, Side view of flower Fic. 831.—Front view of flower,
with petals and sepals cut off except the with all sepals and petals re-
lip, of whic), the near half is cut away, as moved except the lip.
well as the Upper portion of the near side of
the nectary.
a, the pair of anther cells 3 2, labellum ; », nectary ; 7, rostellum ; st, stigma.
the base of the proboscis into contact with the two
viscid disks,“which at once adhere to it, so that when
the insect’ withdraws, it carries away the two pollen
masses. It is easy to imitate this
with a piece of grass, and to carry
away on it the two pollen masses
‘and their stalks. If, however, the pol-
‘\inium retained this erect position when
tihe insect came to the next flower, it
Would simply be pushed into or against
It; old position. Instead, however, of
Telnaining upright, the pollinia, by the
¥ con gee of the minute disk of mem-
Fic. 332.—The two <
yollinia, ad, viscia DYaM\e to which they are attached,
disc; 7, ruptured gradmally turn downwards and for-
rostellum. :
ward's, and thus when the insect sucks
the next flower, the thick end of the club exactly strikes
the stigmatic surfaces Ws, st). The pollinium or pollen
I ORCHIDACEH 403
mass consists of packets of pollen grains, fastened
together by elastic threads. The stigma, however, is so
viscid, that it pulls off some of these packets, and rup-
tures the threads, without removing the whole pollinium,
so that one pollinium can fertilise several flowers.’
This description applies in essentials not only to Orchis
mascula, but also to O. Morio, O. fusca, O. maculata,
and O. latefolia, as well as to Aceras anthropophora
(Man Orchis) in all of which the pollinia undergo, after
removal from the anther cells, the curious movement
of depression which is necessary in order to place them
in the right position to strike the stigmatic surface.
0. pyramidalis differs from the above group in several
important points. The two stigmatic surfaces are
quite distinct, and the rostellum is brought down s0 as
to overhang and partly close the entrance to the
nectary. The viscid disks which support the pollen
masses are united into a single saddle-shaped body.
The lower lip bears two prominent ridges, which serve
to guide the proboscis of the insect into the orifice of
the nectary. It is of course important that the pro-
boscis should not enter obliquely, for in that case the
pollen masses would not occupy exactly the right
position. In this species the spur is too long and
slender for bees, and the plant is specially adapted
to butterflies and moths. It is sweet-scented. Darwin
gives a list of twenty-three Lepidoptera which visit this
species. One of them (Caradrina) had no less than
eleven pairs of pollinia attached to its proboscis.
Following Darwin and other botanists, I have
applied to the spur of Orchis the term “nectary.” As
a matter of fact, however, the flowers of this genus
produce no honey ; whence Sprengel applied to them the
term Scheinsaftblumen or ‘Sham - honey - flowers.”
Darwin does not, however, think that moths (by which
the flowers of this group are principally fertilised) could
be so deceived for generation after generation; and as
he has observed that the membrane of the interior of
1 Avebury (Lubbock), British Wild Flowers considered in relation to Insects.
404 BRITISH FLOWERING PLANTS CHAP.
the spur is very delicate, and the cellular tissue ex-
tremely juicy, he suspected that insects possibly pierce
the membrane, and suck the juicy sap lying beneath.
His suggestion has been confirmed by H. Miiller, and he
himself in a subsequent memoir’ speaks confidently on
the point. Delpino, on the contrary, is confident that
the species examined by him (O. sambucina, O. Morio,
O. mascula, and O. maculata) do not secrete honey
either on or under the epidermis. The weight of
evidence, however, seems to be on the side of the
suggestion made by Darwin. Considering, he observes,
the incalculable number of plants which have been
fertilised, ““we cannot believe in so gigantic an im-
posture.” The case of some flies is different, as they
appear to be very stupid. To test the intelligence of
moths he tried an ingenious experiment. He cut off
about half the spur of six flowers out of twenty-one
on a spike, and found that while thirteen out of the
fifteen intact flowers had the pollinia removed, this was
only the case with half of those with their nectaries
removed. The result, however, though suggestive is
not conclusive; and to make out a strong case the
experiment would have to be tried on a larger scale.
However this may be, there is no doubt that the
tissues between the two membranes of the nectary in
O. pyramidalis contain a copious fluid ; on the other
hand, in allied species the spur of which contains abun-
dance of nectar, as, for instance, Gymnadenia conopsea
and Habenaria bifolia, the two membranes are close
to one another. Darwin makes an ingenious sugges-
tion to account for the difference. In the two latter
species the disk is naked and remains permanently
viscid. On the other hand, in O. pyramidalis the disk
is covered with a pouch. When this is pushed away by
an insect the disk rapidly becomes viscid, and gets hard
in a few minutes. It would therefore be an advantage
that the proboscis should be retained in place for a
short time, so that the viscid matter might have time
' Ann. and Mag. of Nat. Hist., 1869.
Ir ORCHIDACEAE 405
to set. Hence, perhaps, the reason which accounts for
the insects being compelled to pierce the tissues, and
suck out the sweet sap more slowly.
The seeds are small and numerous. Darwin states
that one spike of O. mascula would produce over
186,000; and he calculates that if they all grew, the
great-grandchildren of a single plant would be sufficient
to clothe the entire earth with one uniform green
carpet !
O. hircina (Lizard Orchis).—Though common in some
parts of Europe, this species is very rare in England.
It has been found in Kent and Surrey, but often only a
single plant. Through the kindness of Mrs. Drax I saw
one in 1899 at Ollantigh Towers, near Wye in Kent, but
though a careful search was made only a single plant
was found.
GYMNADENIA
G. conopsea.—This species has an even longer spur
than Orchis pyramidalis, and is even more sweet-
scented. The flowers are red or white; the red ones
probably adapted to butterflies, the white ones to
moths (see Lychnis, p. 107). It secretes so much
nectar that the spur is sometimes half full. H.
Miiller records no less than twenty-six species of butter-
flies which he saw visiting this Orchid.
HaBENARIA
This genus, in which Gymnadenia is generally in-
cluded, hardly seems to me to be sufticiently distinct
from Orchis. The main difference, says Bentham, is
that “the anther cells, instead of converging at the base,
are either parallel or more or less diverging.”
H. chlorantha.—The flowers are greenish, and the
spur is 23-43 mm. in length. The anther cells are
widely separated ; the pollinia slope backwards, and are
much elongated ; the viscid disk is circular, and pyro-
longed on its imbedded side into a short drum-like pedicel.
When exposed to the air this drum contracts on one
406 BRITISH FLOWERING PLANTS CHAP,
side, and alters the direction of the pollen mass, thus
bringing it (as in Orchis mascula) into such a position,
that it comes in contact with the stigmatic surface of
the flower to which it is carried. The pollinia attach
themselves at the side of the insect’s face.
H. bifolia.—This is one of the white species which is
especially adapted to moths, and is particularly sweet-
scented at night. The spur is 13-20 mm. in length.
It is regarded by Bentham and other high authorities
as a mere variety of the last. Yet, as Darwin points
out, it differs in many important particulars. The
viscid disks are oval, and almost touch; the viscid
matter itself is of somewhat different character; the
drum-like pedicel is rudimentary; the stalk of the
pollen mass is much shorter; the packets of pollen
shorter and whiter; and the stigmatic surface more
distinctly tripartite. It would certainly seem, therefore,
that the two species are distinct. The pollinia attach
themselves at the base of the proboscis, not on the side
of the face.
H. albida.—In this species the spur is very short,
but so narrow that it is probably adapted to small
moths.
ACERAS
A. anthropophora (Man Orchis).—The arrangements
of the flower resemble those of O. mascula.
HeRMINIUM
The perianth has no spur, and the anther cells are
distant at the base.
H. Monorchis.—The pollen masses are short and the
disks large. It does not produce honey, but is very
sweet-scented at night, so that it is probably a moth
flower. G. Darwin, however, and H. Miiller found it
visited during the day by ichneumons and small beetles.
The pollinia attach themselves to the joint between the
femur and the trochanter of the first pair of legs.?
1 Darwin, More Letters.
IL ORCHIDACEE 407
OPHRYS
This genus resembles Orchis, but has no spur. We
have three species. O. apifera resembles a bee in form,
and generally has more or less pink sepals; while in
O. aranifera they are green. O. muscifera has small,
narrow, very dark flowers resembling a fly.
O. muscifera.—The lip is long and dark purple, and
when the flower is just open secretes minute drops of
nectar, becoming gradually covered by a thin layer, which,
however, soon disappears. At each side of the base
there are also two spots with a bright metallic lustre,
which closely resemble drops of nectar, and are supposed
by Sprengel and some observers to deceive flies and
other small insects. Darwin observes that if he “could
in any case believe in Sprengel’s ‘sham nectaries,’ |
should believe it in this instance.”' I myself do so.
The visits of insects are, however, very few. The plant
is sometimes abundant in my woods, but I have never
seen an insect visiting them. In one case there were a
group of over a hundred all within five yards of one
another, and I watched them for an hour in the middle
of a bright summer’s day, but not a single insect came.
It is certain, however, that they are visited by insects.
Darwin found that out of 207 flowers which he ex-
amined, 88 had had one or both of their pollinia
removed. Moreover, the plant is not self-fertile, and the
result is that but few flowers set seeds.
O. apifera (Bee Orchis, Fig. 333).—This species is so
named from its curious likeness to a humble bee. Robert
Brown first observed that the Bee Orchis is adapted for
self-fertilisation.” The stalks of the pollen masses are
long, thin, flexible, and too weak to stand upright.
The distance of the pollen masses from one another, and
the shape of the pollen grains is, moreover, variable.
The anther cells open soon after the flower expands, and
the pear-shaped pollen masses drop out, so as to hang
directly over the stigma, with which a breath of air is
1 Fertilisation of Orchids. 2 Trans. Linn. Soc. xvi. (1833).
408 BRITISH FLOWERING PLANTS CHAP,
sufficient to bring them in contact. While, therefore, in
most species of Orchis and Ophrys_self-fertilisation
appears to be impossible, in the Bee
Orchis it is carefully provided for.
Darwin has examined hundreds of
flowers, and has never seen reason in a
single instance to believe that pollen
had been brought from one flower to
another; and he has met with very
few cases in which the pollen mass
failed to reach its own stigma. He
has never seen an insect visit the flowers
of this species, and R. Brown suggested
that the resemblance of the flower to
bees was to deter insects from visiting
them. Darwin does not think this
q probable. Can it be to deter browsing
id: Ste quadrupeds? He believes also that,
apifera. though this species habitually fertilises
itself, the curious arrangements which
it possesses in common with other allied species are of
use in securing an occasional cross, even if only at very
long intervals.
