In the case of what are sometimes termed interrupted leaves, the laminar

portions of the leaf are here and there deficient on both sides of the

midrib, leaving small portions of the latter, as it were, denuded and

connecting the segments of the laminae one with the other. This has been

observed amongst other plants in _Veronica latifolia_, _Broussonettia

papyrifer_, _Codiaeum variegatum_ var. _interruptum_ (hort.),

_Scolopendrium vulgare_, &c.[528] (See p. 328.)

In some of the leaves which have been already referred to in

illustration of the inordinate growth of the cellular portions, the

increased development of parenchyma is associated with a contracted

state of the midrib and its branches, producing a puckered appearance of

the leaf, an exaggerated degree of that change which produces what are

termed "folia bullata." In illustration may be cited various species of

_Mentha_, _Perilla_, _Coleus_, _Fagus silvatica crispa_, _Cytisus_,

_Laburnum_ var., and other forms, cultivated in gardens for their

singularity.

Entire absence of the stalk of the leaf occurs normally in sessile

leaves; on the other hand the blade of the leaf is only occasionally

developed in the phyllodineous Acacias, in some species of _Oxalis_,

_Indigofera_, _Lebeckia_, _Ranunculus_, _Bupleurum_, &c.

De Candolle,[529] from a consideration of _Strelitzia juncea_, in which

the petiole alone is developed, was led to the inference that in many

monocotyledonous plants the blade of the leaf was never developed, the

portion present being the sheath or stalk, unprovided with limb. The

correctness of this inference is shown, amongst other things, by the

occasional presence of a leaf-blade in _Strelitzia juncea_ itself.

Occasionally the laminar portions of the leaf are completely wanting,

leaving only the main ribs, as in the case of _Berberis_, while the

adjoining figure (fig. 215) represents an instance of a cabbage wherein

the innermost leaves are represented by thick fleshy cylindrical bodies

corresponding to the midribs of the ordinary leaves. There is in

cultivation a variety of the cabbage which constantly presents this

peculiarity.

[Illustration: FIG. 215.--Inner leaves of cabbage reduced to their

midribs.]

The suppression of one or more leaflets of a compound leaf has already

been referred to at p. 396.

=Abortion of the perianth, calyx, and corolla.=--Illustrations of

partial development in these organs are not rare, under ordinary

circumstances, as for instance the "obsolete" calyx of Umbellifers. In

the cauliflower the branches of the inflorescence are contracted in

length, while their succulence is much increased; at their extremities

they bear crowds of imperfect flowers, in which the calyx only is

visible, and that only in a rudimentary and partially developed

condition. Imperfect development of the whole or of some of the

constituent parts is more common in the case of the corolla than in that

of the calyx. In _Arenaria serpyllifolia_ the petals, especially in

autumn, are only one fourth the length of the sepals. _Anagallis

phoenicea_, _Honckenya peploides_, _Arabis alpina_, _Ranunculus

auricomus_, _Rubus fruticosus_, and _Geranium columbinum_, also

frequently afford illustrations of this circumstance.

[Illustration: FIG. 216.--Abortion of four out of five petals, _Viola

tricolor_, side and front views.]

At fig. 216 is represented a pansy in which four of the five petals were

very small and colourless, while the lower spurred petal was of the

usual size and colour. In this flower the stamens and pistils were

wholly suppressed, and the flower-stalk, instead of being bent near the

flower, retained its primary straight direction. Similar atrophic

conditions of the corolla occur habitually among _Violaceae_.

The diminished size of the petals sometimes coexists with an increase in

their number, as in a flower of _Streptocarpus Rexii_, mentioned by

Bureau.[530]

Among monocotyledons this partial development seems to be even more

frequent than in dicotyledons. In addition to the well-known cases of

certain species of _Bellevalia_ and _Muscari_, wherein the uppermost

flowers of the raceme are more or less atrophied (see p. 347, fig.

179), a few less common illustrations may be cited. In crocuses it is

not a very uncommon circumstance to find the three inner segments of the

perianth smaller than natural, and generally unequal in size. This

occurs without any other perceptible change in the flower.

Schlechtendal[531] mentions a flower of _Fritillaria imperialis_ in

which the perianthial leaves were relatively very small, and destitute

of the usual nectary, while the stamens, on the other hand, were of

their natural size and appearance. Fresenius[532] records a similar

occurrence in the same plant.

Morren[533] gives details of like appearances in _Hymenocallis

americana_, and Delavaud[534] in _Tigridia pavonia_.

In certain orchids an arrested development of the perianth is habitual,

as in _Oncidium abortivum_ (fig. 217), where, on a large branching

panicle, numerous abortive, but few perfect, flowers are produced.

In a similar way the petals and labellum of _Odontoglossum

Uro-Skinneri_ have been found reduced to filamentous processes.

[Illustration: FIG. 217.--Flower of _Oncidium abortivum_, magnified.]

=Abortion of the stamens.=--Atrophy of one or more stamens is of very

common occurrence, as a general rule, in many genera of plants, _e.g._

_Scrophularia_, _Erodium_, many _Restiaceae_, &c. &c. As a strictly

teratological condition atrophy of the stamens is more rare than

complete suppression. It has been noticed in _Arabis alpina_, _Cerastium

glomeratum_, _C. tetrandrum_, _Rhamnus catharticus_, _Anemone_,

_Hepatica_, &c. It happens frequently among Orchids both wild and

cultivated. In the _Hymenocallis_ flowers described by the elder Morren,

four out of five stamens were atrophied. In other flowers, otherwise

perfectly formed, one abortive stamen was found bearing a spherical

indehiscent anther. All these atrophied anthers of _Hymenocallis_ were

found to contain pollen, differing at first sight but little from what

is usual, but presenting this important peculiarity, that while the

normal pollen does not burst until it comes into contact with the

stigma, in the abnormal flowers the outer coat of the pollen-grains

split while still within the anther, from which latter, indeed, they

could not escape, owing to the indehiscent nature of the latter. Again,

the pollen-tube of the abnormal grains cracked, in its turn, on mere

exposure to the air, and liberated the fovilla, so that the pollen of

these atrophied anthers was necessarily impotent, because it opened

before it could be applied to the stigma, even had that been rendered

possible by the opening of the anther.

An abortive condition of the stamens and of the pollen, is of very

common occurrence among hybridised plants. Gaertner and other writers

have spoken of this defective condition as contabescence.[535] It forms

one reason for the sterility so frequently observed in the case of true

hybrids. In some hybrid passion-flowers, while all other parts of the

flower were apparently perfect, even to the ovules, the stamens were

atrophied, and distorted, and contained little or no pollen; the few

grains of the latter being smaller than usual. (See under Heterogamy,

pp. 193-196, and p. 398.)

=Abortion of the pistil, fruit, &c.=--Traces of the carpels occur in

many male flowers of unisexual plants, _e.g._ _Sterculiaceae_,

_Euphorbiaceae_, _Restiaceae_, &c. &c., and in some natural orders there

appears to be a tendency towards a dioecious condition, _e.g._

_Caryophylleae_, as in _Lychnis dioica_, _Silene otites_, _Arenaria

tetraquetra_, &c. The last-named plant is stated to have, in some cases,

imperfect pistils; in others, rudimentary stamens; while a third set of

flowers are hermaphrodite.[536] The ovary of aconites, according to

Moquin, is very subject to atrophy.

[Illustration: FIG. 218.--Bladder plum.]

During the maturation of the pistil, and its passage to the fruit, great

changes of consistence frequently take place, owing to the development

of cellular tissue, or of woody matter, according as the fruit is

succulent or woody. It sometimes happens that, owing to some disturbing

causes, the changes that usually occur fail to do so; thus, the stone of

plums is occasionally deficient, as in what are termed bladder-plums

(fig. 218); some of these, consisting merely of a thin bladder, are

curiously like the pods of _Colutea_.[537]

MM. Fournier and Bonnet[538] describe a fruit of a _Rubus_, with

perfectly dry fruits, like those of a _Geum_, and this form was

considered by Steudel to form a distinct species. It is, however, merely

a variety in which the fruits have not become succulent.[539]

Schlechtendal describes[540] the ordinarily baccate fruit of a vine as

becoming dry, and even dehiscing by valves like a capsule.

In maize it occasionally happens that one or two of the longitudinal

series of fruits become abortive, leaving a smooth furrow, at first of a

greenish colour, but ultimately of a reddish yellow. Often a second row

of fruits, opposite to the first, is also atrophied, so that the whole

spike changes its cylindrical form for a flattened one.[541] See also

under Heterogamy, Meiophylly, &c.

=Abortion of the ovules.=--In the case of a pluri-ovulate ovary it

rarely happens that all the ovules attain to maturity, some never get

fertilised, others, pressed on by their neighbours on either side,

become impeded in their development, and finally disappear, or remain as

rudiments.[542] This is the case, under ordinary circumstances, and

still more so in the case of hybrid plants, or of monsters. Where the

outer coats of the ovule become more or less leafy in appearance (see p.

262), the inner investments become more or less atrophied, or are even

more frequently entirely suppressed, as is also the nucleus.

In other cases, a simple arrest of development takes place; the ovule,

for instance, which should be anatropal, remains straight, while the

integuments, checked in their development, form imperfect sheaths from

which the shrivelled nucleus protrudes.

=Depauperated Ferns.=--The preceding illustrations have been taken from

flowering plants chiefly, but a similar defective development is

manifested in cryptogamous plants. The contraction and imperfect

development of the fronds of some varieties of ferns, hence called

depauperated, may receive passing notice, as also the cases in which the

sori or clusters of spore cases are denuded of their usual covering,

owing to the abortion or imperfect development of the indusium, as in

what are termed exindusiate varieties.[543]

=General remarks on abortion, coincident changes, &c.=--Reference has

already been made, while treating of hypertrophy, suppression, &c., to

certain other changes affecting the flower at the same time. Atrophy of

one organ or set of organs, for instance, is frequently accompanied by a

compensating hypertrophy or by an increased number of other parts. In

the feather-hyacinth, _Muscari comosum_, var., _monstrosum_, the absence

of flowers is compensated for by the inordinate formation of brightly

coloured threads which appear to be modified pedicels (see pp. 347,

348); so also in the wig plant, _Rhus Cotinus_. So the atrophy of the

stamens, in some flowers, is coincident with the hypertrophy of the

pistil. Thus, Unger, 'Denkschr. d. Kais. Acad. der Wissensch. Math. Nat.

Classe,' Mai 25, 1848, p. 103, tab. ix, describes a case wherein the

corolla and stamens of _Desmodium marylandicum_ were atrophied, while

the calyx and legume, on the other hand, were hypertrophied.

Fusion of the members of one whorl with one another, or with the

components of an adjacent series, often entails atrophy or suppression,

either in the united organs themselves, or in adjacent ones. A

foliaceous condition of the outer portions of a flower is very generally

attended by atrophy or complete suppression of the inner portions.

From this point of view the observations of Morren[544] on the different

degrees of atrophy up to complete suppression, observable in the flowers

of _Bellevalia comosa_, are of importance. According to this observer,

the most highly differentiated parts, such as the stigmas, the ovules,

and the anthers, are the first to disappear, the filaments often being

developed without anthers. Ultimately a deformed and empty perianth

alone remains. In the ordinary course of things the mouth of the

perianth is open, but in some of these malformations it is closed, and

when that happens, the effects of atrophy are the more observable in the

stamens and pistils.

The impotence of the pollen in certain atrophied flowers, as noticed by

the same observer, is of much interest, especially in reference to the

sexual relationship between the different forms in polymorphic flowers

as studied by Mr. Darwin.

A change in direction may also be noted as a common accompaniment of

atrophy or suppression; thus, in a capsule of _Veronica Beccabunga_,

which was one-celled by the abortion of one carpel, the style was

lateral instead of terminal.

As to the causes of these structural deviations but little is known;

certain of them have been already alluded to. In some cases atrophy and

suppression maybe regarded as permanent states of a condition usually

transitory, but this is clearly not always the case. Among external

causes anything bringing about an enfeebled condition might be supposed

to lead to atrophy, or suppression of some parts.

Gaertner[545] attributes the arrested development and fall of flowers to

some among the following causes:--1. non-application of the pollen of

the same variety, and consequent imperfect fertilisation; 2. any

considerable injury to the calyx, &c.; 3. destruction of the style or

stigma before the fertilisation of the ovary; 4. application to the

stigma of imperfect or heterogeneous pollen or indifferent pulverulent

matter; 5. defective conceptive power in the ovary.

Abortion of the ovules is considered by the same authority to be due

to--1. deficiency of heat; 2. excess of moisture; 3. peculiar formation

of the ovary; 4. over-luxuriant development of roots or buds; 5.

peculiar conditions of cultivation; thus, cuttings and layers produce

sterile and abortive seeds much more frequently than plants of the same

species raised from seed; 6. abortion of the seed is often combined with

luxuriant development of the walls of the fruit.

Temperature and climatal changes in general seem not to be without

effect, as has been already mentioned in the case of _Arenaria

tetraquetra_, which is polygamous when growing in mountain districts.

Other illustrations of a similar character are mentioned under the head

of Heterogamy (p. 196).

Pressure has been already alluded to as one of the most obvious of the

inducing causes of atrophy and suppression.

