I have also seen three cotyledons present in embryo-plants of _Correa_,

_Crataegus Oxyacantha_, _Dianthus sinensis_, _Daucus Carota_, _Cerasus

Lauro-cerasus_. De Candolle alludes to a case of the kind in the bean,

and figures a species of _Solanum_ with three cotyledons.[420] Jaeger

alludes to a similar instance in _Apium Petroselinum_;[421] Ehrenberg to

one in the marigold (_Calendula_);[422] Reinsch to an analogous

appearance in the beech (_Fagus_), associated with a union of the

margins of two out of the three cotyledons, and of those of two out of

the three leaves next adjacent.[423] This fusion seems frequently to

accompany increase in the number of cotyledons. It was so in the

_Correa_, and in the _Crataegus_ previously mentioned. Some of these

cases may be accounted for by chorisis or by a cleavage of the original

cotyledons, as happens, according to Duchartre,[424] in some Coniferae,

which he considers to be improperly termed polycotyledonous. Whether

this holds good in the Loranths, where (_Nuytsia_, _Psittacanthus_) an

appearance of polycotyledony exists, is not stated. In the case of the

rue (_Ruta_) figured by M. A. de Jussieu[425] this splitting of one

cotyledon into two is sufficiently evident, as is also the case in the

sycamore (_Acer pseudo-platanus_), seedlings of which may often be met

with divided cotyledons.

In other instances a fusion of two embryo plants may give rise to a

similar appearance, as in the _Euphorbia_ and _Sinapis_ found by M.

Alph. de Candolle (see _ante_, p. 56).

=Pleiotaxy or multiplication of whorls.=--In the preceding section

notice has been taken of the increased number of parts in a single

whorl, but an augmentation of the number of distinct whorls is still

more frequently met with. Many of the so-called double flowers owe their

peculiarity to this condition. The distinction between the two modes in

which the parts of the flower are increased in number has been pointed

out by Engelmann, Moquin, and others, and the two seem to require

distinctive epithets; hence the application of the terms polyphylly and

pleiotaxy, as here proposed.

=Pleiotaxy in the bracts.=--An increase in the number of bracts has been

met with very constantly in a species of _Maesa_, and in a peculiar

variety of carnation, called the wheat-ear carnation.[426] In some of

these cases the increase in the number of bracts is attended by a

corresponding suppression in the other parts of the flower. Such a

condition has been frequently met with in _Gentiana Amarella_, where the

bracts are increased in number, coloured purple, and destitute of any

true floral organs. A similar condition exists in some varieties of

_Plantago major_ (var. _paniculata_), as has been previously stated, p.

109.

[Illustration: FIG. 187.--Wheat-ear carnation. The appearance is due to

the multiplication of the bracts and the suppression of the other parts

of the flower.]

It has been noticed also in the common pea, _Pisum sativum_, and M.

Lortet[427] records a case of the kind in _Erica multiflora_, the

flowers of which, under ordinary circumstances, are arranged in

clusters, but in this case the pedicels were more closely crowded than

usual, and were covered for their whole length with small rose-coloured

bracts arranged in irregular whorls, the upper ones sometimes enclosing

imperfect flowers. In the 'Gardeners' Chronicle,' 1865, p. 769, is

figured a corresponding instance of _Delphinium Consolida_, in which the

bracts were greatly increased in number, petaloid, and, at the same

time, the central organs of the flower were wholly wanting.

[Illustration: FIG. 188.--_Delphinium Consolida_. Multiplication of

bracts at the expense of the other parts of the flower.]

[Illustration: FIG. 189.--Multiplication of bracts, &c., _Pelargonium_.]

In flowers of _Pelargonium_ may occasionally be seen a repetition of the

whorls of bracts, in conjunction with suppression and diminished size of

some of the other portions of the flower (fig. 189).

The common foxglove (_Digitalis purpurea_) has likewise occasionally

been observed subject to a similar malformation.