Mataxis
M. paludosa.—One of our smallest Orchids. As
already mentioned the labellum is theoretically the
upper petal, but assumes the position of a lower lip by
the twisting of the ovary. In Malaxis it is in the
normal position as an upper lip. That Malaxis has
descended from Orchids in which the labellum was
below, is, however, shown by the curious fact that it has
taken its present place by a double twist, so that it now
occupies the position it would have held had there been
no twist at all. When ripe, the ovary gradually
untwists. The edges of the leaves produce cellular
bulbils, hence the leaves if placed in the ground develop
new plants.
II ORCHIDACEZE 409
LipaRis
L. Loeselii (Fen Orchis).—A small orchid with green
flowers, found in spongy bogs in the eastern counties.
CoRALLORHIZA
C. innata.—Brown or yellow plants without green
leaves. They live in leaf-mould under trees, and have
no true roots. The underground stem or rhizome con-
sists of a number of short, thick, fleshy, nearly white
branches, resembling a piece of coral. Rhizomes of this
character occur in other genera, which are denizens of
similar situations. They are associated with a myco-
rhiza (see p. 371), which plays the part of root hairs in
absorbing food from the humus.
NEotTTIA
A genus with brown stems and flowers, scales instead
of leaves, and thick succulent rhizomes. The species
live, like Corallorhiza, under trees, and root among the
dead leaves. The flowers have free or half-concealed
honey. The apex of the root, after forming rudimentary
leaves, throws off the root cap and grows onwards as a
stem.’
N. Nidus-avis (Birds’-nest Orchis).—The flower agrees
in essential points with Listera (see below, p. 411).
EPIpactis
We have two species—. palustris with narrow,
E. latifolia with broad leaves.
E. palustris—The sepals are lanceolate and pale
greenish purple, the petals white, streaked with pink.
The long lip is in two parts connected by a narrow
hinge. In the natural position the outer part of the
lip partly closes the opening of the flower; when,
however, an insect alights on it, it is pressed down.
E. latifolia—The flowers vary from green to dingy
purple. The free part of the lip is smaller than in the
preceding species, and the connecting part is broader.
1 Trmisch, Biol. d. Orchideen, 18538.
410 BRITISH FLOWERING PLANTS CHAP.
It is principally’ visited by wasps; yet, according to
Webster,’ the visits are few and far between. My
experience is the same.
EPIPOGUM
E. Gmelini—This also is a brownish, leafless species,
living among decaying leaves, and with a rhizome con-
sisting of short, thick, fleshy branches, as in Neottia
and Corallorhiza; the flower, however, differs consider-
ably. The plant often goes several years without
flowering. The flowers have a spur, secrete nectar,
smell of Vanilla, and appear to be principally fertilised
by humble bees. It is remarkable in not having its
flowers inverted. It is one of our rarest British plants
(a native of Herefordshire), but spread all over Europe
from Sweden to North Italy.
CEPHALANTHERA
Flowers more or less erect, with incurved sepals and
petals. We have three species—
C. rubra is red, the other two
white; C. grandiflora (Fig. 334)
with broad, C ensifolia with
sword-shaped leaves. The genus
differs from those hitherto described
in not possessing a rostellum, and
in having the pollen grains single.
The flower stands upright, and the
labellum is formed of two por-
tions: a base, and a small tri-
angular flap, which at first closes
the tube, then turns back, thus
forming a small landing-place in
front of a triangular door, situated
Fic. 384.—Cephalanthera half-way up the tube, and, lastly,
grandiflora, 7 a
rises up again and closes the
entrance. The pollen mass is extremely friable; it is
1 Darwin says ‘‘ exclusively,” Fertilisation of Orchids.
2 «On the Fertilisation of Epipactis latifolia,” Trans, Bot. Soc. Edinb. xvi.
(1886).
I ORCHIDACE 411
situated just above the stigma; and while the flower is
in bud, or at any rate before it becomes quite open, the
anther opens and expels the pollen, which stands in two
almost free columns, resting on the sharp edge of the
stigma, and emits a number of tubes which deeply
penetrate the stigmatic tissue. These serve partially,
but, as Darwin has shown, only partially, to fertilise the
flower; he suggests that the principal use of this closing
of the flower and emission of the pollen tubes is probably
to support the pollen, which would otherwise fall out of
the flower. In this curious manner, however, they are
retained in a proper position until the flower is visited
by insects, to which they readily adhere ; and which are
necessary to ensure the perfect fertility of the plant.
Darwin found that plants which were covered up only
ripened one-seventh of the usual quantity of seeds.
©. ensifolia.—According to Delpino this species is
always fertilised by insects. While sucking the nectar,
or as the proboscis is drawn back, the insect slightly
smears itself with the sticky fluid which clothes the
stigma, and then pressing the anther, carries off some
of the pollen, which it deposits on the stigma of the
next flower it visits.
Listers (Twayblade)
A raceme of small greenish flowers, over a pair of
leaves, which in L. ovata are 2-4 inches long, in
L. cordata less than an inch.
L. ovata.—TIn the centre of the lip is a narrow nectar-
secreting tract. The pollen is friable, and would not
of itself adhere to insects, but the moment the rostellum
is touched a drop of viscid fluid exudes on each side,
and when the insect retires it is sure to touch the
anther and carry off the pollen. It is principally visited
by ichneumons, small beetles, and flies. Darwin several
times saw insects enter the flower and afterwards retire
with a pair of bright yellow pollinia sticking to their
foreheads. The number of insect visitors is so large,
having regard to the inconspicuousness of the flower,
412 BRITISH FLOWERING PLANTS CHAP.
that some naturalists have supposed it may have a
scent which we do not perceive.
L. cordata.—The structure is essentially the same as
in the previous species.
SPIRANTHES
We have three species. S. autumnalis has the
radical leaves ovate or oblong; in the other two they
are narrow. SS. estivalis has the flowers in one row,
S. cernua in three.
S, autumnalis (Ladies’ Tresses)—The flowers are
upright, with a scent like that of a Hyacinth.
S. estivalis—Occurs in Britain only in bogs in the
New Forest, and in Wyre Forest, Worcester.
S. cernua.—Only found in a peat bog near Castle-
town in Cork County.
GOODYERA
G. repens.-—-Agrees generally with Epipactis in the
arrangements for fertilisation. The seeds are numerous
and very minute, only weighing ‘00002 of a gram.
CyPRIPEDIUM
Flowers few, large, with an inflated lip.
C. Calceolus ( Ladies’ Slipper).—The lower lip has the
form of a slipper, whence the name. This genus has
two fertile anthers, which are rudimentary in other
Orchids, while the one which is functional in them is
here represented by a singular shield-like body. The
opening into the slipper is small, and partly closed by the
stigma and this shield like body which lies between the
other two anthers. The result is that the opening into
the slipper has a horse-shoe-like form, and that bees or
other insects which have once entered the slipper (Figs.
335, 336) have some difficulty in getting out again.
While endeavouring to do so they can hardly fail to
come in contact with the stigma, which lies under the
shield-like representative of the middle anther. As
the margins of the lip are inflected (q), the easiest exit
rt ORCHIDACEA|—IRIDACE: 413
is at the two ends of the horse-shoe, and by one or other
of these (Fig. 336, e) the insect generally escapes, in doing
which, however, it almost inevitably comes in contact
with, and carries off some of the pollen from the corre-
sponding anther.
The pollen of this
genus is immersed
in a viscid fluid, by
means of which it
adheres first to
the insect, and
secondly to the
stigma, while in
most Orchids it is
the stigma which
is viscid.
In a Trinidad
species, Coryan-
thes macrantha,’
the basal part of ba alias of Cypripedium Calceolus, Front
the lip forms a Fre. 336.—Side view. ee
Bucket. wiih eens ee an ameter!
secretes a coplous
fluid which wets the wings of the bees, and by rendering
them temporarily incapable of flight, compels them to
creep out through the small passages close to the anther
and stigma, thus securing, though by different means,
the object which in Cypripedium is effected by the
inflected margins of the labellum.
Fig. 3385, Fig. 336.
IRIDACEZ
The conspicuousness of the flowers is sometimes
considerably enhanced by the coloured styles and
stigmas. Perianth 6-leaved, petaloid; springing from
the top of the ovary. Stamens 3.
1 See Criiger in Journ. Linn, Soe. viii. (1864).
414 BRITISH FLOWERING PLANTS CHAP,
Crocus
Protandrous butterfly flowers. We have two
species—one C. vernus, flowers in spring ; the other, C.
nudiflorus, in autumn.
C. vernus.—The flowers are white or purple, with stig-
mas of a rich orange. Nectar is secreted by the ovary,
and is protected by hairs. The tube is much too long for
the proboscis of any insects except Lepidoptera, but the
nectar sometimes reaches so far up as to be accessible
to some of the humble bees. There are two forms of
the flower. A small flowered one, with stigmas as long
as, or shorter than, the stamens; and a large flowered
one with longer stigmas. The leaves in Crocus are
arranged round the stem, not in two rows as usual in
the order, and also, unlike those which characterise most
of the genera, have a distinct upper and lower face,
and the tissues of the leaf are markedly differentiated
into palisade cells above, and spongy parenchyma below.
When the leaves are young and tender they are rolled
up, and do not flatten themselves till they are stronger,
and in less danger from frost.
C. nudiflorus—Areschoug and Massart have pub-
lished’ interesting memoirs on the means by which
plants keep to a convenient depth. Plants of Crocus
placed on the surface develop fleshy roots, which eventu-
ally contract and draw the corm down to a suitable
level. On the other hand, if the light is excluded no
such contraction takes place. As Raunkler says, “la
plante est completement desorientée dans |’obscurité.” ”
Iris
The flowers are large and showy—the 3 outer
perianth-segments large, spreading, and reflexed; the
3 inner ones much smaller and erect. The style bears
3 large flattened branches, each with an appendage
1 Areschoug, ‘‘ Beitr. z. Biol. der geophilen Pflanzen,” Act. Reg. Soc. Phys.
Lund, 1896. Massart, ‘‘Comment les plantes vivaces maintiennent leur
niveau souterrain,” Bull. Jard. Bot. Bruxelles, 1903.
2 Overs, det K. Danske Vid, Selsk. Forh, 1904.
Il IRIDACE
415
resembling a petal, which arches over the corresponding
stamen and outer segment
of the perianth (Fig. 337)..
In order to reach the honey,
which is secreted at the base
of the flower, insects have
to force their way between
this segment and the over-
arching style-arm. In so
doing the back will rub
against the outwardly
dehiscing anther. The re-
ceptive surface is the upper
face of a small ledge (st) on
the under side of the style-
arm. In backing out of
the flower a bee would only
come in contact with the
non-receptive lower face,
thus avoiding self-fertilisa-
tion ; on entering the flower
with pollen obtained on a
previous visit it will deposit
some of the pollen on the
upper receptive face. We
Fic. 337.—Iris Pseud-acorus, sp, one of
the large outer petals; a, anther of
the corresponding stamen; s, the
corresponding style-arm arching over
the stamen; st, ledge-like stigma.
Nat. size,
have two species—J. Pseud-acorus, with yellow, and
I. feetidissima, with blue flowers.
GLADIOLUS
Flowers in a one-sided spike.