In the case of _Ranunculus auricomus_ before cited, in which the petals

are rarely perfect, M. de Rochebrune considers that the deficiencies in

question depend, in great measure, on the amount of moisture in the

localities where the plant grows. In most places the flowers and carpels

are apt to become more or less abortive, while the leaves are luxuriant;

while, in dry places, the foliage is small, but the flowers are more

perfect. This is quite consonant with other facts relating to the

development of flowers or of leaves in general.

But while external agencies undoubtedly play some part in bringing about

these changes, it is almost certain that internal causes inherent to the

organization of the plant are more important. Mr. Darwin[546] accounts

for the existence of rudimentary organs by the operation of the general

rule of inheritance, and explains their stunted condition as the effect

of disuse, not so much, of course, in the particular flower as in its

predecessors. This disuse may be the result of the superior efficacy of

foreign pollen as contrasted with that formed in the individual flower

itself. In this way many hermaphrodite flowers tend to become

dioecious, as in _Caryophyllaceae_, _Orchidaceae_, _Plantaginaceae_,

_Primulaceae_ and other orders.

Although many of the circumstances above mentioned apply to plants whose

structure is habitually rudimentary, there is no reason why they may

not, under due restrictions, be applied to plants whose organs are only

occasionally defective.

For further remarks on the subject of Abortion, the reader is

referred to the sections relating to suppression, etc., also to

Moquin-Tandon, 'El. Terat. Veget.,' p. 120; C. Morren, "De

l'atrophie en general," in 'Bull. Acad. Belg.,' t. xviii, 1851,

part i, p. 275.

FOOTNOTES:

[522] 'El. Ter. Veg.,' p. 132.

[523] _Spinosae arbores cultura saepius deponunt spinas in hortis_, 'Linn.

Phil. Bot.,' Sec. 272.

[524] Mr. Selby, in his 'History of British Forest Trees,' p. 465, gives

the following account of the formation of this peculiar growth:--"In the

autumn the parent aphis deposits her eggs at the base of the embryo

leaves, within the bud destined to produce the shoots of the following

year. When these begin to burst and expand in spring, the leaves, at

whose bases the eggs have been deposited, instead of increasing in

length, enlarge at the base, and form a cell or cyst whose mouth is at

first closed by a red velvety-looking substance. If opened in this state

a nest of small greenish aphides is distinctly visible, and at a certain

period, or when they have acquired maturity, which is towards the end of

the summer, the mouth of the cell opens and the insects fly off to

inflict a similar injury upon the nascent buds of the year. In some

instances the leaves of only a portion of the circumference of a shoot

are affected, in which case, though a slight distortion may take place,

the branch is not prevented from elongating; but in others, where the

whole of the leaves around the shoot are converted into nidi, elongation

is prevented and distortion to a great extent takes place."

[525] See Cramer, 'Bildungsabweich.,' pp. 53, 64, for further

references.

[526] 'El. Ter. Veg.,' p. 124.

[527] Schlechtendal, 'Bot. Zeit.,' 1857, vol. xv, p. 67.

[528] On the subject of this paragraph the reader may consult A. Braun,

"Ueber abnorme Blattbildung," &c., in 'Verhandl.,' d. 35,

'Naturforscherversammlung;' Jaeger, 'Flora,' 1850. p. 481, tab. 4,

_Digitalis_.

[529] 'Org. Veget.,' i. p. 286.

[530] 'Bull. Soc. Bot. France, vol. viii, 1861, p. 710.

[531] 'Linnaea,' 1830, vol. v, p. 492.

[532] 'Mus. Senkenb.,' ii. p. 45.

[533] 'Bull. Acad. Roy. Belg.,' 1851, t. xviii. part i, p. 275.

[534] 'Bull. Soc. Bot. France,' vol. viii, 1861, p. 147.

[535] See Darwin, 'Variation of Domest. Anim. and Plants,' ii, 165.

[536] Gay, 'Ann. Sc. Nat.,' ser. i, 1824, t. iii, p. 44.

[537] See De Candolle, 'Mem. Legum.,' tab. 3, f. 1; Wyville Thomson,

'Trans. Bot. Soc. Edinb.,' 1851, July 10th; Berkeley, 'Gardeners'

Chronicle,' June 22nd, 1867, p. 654. A similar case is described by Dr.

Robb, in Sir W. Hooker's 'Journal of Botany,' 1841, vol. iii, p. 99,

with illustrative figures. The specimens there described were produced

at New Brunswick, where plum trees flower very freely, but seldom

produce ripe fruit. Dr. Robb's account is as follows:--"In the summer of

1839 I had an opportunity of watching the process of destruction among

the plums, and it was as follows--Before or soon after the segments of

the corolla had fallen off, the ovarium had become greenish yellow,

soft, and flabby. As the fruit continued to increase in magnitude, its

colour grew darker and of a more ruddy yellow, and at the end of a

fortnight or three weeks the size of the abortive fruit rather exceeded

that of a ripe walnut. In fact, an observer might imagine himself to be

walking amongst trees laden with ripe apricots, but, like the fabled

fruit on the banks of the Dead Sea, these plums, though tempting to the

eye, when examined, were found to be hollow, containing air, and

consisting only of a distended skin, insipid, and tasteless. By-and-bye

a greenish mould is developed on the surface of the blighted fruit; then

the surface becomes black and shrivelled, and at the expiration of a

month from the time of flowering the whole are rotten and decomposed.

The flower appears about the beginning of June, and before August there

is hardly a plum to be seen. It is curious that where two flower-stalks

arise from one point of the branch, one will often go on to ripen in the

normal way, while the other will become abortive, as above described."

In a specimen described by Mr. Berkeley there were two distinct ovules

of equal size close to the apex of the fruit, connected with the base by

vessels running down the walls. It should be observed that there is a

worthless variety of plum, Kirke's stoneless, or Sans Noyau, in which

the kernel is not surrounded by any bony deposit.

[538] 'Bull. Soc. Bot. Fr.,' 1862, vol. ix, pp. 37 et 291.

[539] Carl Schimp, 'Fl. Friburg,' vii, p. 745; Hook, fil., 'Journ. Linn.

Soc.,' vi, p. 9.

[540] 'Linnaea,' vol. v, 1830, p. 493.

[541] Moquin-Tandon, 'El. Ter. Veg.,' p. 325.

[542] Alph. De Candolle states that the position of the abortive ovules

affords a good character for discriminating between certain species of

_Quercus_, 'Bibl. Univ. Genev.,' 1862, t. xv, p. 929.

[543] See Moore, 'Nature-Printed Ferns,' 8vo, for numerous illustrations

both of depauperate and exindusiate ferns. _Scolopendrium vulgare_ seems

to be one of the ferns most commonly affected in this way. Moore, loc.

cit., vol. ii, pp. 135, 147, 159, 165, &c.

[544] 'Bull. Acad. Belg.,' t. xvii, p. 38, t. 1; Lobelia, p. 85.

[545] Cited in 'Henfrey's Botanical Gazette,' i, p. 179.

[546] 'Origin of Species,' p. 450.

CHAPTER II.

DEGENERATION.

While the terms atrophy and abortion apply in the main to a mere

diminution of size, as contrasted with the ordinary standard,

degeneration may be understood to apply to those cases in which not only

is the absolute bulk diminished, but the whole form is altered and

depauperated. Degeneration, thus, is the result not so much of a

deficiency in growth as of a perversion of development.

Under natural, _i.e._ habitual circumstances, the formation of pappus

in place of a leafy calyx may be considered as an illustration of

degeneration. It is evident, however, that no very decided line of

demarcation can be drawn between cases of perversion and of arrest of

development.

=Formation of scales.=--These may be mere epidermal excrescences, or

they may be the abortive rudiments of leaves. Of this latter nature are

the "cataphyllary" leaves which invest the root stocks of so many

perennial plants, the perulae of leaf-buds, or the paleae on the common

receptacle of composite flowers. Other illustrations of a like character

are to be met with in the membranous scales that represent leaves in

_Ruscus_, _Asparagus_, _Pinus_, &c. Similar productions are met with

within the flower, where they may occur as the representatives of

sepals, petals, stamens, or pistils, or as mere excrescences. (See

Enation.) Whole families of plants, _e.g._ _Sapindaceae_, are

characterised by the presence of these organs, which are often of great

interest to the morphologist as indicating the true symmetry of the

flower, while they have acquired fresh importance since the publication

of Mr. Darwin's work on the 'Origin of Species,' wherein we are taught

to regard these rudiments as, in many cases, vestiges of organs that

were more completely developed in the progenitors of the present race of

plants, and the exercise of whose functions, from some cause or other,

having been rendered impossible, the structures become, in process of

time, proportionately stunted.

Thus, in dioecious plants we frequently find traces of stamens in the

female flowers, and rudiments of the pistil in the male flower,

indicating, according to the Darwinian hypothesis, that the ancestors of

these plants were hermaphrodite (see Heterogamy).

Mr. Darwin has also shown that, in some cases, the utmost degree of

fertility is attained, not from the action of the pollen on the stigma

of the same flower, but on the influence of the male element of one

blossom upon the female organs of another flower on another individual

plant.

Hence, in such plants there is a tendency to a separation of the sexes,

while, from what has been before stated, it might be expected that

rudiments of the male or female organs would be found, and also as a

result of the operation of the law of inheritance. On the same

principles it is easy to understand the occasional presence of the

perfect in place of the rudimentary organs, as in _Dianthus_.

In some instances the assumption of a scale-like form by any organ is

attended by a change in texture, the organs becoming dry and scarious,

or fleshy. Moquin cites in illustration of the first phenomenon the

flower of a _Vicia_, in which the petals were thick and fleshy, like the

scales of a bulb; and of the second the leaves of a _Chrysanthemum_,

which were replaced by small, glossy scales, like those which invest

ordinary leaf-buds. Sometimes the entire flower is replaced by

accumulations of small, acute, green scales. Cases of this kind, wherein

the flowers of a pea and of the foxglove were replaced by collections of

small ovate green scales packed one over the other till they resembled

the strobile of a hop, have been already alluded to. Most of these

scales are represented as having had other accumulations of scales in

their axils.

Similar collections of scales may frequently be met with in the birch

and in the oak, and probably represent abortive leaf-buds. Other cases

of a like kind in _Gentiana Amarella_, where the scales are coloured,

are mentioned elsewhere.

In some kinds of _Campanula_ a similar change is not uncommon.

=Formation of hairs, spines, &c.=--The adventitious production of hairs

is likewise frequently due to an arrested growth, in some cases arising

from pressure impeding the proper development of the organ. In other

cases the formation of hair seems to accompany the diminished

development of some organ, as on the barren pedicels of the wig plant,

_Rhus Cotinus_. A similar production of hair may be noticed in many

cases where the development of a branch or of a flower is arrested, and

this occurs with especial frequency where the arrest in growth is due to

the puncture of an insect, or to the formation of a gall. In such cases

the hairs are mere excrescences from the epidermis.

Prickles differ but little from hairs save in their more woody texture,

but true spines or thorns are modifications either of a leaf or of a

branch. Their presence seems often dependent on the soil in which the

plants grow, or on other external circumstances.

They occur normally in the sepals of _Paronychia serpyllifolia_ and

other plants.

=Formation of glands.=--Under this name are associated a number of

(generally) rudimentary organs very different in their morphological

nature and significance, and also in their functions. Some are truly

glandular or secreting organs, while others have no visible office.

Anything like a complete account of these structures would be out of

place, and reference is only made to them here on account of the

occasional existence of intermediate forms, which throw light on the

morphological significance of these structures. Thus, in _Passiflora_

and _Viburnum Opulus_, the so-called glands on the sides of the petiole

appear to represent leaflets, and are not unfrequently developed as

such.

M. Dunal observed a flower of _Cistus vaginatus_ in which some of the

stamens were replaced by an hypogynous disc.[547] Moquin has seen

similar instances in the flowers of a Rose, _Hypericum_, and Poppy.

M. Planchon[548] gives an account of some very curious malformations in

_Drosera intermedia_, which go to show that the ovules are homologous

with the glandular hairs on the margins of the leaves of these plants,

an opinion corroborated by the researches of MM. Groenland and

Trecul.[549]

Dr. Hooker shows that the pitcher of _Nepenthes_ is due to a

modification of a gland placed at the extremity of the midrib.[550]

=Formation of tendrils.=--These are of very varied morphological import;

sometimes they are degenerated peduncles, as in passion-flowers, or

vines; at other times they are of foliar origin; or, again, they may

proceed from the segments of the perianth, as in _Hodgsonia_ and some

other cucurbitaceous plants. From their very different origin in

different plants it is necessary to study the development in each case,

and not apply to the generality what may be peculiar to one. In any case

this formation in question generally belongs more to general morphology

than to teratology.[551]

Kirschleger, however, has recorded the existence of a cirrhose sepal in

_Cucurbita Pepo_.[552]

FOOTNOTES:

[547] 'Consid. Org. Fleur.,' p. 44, pl. ii, fig. 23.

[548] 'Ann. Sc. Nat.,' 3 ser., Bot. ix, pl. 6, ff. 1, 2.

[549] 'Ann. Sc. Nat.,' 3 ser., Bot. 1855, pp. 297, et 303.