_Cornus mas_ and _C. suecica_ sometimes show a triple involucre.[428]

Irmish[429] records an analogous case in _Anemone Hepatica_, wherein the

involucre was doubled. Similar augmentation occurs in cultivated

Anemone. In addition to the plants already mentioned, Engelmann[430]

mentions as having produced bracts in unwonted numbers, _Lythrum

Salicaria_, _Plantago major_, _Veronica spicata_, _Echium vulgare_,

_Melilotus arvensis_, and _Rubus fruticosus_.

It must here be remarked that this great number of the bracts occurs

naturally in such plants as _Godoya_, in which the bracts, or, as some

consider them, the segments of the calyx, are very numerous, and

arranged in several overlapping segments.

In some of the cultivated double varieties of _Nigella_ the finely

divided involucral bracts are repeated over and over again, but on a

diminished scale, to the exclusion of all the other parts of the flower.

=Pleiotaxy or repetition of the calyx.=--The true calyx is very seldom

affected in this manner, unless such organs as the epicalyx of mallows,

_Potentilla_, &c., be considered as really parts of the calyx.

In _Linaria vulgaris_ Roeper observed a calyx consisting of a double

series, each of five sepals, in conjunction with other changes.[431] It

is also common in double columbines, delphiniums, nigellas, &c.

In the 'Revue Horticole,' 1867, p. 71, fig. 9, is described and figured

by M. B. Verlot a curious variety of vine grown for years in the Botanic

Garden at Grenoble, under the name of the double-flowered vine. The

place of the flower is occupied by a large number of successive whorls

of sepals disposed in regular order, and without any trace of the other

portions of the flower. It is, in fact, more like a leaf-bud than a

flower. The outermost whorls of this flower open at the time when the

ordinary flowers of vines do; the second series are gradually produced,

and expand about the time when the ovaries of the normal flowers begin

to swell; a third series then gradually forms, and so on, until frost

puts a stop to the growth. This malformation, it appears, is produced

annually in certain varieties of vine, and may be perpetuated by

cuttings.

The flower of the St. Valery apple, already alluded to under the head of

sepalody, might equally well be placed here. It is not very material

whether the second whorl of organs be regarded as a repetition of the

calyx or as a row of petals in the guise of sepals.

Engelmann[432] cites the following plants as occasionally presenting a

repetition of the calyx, in most cases with a suppression of the other

floral whorls:--_Stachys lanata_, _Myosotis palustris_, _Veronica

media_, _Aquilegia vulgaris_, _Nigella damascena_, _Campanula

rapunculoides_.

=Pleiotaxy in the perianth.=--Increase in the number of whorls in the

perianth is common in lilies, narcissus, hyacinths, &c. It may be also

met with occasionally among orchids. The lily of the valley

(_Convallaria maialis_) seems also to be particularly subject to an

increase in the number of parts of which its perianth consists, the

augmentation being due partly to repetition or pleiotaxy, partly to the

substitution of petaloid segments for stamens and pistils.[433]

In this place may also be mentioned the curious deviation from the

ordinary structure occasionally met with in _Lilium candidum_, and known

in English gardens as the double white lily. In this case there are no

true flowers, but a large number of petal-like segments disposed in an

irregular spiral manner at the extremity of the stem, some of the

uppermost being occasionally verticillate.[434]

[Illustration: FIG. 190.--Double white lily. Multiplication of

perianth-segments and other changes.]

=Pleiotaxy of the corolla.=--With reference to double flowers, it was

remarked by Linne that polypetalous flowers were, as he said,

multiplied, while monopetalous flowers were duplicated, or triplicated,

as the case may be,[435] a statement that is true in the main, though

it requires modification. In the case of polypetalous, or rather

dialypetalous flowers, the petals may be very largely increased by

multiplication, as in roses, anemones, pinks, &c. In the last-named

genus the number is often so much increased that the calyx splits from

the tension exercised on it by the increasing mass within. This

multiplication may happen without any metamorphy or substitution of

petals for stamens, though, in the majority of cases, it is associated

with such a change. It is curious to observe in some of these flowers

that the total number of parts is not greatly increased; thus, in some

of the double-flowered _Leguminosae_, such as _Ulex europaeus_ and _Lotus

corniculatus_, the petals are repeated once or twice, the stamens are

petalodic, but reduced in number, while the carpels are usually entirely

wanting. Thus, owing to the diminished number of parts in the inner

whorls of the flower, these very double-looking blooms do not contain

any greatly increased number of parts.[436]