Some of the flowers are female, the others
The genus is represented in Britain by G.
bee flowers.
complete.
Protandrous humble
alyricus, a Southern European species found in the New
Forest and the Isle of Wight.
SISYRINCHIUM
S. Bermudiana.—This is a North American species,
but is found in the South and West of Ireland.
416 BRITISH FLOWERING PLANTS CHAP,
RoMULEA
R. Columne (or Trichonema Bulbocodium) is a
native of the Mediterranean area, which is also found
in the Channel Islands, and near Dawlish, in Devon.
AMARYLLIDACEA,
This order differs from Iridaceze in having 6 stamens.
Narcissus
This genus has a cup-shaped or tubular crown at’
the mouth of the flower tube. Nectar is secreted at
the base of the flower tube.
There are two species in Britain. MN. Pseudo-
narcissus has yellow solitary flowers; N. biflorus (a
Western European plant which has become naturalised)
has white or yellowish-white flowers generally in pairs.
N. Pseudo-narcissus (Daffodil)—The flower tube is
about an inch long, wider at the top, so that insects can
enter it, and a proboscis 6 mm. long can reach the honey.
There are 3 nectaries. The pistil is a little longer than
the anthers.
LErvucosJuM
There is no free nectar, but the tissues of the flower
appear to contain a sweet sap.
L. estivum (Snow-flake)—The flowers are bell-
shaped, hanging in a cluster of 2-6. The pistil is rather
longer than the stamens. Knuth found traces of sugar
in the tissues under the green spots on the perianth-
leaves.
GALANTHUS
G. nivalis (Snowdrop).—The flowers are homo-
gamous. The pistil is longer than the stamens.
Sprengel found that nectar was secreted by the green
II AMARYLLIDACEZ—DIOSCOREACEZ—LILIACEH 417
parts of the perianth-leaves, and this has been confirmed
by Delpino and Knuth. It is not, however, abundant.
The flowers are principally visited by hive bees. They
are pendulous; the anthers form a cone, and terminate
in rigid points, which can hardly fail to be touched by
the bee, which thus shakes the stamens so that some of
the pollen drops down. In the absence of insect visits
the filaments relax, the anthers separate, and some of
the pollen drops on the viscid stigma.
DIOSCOREACEZ
Climbing plants, with net-veined leaves. Flowers
on the same plan as in Amaryllidacez. Fruit, a berry
in the British genus.
TaMuUS
T. communis (Black Bryony).—The plant is dicecious ;
the flowers are small, yellowish-green, in slender racemes.
The berries are scarlet. Darwin found that the growing
shoot revolves or circumnutates in 24 to 8 hours.’
LILIACE AL
Plants of various habit, often growing from a bulb
or rhizome. Perianth 6-leaved, petaloid; stamens 6,
below the ovary.
Some produce nectar, others are visited for the
pollen only. Some (Paris) appear to attract flies by mock
nectar. In several genera (Fritillaria, Allium, Gagea,
Ornithogalum, and Hyacinthus), the leaves sometimes
produce buds. Some 2500 species are known.
1 Darwin, Climbing Plants, p. 25.
2E
418 BRITISH FLOWERING PLANTS CHAP,
Turia (Tulip)
Some with, some without nectar.
T. sylvestris—The flowers are yellow, homogamous,
and sweet-scented. Nectar is secreted at the base of
the stamens, and protected by a tuft of hairs. The
yellow stigma projects beyond the stamens, and secretes
drops of sweet fluid. The flowers are principally visited
by small bees (Andrena and Halictus) which lick up
the fluid on the stigma before they explore the recesses
of the flower. The flower gradually droops, so that
finally the stigma comes within the fall line of the
pollen.
Lioypia
Protandrous flowers with free honey.
L. serotina.—Nectar is secreted by a ridge at the base
of the perianth. In Britain it only occurs on some of
the Welsh mountains.
GAGEA
Scentless flowers with exposed or half-concealed
nectar, secreted at the base of the flower. According
to Schulz sometimes the stamens, and sometimes the
pistil, fail to develop.
G. lutea—The flowers are slightly protogynous.
According to Kerner the stamens contract after shed-
ding their pollen.
ORNITHOGALUM
Flowers with half-concealed honey, secreted by 3
glands contained in the septa of the ovary.
Three species occur in Britain: O. umbellatum has
the flowers in a corymb, the other two in racemes; in
O. nutans they are few and large, in O. pyrenaicum
many and small.
O. umbellatum (Star of Bethlehem).—The flowers are
protogynous and borne in a corymb; the spreading peri-
anth segments are white, with an outer broad green band.
The stigma is ripe when the flower expands, then, accord-
u LILIACE 419
ing to Kirchner, the three outer anthers open, and after-
wards the inner ones. In the flowers, however, observed
by Kerner the inner stamens opened a day before the
outer ones, and this was also the case. with those ex-
amined by Knuth. After shedding their pollen the
upper half of each stamen bends outwards, while the
lower half remains close to the ovary, thus forming 6
narrow canals, of which the 3 corresponding to the
septal glands are nectariferous. Finally, the stamens
turn inwards, and the shorter ones deposit pollen on the
stigma. In the afternoon, and in wet weather, the
flowers close.
0. nutans.—The flowers are protandrous; at first
upright, then horizontal, finally hanging. When the
bud expands the anthers of the 3 stamens standing in
front of the nectaries also open, and in such a position
as to be touched by any insect coming for the nectar.
Subsequently they bend outwards, the stigma ripens, the
other 3 anthers open, and the flower becomes horizontal.
Finally, the flower droops, the anthers contract, and press
out the pollen, which falls on the stigma, so that in the
absence of insect visits the flower fertilises itself.
O. pyrenaicum occurs in woods in some of our
southern counties, and is very common near Bath. It
is an undoubted native, whereas the other two species
are naturalised in Britain.
ScILLA
Flowers generally violet, sometimes white or pink,
with free or half-concealed nectar, secreted by glands in
the septa of the ovary. We have three species—S.
nutans with hanging, the other two with erect flowers ;
S. verna having a bract under each pedicel ; S. autum-
nalis without bracts.
8. nutans (Bluebell).—This beautiful flower often
carpets our woods with a sheet of blue, bringing, as
Ruskin said, the heavens down to earth. It is re-
markable that it does not occur in parts of Central
Europe, as for instance in Switzerland.
420 BRITISH FLOWERING PLANTS CHAP.
MuscarRi
Bee flowers; the tissues at the base of the flower
containing a sweet juice. Flowers in a spike; those at
the apex sometimes only for show. Perianth contracted
at the mouth, with 6 lobes.
M. racemosum has dark violet protogynous flowers.
It occurs in sandy fields in some of the eastern counties.
ALLIUM (Onion)
Flowers in a terminal head or umbel, with con-
cealed nectar surrounded by a spathe of 2 or 3 bracts.
Perianth of 6 segments. Stamens, 6, in two sets of 3.
It is a genus with many species, of which eight are
British.
A. ursinum.—The flower is snowy white and pro-
tandrous. The anthers of the 3 inner stamens open
before those of the outer ones. During this time the
pistil lengthens from 2-3 mm. to 6 mm. and the
stigmas ripen. Finally, in the absence of insect visits,
the stigmas touch the anthers, and the flower fertilises
itself. The visitors are principally bees, humble bees,
and flies. The leaves are reversed, so that the morpho-
logically upper side is turned downwards, and develops
stomata.
Scott Elliot in his Nature Studies gives an
interesting account of this species. The seed begins
to develop on the surface of the earth, but as soon
as germination begins the growing embryo becomes
buried in the soil through a peculiar elongation of the
stalk of the cotyledon, which carries plumule and radicle
to a depth of 3-4 mm. Its subsequent yearly history
is as follows :—‘ In April a circle of peculiar fleshy roots
is formed; they grow obliquely downwards, and when
they are firmly fixed by root hairs at their ends, they
contract, losing about 30 per cent of their original
length; in so doing they draw the bulb downwards
into the soil. From May to July the green leaves
perform their work, and the flowers and fruit are
I LILIACE 421
formed. In September another series of roots grow,
not downwards, but outwards; these are thin, they have
no power of contraction, and simply absorb nourish-
ment like those of ordinary plants. From November
to April is the winter rest, and in April another circle
of stout contracting roots is produced, which again drag
the bulb downwards. Eventually it comes to lie at a
depth of 10-15 cm.”
A. oleraceum.—The flowers, according to Bentham,
are pale brown; Knuth describes them as at first
greenish white, and gradually becoming rose colour.
They are protandrous, and usually few in number ; some
are replaced by bulbils.
A. Schenoprasum (Chives).—A very rare plant in
Britain; found in rocky pastures in a few counties.
This is one of the species with fistular leaves—an arrange-
ment which is useful
as a protection against
undue transpiration, and
also probably against
wind.
A. triquetrum is a
South west European
species which occurs in
Britain only in Corn-
wall.
In the other British
species the 3 inner
stamens are flattened
and three-cleft (Fig.
338, c). I have seen no
suggestion as to the
purpose of this curious Fi. 338.—Allium sphueroeephatun. | Figure
arrangement een
A. — spherocephalum ; ;
(Fig. 338) has a globular, dense umbel. Tt is found in
Britain only on St. Vincent’s Rocks, Bristol.
422 BRITISH FLOWERING PLANTS CHAP.
SIMETHIS
8. bicolor.—The filaments of the stamens are very
woolly. It occurs in Britain only near Bournemouth,
and in a locality in Kerry, Ireland.
NaRTHECIUM
N. ossifragum (Bog Asphodel).—The stamens are
like those of Simethis. The flowers are homogamous,
and have a scent like that of Habenaria bifolia, but
no honey. They are, however, visited by insects
for the sake of the pollen. Possibly also the juicy
sap may be an inducement. The fruit is a narrow,
oblong, glabrous, dark yellow
3, capsule, with 6 longitudinal
__ ridges separated by furrows. It
Fic. 339.—Seed of Narthecium :
ossifragum. s, body of sed; CONtains a number of pale yel-
f thread-like appendage. En- low minute seeds (Fig. 339)
a only about 1 mm. in length.
The testa, however, is prolonged at each end into a thin
thread (¢ t) 8-9 mm. long.
Paris
Protogynous flowers without honey. Perianth of 8
or sometimes 10 segments. Stamens as many. Styles
4 or sometimes 5.
P. quadrifolia.—Leaves, generally 4, but sometimes
5,in a whorl. In the first case the parts of the flower
are in fours; but when there are 5 leaves, the parts of
the flower are also in fives. Flies are supposed to be
attracted by the dull reddish colour of the ovary, which
looks not unlike a piece of decaying meat. Flowers
sometimes occur without stamens. They are said to be
very long-lived.