[550] 'Trans. Linn. Soc.,' xxii, p. 415.

[551] See Darwin, "On Climbing Plants," 'Journal of Linnean Society,'

vol. ix, p. 1.

[552] 'Flora,' 1845, p. 615.

GENERAL CONCLUSIONS.

At the end of many of the preceding sections, and whenever the

requirements of the case demanded it, a brief summary of the main facts

and of the inferences to be derived from them has been given. It may be

useful to give in conclusion a few general remarks on the whole subject.

It will be seen from the numerous facts herein cited, that the so-called

monstrous formations (excluding morbid growths the result of disease or

injury) present no peculiarities absolutely foreign to the normal

organisation of plants. The difference between the natural and monstrous

development is one of degree and frequency of occurrence, not of kind.

Deviations from the customary form have been shown to arise from

excessive or diminished growth, or from arrested or exalted development.

Even in those instances where, for convenience' sake, the term perverted

development has been used, it must be understood as applying only to the

particular plant or organ under consideration, as the form assumed is

perfectly in accordance with the ordinary conformation of some other

plant or group of plants.

The period at which malformations occur is a matter of some importance;

this is, indeed, implied in the term arrest of development; evolution

goes on with growth up to a certain point and is then stopped, and thus

changes are brought about in the part affected of a different nature

from those dependent on non-development or suppression.

Some malformations are congenital, therefore, while others are

acquired--in the former instance the disturbance is coeval in origin,

and contemporaneous in its growth and development, with those of the

affected part; in the latter case the organ may have attained its

ordinary degree of perfection, or at least may have advanced some way

towards it, before any deviation shows itself. True chorisis or fission,

for instance, is usually a congenital affection, arising at a very early

period of development, while enation takes place from structures which

are all but complete as to their organisation, even though they may not

have attained their full dimensions. The date of appearance is also of

consequence in determining the true nature of some changes; it does not

always follow, for instance, that because one organ occupies the

position of another, it is of the same nature as the one whose place it

fills. The presence of anthers on petals or on such organs as the corona

of _Narcissus_ does not necessarily constitute those parts actual

stamens, but rather staminodes. The true stamens are either wanting, or

if present, they are in advance of their imitators as regards their

development.

=General morphology of the leaf and axis. Homology.= Since the time when

Goethe's generalisations were adopted by A. P. De Caudolle, special

attention has been given to the form and mode of development of the

leaf-organ; for as it was well said by Wolff, if once the course of

evolution and the structure of the leaf were known, those of the parts

of the flower would follow as a matter of course.

It is not necessary, in this place, to pursue the subject of the

development and construction of the leaf further than they are

illustrated by ordinary teratological phenomena.

From this point of view perhaps the most interesting circumstance is the

part that the sheath of the leaf plays.[553] In many cases of so-called

metamorphosis, it is the sheath of the leaf that is represented and not

the blade. In normal anatomy the sepals, petals, carpels, and even the

stamens, as a general rule, correspond to the sheath rather than to the

blade of the leaf, as may be seen by the arrangement of the veins. The

blade of the leaf seems to be set apart for special respiratory and

absorbent offices, while the sheath is in structure, if not in office,

more akin to the stem. It would not be easy apart from their position to

distinguish between a tubular sheathing leaf and a hollow stem. The

development of adventitious growths by chorisis or enation has been

frequently alluded to in the foregoing pages, and many illustrations

have been given of the power that leaves have of branching in more than

one plane, owing to the projection of secondary growing-points from the

primary organ. These new centres of development are closely connected

with the fibro-vascular system of the leaf, so that no sooner does a new

growing point originate, than vessels are formed to connect the new

growth with the general fibrous cord, see pp. 355, 445. This leads M.

Casimir De Candollo to consider the entire leaf as a composite

structure. The morphological unit, says he, is the cellular protrusion

or growing point (_saillie_) and its corresponding fibro-vascular

bundle.[554]

The identity, in a morphological point of view, of the leaves and the

lateral parts of the flower is so thoroughly recognised that little

need be said on that score, save to repeat that the homology of the

floral organs is usually not so much with the entire leaf as with its

sheath.

The most singular instances of morphological identity are those relating

to the sexual organs. We have seen the gradual transition of stamens to

pistils, and of pistils to stamens, the development of ovules on the

edges of the anther, the co-existence of pollen with ovules on an

antheroid body, and, stranger still, the actual development of pollen

within the tissues of the ovule itself! From such facts, in addition to

what we know of the relative position, internal structure, and mode of

development of the organs, it is impossible to avoid coming to the

conclusion that, however distinctly these parts may, under ordinary

circumstances, be set apart for the performance of distinct functions,

morphologically they are homologous.

These ideas may be carried yet farther--the same sort of evidence, which

is adduced in support of the morphological identity of leaves with the

parts of the flower, may be advanced in confirmation of the opinion,

that, morphologically, there is no distinction between axis and leaf.

The leaf, according to this view, is a specialised portion of the axis

set apart to do certain work, just as the petals, stamens, &c., are

leaves told off for distinct uses. It is unnecessary to refer to the

intermediate productions linking the leaf-form to that of the axis, all

that is requisite here is to point out the facts that teratology lends

in support of these views. These may be summed up by the statement that

almost all those attributes which morphologists recognise as peculiar to

one or the other organ respectively, may be and are manifested by both.

We have the stem acquiring the characters of the leaf, and the leaf

those of the stem. Thus we have seen leaves, leaf-buds, branches, and

flower-buds springing from leaves or leaf-organs;[555] see pp. 174, 177,

445, &c. The structure that we are apt to associate exclusively with

one is found to pertain to the other. The arrangement of the vascular

cords in the leaf-organ finds its counterpart in the axis, generally, it

is true, modified to suit altered circumstances or diverse purposes. In

some cases the disposition is absolutely indistinguishable in the two

organs. It may then be said that the distinctions usually drawn between

axis and leaf are not absolute, and that, however necessary such a

separation may be for descriptive or physiological purposes,

morphologically the two organs are identical. Again, it may be said that

leaf and axis are two phases of the same organ,--an organ capable of

existing in its undifferentiated state in the form of a thallus among

Cryptogams, but which in the higher groups of plants becomes marked out

into separate portions, each portion having its own distinct functions

to fulfil for the common benefit of the whole organisation.[556]

=Special morphology.=--Under this heading brief reference may be made to

some of the organs whose morphological nature has been, and still is,

much contested. It is clear that for the due elucidation of these

matters, development and the comparative investigation of similar

structures in different plants must be studied. Teratological data by

themselves can no more be trusted to give a correct solution of any

particular question, than the evidence furnished by other departments of

botanical science taken separately. With this statement by way of

caution, allusion may be made to some of the organs whose morphological

construction is illustrated by the facts recorded in the present

volume.

=Calyx-tube.=--In descriptive botany it is the common practice to speak

of a calyx-tube, by which is meant a tubular or sheathing portion at the

base of the flower, below the sepals or calyx-lobes, and distinct or

inseparable from the ovary. The question morphology has to solve is

whether this tubular structure is to be considered as a portion of the

axis, or whether it is to be regarded as composed of the confluent bases

of the sepals.

Mr. Bentham, who has recently reviewed the evidence as to the nature of

the calyx-tube in his paper on _Myrtaceae_,[557] still holds to the

notion that the "calyx-tube" or "hypanthium" is formed from the

concretion of the basal portions of the sepals. He founds his

conclusions upon such facts as the following: the circumstance that the

point of origin of the leaf is not always the same as the point of

disarticulation or separation from the axis, inasmuch as the basal

portion of the leaf is often adherent to the stem for some distance,

though still recognisable as foliar not axial in its nature. In the same

manner, the corolla and androecium may be concrete at the base, so

that the stamens are for convenience' sake described as inserted into

the tube of the corolla, though it is generally admitted that both

stamens and petals are really hypogynous, and it is not usual to

consider the corolla-tube up to the divergence of the stamens as part of

the receptacle. A similar remark applies to the carpels and placentas.

Mr. Bentham further considers that the gradual disconnection of the

various whorls, that may be traced in many plants, is a further proof of

concretion, rather than of expansion of the axis, but this argument may

fairly be met by the consideration that the several whorls emerge at

different heights.[558]

Organs originally free and distinct become ultimately combined at the

base by the gradual protrusion from the receptacle of a ring or tube

under them, as in the stamens of _Leguminosae_; yet, says Mr. Bentham, no

one would propose to describe the staminal tube of monadelphous

_Leguminosae_ as part of the receptacle and not of the stamens. Perhaps

not, for descriptive purposes, but morphologically it would not be easy

to separate such a tube from the receptacle. The principal kinds of

malformation which have a bearing on this subject are mentioned at pp.

77-81 and 247, from which it may be seen that the evidence furnished by

teratology is conflicting. It would seem, indeed, that while in some

families of plants there may be a real calyx-tube, in others the tubular

portion is a sheath-like prolongation of the axis. In _Primula_ or

_Pedicularis_, where the venation is clearly laminar, the tubular

portion is distinctly calycine. In other cases the so-called calyx-tube

seems as certainly to be an expansion of the receptacle, as in

_Rosaceae_, _Myrtaceae_, _Melastomaceae_, _Passiflora_,[559] &c.

Where the petals and stamens are described as being inserted into the

throat of the calyx, or are perigynous, it may be assumed as a general

rule, subject to but few exceptions, that the so-called calyx-tube is

really a portion of the receptacle.[560] After all, this is very much a

question of words, and for the following reasons,--very often the base

of the calyx does evidently form a tube, and no one can say where the

calyx ends and the receptacle begins. Again, many leaves are known to

originate in the form of a ring-like protrusion from the axis, and from

this primary ring originate secondary developments. Thus the asserted

difference between a leaf, with such a history of development, and an

axial structure becomes obliterated. From this point of view, peltate

leaves like those of _Tropaeolum_ or _Nelumbium_ become very significant.

In both the leaf-stalk is cylindrical and traversed, as in the case of

all cylindrical leaf-stalks, by a circle of fibro-vascular cords, as in

a branch, and which radiate in all directions in the blade of the leaf.

Now, if (as often happens to a slight extent) the central portion of the

leaf were much depressed, owing to the disproportionate growth of the

peripheral, as contrasted with the central portions, we should have a

funnel-like or tubular formation, precisely similar to many of the

so-called calyx-tubes. And, if we further suppose new growths to

originate from the sides of this funnel or tube, by chorisis or enation,

we should have the homologue of a tubular calyx, to the inner surface of

which are attached petals, stamens, &c. From the consideration of

circumstances such as these just detailed, together with that of the

arrangement of the vascular cords, M. Casimir De Candolle arrives at the

conclusion that the calyx-tube is a ring-like projection from an axis

whose further direct development is arrested. The secondary projections

or growing-points correspond to the several fibro-vascular cords of the

primary ring, and are ultimately developed into sepals, petals, stamens

and ovaries (see pp. 394, 509).

=Androecium.=--The main points of morphological interest relating to

the androecium, referred to in this volume, are those concerning the

structure of the anther (see p. 292), the compound nature of the stamens

in some orders (see pp. 294, 345), and the nature of the androecium in

orchids (see p. 380).

=Inferior ovary.=--Is the pistil always foliar in its morphological

nature, or is it, in some cases, as Schleiden taught, formed from the

axis alone? To a great extent the reply to this question is dependent on

the conclusions that may be arrived at as to the true nature of the

calyx-tube. Considered from a teratological point of view, there is no

reason for considering the inferior ovary to be purely axial. On the

contrary, the evidence derived from this source supports the ordinary

opinion that the carpels are invaginated within the expanded top of the

flower-stalk and more or less adherent to it. Some of the gourds afford

good illustrations of this, the upper part of the carpels in these

fruits projecting beyond the axial portion. But this matter loses much

of its importance if the morphological identity of axis and leaf-organ

be conceded. The carpels in inferior ovaries seldom or never correspond

to the lamina of the leaf, and between the vaginal portion of the

carpellary leaf, and the axis who shall draw the distinction?

=Placentation.=--Some botanists have considered the placentas to be

portions of the carpel, and have compared the production of ovules on

them to the formation of buds on the leaf of _Bryophyllum_. Others have

been led to see in each placenta, even when it is, to all outward

appearance, a portion of the carpellary leaf, a direct prolongation from

the axis, adherent to the leaf. Teratology shows that ovules may be

formed indifferently on leaf-organs or on stem-organs. Sutural,

parietal, axile, free-central placentation, and, if there be more forms,

all may be met with even in the same ovary (see pp. 96, 508). Now, if

there were such special tendencies in the axis, as contrasted with the

leaf, to produce ovules, it is hardly likely that such anomalous

arrangements as those just mentioned would be as frequent as they are.

But as leaves produce other leaves, from their edges or their surfaces,

and as they form buds in the same situations, just as axial organs

do,[561] there is surely little ground for considering the placentas, or

ovuliferous portions of the plant, to be of necessity axial. Here again,

much of the difficulty vanishes if the morphological identity of the

leaf-form and of the stem-form be admitted.