Flowers that, under ordinary circumstances, are gamopetalous, become, in

some instances, multiplied by the formation of additional segments, just

as in the case of polypetalous corollas; but in these cases the corollas

become polypetalous, their petals do not cohere one with another. Among

double flowers of this character may be mentioned _Campanula

rotundifolia_, _Gardenia_ sp., _Nerium Oleander_, _Serissa_ sp.,

_Arbutus Unedo_, &c. The change is associated with petalody of the

stamens and pistils.

A more frequent change among the monopetalous orders is the duplication

or triplication of the corolla, in consequence of which there appear to

be a series of corollas enclosed one within the other, the lobes of

which generally alternate with one another, but which sometimes are

superposed. This happens occasionally in the primrose (_Primula

acaulis_), and constitutes the variety called by the gardeners "hose in

hose."

The same condition occurs frequently in some species of _Datura_ and

_Campanula_.

[Illustration: FIG. 191.--_Campanula rotundifolia_. "Double flowers"

resulting from dialysis and multiplication of the petals.]

In _Antirrhinum majus_ double flowers of this character sometimes occur;

the outermost corolla is normal, the succeeding ones usually have their

petals separate one from the other; the stamens are sometimes present,

sometimes absent, and at other times petalodic. Similar occurrences may

be met with in labiates and jasmines, and in _Erica hyemalis_.

Mr. W. B. Hemsley has kindly furnished me with flowers of a similar kind

occurring in wild specimens of _Epacris impressa_,[437] and there are

analogous phenomena in the common honeysuckle (_Lonicera Periclymenum_),

in which three corollas and no stamens often occur.

This duplication may either be accounted for on the theory of chorisis

above alluded to, or by supposing that the extra corolline whorl is due

to a series of confluent petalodic stamens; that the latter is the true

explanation, in certain cases at least, is shown by some flowers of

_Datura fastuosa_, in which the second corolla was partially staminal in

its appearance, and bore nearly perfect anthers, in addition to the five

ordinary stamens, which were unaltered either in form or position. Some

partially virescent honeysuckle flowers have a similar structure.

There are other cases of apparent multiplication or duplication, due,

probably, rather to the formation of outgrowths from the petals than to

actual augmentation of their number. These excrescences occur sometimes

on the inner surface of the petals, or of the corolla; at other times on

the outer surface, as in some gloxinias, &c. This matter will be more

fully treated of under the head of hypertrophy and enation.

=Pleiotaxy of the androecium.=--An increase in the number of whorls in

the stamens is very common, especially in cases where the number of

circles of stamens is naturally large. The augmentation of the number of

stamens is still more frequent where these organs are arranged, not in

verticils, but in one continuous spiral line.

In _Cruciferae_ there is always an indication of two whorls of stamens,

and this indication is rendered even more apparent in some varieties

accidentally met with. So in _Saponaria_, in _Dianthus_, and other

_Caryophylleae_, three and four verticils of stamens have been met with.

In _Lonicera Periclymenum_ a second whorl of stamens more or less

petalodic sometimes occurs.

Moquin mentions a variety of _Rubus fruticosus_ in which nearly 900

petaloid organs existed in the place of the twenty-five or thirty

stamens natural to the plant, the other organs of the flower being in

their ordinary condition, with the exception of the pistil, which did

not attain its full size. Baillon records the occasional existence of

two rows of stamens in _Ditaxis lancifolia_.