MaIaNTHEMUM
M. Convallaria.—The flowers are protogynous and
sweet-scented. A very rare plant, found in woods in a
few counties.
u LILIACEA 423
PoLYGoNATUM
Homogamous bee and humble bee flowers, richly
supplied with nectar, which is secreted by septal glands
in the ovary. There are three British species; P.
verticillatum has the leaves in whorls; P. officinale has
1 or 2 flowers in each axil, and glabrous filaments; P.
multiflorum several flowers in each axil and hairy
filaments.
P. verticillatum.—A very rare British plant, only
found in woods in Northumberland and Perth.
P. officinale—The flower has the scent of bitter
almonds. The flower-tube has a length of 14-17 mm.,
and is only accessible to humble bees with a long
proboscis. No honey is secreted, but the tissues con-
tain a sweet sap. The flower is often bitten into by
Bombus mastrucatus. A rare plant, found in woods in
England.
P. multiflorum (Solomon’s Seal).—This species, on
the contrary, is said to secrete honey, though in Sweden
Almquist found none. Warnstorf was also unable to
find any. Also a rare plant, in woods in England and
Scotland.
ConvaLLaRia (Lily of the Valley)
Slightly protandrous pollen flowers. The tissues
contain a sweet sap, but there is no free nectar.
C. majalis—The flowers are drooping, pure white,
and very sweet-scented. The pistil projects beyond
the anthers.
ASPARAGUS
Flowers dicecious, or rarely complete, and occasionally
with intermediate forms. They secrete nectar.
A. officinalis.—The male flowers, as usual, are larger
than the female, and first visited by insects. The fruit
is a berry, globose, smooth, shining, red, and three-celled
with 3-6 seeds. The seeds are large, flattened on the
ventral aspect, hard, black, and smooth to the naked
424 BRITISH FLOWERING PLANTS CHAP,
eye. They are evidently adapted for transport by
birds. Only native on our western and south-western
shores, and the coasts of Waterford and Wexford. The
plant has been cultivated since Roman times.
Ruscvus (Butcher’s Broom)
R. aculeatus.—The place of leaves is taken by flat-
tened branches (cladodes) which are generally twisted
at the base, so that the lower surface is turned upward.
The small white flowers are solitary ; each on the true
upper (actually the lower) surface of a cladode, the
flower stalk being adnate to it. The berries are red.
The flattened branches are tough, woody, and further
protected by running out into a fine point. It is a
rare plant, in copses and woods in the southern half
of England.
FRITILLARtIA (Fritillary)
Large protogynous hanging flowers with concealed
nectar, which is secreted by the leaves of the perianth.
F, Meleagris.—F lowers of a dull red, chequered with
more brightly coloured lines and spots. According to
Kerner they last 5 days.
CoLcHICUM
This genus closely resembles Crocus, but has 6
stamens instead of 3, and the perianth springs from
below the ovary. The flowers are protogynous, with
concealed honey, secreted by the lower ends of the
free part of the staminal filaments, and protected by
woolly hairs.
C. autumnale (Meadow Saffron).—The leaves appear
in spring, and wither before the flowers open.
The arrangements of the flower in this species are
very complicated. Three of the petals are longer than
the others, and all elongate during the life of the
flower. It is hetero-styled, as in the case of Lythrum
(see ante, p. 192), having three forms—long-styled,
I LILIACE.E—JUNCACEA 425
mid-styled, and short-styled flowers, and the elonga-
tion of the corolla is by no means
the same in the three forms. In
the long-styled, according to Kerner,
the longer petals grow 9 mm. and the
shorter 12°6; in the mid-styled the
longer grow 13°5 mm. and the shorter
18°5; in the short-styled the longer
grow 10 mm. and the shorter 15 mm.
The anthers open outwards, which also
tends to cross - fertilisation, but the
stigmas remain fresh, and in the
absence of insects the flower fertilises
itself. It opens about 9 a.m. and closes
about 6 P.M.
What appears to be the flower
stalk is really the tube of the corolla,
and the ovary is underground. Per-
haps the advantage of this is that as
the plant is an autumn flower, and
lives in northern and mountainous
districts, the seeds would not have time
to ripen before the cold weather sets 7) 77 Cue
in. The seed capsule remains, how- and ovary. About
ever, underground all the winter, rising pala See
to the surface and ripening its seeds in the following
spring.
J UNCACEAL
Perianth regular, dry, in 6 segments. The Juncaceze
are wind flowers, almost invariably protogynous. The
female condition may last a few minutes (J. squarrosus),
a few hours, or several days. Cleistogamous flowers
occur in some species; in such cases the three inner
stamens are generally absent.
A remarkable feature in the flowering of rushes is
426 BRITISH FLOWERING PLANTS CHAP.
that it occurs in pulses. For some days, perhaps, no
flowers will be open ; then suddenly, without apparently
any change in the weather to account for it, the flowers
will all open together. This feature is especially marked
in the species which have single, or few flowers. For
wind-fertilised species the arrangement is obviously
advantageous. The flowers open once for all.
There are 15 British species, mostly perennial.
Buchenau’ makes altogether 176, but many of these
vary considerably in certain districts, and he observes
that the more he studied these variations, the more
he was disposed to diminish the number of species.
Juncus (Rush)
J. articulatus.—EKach flower lasts a day. It is female
in the morning, then hermaphrodite. The species is
supposed to flower in pulses. The leaves are hollow
and divided by partitions of pith,
giving them a jointed appearance,
whence the name.
Leaves formed on the model of
the rush have several advantages in
northern regions. They are flexible,
and not liable to be broken in storms ;
Fra. 341.—Flower of their thick epidermis protects them
Juncus artiewatus. from cold; they resist evaporation ;
ae and they catch the low light which
would not, as in temperate regions, fall on the upper
side of the leaf. They would also be well suited to
benefit by the low light glinting from the surface of
the shallow water in which they so often grow.
The fruit is an upright capsule from which the seeds
are jerked by the wind. It has three chambers, opening
by three valves which alternate with the walls. The
exterior walls of the pericarp are strongly lignified, and
their contraction causes the dehiscence.
J. balticus—This species flowers in pulses.
J. bufonius.—Annual. In some districts-—as, for in-
1 “ Monographia Juncacearum,” Engler’s Bot. Jahrb. xii.
I JUNCACE.E 427
‘stance, in parts of Russia '—all, elsewhere some, flowers
are cleistogamous and have 3 stamens only. The
flowers open between 5 and 6 in the morning, and the
stigma is ripe about 2 hours before the stamens open.
Towards mid-day the flowers close.
J. capitatus—Annual. In this species the stamens
are generally reduced to 3. The flowers are sometimes
cleistogamous.
J. castaneus—The life of the flowers lasts 2-3 days :
they do not open wide.
J. compressus.—This species generally flowers in
pulses. The flowers only last one day.
J. communis.—This species has two forms which are
often regarded as separate species—J. conglomeratus,
with flowers in close heads, and J. effusus, in which they
are much looser. But though the difference is generally
well marked, every gradation may be found between
them. They generally flower in pulses, and are open
from about 7 to 3. The anthers open a few hours
after the stigmas are ripe. There are generally only
3 stamens.
J. filiformis—Flowers short-lived, protogynous.
Pulses not so marked as in the previous species. The
flower opens, and the stigma is ripe between 5 and 6
AM. The anthers open later, and the flower closes
about mid-day.
J. glaucus—The flowering is like that of J. effusus, but
the flowers remain open longer, and there are generally
6 stamens. The pulse is very marked. Some flowers
are cleistogamous.
J. maritimus.—The female condition lasts for a day ;
the whole flower-life being 36 hours.
J. obtusiflorus.—Pulses well marked, with 3-4 days’
intervals, in which scarcely any, if any, flowers open.
The flower-life is only one day; the female condition
lasting 2-4 hours.
J. squarrosus.—The flowering pulses are well marked.
The flowers open early, by 8 a.m. the anthers are ripe,
1 Ascherson, Bot. Zeit. xxix. (1871) p. 551.
428 BRITISH FLOWERING PLANTS CHAP.
and they close soon after mid-day. In wet weather they
are almost cleistogamous.
J. trifidus—The female condition lasts 2 days, the
whole flower-life is probably 4.
Luzuta (Wood-rush)
This genus has softer and more grass-like leaves, often
with a fringe of hairs. We have five species—three with
flowers in panicles, two in compact heads.
L. campestris.—The perianth segments are very
pointed. As soon as the bud begins to open the three
stigmas push out, and soon wither. Several days (5-9)
then elapse before the flower is completely open, and
another, making 6-10, before the anthers are ripe. The
flower remains fully open for about 36 hours. From the
long interval between the withering of the stigmas and
the ripening of the anthers, it is evident that the flower
can never fertilise itself.
L, pilosa—In this species the stigmas remain fresh
for 4-5 days, during which the perianth is only partially
open. It then expands for some hours, the anthers
open, and finally the flower closes.
L. sylvatica.—This is the largest of our species.
The female condition lasts one or two days. Then
the flower and the anthers open. In this case, how-
ever, they do so while the stigmas are still fresh.
L. arcuata is an Arctic and Alpine plant found in
Britain only on the Scotch alps.
ERIOCAULEA
Small herbs with a dense tuft of narrow grass-like
radical leaves, and a scape bearing a dense head of
minute sessile flowers, subtended by an involucre of
bracts, and suggesting a Composite. It is almost
restricted to the warmer parts of the earth; it is
represented in Europe by the following species.
I ERIOCAULEAS—CYPERACEAS 429
ERIOCAULON
E. septangulare—A North American species which
is also found in lakes in one or two of the Hebrides,
and near Connemara in West Ireland.
CYPERACEAE
Wind flowers, with a few exceptions protogynous.
They resemble grasses superficially, though the flowers
are very different, but may be at once distinguished by
having generally a triangular stem, sometimes with very
sharp edges, while that of grasses is round,! or com-
pressed. Perianth absent or replaced by six bristles
or minute scales representing the six leaves. In some
cases the number of bristles is indefinite. Stamens,
generally 3, sometimes 2. Style, with two or three
branches. The fruit is flat, or with two ridges, in
species with two styles, triangular when there are three.
The embryo is embedded in the endosperm, while in
grasses it is outside. The plants are visited, though
not very frequently, by pollen-eating insects, which
sometimes cross the species.
EriopHoruM (Cotton-grass)
A North Temperate and Arctic genus, represented in
Britain by four species. It derives its name from the
long cotton-like hairs which represent the perianth, and
reach their full development in the fruiting stage; they
form a light envelope in which the nut is carried. The
plants grow in wet moss or in hogs.
Carex (Sedge)
The largest genus of the order in temperate climates.
It is also the largest genus, as regards number of
1] have suggested (Brit. Ass. Cambridge, 1904) that this is because the
leaves of Carex are in threes, while those of grasses are distichous.
430
BRITISH FLOWERING PLANTS
CHAP.
species, in our flora, numbering about sixty species.
Fig. 342, Fig. 343.
Fie. 342.—Sedge (Carex acuta), Male
flower, consisting of three stamens in
the axil of a bract, 0.