=Structure of the ovule.=--The nature of the ovule and of its coverings

has been a fertile source of controversy. The teratological data bearing

on this subject have been given at pp. 262-272. These data strongly

support the notion of the foliar nature of the coatings, and of the

axial nature of the nucleus, taking leaf and axis either in the ordinary

sense, or as modifications one of the other. It has been shown that the

ovular coats may themselves become carpels, and that ovules may be

developed upon ovules, p. 268. Whether the intra-carpellary siliques of

_Cheiranthus_, not uncommonly met with (p. 182), are instances of ovular

transmutation may be open to doubt.

The axial nature of the nucleus has been inferred from its position,

mode of growth, and from its occasionally lengthening into a leafy or

even a floriferous shoot. Probably it may occasionally be invested by

sheathing coats, more analogous to tubular processes from the

receptacle, than to foliar organs, as is the case in _Welwitschia_. The

discussion of this matter, however, pertains rather to normal morphology

than to teratology.

=Morphology of conifers.=--The nature of the pseudo-leaves of

_Sciadopitys_, and probably of other Conifers, is illustrated by

teratology, as also is the true constitution of the scale of the cone

(see pp. 192, 245, 352), though it must be admitted that little or no

light is thrown on that much-contested point--the true nature of the

ovule of Gymnosperms.

=Relative position of organs.=--When organs are considered, not

separately, but in their relations to each other, the appearances

presented are referable to similar causes. Thus, the separation of parts

usually united has been shown to depend on an excess of development,

the persistent union of parts, usually separate in the adult state, has

been traced to an arrest of the process of development, by no means

necessarily coexistent with diminished growth. The diminished or

increased number of parts is, in like manner, attributable to analogous

causes, as also are the variations in arrangement and form, spoken of

under the heads of Displacement, Peloria, Substitution, &c.

In the instance of displacements, it has been shown how slight a change

is required to transform the so-called inferior ovary into a superior

one. A defective development of the top of the flower-stalk in some

cases, in others a lack of union between the tube of the receptacle or

of the calyx (comprising in those terms not only the apex of the

receptacle, but the base of the sepals) and the carpels, suffice to

bring about this change in a character which for systematic purposes is

of great value.

=Law of alternation.=--The circumstances that interfere with the law of

alternation may be briefly alluded to. The deviations from the customary

arrangement have been very generally attributed to suppression, or to

chorisis. It is unquestionable that either of these affords an efficient

explanation of the arrangement in question, as also does that

modification of chorisis, as it may be considered, which has been

treated of under the head of Enation. Spiral torsion of the axis would

likewise bring about analogous results. Still, it is quite conceivable

that opposition or superposition of organs may occur without the

intervention of any such operations. This will be the more readily

conceded when it is remembered that the phyllotaxis of leaves not

unfrequently varies on different branches of the same individual tree,

and that a similar variation in the flower would at once disturb the

customary alternate arrangement. Coalescence of the vascular bundles in

an unusual manner, and an irregular disposition of these cords have

also been considered to bring about deviations from the rule of

alternation, but in general the formation of the cords is subsequent to

that of the growing points or mamelons.

Adhesions, accompanied by displacements, occasionally produce similar

deviations, the nature of which is usually easily detected.

=Co-relation.=--The importance of this subject first prominently brought

into notice by Geoffroy St. Hilaire gains in force daily. Rarely is a

malformation an isolated phenomenon, almost always it is associated,

from the operations of cause or effect, with some others. Instances of

this co-relation have been cited in the preceding pages, and many more

might have been mentioned, had the consideration of the relationship

between form and function formed part of the plan of this volume. A

change in itself slight, often acquires importance from its association

with other alterations. This is particularly well seen in the case of

the receptacle. Let an ordinarily concave thalamus remain, from

defective development, flat, and how great the change in the appearance

of the flower. Let the usually contracted receptacle be lengthened, and

the whole aspect of the flowers so affected is altered to such an extent

that, were their history not known, botanists would have no hesitation

in assigning them to widely separate groups in their schemes of

classification. Peloria, too, of either form, affords excellent

illustrations of the co-existence of one changed condition with another.

Not only is the form of one set of organs altered, but the number, the

relative proportion, and the direction of the other organs of the flower

are altered likewise.[562] Not only is the whole symmetry changed, but

the physiological operations carried on in the flower undergo

corresponding alterations.

There are certain co-relations which do not appear to have hitherto

attracted the attention they merit; such, for instance, is that which

exists between the particular period at which an organ is developed and

its position and form. In normal morphology this has, to some extent,

been worked out, as in the case of definite and indefinite, centrifugal

and centripetal inflorescences, and in the definite or indefinite

formation of shoots, &c.

Other instances may be cited in the frequent co-existence of regular

flowers and definite inflorescence, the terminal position of many

peloriated flowers, the relationship between indefinite inflorescence

and prolongation of the axis, &c.

Again, the simultaneous evolution of the parts of the flower and their

consequent verticillate arrangement, are often associated with the

production of different forms from those characteristic of organs

developed in succession, and, in consequence, arranged spirally. In the

case of simultaneous development we meet with a repetition of whorls,

as in what are termed hose-in-hose flowers (flores duplicati,

triplicati, &c.), and also with cases of peloria. In instances where the

organs are formed successively in spiral order, we meet with such

changes as median prolification, petalody, and phyllody. All these are

alterations which we might anticipate from the activity of the growing

point being checked at a certain stage in the one case, while it is

continuous in the other. This relationship between the definite and

indefinite modes of growth and the form of the several organs of the

flower, is more constant in reality than it may appear to be from a

perusal of the lists of genera in the foregoing pages, in which it was

not possible to show sufficiently well the comparative frequency of any

given changes in individual plants. Had it been possible to give

statistics setting forth the frequency of certain deviations in plants

or groups having a particular organisation, as compared with the rarity

of their occurrence in other plants of a different conformation, these

co-relationships would have been rendered much more evident. A hundred

different plants, for instance, may be named in any particular list, of

which fifty shall be of one type of structure, and the remainder of

another. And the co-relative changes in each fifty may appear to be

evenly balanced, but so far is this from being the case, that the

frequency of the occurrence of a particular change, in one species in

the list, may be so great as far to exceed the instances of its

manifestation in all the rest put together. This difficulty is only very

partially obviated by the addition of the * to signify especial

frequency of occurrence of any given malformation in the plants to whose

names it is affixed.

=Compensation.=--But little further need be said on this head. An

atrophied condition of one part is generally associated with an

hypertrophied condition of another, and scarcely a change takes place in

one direction, but it is associated with an inverse alteration in some

other. This principle is not universal, and its application must not be

unduly strained. It requires specially to be considered in reference to

differences in the degree or kind of functional activity exercised by

the organs implicated--points beyond the scope of the present volume.

=Teratology and classification.=--Lastly, there remain to be mentioned

the bearings of teratology on systematic botany. There are those who

would entirely exclude teratology from such matters. It may be expedient

to do so when the object sought is one of convenience and facility of

determination only, but when broader considerations are concerned,

teratology must no more be banished than variation. In most instances

the one differs but in degree from the other. If variation affords aid

in our speculations as to the affinities and genealogical descent of

species and other groups, so does teratology, and in a far higher

degree.

Take the characters of exogens as distinct from endogens; even under

ordinary circumstances, no absolute distinction can be drawn between

them. There are plants normally of an intermediate character, while, to

take exceptional instances, there are exogens with the leaves and

flowers of endogens, and endogens whose outward organisation, at any

rate, assimilates them to exogens. Diclinous or monochlamydeous plants

owe their imperfect conformation to suppression, and may become

structurally complete by a species of peloria. Structurally

hermaphrodite flowers become unisexual by suppression, or are rendered

incomplete by the non-development of one or more of their floral whorls.

Hypogynous flowers become perigynous by adhesion, or by lack of

separation; perigynous ones become hypogynous by an early detachment

from the receptacle that bears them, or by the arrested development of

an ordinarily cup-like receptacle.

How the relative position of the carpels and the calyx may be altered

has already been alluded to, as has also the circumstance that while it

is common to find an habitually inferior or adherent ovary becoming

superior or free, it is much more rare to find the superior ovary

adherent to the receptacle or to the calyx.[563] Regular and irregular

peloria, too, serve to show how slight are the boundaries, not only

between different genera, but also between different families.

While, therefore, teratology may be an unsafe guide in strictly

artificial schemes, it is obvious that its teachings should have great

weight in all philosophical systems of classification.

The questions will constantly arise, does such and such a form represent

the ancestral condition of certain plants? Is it a reversion to that

form? or is it, on the other hand, the starting point of new forms?

Such questions cannot receive at present any satisfactory answer, but

the evidence we have seems to indicate that pre-existing forms were

simpler, and less specialised in structure than those now existing, and

hence if we meet with malformations of a simple kind, we may consider

them as possible reversions; while, if they present features of

increased complexity, and more sharply defined differentiation, we may

assume them to be evidences of a progressive rather than of a

retrogressive tendency.

That monstrosities so called may become the starting points of new forms

is proved by circumstance that, in many cases, the peculiarities are

inherited so that a new "race" is produced and perpetuated: and if a new

race, why not a new species? The difference is one of degree only.

FOOTNOTES:

[553] See Clos., 'Bull. Soc. Bot. Fr.,' 1856, vol. iii, p. 679.

[554] 'Theorie de la Feuille,' p. 26.

[555] An additional illustration of this may be cited, which has been

brought under the notice of the writer by Dr. Welwitsch recently, and in

which some of the leaflets of the pinnate leaf of a species of

_Macrolobium_ were absent, and their place supplied by flowers arranged

in cymes.

[556] The presence of a bud at the extremity once considered to be an

absolute distinction between branch and leaf, which latter never forms a

bud exactly at the apex--is invalidated by the case of the Nepaul

barley, p. 174.

[557] 'Journ. Linn. Soc.,' vol. x, p. 103 _et seq._

[558] See also the receptacular tube (ovary?) of _Baeckea_ bearing

stamens, see p. 183. It would be natural to see stamens springing from

the receptacle but not from the ovary.

[559] In _Passiflora_ the organogeny of the flower clearly shows the

truth of this assertion, as was indeed shown by Payer and Schleiden.

[560] See Payer, 'Organ. Veget.'

[561] It must, however, be borne in mind that no true leaf-organ has yet

been seen with a bud at its exact apex (unless it be the nepaul barley),

while in the case of an axial organ such a position of the bud is

constant. The nearest approach is in the case of impari-pinnate leaves

in which the terminal leaflet is jointed to the common rachis, and in

the leaves of some _Meliaceae_ which continue to push forth new leaflets

even after the leaf has attained maturity.

[562] A singular instance of co-relation was shown by Mr. Saunders at

the Scientific Committee of the Royal Horticultural Society, February

16th, 1868, in a hyacinth with perfectly green, long, tubular, erect,

not horizontally spreading flowers.

[563] An illustration of this latter nature in the case of a cherry,

which was surmounted by the calyx lobes, precisely as in the case of a

pomaceous fruit, has been given at p. 424, _adnot._

APPENDIX

DOUBLE FLOWERS.[564]

In ordinary language, the epithet double flowers is applied to flowers

of very varied structural conformation. The most common conditions

rendering a flower double, in the popular acceptation of the term, are

substitutions of petals or petal-like bodies for stamens and pistils,

one or both. (See Petalody, p. 283.) Another very common mode of

doubling is brought about by a real or apparent augmentation in the

number of petals, as by multiplication, fission, or chorisis. (See pp.

66, 343, 371, 376.) Sometimes even the receptacle of the flower within

the outer corolla, divides, each subdivision becoming the centre of a

new series of petals, as in some very luxuriant camellias and anemones.

The isolation of organs which, under ordinary circumstances, are united

together, is another circumstance, giving rise, in popular parlance, to

the use of the term double flower. (See Adesmy, Solution, pp. 58, 76,

82.) Prolification is another very frequent occurrence in the case of

these flowers, while still other forms arise from laciniation of the

petals, or from the formation of excrescences from the petals or

stamens, in the form of supplementary petal-like lobes. (See Enation, p.

443.)

As these matters are all treated of under their respective headings, it

is not necessary to allude to them again in detail. It may be well,

however, to allude, in general terms, to the causes which have been

assigned by various writers for their formation, and to the means which

have been adopted by practical experimenters to secure the production of

the flowers often so much esteemed by the florist. It must be admitted

that, in spite of all that has been written on the subject, but very

little is known about these matters. In the case of the stock the

following means have been adopted by cultivators in order to obtain

plants bearing double instead of single flowers. There is first the

crossing of single flowers with double ones, effected by planting a

double-flowered plant in proximity to a single-flowered one; but this,

it is obvious, could lead to no important results, since the double

flowers, having no pollen, could not possibly influence the seed, which

is borne only by the single-flowered plants. Another plan is the

degustation of the buds, that is to say, the chewing of the well-formed

buds; it is held that the single plants can be recognised by their

sweeter taste and greater consistence, and may thus be weeded out; but

there is at least the disadvantage attending this method, that the

plants, single as well as double, must all be grown up to the period

when these buds are tolerably well advanced. A third method which has

been adopted is, that of sowing the seeds at a particular lunar epoch,

great confidence being placed in the plan of planting them during the

last quarter of the moon, but such confidence is found to be misplaced.