=Increased number of stamens in orchids, &c.=--Various deviations from

the ordinary type of orchid structure have been already alluded to under

the head of displacement, fusion, peloria, substitution, &c., but the

alterations presented by the androecium in this family are so

important in reference to what is considered its natural conformation,

that it seems desirable, in this place, to enter upon the teratological

appearances presented by the androecium in this order, in somewhat

greater detail than usual. The ordinary structure of the flower with its

three sepals, two petals, labellum, column; and inferior ovary, is well

known. Such a conformation would be wholly anomalous and inexplicable

were it not that the real number and arrangement of parts have been

revealed by various workers labouring to the same end in different

fields. Thus, Robert Brown, Link, Bauer, Darwin, and others, paid

special attention to the minute anatomy and mode of distribution of the

vessels; Irmisch, Crueger, Payer, and others, to the evolution of the

flower; Lindley, St. Hilaire, and Reichenbach, to the comparison of the

completed structures in the various genera and species; while the

teratological observers have been numerous, as will be seen from the

selected references cited at the end of this paragraph and in other

places. The result of this manifold study has been a pretty general

agreement that the structure of the order (omitting minor details) is as

follows:--A six-parted perianth in two rows, the outer three (sepals)

generally regular and equal in shape; of the inner three (petals or

tepals) two are regular, and one, the labellum very irregular,

consisting not only of a petal, but of two abortive stamens incorporated

with it. The column is considered to be made up of one perfect and three

abortive stamens, in inseparable connection with three styles. By some,

however, it is supposed that all the stamens are confluent with the

column and none with the lip.

[Illustration: FIG. 192.--Diagram showing the arrangement of parts in an

orchid flower. According to Crueger, the stamens A 2, A 3, should be

distinct from the lip. The uppermost figure 2 should have been 1. (See

text.)]

In either case it is admitted that there are six stamens in two rows.

The first row consists of one posterior stamen, which is generally

perfect, and two abortive stamens incorporated with the labellum. The

second row also consists of three stamens, all of which are usually

abortive and inseparable from the column. Traces of them may

occasionally be met with in the form of tubercles or wing-like processes

from the column. In _Cypripedium_, while the ordinary stamen of the

outer row is deficient, two of the inner series are present. The

diagram, fig. 192, will serve to show the arrangement of the parts as

above described. + represents the situation of the stem or axis; on the

opposite side is the bract; between these are placed the sepals, one

posterior or next the axis (incorrectly numbered 2 in the plan), two

lateral 1, 1; next in order follow the petals, 2, 2, 2, two lateral and

somewhat posterior, one larger (the lip), anterior; the outer series of

stamens are represented by A 1, A 2, A 3, the two latter being fused

with the labellum; _a_ 1, _a_ 2, _a_ 3 represent the position of the

inner verticil of stamens, while s, s, s denote the three carpels. It is

foreign to the purpose of this book to detail the varied evidence in

support of this explanation of the homologies of orchid flowers.[438]

All that can be done in these pages is to set forth the evidence

furnished by teratology as to this matter--evidence for the most part

accumulated and recorded without any special reference to any theory of

orchid structure.

The following details all refer to flowers in which the number of

stamens in orchidaceous plants was increased beyond what is necessary.

They are arranged with reference to the number of adventitious organs,

beginning with those in which the number was smallest, and proceeding

thence to those in which it was greatest. In some cases it has not been

possible to ascertain whether the adventitious organs were really

restorations of the numerical symmetry, substitutions of one part for

another, stamen for petal, &c., or wholly adventitious productions.

Unless otherwise stated, the interpretation put upon the facts thus

recorded is that of the present writer, and not necessarily that of the

original observer.

Mr. J. T. Moggridge has described and figured a flower of

_Ophrys insectifera_ in which there was a vestige of a second

stamen present, probably one of the inner series fig. 192

(_a_^2).[439] The same observer also records the presence of a

second anther between the lobes of the normal one. This can

hardly be referred to either of the typical stamens, but would

seem to be a perverted development of the rostellum.[440]

Roeper is stated by Cramer[441] to have seen a specimen of

_Orchis morio_ with two stamens.