Fic. 343.—Female flower. The bract
subtends a compressed ovary sur-
rounded by a sac from which project
the two hairy stigmas.
below ; sometimes, however,
Mr. Reid records fruits of
nine species’ from pre-
glacial and interglacial beds
in various parts of the
country.
In some species the
male and female florets are
on different plants (C.
diotca); in those which
are regarded as most typi-
cal there are one or more
spikelets, consisting of male
flowers above, and one or
more of female flowers
the male and female florets
are in the same spike, either the male above and the
female below, or vice versa.
there are 2 stigmas, in others 3.
seeded fruits
In some species (Fig. 343)
The form of the one-
or
‘utricles” also Jae oeeareee: pss
gives good specific reese 5s ae: aeourie lace
characters. wa al Se Ce wae!
In some species, bY : e a »
. for frais in ie aA ar a
. paludosa, the Oar a ae >
ie are pro- Sots, pS ay: 86 a Ur
tected by a series of y BAe a
cuticular pegs (Fig.
344). These hold the
air, thus keeping the
stomata clear and
dry. Even if the
leaf be immersed in water
like a sheet of silver.
eee eee’ 2 | u
alatactat (atantataslea
Fic. 844.—Vertical section through part of a leaf of
Carex paludosa (x 200), showing protection of
stomata from moisture by papilla-like outgrowths
of the under-surface.
it is not wetted, but looks
C. pulicaria.—In this species and in C. pauciflora
the fruits are narrow, pointed, and spreading or reflexed,
so that they would readily be carried away by any
passing animal.
II GRAMINE 431
GRAMINEZ?
Wind flowers. Generally protandrous. Stem round
or compressed, generally hollow. The flower, or floret,
of grasses is enclosed in two bracts or glumes, one
slightly above the other ; it consists of two ‘“‘ glumelles,”
the lower one of which is often termed the flowering
glume, the upper the pale.
Above these two leaves are two
very minute scales known as
lodicules or glumellules, followed
by the stamens and pistil. The
lodicules swell and separate the
pale and glume, thus enabling
the stamens and stigmas to
protrude. Theoretically the
flower may be regarded as con-
sisting normally of one carpel
with 2 styles, and 3 stamens
(exceptionally 2-6), without
any perianth. On this view
the lodicules are bracteoles, en- ;
. ‘i Fic. 3845.—Diagram of a spikelet
closed in a second pair—the of Wheat dissected ( x about 4),
P } showing—from below upwards
pale, and the flowering glume. ee ee
Another view regards the lodi- — fiowering glume (right) and pale
(left), 2 lodicules, 3 stamens,
cules as representing two mem- and the pistil.
bers of a perianth. The “awn,”
which is sometimes present, stands to the palea in the
relation of a leaf-blade to its sheath.
Hildebrand thinks? that while the awns in
some cases promote dispersal, because their roughness
enables them to attach themselves to animals, their
principal use is that they move the seeds by hygroscopic
changes, and by serving as wings. No doubt they are
1H. Marshall Ward has recently published a small but very useful book
on the family. Grasses (Cambridge Nat. Sci. Manual). See also Lowe,
British Grasses.
2 Bot. Zeit. 1872, p. 890.
432 BRITISH FLOWERING PLANTS CHAP,
useful in these ways, but is not an even more important
service that they tend to pre-
vent the seeds being eaten ?
Fig. 346 gives a diagram
of a spikelet of Antho-
xanthum, and Fig. 345 of
Wheat.
The flowers open only
once, generally in the morn-
ing, through the swelling
of the lodicules. As usual
in wind flowers the fila-
ments are very thin, so that
the anthers are easily shaken
by the wind. Some species
Fig. 346.— Diagram of a spikelet of Fane: Gleiehogamions, lowers,
‘Anthoxanthines disaceted (5 abont Lhe flowers are generally
8), ae showing—from below up- complete, but sometimes, as
wards —2 outer and 2 (awned) . e P
inner barren glumes, fertile glume 10 Maize, unisexual. The
and ee amen, and pistil. leaves consist of two parts
—a sheath which encloses
and strengthens the stem, and a free blade (Fig. 347).
The sheath is generally split open on the side opposite
the blade. At the pomt where the
blade quits the sheath is a small,
scarlous appendage known as the ligule.
Its probable use is to serve as a dam,
and prevent the rain which runs down
the blade from getting between the
sheath and the culm, and to turn the
little stream on each side down a
groove, and so to the exterior of the 7
sheath. Species which grow in the se el ae
shade of woods have thin flat leaves; of leaf. 4, base of
those of moor and heath grasses are ee nae a
thicker, stronger, setaceous, or rolled pees a - culm,
in at the edges (Fig. 349). This is *“*"'™
effected by ‘“‘ motorcells,” which are thin-walled, vary in
turgescence, and are seated on each side of the mid-rib.
li GRAMINE 433
In some of the species the points of the roots are
covered with hard scales, which enables them to force
their way. The common Couch-grass has thus been
known to bore through the roots of trees.
mM.
>
i)
Fic, 848,—Transverse section of half of leaf of Poa annua including the median
keel. x about 50. Six vascular bundles are represented in the half of the
blade, the strongest one is girdered with sclerenchyma. m, lines of motor cells
on upper face above the median vascular bunile.
The flowers of Grasses have as a rule definite hours
for opening. Poa, Keeleria, and Avena elatior take the
lead between 4 and 5 a.m.; Briza media, Aira cespitosa,
and Barley, are a little later, between 5 and 6; a good
many species, Rye, some Festucas, Andropogon, Dactylis,
between 6 and 7; Alopecurus, Phleum, and Antho-
xanthum, between 7 and 8. Then
comes an interval. At 11 Agrostis
opens; between 12 and 1 Melica,
Molinia, Nardus, Elymus, Sclero-
chloa, and some species of Calam-
agrostis. Some species of Bromus
open about 2, some of Avena
about 3, Agropyrum at 4, and,
lastly, Avra flexwosa between 5
and 6. MHolcus is peculiar. It
Fic. 349.—Transverse section
of leaf of Nardus stricta.
opens under favourable circum- — x about 50. he Aede
: . portions represent support-
stances twice, at 6 in the morn- ing tissue -(sclerenchyma),
ing, and 7 in the evening. EKach ™ tgs ek ee cells
flower takes from 15 to 20 jt bese of furrow in upper
minutes.
Wheat is said to open at any time of the day. The
anthers scatter about two-thirds of their pollen, and
drop one-third in their own flower, which, however,
gives better results if cross-fertilised. Rye is said to be
quite sterile to its own pollen.
2F
434 BRITISH FLOWERING PLANTS CHAP.
The seeds are not free, but are combined with the
wall of the ovary, thus forming a one-seeded fruit,
known as the “grain.” The embryo is outside the
endosperm, not within it.
The dissemination of the seeds is provided for in
several ways.’ Sometimes they are very minute, as, for
instance, in Eragrostis; generally, however, when
leaving the plant they carry with them parts of the
spikelet, which act as a balloon. In the quaking grass,
Briza, the glumes fulfil this function, and the same is
the case with species of Poa, Dactylis, Holcus, Festuca,
and Phalaris. In many cases the awns attach them-
selves to animals; and in some the dissemination is due
to hygroscopic movements.
Perhaps the most remarkable case is that of a
South European species, Stepa pennata (Fig. 350), the
structure of which has been described by Vaucher,
and more recently, as well as more completely, by
Francis Darwin. The grain is enveloped in the per-
sistent glume which is continued below into a sharp
point, and bears stiff short hairs pointing backwards.
The upper end is produced into a fine twisted cork-
screw-like rod, which is followed by a plain cylindrical
portion, attached at an angle to the corkscrew, and
ending in a long and beautiful feather, the whole being
more than a foot in length.
The long feather no doubt facilitates dispersion by
wind; eventually, however, they sink to the ground,
which they tend to reach, the fruit being the heaviest
portion, point downwards. So the fruit remains as
long as it is dry; but if a shower comes on, or when
the dew falls, the spiral unwinds, and if, as is most
probable, the surrounding herbage or any other ob-
stacle prevents the feather from rising, the fruit
itself is forced down and so driven by degrees into the
ground.’
1 TWildebrand, ‘‘ Uber d. Verbreitungsmittel der Gramineen Friichte,” Bot.
Zeit. 1872.
2 Avebury (Lubbock), Flowers, Fruits, and Leaves, p. 90.
11 GRAMINEE 435
The flinty epidermis not only serves as a support
Wap
Fic. 350.—Floret of Stipa pennata.
to the stem, but no doubt protects the plants against
snails and other herbivorous animals.
The leaves of some species of Festuca present a
436 BRITISH FLOWERING PLANTS CHAP.
good illustration of plants which are protected by barbs
at the edges of the leaves, convert-
: ing them into fine saws. If loose
Et pieces of such a leaf are shaken on a
ER flat surface they will move in the
IE a4 direction opposed to the points of the
barbs. Such leaves are awkward to
eat, and if they are stroked the wrong
way they cut like a knife.
There are some 3500 species. Ours
Fic, 851.—-Margin of a are all small, but some of the bamboos
eae se reach a height of over 100 feet. This
is one of the largest, and perhaps the
most useful, of all the orders of plants.
dE
°
aN
BAYS
ZEA
Z. Mays (Maize).—This widely cultivated plant is
not a British species, but I mention it because the
male and female flowers are on different heads, some-
times, however, with a few male flowers among the
female, and female among the male. The male flowers
smell of cumarin, the female are scentless. It is only
partially self-fertile.
LEERSIA
L. oryzoides.—Besides the usual, there are cleisto-
gamous flowers, which are very small, and do not
generally emerge from the sheaths of the leaves.’ The
perfect flowers are rare, and still more rarely produce
seeds.
Mittum
M. effusum is slightly protogynous.
SETARIA
8. verticillata—which is sometimes found in culti-
? Douval-Jouve, Bull. Soc. Bot. France, 1863.
rat GRAMINEE 437
vated fields though not a native—has small spikelets
interspersed with numerous barbed bristles, which would
easily attach themselves to any passing animal.
ANTHOXANTHUM
A. odoratum.—This is the species which contributes
the most to the delightful scent of new-made hay.
It is markedly protogynous; the anthers are not
ripe till the stigma is quite faded, so that the flower
cannot fertilise itself. The flowers open between 7
and 8 in the morning. The anthers are generally
yellow, sometimes red.
PHALARIS
P. canariensis (Canary Grass).—The flowers open in
the afternoon. The plant is often found as an escape
in fields and waste places.
DiGRAPHIS
D. arundinacea.—This is slightly protogynous, so
that a flower can at first only be fertilised by the
pollen of an older flower; it is, however, long-lived, so
that it may afterwards be fertilised by its own pollen,
and lastly by that of a younger flower.
PHLEUM
P. pratense.—According to Axell and Kirchner the
flowers are markedly protogynous, but Warnstorf found
the plants homogamous. The anthers are yellow or
violet.