The plan of removing the stamens has had its supporters, but as this

must be done at an early stage of development, and could only influence

the result by diverting the vital force which would be expended in the

maturation of the pollen, to the perfecting of the seeds, it is obvious

that the plan is impracticable for all ordinary purposes, even if in any

degree efficient, which from the plasticity of vegetable development,

and the faculty of doubling which is inherent in the stock family, is

not at all improbable. Still another mark, the presence of a fifth petal

in the single or seed-bearing flower, has been held to indicate the

assurance of obtaining a crop of double-flowered plants from seeds saved

from flowers possessing this peculiarity. To a certain extent,

doubtless, this expectation would be realised, owing to the plasticity

and inherent quality just alluded to, but the proportion would be too

small for any useful practical purpose.

"The gardeners of Erfurt," observes M. Chate, who has written a

book[565] on the subject, in which he makes known a means of obtaining

double-flowered stocks founded on more than fifty years' practice in his

family, "have, for a long time, to a certain extent monopolised the sale

of seeds of these plants. To obtain these seeds, the Erfurt gardeners

cultivate the flowers in pots, and place them on shelves in large

greenhouses, giving them only sufficient water to prevent them from

dying. So cultivated the plants become weakened, the pods shortened, and

the seeds less numerous, and better ripened; and these seeds give from

60 to 70 per cent. of double flowers.

"The seeds from these plants are said to be mostly of an abnormal shape,

which is so striking that experienced cultivators are able to separate

those which would furnish double flowers from those which would produce

single ones."

M. Chate's method, which he calls the French one, gives still greater

results, viz.: 80 per cent. of double flowers, and these produced by

very simple means. "When my seeds," he observes, "have been chosen with

care, I plant them, in the month of April, in good dry mould, in a

position exposed to the morning sun, this position being the most

favourable. At the time of flowering I nip off some of the flowering

branches, and leave only ten or twelve pods on the secondary branches,

taking care to remove all the small weak branches which shoot at this

time. I leave none but the principal and the secondary branches to bear

the pods. All the sap is employed in nourishing the seeds thus borne,

which give a result of 80 per cent. of double flowers. The pods under

this management are thicker, and their maturation is more perfect. At

the time of extracting the seeds the upper portion of the pod is

separated and placed aside, because it has been ascertained that the

plants coming from the seeds situated in this portion of the pod, give

80 per cent. of single flowers. They yield, however, greater variety

than the others. This plan of suppressing that part of the pod which

yields single flowers in the largest proportion, greatly facilitates the

recognition of the single-flowered plants, because there remains to be

eliminated from among the seedlings only from 10 to 15 per cent.

This separation of the single from the double-flowered plants, M. Chate

tells us is not so difficult as might be supposed. The single stocks, he

explains, have deep green leaves (glabrous in certain species), rounded

at the top, the heart being in the form of a shuttlecock, and the plant

stout and thickset in its general aspect, while the plants yielding

double flowers have very long leaves of a light green colour, hairy, and

curled at the edges, the heart consisting of whitish leaves, curved so

that they enclose it completely. Such is the substance of M. Chate's

method of securing so large a proportion of double-flowered plants, and

then of separating them from the remaining single ones--a method which

commends itself to the good sense of the intelligent cultivator."[566]

Signor Rigamonti, a great cultivator of pinks, asserted that he was able

to distinguish double from single-flowered pinks, in the seedling state.

According to this gentleman, those seedlings which produce three

cotyledons in a whorl in place of two, form double flowers. In the case

of _Primula sinensis_ the same results occurred. Some had three leaves

in a ring, others two; most had the leaves standing one over the other

as usual. These were divided into three sets, and when they flowered,

the first lot were all double, the second semi-double, the third single.

But these statements have not been confirmed by other observers; and the

writer can safely assert that seedling pinks occasionally produce three

cotyledons, and subsequently single flowers. He has never observed a

double flower under these circumstances, though it is true his

experience in this matter has been but small.

A writer in Otto's 'Gartenzeitung,' considers that double flowers are a

consequence of dryness of soil and atmosphere, and not of a luxurious

soil, rich in nutritious matter, having arrived at this conclusion from

an observation of the following circumstances:

"Fifty years ago we saw _Kerria japonica_ in a hothouse with single

flowers. Twenty years later we met with it in several gardens, in the

open air, but always with double flowers. At this time we were assured

that single-flowered plants were no more to be found in the whole of

Europe, and botanists forming herbaria offered considerable sums for a

branch of _K. japonica_ with single flowers. We were requested to take

the plant in hand for the purpose of inducing it to produce single

flowers. We were advised to plant it out in a rich soil, which was done,

but, by chance, the situation was sloping, consequently it did not

retain moisture, and all the flowers produced for several years in

succession were double. Shortly after, the captain of an English ship

again brought plants bearing normal flowers from Japan, which were soon

spread over the continent, and of which we received one plant. After

three years all the young plants raised from cuttings were

double-flowered.

"In the year 1820 we several times visited a garden in the neighbourhood

of Vienna, well known on account of its plant culture. The gardener

there possessed an immense plant of _Camellia japonica_ with single

flowers, and some small plants raised from this by cuttings, but no

other variety of camellia. He fertilised the flowers with their own

pollen, harvested seeds, which he sowed, and the plants raised from them

were placed in an extremely dry, lofty conservatory, where, after some

years, instead of producing single flowers, they all produced double

ones. The seedlings and mother plant were planted in one and the same

kind of earth, and some of the flowers on the old plant also showed an

inclination to become double.

"This, at that time, to us, enigmatical phenomenon, was kept in mind

until we had an opportunity of instituting comparisons between the

climate of Japan and China and our own, and we then concluded that in

the case of a plant imported from thence, and exposed to such different

climatical influences, the origin of the greater or less imperfection of

its sexual organs was probably owing to this change, as we had

experienced in _Kerria_ and _Camellia_; and that the sterility of many

other exotic plants might be attributed to the same cause. The

difference in the climatical relations of Japan and Europe is very

considerable. In Japan, previous to the new growth of _Kerria_ and

_Camellia_, a rainy season of three months' duration prevails; in

Europe, on the contrary, dry winds prevail especially in the eastern

part, where our plains are often transformed into deserts. Is it,

therefore, remarkable that a plant introduced from Japan into Europe,

exposed to the influences of this great diversity of climate, should

produce imperfect sexual organs incapable of further propagating the

plant from seeds? A rich soil, with the necessary amount of moisture,

will never engender double flowers."[567]

Mr. Darwin[568] describes a peculiar form of _Gentiana Amarella_, in

which the parts of the flower were more or less replaced by compact

aggregations of purple scales in great numbers. A similar condition is,

indeed, not uncommon in this plant, and, as Mr. Darwin also remarked, on

hard, dry, bare, chalky banks, thus bearing out the views expressed by

the writer in the 'Gartenzeitung' just cited. Some double flowers of

_Potentilla reptans_ found growing wild near York, and transmitted to

the writer by a correspondent, were observed growing along a high wall,

in a dry border, close to a beaten path, bordering on a gravel pit,

others were found on a raised bank, which, from its elevation and

exposure to the sun, was particularly dry.

On the other hand, the double-flowered _Cardamine pratensis_, which is

occasionally found in a wild state, always grows in very wet places.

Of late years a remarkable double-flowered race of _Primula sinensis_

has been obtained. In particular, Messrs. Windebank and Kingsbury, of

Southampton, have succeeded in raising a set of plants in which the

flowers are very double and very attractive in a florist's point of

view. The corollas in these flowers are not merely duplicated, but from

their inner surface spring, in some cases, funnel-shaped or tubular

petals (p. 315), so regular in form as quite to resemble a perfect

corolla. These tubes are attached to the inner side of the tube of the

corolla, in the same way as are the stamens, these latter organs being,

it appears, absent. The carpels are present, but open at the top, and

bear numerous ovules, hence it was at first surmised that these plants

were obtained and perpetuated, by the application of pollen from single

flowers to these double-flowered varieties.

The raisers of this fine race however assert that "the double kinds are

all raised from the seed obtained from _single_ flowers; the double

blooms do not produce seed, as a rule, and even if they did yield seed,

and it were to germinate, the plants so raised would simply produce

single flowers." Semi-double flowers will produce seed, but it is

necessary that they should be fertilised with the pollen from the single

blooms. They rarely, however, if ever, produce really double flowers

when so fertilised, and the number of semi-double flowers, even, is

always small, the remainder, and, consequently, the larger part, proving

single. To obtain double varieties, the raiser fertilises certain fine

and striking single flowers, with the pollen of other equally fine

single blooms, and the desired result is obtained. This is Messrs.

Windebank and Kingsbury's _modus operandi_, the exact process or mode of

accomplishment being, however, a professional secret.[569]

From what has been said, as well as from other evidence which it is not

necessary to detail in this place, it may be seen that the causes

assigned by physiologists, and the plans proposed by cultivators for the

production of double flowers, are reducible to three heads, which may be

classed under Plethora, Starvation, and Sterility. These three seem

inconsistent one with the other, but are not so much so as they at first

sight appear to be.

Tho advocates of the plethora theory have much in their favour: for

instance, the greater frequency of double flowers among cultivated

plants than among wild ones. The great preponderance of double flowers

in plants derived from the northern hemisphere, when contrasted with

those procured from the southern, as alluded to by Dr. Seemann, seems

also to point to the effect of cultivation in producing these flowers.

Now, although this is, to a large extent, due to the selection that has

been for so long a period practised by gardeners, still that process

will not account for the appearance of double flowers where no such

selection has been exercised; as in the case of wild plants. Some double

peas, observed by Mr. Laxton, appeared suddenly; they had not been

selected or sought for, but they were produced, as it would appear, as a

result of high cultivation, and during the period when the plant was in

greatest vigour; and as the energies of the plant failed, so the

tendency to produce double flowers ceased. Indeed, in reference to this

subject, it is always important to bear in mind the time at which double

flowers are produced; thus, an annual plant subjected to cultivation,

will, it may be, produce single flowers for the firet year or two, then

a few partially double flowers are formed, and from these, by careful

selection and breeding, a double-flowered race may be secured.

Sometimes, as in the peas before alluded to, in the same season the

earlier blossoms are single, while later in the year double blossoms are

produced. This happens, not only in annuals, but also in perennials, and

is not infrequent in the apple; an illustration of this occurrence in

this tree is given in the 'Gardeners' Chronicle' for 1865, p. 554.[570]

Sometimes the flowers on a particular branch are double, while those on

the rest of the plant are single.[571] On these points, the evidence

furnished by a double white hawthorn in the Royal Botanic Gardens at

Edinburgh is important. Professor Balfour kindly wrote as follows in

reply to an inquiry respecting this plant:--"A double white hawthorn in

the Royal Botanic Gardens produced double flowers in spring. It retained

its leaves during autumn and winter, until the following spring. It then

flowered in the second spring, but produced weak single flowers only,

and has continued to do so ever since. The flowering has been always

weak, since this change of flowers from double to single. Mr. M'Nab

attributes the change in the duration of the leaves to the filling up of

the ground round the tree, to the height of a foot and a half on the

stem. He is now trying the effect of extra manure in giving extra vigour

to the plant." Here, at least, the production of single flowers would

seem to be the result of debilitating causes, connected with the unusual

persistence of the leaves, &c., for while the tree was healthy, double

flowers were produced.

A similar illustration came under the writer's own notice. Some seedling

balsams, of a strain which from long selection and hereditary tendency

produces, year after year, double flowers were, in the spring (of 1866),

allowed to remain in the seed-pans for many weeks after they were ready

to be potted off; they were hence partly starved, and when they bloomed,

they produced single flowers only. But these same plants, when more

liberally treated, produced an abundance of double flowers. Moreover,

other seedlings of the same batch, but sown later, and potted off at the

usual time, produced double flowers as usual. Of a like character is the

fact that the double _Ranunculus asiaticus_ loses its doubleness if the

roots are planted in a poor soil.

On the other hand, the way in which double stocks are stated to be

produced at Erfurt, viz.: by giving the plants a minimum supply of

water, and the other circumstances alluded to as showing the connection

between the production of double flowers, and a deficiency of water, as

well as the experiments of Mr. Monro, go to show that, so far from

plethora, the inducing cause must be more nearly allied to inanition,

though the impoverishing process is, to a certain extent, counteracted

by only allowing a few of the seed-pods to ripen, and thus concentrating

in a small number of flowers the nutriment intended for many.

Professor Edward Morren ('Bull. Acad. Roy. Belg.,' 2me ser., vol. xix,

p. 224) considers the existence of true variegation in leaves, and the

production of double flowers, as antagonistic one to the other; the

former is a sign of weakness, the latter of strength. But it would seem

that the exceptions are so numerous--so many cases of the co-existence

of variegated leaves, and double flowers are known, at least in

individual plants if not in species--that no safe inferences can be

drawn as to this point. Since the above remarks were printed, Professor

Morren has published a second paper on the subject, upholding his former

views as to the incompatibility of variegated foliage (not mere

colouration) and double flowers. In this paper he criticises the

objections raised by the present writer and others, and examines some

of the alleged exceptions. Some of these the Belgian savant finds to

prove his rule, inasmuch as although there is a co-existence of

variegated foliage and double flowers in these illustrations, yet the

plants are weakly, the flowers ill formed, or fall off before expansion.