P. alpinum is, according to Schréter, protogynous.
Atopgcurus (Fox-tail)
A. pratensis.—This species is markedly protogynous.
The anthers are white or grey, turning to red. The
flowers open, according to Kerner, from 7 to 8 A.M., but
438 BRITISH FLOWERING PLANTS CHAP.
Warnstorf found those near Ruppin did not do so till
between 10 and 11.
A. agrestis. —The flower arrangements are as in the
preceding species.
LaGurvus
L. ovatus.—In this species the long silky hairs do
not fall with the fruit, but Hildebrand suggests that
they catch the wind, with the result that the plant is
violently waved about, and thus the fruits are thrown
to some distance.
APERA
A. Spica-venti—The flowers, which are borne in a
large pyramidal panicle, open about 6 a.m.
GasTRIDIUM
The genus derives its name from the inflated base of
the barren glumes.
G. lendigerum occurs in maritime sandy marshes in
South Wales and the southern portion of England.
Psamma (Marram Grass)
P. arenaria.—This is the common grass of our sand
dunes. It is very valuable in binding the sand together
by its long creeping stems, and thus preparing for other
plants.
AIRA
A. cespitosa opens, according to Kerner, between
6 and 7 A.M.
A. flexuosa.—The flowers are homogamous, with
bluish-black anthers.
A. canescens.—In this species the awn is pointed, and
has a minute tuft of hairs about the middle.
II GRAMINEE 439
AvENA (Oat)
A. sativa (Oat).—The flowers are homogamous, and
open between 2 and 4 p.m. According to Godron the
stamens turn downwards before the anthers open, so
that the flower could not often fertilise itself. Other
observers, however, dispute this. Kérnicke found that
in some varieties, a few of the flowers open in the
morning, and the rest in the afternoon. In wet weather
the flowers are almost cleistogamous.
The awns are very hygroscopic, thus moving the
fruits and making them seem almost alive. Hildebrand
explains! the mechanism as follows. The awn contains
two kinds of tissues—(1) long, thick-walled cells; and
(2) more rounded parenchymatous cells. The long cells
form a pillar in the shape of a T, with the upper arms
turned down, and a very large foot. As the upper pait
presents a larger proportionate surface it contracts more
rapidly than the foot. It is probable that the twisting
of the awn is due to the same cause as in Erodium (see
ante, p. 132).
A. fatua (Wild Oat), a common weed of cultivation
in all corn countries, has been regarded as the original
form of the cultivated Oats. It is annual, while our
two other British species, A. pratensis and A, pubescens,
are perennial.
ARRHENATHERUM
A. avenaceum.—Each spikelet contains two flowers ;
one male and one complete. They open simultaneously.
The stamens then elongate rapidly, so that in ten
minutes they have increased their length three- or
even four-fold, growing from 2-4 mm. in a minute.
They are at first stiff, but as they elongate they become
flexible, and when ripe they hang down, and the anthers
open at the point. The anthers curl outwards at the
tips, thus forming little cups, in which a certain quantity
of pollen accumulates. As long as the weather is calm,
1 Pringsheim’s Jahrb. ix. (1873-4).
440 BRITISH FLOWERING PLANTS CHAP.
here it rests; but when there is any wind it is thrown
out, and a fresh supply drops down, to be scattered in
its turn. The plant is protected against browsing quad-
Fig. 352.—Arrhenatherum avenaceum. 1,2 x12. 3,4 x5. 1, A closed anther;
2, an open anther ; 3, spikelets on a calm day with glumes distended, and anthers
pendulous ; 4, spikelets in a wind, The pollen escaping from the pendulous
anthers in the spikelet to the right; in that to the left (and below) the
anthers (two only remaining) have shed their pollen; in a third flower (in the
same spikelet as the last mentioned) the authers are still closed and in process
of being exserted.
rupeds by the scabrid leaves. Kerner, however, saw
thousands of the tufts on the meadows near Oberiss in
the Tyrol, which cattle had torn up, as he supposes, so
as to get at the edible plants growing near them.
Hocus
H. lanatus.—The floral arrangements resemble those
of Arrhenatherum. According to Kerner some florets
open in the morning about 6 a.m. and others about 7 P.M.
II GRAMINEA 44]
Kérnicke confirms this, but says that comparatively few
open in the morning. Hildebrand, on the contrary,
says that they open about mid-day.
CYNoDON
C. Dactylon.—aA widely distributed grass, forming
the chief pasture of many dry climates. It occurs on
sandy shores in the south-west of England.
Narpvus
N. stricta.—A low-growing species with very slender,
rigid, erect stems, found on heaths and in dry pastures.
The Howers are protogynous. The spikelets open at
the apex for the protrusion of the stamens and single
stigma.
E.ymus (Lyme Grass)
E. arenarius is found on sandy sea-shores ; its creep-
ing stems help to bind the sands.
Horpeum (Barley)
The spikelets are in threes: one or two either empty
or with a male or rudimentary flower; the other two or
one, as the case may be, contain each a complete flower.
H. vulgare.—The flowers open between 5 and 6 a.M.,
and, according to Lindau, even at a temperature of
123° C. The flowers of the middle row, according to
Delpino, never open, but are cleistogamous. Those
of the four outer rows are homogamous. Godron,
however, found the flowers of all the rows open. The
awns attach themselves to animals and thus promote
the dissemination of the fruits.
Triticum (Wheat)
Flowers in a simple spike, the side of the spikelet being
next the axis. TZ. sativum (Wheat) is probably derived
from a species belonging to the subgenus Aigilops.
T. repens (Couch-grass) has a long creeping root-stock,
and is a troublesome weed in cultivated land.
442 BRITISH FLOWERING PLANTS CHAP.
LoLium
This genus resembles Triticum, but the face of the
spikelet is applied to the axis.
L. perenne (Ray-grass).—The flowers are slightly
protogynous or homogamous; they open in the early
morning. This species is common in waste places and
is also a valuable pasture-grass.
L. temulentum (Darnel) resembles the last species, |
but differs in being an annual. It occurs in cornfields,
and is probably not a genuine native. The fruit is
very poisonous.
BRACHYPODIUM
B. pinnatum.—The flowers open before 6 a.m., and
the anthers between 6 and 7.
Bromus
B. erectus, which occurs in fields and waste places
in dry soil, has homogamous flowers. The anthers are
orange yellow.
B. sterilis occurs in similar localities to the last
species. Warnstorf found only cleistogamous flowers.
B. arvensis, a continental species, is classed as a
casual in Britain. The flowers rarely open.
Frstuca
As to the number of British species there is much
difference of opinion. Bentham admitted five, others
make several more. The genus is closely connected
with Poa and Bromus, differing from the former in the
sharp-pointed or awned flowermg glume, and from the
latter in absence of hairs on the top of the ovary.
F. ovina is often viviparous, especially in mountain
regions.
DactTYLis
D. glomerata (Cock’s-foot).—A coarse grass common
in waste places. The flowers are slightly protogynous,
with a long-lived stigma. The stamens do not tur
I GRAMINEA? 443
down as in so many other grasses. The flowers open,
according to Kerner, between 6 and 7 a.M., according
to Warnstorf, between 6 and 9.
Cyyosurus (Dog’s-tail)
C. cristatus.—A slender species with almost filiform
leaves. The flowers are homogamous, with anthers
yellow or violet.
Briza (Quaking Grass)
B. media.—The flowers are homogamous, and open
once in the morning and once in the evening between
6 and 7. The glumes are large, concave, and serve
as a wing to the small fruit.
Poa (Meadow Grass)
P. pratensis—A common meadow grass. The
flowers are homogamous; the anthers open about
mid-day.
P. annua.—Though annual with us, this species is
said to be perennial on the summits of the Pyrenees.’
Similarly in the Flora of British India, where it appears
as an alpine on the hills of Northern and Southern
India, it is described as annual or perennial. In the
Swiss Floras it is given as an annual. This is the
commonest grass in our parks and by our roadsides.
P. alpina.—This species is often viviparous, the
spikelets being converted into buds. The association
of the viviparous condition generally with an alpine or
arctic habit is a point of interest.
MEtLica
Our two species of this genus, M/. nutans and
M. uniflora, occur in woods. The spikelets are two-
flowered; in M. nutans both flowers are hermaphrodite,
while in M. uniflora the upper is male.
1 See Cardamine hirsuta, p. 79, and Constantin, Les végdtaua et les milieux
cosmiques, p. 30.
A444 BRITISH FLOWERING PLANTS CHAP. II
TRIODIA
The genus takes its name from the three-toothed
flowering glume. Our one species, 7. decumbens, is
found in dry pastures and on moors.
K@LERIA
K. cristata has a slender silvery panicle. The
flowers are homogamous; the anthers bluish-black.
The- genus is named after Koeler, a German writer
on Grasses.
SESLERIA
S. cerulea.—A Central and South European species
found in hilly pastures, especially in limestone districts.
The flowers are protogynous. The genus takes its
name from Sesler, an Italian botanist.
‘Sesleria is one of the plants which has stomata on the
upper surface of the leaf. In the morning, or if the
weather is damp, the leaf is flat; but as the sun rises
and the air becomes drier, the sides rise and at last
the two edges almost meet, thus protecting the leaf
from too rapid transpiration. The movement is effected
by a special tissue of motor cells on each side of the
mid-rib, comparable to those illustrated on p. 433,
Many other grasses protect themselves in a more or less
similar manner.
PHRAGMITES
P. communis (Reed).—As a rule the florets in a
spikelet are close together, but in this species there is
a slight interval, clothed with long silky hairs, forming
a parachute. The stem is round, and, as well as the
leaf-sheath, quite smooth at the surfaces of contact.
The result is, that in a high wind the leaf turns partly
round, so as to fly with the wind, like a pennon. Even
if the sheath splits a little, this does not injure the
plant.