Admitting all this, there still remain cases in which double flowers and

variegated foliage do exist in conjunction, and where the plants are

vigorous and the flowers well developed. Instances of this are known to

cultivators in species of _Dianthus_, _Hemerocallis_, _Althaea_,

_Paeonia_, _Rosa_, _Ranunculus_, _Serissa_, _Saponaria_, etc., and

probably the art of the cultivator would speedily be successful in

raising other examples, were it a matter of importance or interest to

them to do so. At any rate, the existence of a few unimpeachable

illustrations is sufficient to support the opinion of the present

writer, and objected to so strongly by M. Morren that, in the present

state of our knowledge, "no safe inferences can be drawn" from the facts

alluded to by the Belgian professor.[572]

Mr. Darwin[573] has thrown out the suggestion that the cause for the

appearance of double flowers may be sought for in some previous state of

things, bringing about sterility or imperfect formation, or functional

activity of the genitalia of the flower, and consequent compensatory

increase of the petaline element, either in the form of an increased

number of bracts, petals, &c., or in the substitution of petals for

stamens and pistils, &c.

In considering these points the question arises whether they can be

reconciled one with another. And there is little doubt but that they may

be. The production of a flower is preceded by an arrest of vegetation;

this is obvious: the current of the plant's life becomes changed, the

growth of the leaves is checked, the lengthening of the branches is

arrested as the flower-bud forms; moreover, there is a close

relationship in a large majority of flowers between the outer envelopes

of the flower and the scales of a leaf-bud; this is especially so in

regard to the venation, and is admitted by all morphologists. So far,

then, it may be said that the production of a flower, like that of a

bud, is due to a diminution of vegetative action; and as in double

flowers we have, for the most part, merely a repetition and exuberant

formation of floral envelopes, so we may attribute their formation to a

continuance of the same feeble vegetative action as that which produced

the first or normal series. How, then, can a copious supply of rich

food, such as is provided by cultivation, produce double flowers? To

this question, according to our theory, the reply would be that the

quantity of food is excessive, more than the plant can properly digest;

and hence vegetative action is stopped, at least partially--pretty much

as it would be if the plant were placed in the opposite condition of

starvation. The effect of supplying a plant (or an animal) with an

excessive supply of food, which it cannot assimilate, is in many

respects similar to that which results from partially cutting off the

supplies. And the same reasoning applies to sterility. If by high

culture, or the supply of an undue quantity of nourishment, the

constitution of the plant be impaired, or if the plant be pampered, it

is no wonderful thing that sterility should ensue. Hence, then, may it

not be asserted as a general principle that in the production of double

flowers a partial arrest of development, if not of growth, however

produced, is an essential preliminary? All the attendant phenomena, such

as the obliteration of the stamens, the augmentation in the number of

floral whorls, the occurrence of prolification, are consistent with the

supposition of a primary arrest of development, more or less complete,

as the case may be: at one time permanent, at another time relaxed and

intermittent, or in a third set of cases the vegetative activity or

power of growth may be restored, and from the centre of the flower may

spring a perfect branch with perfect leaves, the production of sheaths

only being superseded by the development of leaves, in which all the

parts--sheath, stalk, and blade--are present.

When once the disposition to form double flowers is established, that

tendency becomes hereditary: there are races of single Stocks in which,

out of hundreds of plants, scarcely one double-flowered form is met

with; but when the tendency to produce double blooms is set up, single

flowers become the exception: thus, in the Balsams, before mentioned,

not one in fifty now produces single flowers, and the seeds of these

double Balsams produce double-flowered seedlings, with scarcely a

"rogue" among them.

The following list of plants producing double flowers of any kind is

taken from that given in 'Seemann's Journal of Botany,' vol. ii, p. 177,

and to which some additions have been made. Miscalled double flowers,

such as those of the _Compositae_, _Viburnum Hydrangea_, &c., are

excluded.

RANUNCULACEAE.

Clematis Viticella, _Linn._, S. Europe.

florida, _Thunb._, Japan.

Fortunei, _Moore_, Japan.

patens, _Desne_, Japan.

Anemone japonica, _Sieb. et Zucc._, Japan.

coronaria, _Linn._, S. Europe, Asia Minor.

hortensis, var. _Linn._, S. Europe.

palmata, _Linn._, N. Africa, Spain, Portugal.

nemorosa, _Linn._, Europe, N. America, Siberia.

sylvestris, _Linn._, S. Europe, Siberia.

Hepatica triloba, _Chaix._, Europe.

Ranunculus bulbosus, _Linn._, Europe, N. Amer.

repens, _Linn._, Europe, Siberia, N. Amer.

acris, _Linn._, Europe, Siberia.

aconitifolius, _Linn._, Europe.

gramineus, _Linn._, Italy, France, Portugal, Switzerland.

bullatus, _Linn._, S. Europe.

asiaticus, _Linn._, The East.

Ficaria ranunculoides, _Moench._, Europe.

Thalictrum anemoides, _Michae._, N. America.

Caltha palustris, _Linn._, Europe, Asia, N. America.

Trollius europaeus, _Linn._, Europe.

nepalensis, Himalaya.

Nigella damascena, _Linn._, Mediterranean.

Aquilegia vulgaris, _Linn._, Europe.

canadensis, _Linn._, N. America.

Delphinium Ajacis, _Linn._, S. Europe.

grandiflorum, _Linn._, Siberia, N. America.

Consolida, _Linn._, Europe, N. America.

cheilanthum, _Fisch._, Siberia.

elegans, _D. C._, North America.

Adonis autumnalis, _Linn._, Europe.

vernalis, _Linn._, Europe, Asia.

Paeonia Moutan, _Sims_, China, Japan.

officinalis, _Retz._, Europe.

tenuifolia, _Linn._, Tauria.

albiflora, _Pall._, Siberia.

paradoxa, _Andr._, S. Europe.

NYMPHAEACEAE.

Nelumbium speciosum, _Willd._, Africa, Asia.

BERBERIDACEAE.

Berberis, _sp. cult._

PAPAVERACEAE.

Papaver Rhoeas, _Linn._, Europe.

bracteatum, _Lindl._, Russia.

somniferum, _Linn._, S. Europe, Asia Minor, Egypt.

Chelidonium majus, _Linn._, Europe, Asia.

Sanguinaria canadensis, _Linn._, N. America.

Podophyllum peltatum, _Linn._, N. America.

CRUCIFERAE.

Mathiola incana, _R. Br._, Mediterranean.

glabrata, _D. C._

annua, _Sweet._, South Europe, Syria.

Cheiranthus Cheiri, _Linn._, Europe.

Iberis umbellata, _Linn._, Europe.

amara, _Linn._, Europe.

Cardamine pratensis, _Linn._, Europe, Asia, Africa, America.

Hesperis matronalis, _Linn._, Europe, Siberia.

Barbarea vulgaris, _R. Br._, Europe.

Sinapis arvensis, _Linn._, Europe.

Brassica oleracea. _Linn._, Europe.

CISTACEAE.

Helianthemum vulgare, _Spach._, Europe, N. Africa.

VIOLACEAE.

Viola odorata, _Linn._, Europe, Siberia.

grandiflora, _Linn._, Europe,

tricolor, _Linn._, Europe.

CARYOPHYLLEAE.

Dianthus barbatus, _Linn._, France, Germany.

chinensis, _D. C._, China.

Poiretianus, _Seringe_, ?

Caryophyllus, _Linn._, France, Italy.

arboreus, _Linn._, Crete.

hybridus (_gardens_).

corymbosus, _Sibth._, Asia Minor.

plumarius, _Linn._, Europe, Siberia, N. America.

deltoides, _Linn._, Europe.

Saponaria officinalis, _Linn._, Europe.

Lychnis sylvestris, _Schkr._, Europe.

vespertina, _Linn._, Europe.

flos cuculi, _Linn._, Europe.

Viscaria, _Linn._, Europe.

chalcedonica, _Linn._, Japan, Asia Minor.

Silene inflata, _Sm._; _var._ maritima, _D. C._, Europe.

ALSINEAE.

Sagina procumbens, _Linn._, Europe.

MALVACEAE.

Hibiscus Rosa sinensis, _Linn._, E. Indies.

flavescens, _Cav._, China.

alba, _Hook._, China.

syriacus, _Linn._, Syria, Carniola.

Althaea rosea, _Cav._, Caucasus, &c.

Malva rotundifolia, _Linn._, Europe.

moschata, _D. C._, Europe.

HIPPOCASTANEAE.

AEsculus Hippocastanum, _Linn._, Europe, N. America.

GERANIACEAE.

Geranium pratense, _Linn._, Europe, Siberia.

sylvaticum. _Linn._, Europe.

Pelargonium zonale, _Willd._, S. Africa.

Tropaeolum majus, _Linn._, Peru.

minus, _Linn._, Peru.

Oxalis cernua, _Thunb._, S. Africa.

Impatiens Balsamina, _Linn._, E. Ind.

TERNSTROEMIACEAE.

Camellia reticulata, _Lindl._, China.

Sasanqua, _Thunb._, China.

japonica, _Linn._, Japan.

Thea maliflora, _Seem._, Japan.

AURANTIACEAE.

Citrus Aurantium, _Linn._, Asia, South Europe.

PAPILIONACEAE.

Trifolium repens, _Linn._, Europe, S. America.

Medicago sp., ?., Europe.

Ulex europaeus, _Link._, Europe.

Spartianthus junceus, _Linn._, S. Europe.

Clitoria Ternatea, _Linn._, E. India.

Orobus viscoides, _D. C._, Croatia, &c.

vernus, _Linn._, Europe.

Genista tinctoria, _Linn._, Europe.

sibirica, _Linn._, Siberia.

scoparia, _Lam._, Europe.

Cytisus albus, _Link._, Portugal.

Anthyllis Vulneraria, _Linn._, Europe.

Coronilla Emerus, _D. C._, Europe.

Lotus corniculatus, _Linn._, Europe.

ROSACEAE.

Rosa lutea, _Mill._, Europe.

cinnamomea, _Linn._, Europe, N. America.

spinosissima, _Linn._, Central Asia.

Carolina, _Linn._, N. America.

villosa, _Linn._, Europe, Central Asia.

centifolia, _Linn._

damascena, _Linn._, Syria.

rubiginosa, _Linn._, Europe, Asia, N. America.

moschata, _Ait._, Madeira, N. Africa.

canina, _Linn._, Europe.

alba, _Linn._, Europe, Caucasus.

indica, _Linn._, China.

nivea, _D. C._, China.

Eglanteria, _Linn._, Europe.

gallica, _Linn._, Europe, Caucasus.

pimpinellifolia, _Linn._, Europe, Central Asia.

Banksiae, _R. Br._, China.

sulphurea, _Ait._, East.

Rubus fruticosus, _Linn._, Europe.

rosifolius, _Linn._, Mauritius, E. India.

corylifolius, _Smith_, Europe.

caesius, _Linn._, Europe.

Kerria japonica, _D. C._, Japan.

Spiraea Filipendula, _Linn._, Europe.

Ulmaria, _Linn._, Europe.

prunifolia, _Sieb. et Zucc._, Japan.

Reevesii, _Lindl._, China.

strobilacea, _Sieb. et Zucc._, Japan.

Fragaria vesca, _Linn._, Europe, N. America.

Potentilla alpestris, _Hall. f._, Europe.

reptans, _Linn._, Europe, Asia.

Tormentilla, _Schrank_, Europe, Asia.

anserina, _Linn._, Europe.

Geum rivale, _Linn._, Europe.

POMACEAE.

Crataegus Oxyacantha, _Linn._, Europe.

Crus galli, _Linn._, N. America.

Cydonia japonica, _Pers._, Japan.

Pyrus communis, _Linn._, Europe.

Malus, _Linn._, Europe.

Eriobotrya japonica, _Lindl._, Japan.

AMYGDALEAE.

Amygdalus Persica, _Linn._, Persia.

communis, _Linn._, Mauritania.

Prunus domestica, _Linn._, Europe.

spinosa, _Linn._, Europe, N. America.

avium, _Linn._, Europe.

Cerasus, _Linn._, Europe.

Kerii, _Steud._, Japan.

japonica, _Thunb._, China, Japan.

insititia, _Linn._, Europe.

triloba, _Lindl._, China.

MYRTACEAE.

Myrtus communis, _Linn._, S. Europe.

Punica Granatum, _Linn._, S. Europe, Marocco.

PHILADELPHACEAE.

Philadelphus Coronarius, _linn._, S. Europe.

Deutzia Crenata, _sieb. Et Zucc._, Japan.

ONAGRACEAE.

Fuchsia globosa, _Lindl._ (and var. hort. pl.), Mexico.

Epilobium tetragonum, _D.C._, Europe.

Clarkia pulchella, _Pursh._, California.

elegans, _Douglas_, N. America.

PORTULACACEAE.

Portulaca grandiflora, _Hook_, Chili.

GROSSULARIACEAE.

Ribes sanguineum, _Pursh._, N. America.

SAXIFRAGACEAE.

Saxifraga granulata, _Linn._, Europe.

UMBELLIFERAE.

Daucus Carota, _Linn._, Europe.

RUBIACEAE.

Ixora grandiflora, _De Cand._, E. India.

Serissa foetida, _Comm._, China, Japan.

Gardenia Fortuniana, _Hook._, China.

florida, _Linn._, China, E. India.

radicans, _Thunb._, Japan.

CAPRIFOLIACEAE.

Lonicera Periclymenum, _Linn._, Europe.

Sambucus nigra, _Linn._, Europe.

CAMPANULACEAE.

Campanula latifolia, _Linn._, Europe, Asia.

Tenorei, _Morett_, Naples.

Trachelium, _Linn._, Europe.

Vidallii, _H. C. Wats._, Europe.

pyramidalis, _Linn._, S. Europe.

rotundifolia, _Linn._, Europe, N. America.

persicifolia, _Linn._, Europe.

glomerata, _Linn._, Europe, Asia.

Medium, _Linn._, Europe.

rhomboidea, _Linn._, Europe.

Platycodon grandiflorum, _D. C._, Siberia.

ERICACEAE.

Calluna vulgaris, _Linn._, Europe, N. America.

Rhododendron indicum, _Sweet._, E. India.

ponticum, _Linn._, Asia Minor.

Azalea nudiflora, _Linn._, N. America.

glauca, _Lam._, N. America.

Arbutus Unedo, _Linn._, S. Europe.

Erica Tetralix, _Linn._, Europe.

cinerea, _Linn._, Europe.

hyemalis, gardens.

EPACRIDACEAE.

Epacris impressa, _R. Br._, Australia.

PRIMULACEAE.

Primula villosa, _Jacq._, Europe.

Auricula, _Linn._, Europe.

denticulata, _Smith_, E. India.

acaulis, _Jacq._, Europe.

clatior, _Jacq._, Europe.

praenitens, _Ker._ = sinensis, _Lindl._, China.

Lysimachia Nummularia, _Roem et Schult._, Europe.

Anagallis tenella, _Linn._, Europe.

JASMINACEAE.

Jasminum officinale, _Linn._, S. Europe.

Sambac., _Ait._, E. India.

hirsutum, _Hook._, China.

grandiflorum, _Lindl._, S. Europe.

OLEACEAE.

Syringa persica, _Linn._, Persia.

vulgaris, _Linn._, Europe, Persia.

APOCYNEAE.

Vinca minor, _Linn._, Europe.

major, _Linn._, Europe.

Nerium odorum, _Ait._, E. India.

Oleander, _Linn._, S. Europe.

Tabernaemontana coronaria, _Willd._, E. India.

Allamanda cathartica, _Aubl._, S. America.

CONVOLVULACEAE.

Calystegia sepium, _R. Br._, Europe, America, Asia.

pubescens, _Lindl._, China.

Convolvulus tricolor, _Linn._, S. Europe.

Ipomoea pandurata, _Meyer_, S. America.

SOLANACEAE.

Datura cornigera, _Hook._, Peru.

fastuosa, _Linn._, S. America, Egypt.

arborea, _Linn._, S. America.

chlorantha, _Hook._

humilis, _Desf._

Petunia nyctaginiflora, _Juss._, S. America.

violacea, _Hook_, S. America.

Solanum Dulcamara, _Linn._, Europe.

GENTIANACEAE.

Gentiana Amarella, _Linn._, Europe.

OROBANCHACEAE.

Orobanche sp.

SCROPHULARIACEAE.

Mimulus luteus, _Linn._, Chili.

Antirrhinum majus, _Linn._, S. Europe.

Digitalis purpurea, _Linn._, Europe.

Linaria vulgaris, _Mill._, Europe, N. America.

Veronica, sp.

Calceolaria, var. cult.

GESNERACEAE.

Achimenes longiflora, _D. C._, Mexico.

Gloxinia var. hort.

VERBENACEAE.

Clerodendron fragrans, _Willd._, Japan.

Verbena var. hort.

NYCTAGINEAE.

Mirabilis Jalapa, _Linn._, Trop. America.

LAURINEAE.

Laurus nobilis, _Linn._, S. Europe.

Sassafras, _Linn._, N. America.

IRIDACEAE.

Gladiolus tristis, _Linn._, Cape of Good Hope.

Crocus aureus, _Sibth_, Europe, Asia Minor.

Susianus, _Curt._, Asia Minor.

pusillus, _Tenore_, Italy.

vernus, _Smith_, S. Europe.

Iris sibirica, _Linn._, Europe.

Iris Kaempferi, _Siebold_, Japan.

AMARYLLIDACEAE.

Galanthus nivalis, _Linn._, Europe.

Leucoium vernum, _Linn._, Europe.

Sternbergia lutea, _Gawl._, Europe, Asia Minor.

Hippeastrum equestre, _Herb._, S. America.

Narcissus cernuus, _Salisb._, S. Europe.

Telamonius, _Schult._, Europe.

lobularis, _Schult._

concolor, _Schult._, Portugal.

biflorus, _Curt._, Europe.

italicus, _Ker._, Italy.

incomparabilis, _Curt._, Italy.

Cypri, _Haw._, Cyprus.

Pseudo-Narcissus, _Linn._, Europe.

poeticus, _Linn._, Europe.

Jonquilla, _Linn._, S. Europe, East.

Tazetta, _Linn._, S. Europe.

poculiformis, _Salisb._, S. Europe.

ORCHIDACEAE.

Orchis Morio, _Linn._, Europe.

mascula, _Linn._, Europe.

pyramidalis, _Linn._, Europe.

Ophrys fucifera, _Linn._, Europe.

See also pp. 380, 509.

HYDROCHARIDACEAE.

Hydrocharis Morsus ranae, _Linn._, Europe.

ASPHODELEAE.

Asphodelus luteus, _Linn._, S. Europe.

LILIACEAE.

Tulipa Gesneriana, _Linn._, Asia Minor.

sylvestris, _Linn._, S. Europe.

Scilla autumnalis, _Linn._, Europe.

nutans, _Smith_, S. Europe.

Convallaria majalis, _Linn._, Europe, America.

Polygonatum, _Linn._, Europe.

Trillium grandiflorum, _Spreng._, America.

Fritillaria Meleagris, _Linn._, Europe.

imperialis, _Linn._, Persia.

Lilium Martagon, _Linn._, Europe.

candidum, _Linn._, Syria, Persia.

Hyacinthus orientalis, _Linn._, East.

Polianthes tuberosa, _Linn._, E. India.

Hemerocallis disticha, _Don._, Nepal.

Kwanso, gardens.

fulva, _Linn._, S. Europe.

COLCHICACEAE.

Colchicum autumnale, _Linn._, Europe.

Tofieldia calyculata, _Wahl._, Europe.

BUTOMACEAE.

Sagittaria latifolia, _Willd._, N. America.

sagittifolia, _Linn._, Europe, Asia, America.

COMMELYNACEAE.

Tradescantia virginica, _Linn._, N. America.

alba, gardens.

FOOTNOTES:

[564] This appendix forms a portion of a paper published in the

'Proceedings of the International Botanical Congress,' London, 1886, p.

127, and which it has been deemed advisable to reproduce with sundry

additions and modifications.

[565] 'Traite des Giroflees,' per E. Chate.

[566] Leading Article in the 'Gardeners' Chronicle,' p. 74, 1866.

[567] Otto's 'Gartenzeitung,' 1866.

[568] 'Gard. Chron.,' 1843, p. 628.

[569] 'Gard. Chron.,' 1867, p. 381.--Art. "Chinese primroses."

[570] See also p. 79, fig. 36. A similar flower is figured in 'Hort.

Eystett. Ic. Arb. Vern.,' fol. 5. "Fructus nondum observatus est

fortassis alimento uberius in flores refuso, nullus sperari possit."

[571] See De Candolle, 'Plant. Rar. Genev.,' 1829, p. 91; and Alph. de

Candolle.' Geog. Bot.,' p. 1080.

[572] See 'Gardeners' Chronicle,' 1868, p. 1113.

[573] Ibid., 1843, p. 628.

NOTE.

During the progress of the foregoing pages through the press, several

additional illustrations of particular malformations have come under

notice. Some of the more important of these may here be recorded.

_Fasciation_ (see p. 11).--The following plants may be added to the

list:--_Acer eriocarpum_, _Arabis albida_, _Brassica oleracea_, var.,

_Guarea_, sp., _Artabotrys_ sp. In all, with the exception of the

first-named, the fasciation occurred in the inflorescence. In some

species of _Artabotrys_, indeed, fasciation and curvation of the

inflorescence are common.

_Synanthy_ (p. 39).--Several additional instances of adhesion of two or

more flowers in _Calanthe vestita_, _C. Veitchii_, and other forms of

this genus may be cited. These furnish further illustrations of the much

greater liability of some plants to particular changes as compared with

others. _Scilla bifolia_, _Gagea arvensis_, and _Viola odorata_ may be

added to the list of synanthic plants.

_Alterations of placentation, &c._ (see pp. 98, 483).--M. Casimir De

Candolle, in a letter to the author, dated March 8th, 1869, thus writes

of the existence of a double row of carpels in _Pyrus spectabilis_ and

_Crataegus Oxyacantha_, "a longitudinal section of a double flower of

_Pyrus spectabilis_ shows two rows of carpels, placed one above another.

The arrangement of the vascular bundles shows that the upper row is

external in relation to the lower series. The carpels of the latter are

wholly coalescent as in a pear, while those of the upper verticil are

only partially coherent or sometimes quite distinct. The placentation is

constantly axile in the inferior row and parietal in the upper one. The

number of ovules in each carpel of the superior row varies greatly, and

they are often, but not always, inserted in two longitudinal ranks, as

is constantly the case in the lower carpels. Double flowers of _Crataegus

Oxyacantha_ present the same anomalies." For analogous instances in

_Digitalis_, see p. 98. See also p. 380, _Saxifraga_.

_Prolification_, p. 120.--A. P. De Candolle, "Organographie Vegetale,"

tab. 40, figures an instance of suppression of one lobe of the ovary in

_Iris chinensis_, and of the presence at the base of the flower of an

adventitious and imperfect flower-bud, as in the _Phlomis_, mentioned at

p. 119.

_Monoecious Misleto_, p. 193.--In this specimen, exhibited at one of the

meetings of the Scientific Committee of the Royal Horticultural Society

in 1869, there were both male and female flowers on the same bush. The

plant was of the male sex, with numerous long slender whip-like,

somewhat pendulous, branches bearing comparatively large broad yellowish

leaves, and fully developed male flowers at the end. From the side of

one of these male branches, near the base, protruded a tuft of short,

stiff branches, bearing small, narrow, dark green leaves, ripe berries

and immature female flowers. There was no evidence of grafting or

parasitism, of the female branch on the male, the bark and the wood

being perfectly continuous so that the only tenable supposition is that

this was a case of dimorphism.

_Adventitious leaflet and pitcher_, see pp. 30 and 355. In a species of

_Picrasma_, in which the leaves are impari-pinnate and spread

horizontally, an adventitious leaflet was observed to project at right

angles to the plane of the primary leaf. It emerged at a point nearly

corresponding to that at which the normal pinnae were given off. The

appearance presented was thus like that of a whorl of three leaves,

except that the shining surface of the adventitious leaflet,

corresponding to the upper face of the normal leaflets, was directed

towards the axis, _i.e._, away from the corresponding portion of the

neighbouring pinnae, while the dull surface, corresponding to the lower

part of an ordinary leaflet, looked towards the apex of the main leaf,

or away from the axis. In one instance, a stalked pitcher was given off

from the same point as that from which the supernumerary leaflet

emerged, the pitcher being apparently formed from the cohesion

(congenital) of the margins of a leaflet.

In the normal leaf of this plant there is between the bases of the

pinnae, a small reddish gland or stipel? attached to, or projecting from,

the upper surface of the rachis. It appeared from some transitional

forms that the adventitious leaflet, just mentioned, was due to the

exaggerated development of this gland, but no clue was afforded as to

the origin of the ascidium. It was not practicable to examine the

arrangement of the vascular bundles in the rachis.

_Additional labella in Phaius._--A flower of _Phaius grandiflorus_ was

found in the same condition as the _Catasetum_, mentioned at pp. 291 and

382.

_Tubular stem._--A species of _Sempervivum_, exhibited by Mr. Salter, of

Hammersmith, at one of the summer exhibitions of flowers at the Royal

Horticultural Society in 1868, under the name of _S. Bollei_, deserves

notice from its bearing on the question of such structures as the

calyx-tubes, the hip of the rose and such like, see pp. 394, 482. In

this plant the leaves appeared to be arranged some on the outside,

others on the inside, of an erect hollow cylinder, some six inches in

height. The oldest leaves were outside, the youngest within, so that the

appearance presented was as if the summit of the axis had been pushed or

drawn in, much as the finger of a tight glove might be invaginated in

withdrawing it from the hand.

The plant in question thus furnishes an actual illustration of the

supposititious case mentioned at p. 482.

_Double flowers_, see pp. 499, et seq.--The following species may be

added to those already recorded: _Lychnis coronaria_, _Hibiscus

mutabilis_, _Lotus major_, _Pisum sativum_, _Godetia_ sp., _Ipomoea

purpurea_, _Convolvulus minor_, _Heliotropium peruvianum_, _Trillium

grandiflorum_, and _Phaius grandiflorus_.

INDEX TO SUBJECTS.

A.