Acer, 142
Aceras, 406
Achillea, 240
Aconitum, 65
Acorus, 391
Adonis, 52 ie
Adoxa, 218
Aigopodium, 209
A&thusa, 210
Agrimonia, 181
Aira, 438
Ajuga, 334
Alchemilla, 180
Alder, see Alnus
Alisma, 397
Alismacee, 396
Alliaria, 82
Allium, 420
Alnus, 366
Alopecurus, 437
Alsine, 110
Althea, 119
Alyssum, 84
Amaryllidacee, 416
Amentacer, 360
Anagallis, 273
Anchusa, 296
Andromeda, 259
Anemone, 50
Anemophilous plants, 5
Angelica, 211
Annuals, 3
Authemis, 240
Auther, 4
Anthoxanthum, 437
Anthriscus, 213
Anthyllis, 166
Antirrhinum, 307
Apera, 438
Apium, 209
Apocynacee, 284
Aquifoliacer, 281
Aquilegia, 64
Araliacez, 215
Arctium, 244
Arctostaphylos, 261
INDEX
445
Arenaria, 111
Aristolochiace, 350
Armeria, 340
Arnoseris, 253
Aroidex, 390
Arrhenatherum, 439
Artemisia, 241
Arum, 890
Asarum, 350
Ash, 282
Asparagus, 423
Asperugo, 298
Asperula, 225
Aster, 237
Astragalus, 165
Astrantia, 206
Atriplex, 345
Atropa, 301
Avena, 439
Azalea, 259
Ballota, 334
Balsam, 139
Barbarea, 78
Barley, 441
Bartsia, 317
Beech, 366
Bellis, 238
Berberis, 67
Beta, 345
Betonica, 334
Betula, 374
Bidens, 243
Birch, 374
Blackberry, 177
Bladderwort, 274
Borage, 297
Boraginee, 292
Borago, 297
Brachypodium, 442
Brassica, 82
Briza, 443
Bromus, 442
Broom, 151
Broomrape, 302
Bryony, 194
446 BRITISH FLOWERING PLANTS.
Bryony, Black, 417 Columbine, 64
Buckthorn, Sea, 349 Comfrey, 298
Bud, 24-31 Composite, 280
Bupleurum, 207 Conifers, 381
Butcher's Broom, 424 Conium, 208
Butomus, 396 Convallaria, 423
Butterwort, 279 Convolvulacer, 290
Buxus, 352 Convolvulus, 290
Corallorhiza, 409
Cabbage, 82 Corn Cockle, 105
Cakile, 89 Cornacese, 217
Calamintha, 329 Cornus, 217
Callitriche, 354 Corolla, 3
Calluna, 263 Corydalis, 75
Caltha, 58 Corylus, 376
Calyx, 8 Cotoneaster, 186
Campanula, ‘255 Cotyledon, 195
Campanulacer, 253 Cotyledons, 34
Caprifoliacee, 218 Cowslip, 269
Capsella, 87 Crambe, 90
Cardamine, 79 Crane’s Bill, 127
Carduus, 244 Crassulacee, 195
Carex, 429 Crategus, 184
Carlina, 245 Crepis, 251
Carpinus, 375 Crithmum, 211
Carum, 209 Crocus, 414
Caryophyllaces, 103 Cross-fertilisation, 4
Castanea, 371 Crowberry, 353
Caucalis, 214 Cruciferee, 76
Celandine, 74 Cucurbitacee, 194
Celastracez, 144 Cuscuta, 292
Centaurea, 246 Cyclamen, 270
Centranthus, 227 Cynodon, 441
Centunculus, 274 Cynoglossum, 299
Cephalanthera, 410 Cynosurus, 443
Cerastium, 114 Cyperacer, 429
Ceratophyllacer, 355 Cypripedium, 412
Cherophyllum, 213
Cheiranthus, 77 Dactylis, 442
Chelidonium, 74 Daisy, 238
Chenopodiacew, 343 Damasonium, 397
Chenopodium, 344 Dandelion, 250
Chervil, 213 Daphne, 349
Chestnut, Spanish, 371 Datura, 299
Chickweed, 113 Daucus, 212
Chicory, 253 Dead-nettle, 325
Chlora, 288 Delphinium, 61
Chrysanthemum, 289 Dentaria, 80
Chrysosplenium, 199 Dianthus, 104
Cicendia, 286 Dicotyledons, 47
Cichorium, 253 Dictamnus, 7
Circa, 190 Digitalis, 312
Cistacer, 93 Digraphis, 487
Claytonia, 115 Dioscoreacese, 417
Cleavers, 225 Diotis, 241
Cleistogamous flowers, 8 { Diplotaxis, 83
Clematis, 48 i Dipsacus, 228
Clover, 160 | Dock, 346
Cochlearia, 85 ; Dodder, 292
Colchicum, 424 Doronicum, 243
Coltsfoot, 235 Draba, 84
Drosera, 201
Droseracex, 201
Dryas, 175
Echium, 293
Eleagnacee, 349
Eldor, 219
Elm, 358
Elodea, 398
Elymus, 441
Empetrum, 353
Endogens, 34
Entomophilous plants, 5
Epilobium, 186
Epipactis, 409
Epipogum, 410
Erica, 262
Ericacee, 258
Erigeron, 237
Eriocaulon, 429
Eriophorum, 429
Erodium, 131
Eryngium, 207
Erysimum, 82
Erythrea, 286
Euonymus, 144
Eupatorium, 235
Euphorbia, 351
Euphorbiaceew, 351
Euphrasia, 321
Evening Primrose, 189
Exogens 34
Fagus, 366 |
Festuca, 442
Filament, 4
Fir, 386
Flax, 117
Fleabane, 237
Flower, structure of, 3
Feniculum, 211
Foxglove, 312
Fragaria, 178
Frankeniacer, 103
Fraxinus, 282
Fritillaria, 424
Fruits, 15
Fumaria, 74
Furze, 156
Gagea, 418
Galanthus, 416
Galeopsis, 333
Galium, 225
Gastridium, 438
Genista, 154
Gentiana, 286
Gentianacee, 285
Geraniacer, 124
Geranium, 124
Geum, 176
INDEX
447
Gladiolus, 415
Glaucium, 73
Glaux, 272
Guaphalium, 242
Goodyera, 412
Graminex, 431
Grasses, 431
Ground Ivy, 330
Groundsel, 242
Guelder Rose, 219
Gymnadenia, 405
Habenaria, 405
Hairs, 25
Haloragee, 190
Hawkweed, 252
Hazel, 376
Heath, 262
Hedera, 215
Helianthemum, 93
Hellebore, 59
Helminthia, 247
Henbane, 300
Heracleum, 212
Herb Robert, 128
Herminium, 406
Hesperis, 80
Hieracium, 252
Hippocrepis, 166
Hippophae, 349
Hippuris, 191
Holcus, 440
Holly, 281
Holosteum, 115
Honey, 5
Honeysuckle, 221
Hop, 357
Hordeum, 441
Hornbeam, 375
Hottonia, 270
Humulus, 357
Hydrocharidee, 398
Hydrocharis, 398
Hydrocotyle, 206
Hyoscyamus, 300
Hypericum, 115
Hypocheeris, 248
Tlex, 281
Impatiens, 139
Inula, 238
Tridacee, 413
Tris, 414
Ivy, 215
Jasione, 254
John-go-to-bed-at-noon, 11, 247
Juncacee, 425
Juncus, 426
Juniperus, 388
Keeleria, 444
448
Labiate, 323
Lactuca, 249
Lady’s mantle, 180
Lagurus, 438
Lamium, 325
Lampsana, 253 -
Larkspur, 61
Lathreea, 303
Lathyrus, 168
Lavatera, 119
Leaves, 20; arrangement of, 13,
22; fall of, 33; shapes of, 26; |
sleep of, 29
Leersia, 436
Leguminosie, 146
Lemna, 392
Lentibulariacee, 274
Leontodon, 248
Leonurus, 331
Lepidium, 88
Leucojum, 416
Ligustrum, 283
Liliacee, 417
Lily of the Valley, 423
Lime, 121
Limnanthemum, 289
Limosella, 312
Linacee, 117
Linaria, 308
Ling, 263
Linnea, 223
Linum, 117
Liparis, 409
Listera, 411
Lithospermum, 294
Littorella, 343
Lloydia, 418
Lobelia, 254
Loiseleuria, 259
Lolium, 442
Lonicera, 221
Loranthacee, 216
Lotus, 152
Ludwigia, 190
Luzula, 428
Lychnis, 105
Lycopsis, 297
Lycopus, 336
Lysimachia, 271
Lythrarieew, 191
Lythrum, 191
Maianthemuin, 422
Malaxis, 408
Mallow, 119
Malva, 119
Malvaceze, 119
Marjoram, 325
Marrubium, 332
Matricaria, 240
Medicago, 157
BRITISH FLOWERING PLANTS
Melampyrum, 319
Melica, 443
Melilotus, 159
Melittis, 332
Mentha, 324
Menyanthes, 288
Mercurialis, 351
Mertensia, 294
Mespilus, 186
Meum, 211
Mignonette, 92
Milium, 4386
Mimiery, 17, 30
Mimulus, 311
Mint, 324
Monocotyledons, 389
Monotropa, 265
Montia, 115
Mullein, 305
Muscari, 420
Myosotis, 295
Myosurus, 52
Myrica, 366
Myriophyllum, 190
Myrrhis, 214
Naiadaces, 393
Najas, 394
Narcissus, 416
Nardus, 441
Narthecium, 422
Nasturtium, 78
Neottia, 409
Nepeta, 329
Night flowers, 11
Nuphar, 70
Nymphea 69
Oak, 872
Oat, 439
Cinanthe, 210°
Cnothera, 189
Oleacer, 282
Onagraceex, 186
Onion, 420
Ononis, 157
Onopordon, 245
Ophrys, 407
Orchidacee, 399
Orchis, 401
Orientation, 44
Origanum, 325
Ornithogalum, 418
Ornithopus, 165
Orobanchacese, 301
Orobanche, 302
Ovary, 4
Oxalis, 134
Oxytropis, 165
Papaver, 71
Papaveracer, 71
Parietaria, 357
Paris, 422
Parnassia, 200
Pastinaca, 211
Pea, 168
Pedicularis, 320
Pellitory, 357
Penny Cress, 86
Peplis, 194
Perennials, 3
Periwinkle, 284
Petals, 4
Petroselinum, 209
Peucedanum, 211
Phalaris, 437
Phaseolus, 150
Phleum, 437
Phragmites, 444
Phyllotaxy, 12
Physospermum, 214
Phyteuma, 255
Picea, 386
Picris, 248
Pimpinella, 210
Pinguicula, 279
Pinus, 383
Pistil, 4
Plantagine, 341
Plautago, 341
Plumbaginacee, 340
Poa, 443
Polemoniacee, 289
Polemonium, 289
Pollen, 4
Polycarpon, 115
Polygala, 94
Polygonacee, 346
Polygonatum, 423
Polygonum, 347
Poplar, 379
Poppy, 72
Populus, 879
Portulacexw, 115
Potamogeton, 395
Potentilla, 179
Poterium, 181
Primrose, 269
Primula, 266
Primulacee, 266
Privet, 283
Prunella, 330
Prunus, 174
Psamma, 4388
Pulmonaria, 293
Pyrola, 264
Pyrus, 184
Quercus, 372
Radiola, 119
Ranunculaces, 47
INDEX
Ranunculus, 53
Raphanus, 90
Raspberry, 178
Red colour, 23
Reseda, 92
Rhamnacee, 145
Rhinanthus, 316
Ribes, 197
Ribesiacesw, 197
Romulea, 416
Rosa, 182
Rosacex, 174
Rubia, 224
Rubus, 177
Rumex, 346
Ruppia, 395
Ruscus, 424
Rushes, 425
Sagina, 111
Sagittaria, 397
St. John’s Wort, 115
Salicornia, 344
Salix, 877
Salsola, 344
Salvia, 337
Sambucus, 218
Samolus, 274
Sanguisorba, 180
Sanicula, 206 |
Santalacee, 350
Saponaria, 110
Sarothamnus, 151
Saussurea, 244
Saxifraga, 198
Saxifragacee, 198
Seabiosa, 229
Scandix, 213
Scent of flowers, 6
Scilla, 419
Scrophularia, 310
Scrophulariacex, 305
Scutellaria, 831
Sea Lavender, 341
Sedge, 429
Sedum, 195
Seeds, 15
Sempervivum, 197
Senebiera, 86
Senecio, 242
Sense organs, 42
Serratula, 244
Sesleria, 444
Setaria, 436
Shepherd’s Purse, 87
Sherardia, 224
Silene, 107
Siler, 212
Simethis, 422
Sisymbrium, 81
Sisyrinchium, 415
26
449
450 BRITISH FLOWERING PLANTS
Sium, 210
Sleep of flowers, 11
Sleep of leaves, 30
Snapdragon, 307
Snowdrop, 416
Snow leaves, 28
Solanacee, 299
Solanum, 300
Solidago, 238
Sonchus, 249
Sowthistle, 249
Sparganium, 390
Specularia, 253
Spergula, 114
Spergularia, 114
Spirsea, 175
Spiranthes, 412
Stachys, 332
Stamens, 4
Standard (of Leguminose) 146
Statice, 341
Statocysts, 44
Stellaria, 112
Stellate, 224
Stem, 34
Stigma, 4
Stipa, 434
Stipules, 23
Stratiotes, 399
Strawberry, 179
Style, 4
Subularia, 86
Sundew, 200
Symphytum, 298
Tamus, 417
Tanacetum, 241
Taraxacum, 250
Taxus, 389
Teesdalia, 87
Teucrium, 336
Thalictrum, 49
Thesium, 350
Thistle, 244
Thlaspi, 86
Thrift, 340
Thyme, 324
Thymeleacem, 319
Tilia, 121
Tiliacew, 121
Tillea, 195
Toadflax, 308
Tragopogon, 247
Transpiration, 28
Trefoil—see Trifolium
Trientalis, 272
Trifolium, 160
Triglochin, 398
Trinia, 209
Triodia, 444
Triticum, 441
Trollius, 59
Tulip, 418
Tussilago, 235
Twayblade, 411
Typha, 389
Typhacee, 389
Ulex, 156
Ulmacez, 358
Ulmus, 358
Umbellifere, 204
Urtica, 355
Urticacer, 355
Utricularia, 274
Vaccinium, 259
Valeriana, 226
Valerianacee, 226
Valerianella, 227
Vallisneria, 9
Verbascum, 305
Verbena, 340
Veronica, 313
Vetch, 166
Viburnum, 219
Vicia, 166
Vinca, 284
Viola, 96
Violacer, 95
Viscum, 216
Wahlenbergia, 258
Walltlower, 77
Waterlily, 69
Wheat, 441
Willow, 377
Willow Herb, 186
Wintergreen, 264
Woodruff, 225
Woodrush, 428
Xanthium, 244
Zannichellia, 395
Zea, 436
Zostera, 394
THE END
Printed by R. & R. Crark, Limitep, Adinburgh.
BY THE SAME AUTHOR.
THE LIFE-HISTORY OF BRITISH FLOWERING PLANTS. §8vo.
15s. net. (Macmillan and Co., Ltd.)
FREE TRADE. Third Edition. 8vo. 2s. 6d. (Macmillan and Co., Ltd.)
ESSAYS AND ADDRESSES. 1900-1903. 8vo. 7s. 6d. net. (Macmillan
and Co., Ltd.)
THE SCENERY OF ENGLAND, and the Causes to which it is Due.
Third Edition. Crown 8vo. 6s. (Macmillan and Co., Ltd.)
THE SCENERY OF SWITZERLAND, and the Causes to which it is
. Due. Fourth Edition. Crown 8vo, 6s. (Macmillan and Co., Ltd.)
THE USE OF LIFE. One hundred and thirty-fourth Thousand. Globe 8vo.
Popular Edition, 1s. 6d.; sewed, 1s. Library Edition, 3s. 6d. 8vo.
Sewed, 6d. (Macmillan and Co., Ltd.)
THE BEAUTIES OF NATURE. Sixty-first Thousand. Crown 8vo. 6s.
New Edition, without Illustrations. Globe 8vo. Cloth, 1s. 6d. Paper,
1s. (Macmillan and Co., Ltd.)
THE PLEASURES OF LIFE. Part I. Two hundred and twenty-fourth
Thousand. (Macmillan and Co., Ltd.)
Popular Edition. 1s. 6d. ; sewed, 1s.
THE PLEASURES OF LIFE. Part II. One hundred and eighty-first
Thousand. (Macmillan and Co., Ltd.)
Popular Edition. 1s. 6d. ; sewed, is.
THE PLEASURES OF LIFE. (Two Partsin one Vol.) Globe 8vo. 2s. 6d.
(Macmillan and Co., Ltd.)
SCIENTIFIC LECTURES. Third Thousand. 8vo. 8s. 6d. (Macmillan
and Co., Ltd.)
FIFTY YEARS OF SCIENCE. Being the Address delivered at York to
the British Association, August 1881. Sixth Edition. 8vo. 2s. 6d.
(Macmillan and Co., Ltd.)
BRITISH WILD FLOWERS CONSIDERED IN RELATION TO
INSECTS. With Illustrations. Nature Series. Ninth Thousand.
Crown 8vo. 4s. 6d. (Macmillan and Co., Ltd.)
FLOWERS, FRUITS, AND LEAVES. With Illustrations. Nature Series.
Eighth Thousand. Crown 8vo. 4s. 6d. (Macmillan and Co., Ltd.)
THE ORIGIN AND METAMORPHOSES OF INSECTS. With Illustra-
tions. Nature Series. Seventh Thousand. Crown 8vo. 3s. 6d.
(Macmillan and Co., Ltd.)
ON SEEDLINGS. With 690 Illustrations. Two Volumes. 8vo. 36s.
(Kegan Paul, Trench and Co.)
ON SEEDLINGS. Popular Edition. With 282 Illustrations. Crown 8vo.
5s. (Kegan Paul, Trench and Co.)
ANTS, BEES, AND WASPS. With Illustrations. International Scientific
Series. Sixteenth Edition. Crown 8vo. 5s. (Kegan Paul, Trench
and Co.)
ON THE SENSES INSTINCTS, AND INTELLIGENCE OF ANIMALS.
With Special Reference to Insects. With 100 Illustrations. International
Scientific Series. Fifth Edition. Crown 8vo. 5s. (Kegan Paul, Trench
and Co.)
CHAPTERS IN POPULAR NATURAL HISTORY. 12mo. 1s. 6d.
(National Society.)
MONOGRAPH ON THE COLLEMBOLA AND THYSANURA. 1871.
(Ray Society.)
PREHISTORIC TIMES. As Illustrated by Ancient Remains and the
Manners and Customs of Modern Savages. Sixth Edition. 8vo. 18s.
(Williams and Norgate.)
THE ORIGIN OF CIVILISATION AND THE PRIMITIVE CON-
DITION OF MAN. Sixth Edition. 8vo. 18s. (Longmans, Green and Co.)
ON REPRESENTATION. Seventh Edition. Crown 8vo. 1s. (Swan
Sonnenschein and Co.)
ON BUDS AND STIPULES. International Scientific Series. (Kegan
Paul, Trench and Co.)
LA VIE DES PLANTES. 8vo. (J. B. Bailliére et Fils.)
THE CAMBRIDGE NATURAL HISTORY.
Edited by S. F. Harmer, 8c.D., F.R.S., and A. E, Sarpnmy, M.A.
Medium 8vo. 17s, net each.
VOLUMES NOW READY.
Vor. 11. WORMS, ROTIFERS, anp POLYZOA. By F. W.
GamBie, M.Sc.; Miss L. SHetpon ; A. E. Surpey, M.A.;
F.R.S. ; M. Hartoc, M.A.; W. B. Bennam, D.Sc. ; F. If.
Bepparp, M.A., F.R.S.; and S. F. Harmer, M.A.
Vou. III. MOLLUSCS anp BRACHIOPODS. By Rev. A.
H. Cooxsr, M.A.; A. E. SarpLey, M.A., F.R.S.; and F. R. C.
REeEp, M.A.
Vout. V. PERIPATUS, MYRIAPODS, INSECTS. Part I. By
A. Sepewick, M.A., F.R.S.; F. G. Srnonarr, M.A.; and
. D. Suarp, M.A., F.R.S.
Vou. VI. INSECTS. Part Il. By D. Suarp, M.A,, F.R.S.
Vou. VIL HERMICHORDATA, by 8S. F. Harmer, 8c.D.,
F.R.S.; ASCIDIANS and AMPHIOXUS, by W. A.
Hurpman, D.Sc., F.R.S.; FISHES, by T. W. Briper,
Sc.D., F.R.S., and G. A. BouLENGER, F.R.S.
Vou. VIH. AMPHIBIA anp REPTILES. “By H. Gapow,
M.A., F.RS. ,
Vou. IX. BIRDS. By A. H. Evans, M.A,
Vou. X. MAMMALIA. By F. E. Bepparp, M.A. (Oxon.),
F.R.S. (Prosector to the Zoological Society).
IN THE PRESS.
Vou. I. PROTOZOA. By Marcus Harroc, M.A., D.Sc. ;
SPONGES, by W. J. Sou.as, Se.D., F.R.S. ; JELLY-FISH,
SEA-ANEMONES, Erc., by S. J. Hickson, M.A., F.R.S.;
STAR-FISH, SEA-URCHINS, Erc., by E. W. Macsrine,
M.A.
Vou. IV. SPIDERS, MITES, Erc., by C. Warpurton, M.A. ;
SCORPIONS, TRILOBITES, Erc., by M. Laurin, B.A.,
D.Sc. ; PYCNOGONIDS, by D’Arcy W. THompson, M.A.,
C.B.; LINGUATULIDA anp TARDIGRADA, by A. E.
Surp.ey, M.A., F.R.S.; CRUSTACEA, by W. F. R. WELDON,
M.A., F.R.S.
MACMILLAN AND CO., Lrp., LONDON.
sani
i
(
4}
i
Mr
Buy
Waller t
ul
ea EU sa ee
i aa iy ‘itis i iat it
iit be Whahea aT ASE aa
Ht) i Brin sy yee ]
i) \ sib AGH NICW
eT RO aU Mi HAR
an Mi i Wh l 4 Sat tH)
Le iy *)
Hh eh
yy ni ne ‘
RR it ‘i ‘i Ne
eit i Nt haath A i Nit \
Hala ting THERE RATDRANPUN EW TEAR Np PHU
Aaa Oa A SaaS ie ue EA \ i
Fe RUT aan can auraetelisatinGanacs
RU USRRAMTAMLANR AS
Live Music Archive
Librivox Free Audio
Metropolitan Museum
Cleveland Museum of Art
Internet Arcade
Console Living Room
Books to Borrow
Open Library
TV News
Understanding 9/11