Abortion, 455, 467

of axile organs, 455

calyx, 460

corolla, 460

indusium, 467

leaves, 458

ovules, 466

perianth, 460

pistil, 464

receptacle, 457

stamens, 463

Acaulescence, 393

Acaulosia, 393, 456

Acheilary, 398

Adesiny, 58, 76

Adhesion, 32

of axes, 50, 55

embryos, 56

leaves, 33

parts of flower, 34

roots, 53

Adventitious buds, 156, 176

flowers, 174, 176, 180

gemmae, 173

leaves, 162

roots, 156

shoots, 161

Albinism, 337

Alternation, 3, 485

Androecium, enlargement of, 430

meiophylly of, 398

meiotaxy of, 405

of orchids, 380

pleiotaxy of, 379

polyphylly of, 361

Androgynism, 193

Anther (see connective), contabescence of, 463

morphology of, 291

ovuliferous, 200

petalody of, 291

sutures of, 291

Apilary, 397

Apostasis, 440

Aphylly, 395

Arrangement, 1

Ascidia, 30, 313

bibliography, 30

plants with, 30

Atrophy, 454 (see abortion)

Antophyllogeny, 355

Avalidouires (vines), 211

Axes, abortion of, 455

adhesion of, 50, 55

cohesion of, 9

enation from, 444

enlargement of, 418

fission of, 60

suppression of, 398

Axile organs, see Axes

B.

Barley, Nepaul, 174

Bigarades cornues, 303

Bladder-plums, 465

Bracts, multiplication of, 358

staminody of, 298

phyllody of, 242

Buds, adventitious on fruits, 178

on leaves, 170, 174

in ovary, 180

on petals, 177

in pith, 171

on roots, 160 (see flower-buds, prolification)

variations of, 336

Bulbs, displacement of, 84

multiplication of, 172, 350

Burrs, 347, 420

C.

Catacorolla, 450

Calycanthemy, 283

Calyphyomy, 34

Calyx, abortion of, 461

dialysis of, 70

meiophylly of, 396

meiotaxy of, 403

obsolete, 460

petalody of, 283

pleiotaxy of, 374

polyphylly of, 359

solution of from ovary, 77

Calyx-tube, 394, 480, 509

Carnation wheat-ear, 371

Carpels (see Pistil, Fruit, Ovary), adventitious, 182

dialysis of, 73

enation from, 453

fission of, 68

in ovary, 182

Cauliflower, 421

Cenanthy, 408

Chloranthy, 273, 279

bibliography, 280

remarks on, 279

plants subject to, 280

Chorisis, 59, 343

parallel, 344

collateral, 344

Chromatism, 339

Cladodes, 328

Classification, teratology in relation to, 488

Cohesion of leaves, 21, 25

of petals, 28

pistils, 29

sepals, 27

stamens, 29

stems, 9

Colour, alterations of, 337

Columella, 395

Coniferae, leaves of, 217, 352, 484

inflorescence of, 245

scales of, 192, 245, 484

Compensation, 488

Connective, petalody of, 293

Consistence, alterations of, 432

Contabescence, 463

Contortion, 317

Co-relation, 486

Cornute leaves, 328

Corolla, abortion of, 461

dialysis of, 71

duplicate, 376

hose in hose, 377

meiophylly of, 397

meiotaxy of, 403

pleiotaxy of, 374

polyphylly of, 359

virescence of, 338

Cotyledons, increased number of, 370

shoots, below, 161

Cuttings, formation of, 159

D.

Dedoublement, 59 (see Chorisis)

Deflexion, 209

Deformities, 311

Degeneration, 470

Depauperate ferns, 466

Diadelphia, 29

Dialysis, 58, 69

of calyx, 71

carpels, 73

corolla, 72

plants subject to, 72

of leaves--margins of, 70

stamens, 73

Diaphysis, 103

Dioecious plants, 192, 193

Dimorphism, 333

Dimorphic flowers, 403

Direction, changes of, 201

Diremption, 87

Disjunction, see Dialysis, Fission, Solution

Displacement, 84

of bulbs, 84

carpels, 96

flower-parts of, 91

inflorescence, 85

leaves, 87

ovules, 96

placentas, 96

Distension, 419

E.

Ecblastesis, 107, 138

Elongation, 433

of parts of flower, 438

flower-stalks, 435

inflorescence, 434

leaves, 437

nucleus of ovule, 269

placenta, 440

receptacle, 440

root, 434

thalamus, 440

Embryos, adhesion of, 56

increased number of, 369

Enation, 443

from axile organs, 444

carpels, 453

corolla, 449

foliar organs, 445

sepals, 448

stamens, 453

Enlargement, 417

of androecium, 430

axile organs, 418

buds, 420

flower stalk, 421

fruit, 431

gynoecium, 430

perianth, 428

placenta, 425

Epanody, 226

Epistrophy, 226

Etiolation, 337

Eversion, 204

Excrescences, 444 (see Enation)

F.

Fasciation, 11

plants affected with, 20, 508

Fastigiation, 202

Ferns, crested, 63, 447

depauperated, 466

exindusiate, 467

supra-soriferous, 189

Filaments, see Stamens

petaloid, 290

4-winged, 290

Finger and toe, 69

Fission, 59

of carpels, 68

leaf-organs, 61, 66

plants, subject to, 66

of petals, 66

stem-organs, 60

stamens, 68

Flattening, 328

Floral organs, displacement of, 91

elongation of, 439

metamorphy of, 281

Florets, increased number of, 351, 390

Flowers, adventitious, 174

on fruits, 177

on leaves, 174

in ovary, 180

on petals, 177

on spines, 177

apetalous, 404

double, 490, 510

hermaphrodite, 196

homomorphic, 188

increased number of, 390

mutilated, 403

unisexual, 193

Flower-stalk, enlargement of, 421

Flower-bud (see Prolification), replaced by leaves or scales, 164

in place of leaf-buds, 176

Foliar organs (see leaves), adhesion of, 32

Foliar organs, cohesion of, 21, 25

enation from, 445

fission of, 61

suppression of, 396

Form, alterations of, 213

juvenile, persistence of, 217

Frondescence, 241, 279, see Phyllody, Virescence

Fruit, adhesion of, 44

enlargement of, 431

G.

Gemmae, formation of, 173

Glands, formation of, 473

Gnaurs, 158, 347, 417, 419

Grafting, 53, 56

Greffe des Charlatans, 56

Growth interrupted, 327

irregular, 228

Gymnaxony, 211

Gynantherus, 305

Gynoecium (see pistils)

enlargement of, 430

meiophylly of, 399

meiotaxy of, 406

pleiotaxy of, 388

polyphylly of, 363

suppression of, 406

H.

Hairs, formation of, 472

Hermaphroditism, 197

Heterogamy, 190

Heteromorphy, 311

Heterophylly, 330

Heterotaxy, 156

Homology, 476

Homomorphy, 188

Hose in hose corollas, 291, 377

Hypertrophy, 415, see Enlargement

I.

Independence, 58

Indusium, abortion of, 467

Inflorescence, displacement of, 84

elongation of, 434

prolification of, 102, 115

Interrupted growth, 327

Inversion of organs, 206

Irregularity, 213

Irregular growth, 228

K.

Knaurs, (see gnaurs)

Kail, 426

L.

Laciniation, see fission

Layering, 156

Leaders, formation of, 203

Leaf-sheath, 477

Leaves, see foliar organs

abortion of, 458

adhesion of,

by surfaces, 33

to stem, 34

adventitious, 162-165, 509

cornute, 328

displacement of, 86

elongation of, 437

enlargement of, 421

frondiferous, 355

geminate, 352

multiplication of, 358

nature of, 477

palmate-passage of to pinnate, 439

spiral torsion of, 326

supernumerary, 353

Lily, double white, 375

M.

Meiotaxy of androecium, 405

of calyx, 403

corolla, 403

gynoecium, 405

Meiophylly of androecium, 398

of calyx, 397

corolla, 397

gynoecium, 399

perianth, 397

Mellarose, 134

Metaphery, 91

Metamorphy, 239, 281

calycanthemy, 283

chloranthy, 273

petalody, 283

phyllody, 241

pistillody, 302

sepalody, 282

staminody, 298

Mischomany, 348

Monadelphia, 29

Monoecious, 192, 193, 509

Monosy, 58

Morphology, 479

Multiplication, see pleiotaxy, pleiophylly

of bracts, 358, 371

bulbs, 350

cotyledons, 370

embryos, 369

florets, 351

foliar organs, 352

whorls, 371

N.

Nepaul Barley, 174

Number, alterations of, 341

increased, 343, 353

diminished, 392

O.

Orchids, androecium of, 380

prolification in, 153

Organs, rudimentary, see Atrophy

Ovary, inferior, nature of, 394, 482

solution from calyx, 77

stamens in, 184

Ovules, abortion of, 466

increase of, 367

in place of pollen, 200

polliniferous, 183

petalody of, 297

phyllody of, 262

pistillody of, 310

suppression of, 407

malformations of, 262

bibliography of, 272

P.

Parasitical plants, 55

Peduncles, elongation of, 435

Peloria, 207, 228

bibliography of, 227, 239

regular, 219

plants subject to, 226

irregular, 229

plants, subject to, 239

Perianth, abortion of, 460

enlargement of, 428

meiophylly of, 396

pistillody of, 303

pleiotaxy of, 375

Persistence, xxxvi _adnot._, 217

Petalody, 283

of accessory organs, 297

anther, 291

calyx, 283

connective, 292

ovules, 297

pistils, 297

stamens, 284

plants, subject to, 295

Petals, cohesion of, 28

enation from, 448

fission of, 66

phyllody of, 251

staminody of, 298

tubular, 23, 314

Phyllode, 328

Phyllody, 240 (see Virescence, Chloranthy)

of accessory organs, 272

bracts, 242

calyx, 244

plants subject to, 250

in Conifers, 245

of corolla, 251

plants subject to, 252

of ovules, 262

plants subject to, 271

pistils, 256

plants subject to, 261

stamens, 253

plants subject to, 256

Phyllomania, 352

Phyllomorphy, see Phyllody

Phyllotaxy, 1, 320

Pistil, abortion of, 464

cohesion of, 29

petalody of, 296

staminody of, 298

Pistillody, 302

of ovules, 268, 310

perianth, 302

sepals, 302

stamens, 303

plants subject to, 310

Pitchers, 30, 313, 509, see Ascidia

Placentation, changes in, 96, 508

bibliography, 100

nature of, 483

Placenta, elongation of, 439

enlargement of, 421

Pleiomorphy, 228

Pleiophylly, 353

Pleiotaxy, 371

of androecium, 375

bracts, 371

calyx, 374

corolla, 376

gynoecium, 388

perianth, 375

Plien, 346

Plymouth Strawberry, 275

Polyadelphia, 29

Pollen in ovules, 183

abortion of, 463

replaced by ovules, 200

Polyclady, 346

Polycotyledony, 370

Polyembryony, 369

Polymorphy, 328

Polyphylly of androecium, 361

of calyx, 350

corolla, 359

plants subject to, 360

of flower, 363

gynoecium, 363

Polyphylly, bibliography, 364

plants subject to, 364

Position, changes of, 83

relative, 485

Prolification, 100

axillary, 138

foliar, 141

floral, 142

plants affected with, 148

bibliography of, 154

complicated, 151

of embryo, 155

of flower, 115

coincident changes, 128

median foliar, 116

median floral, 119, 508

plants affected with, 137

of fruit, 134

inflorescence, 102

bibliography, 115

median foliar, 103

median floral, 105

lateral floral, 107

lateral foliar, 106

R.

Receptacle, abortion of, 457

elongation of, 116, 440

spiral torsion of, 325

Reflexion, 209

Regularity, 213

Rhizotaxy, 1

Rose Willow, 166, 168

Roots, adventitious, 156

elongation of, 434

Rudimentary organs, 469

S.

Saint Valery Apple, 135, 282, 304, 375, 388

Savoys, 426

Scales, formation of, 164, 448, 470

Scape, leaves on, 163

Seeds, abortion of, 407

union of, 50

Sepals, adhesion of, to petals, 34

cohesion of, 27

enation from, 448

phyllody of, 243

pistillody of, 303

staminody of, 298

Sepalody, 282

Separation, 58

Sex, changes of, 190, 509

Shamrock, four-leaved, 356

Shoots below cotyledons, 167; _see_ Leaders

Size, alterations in, 411

Solenaidie, 21, 316

Solution, 59, 76

bibliography, 82

of calyx, 77

plants subject to, 82

of stamens, 82

Spathes, increased number of, 357

Speiranthy, 91, 325

Spiral torsion, 319

plants subject to, 325

of leaf, 326

of receptacle, 324

Spines, 456

Sports, 336

Spurs, formation of, 228, 315

Stamens, see Androecium

abortion of, 463

adhesion of, 34, 35

cohesion of, 29

compound, 294, 345

dialysis, 73

enation from, 453

fission of, 68

in ovary, 183

petalody of, 283

phyllody of, 253

pistillody of, 303

tubular, 316

Staminody, of accessory organs, 301

of bracts, 298

petals, 298

pistils, 299

sepals, 298

Stasimorphy, 216

Stem, see axes

Stipules, increased number of, 357