In a flower of _Habenaria chlorantha_, described by the late

Professor Henslow,[442] the outer three stamens are suppressed,

while two of the inner group are present, as happens normally

in _Cypripedium_.

A flower of _Cattleya violacea_ afforded a similar

illustration; but in this case only one of the inner stamens

was developed, and this in the form of a small petal, partly

adherent to the column.

In _Dendrobium normale_, Falconer, not only is the perianth

regular, but the column is triandrous,[443] the three stamens

(according to the diagram of its structure given by Lindley)

pertaining to the outer row.

In a specimen of _Dendrobium hoemoglossum_ kindly forwarded

from Ceylon by Mr. Thwaites there were three stamens present,

of which one posterior belonged to the outer series A 1, and

two lateral to the inner _a_ 1, _a_ 2, fig. 192.

M. His observed, several years in succession, some flowers of a

species of _Ophrys_ with three sepals, no lateral petals, one

lip, and three perfect stamens. In this case probably the two

supernumerary stamens were petals which had assumed an

anther-like character.

Wydler describes a flower of _Ophrys aranifera_ in which one

outer and two inner stamens were present.[444] I have myself

met with three such flowers in the same species. The stamens

present were A 1, _a_ 1, _a_ 2.

Dr. J. E. Gray exhibited at the Botanical Society of London, in

August, 1843, a specimen of _Ophrys apifera_ with a triandrous

column, the supernumerary anthers belonging, apparently, to the

inner whorl.

In his 'Catalogue of the Plants of South Kent,' p. 56, tab. iv,

f. 16, the Rev. G. E. Smith describes and figures a flower of

_O. aranifera_ with a triandrous column, seemingly of the same

kind as that spoken of by Dr. Gray.

Mr. Moggridge met with a triandrous flower in the same species,

and refers the appearance to "a fusion of two flowers,

accompanied by suppression and modification."[445] As, however,

no details are given in support of this opinion, it may be

conjectured that the two additional stamens were members of the

inner whorl _a_ 1, _a_ 2, and thus the conformation would be

the same as in the flowers just mentioned. The figures given by

Mr. Moggridge bear out this latter view, while they lend no

support to the hypothesis advanced by him. Nevertheless, no

decided opinion can be pronounced by those who have not had the

opportunity of examining the flowers in question.

Alphonse de Candolle[446] figures a flower of _Maxillaria_ in

exactly the same condition, so far as the stamens are

concerned, as in the Ophrys flowers just mentioned. It is

curious to observe that in many of these cases the two lateral

petals are suppressed.

Von Martius mentions the occurrence of three anthers

(_naturaliter conformatae_) in _Orchis morio_.[447] Richard,

as cited by Moquin-Tandon, Lindley, and others, describes and

figures a peloria of _Orchis latifolia_ with regular triandrous

flowers.[448]

The writer has examined, in the Royal Gardens at Kew, a flower

of _Cattleya crispa_ in which were three stamens, the central

one normal; the two lateral ones, belonging probably to the

inner whorl, were in appearance like the lateral petals, and

one of them was adherent to the central perfect column.

Duchartre[449] mentions a flower of _Cattleya Forbesii_ in

which there were two labella in addition to the ordinary one,

the column being in its normal condition. From the analogy of

other cases it would appear as if the additional labella in

this instance were the representatives of two stamens of the

outer whorl. Beer likewise has put on record the existence of a

triandrous _Cattleya_.[450]

A specimen of _Catasetum eburneum_ forwarded by Mr. Wilson

Saunders was normal so far as the sepals and two lateral petals

were concerned, but the anterior petal or labellum was flat and

in form quite like the two lateral ones; the column was normal

and in the situation of the two anterior stamens of the outer

series A 2, A 3, were two labella of the usual form (fig. 156,

p. 291). Perhaps the _Oncidium_ represented at p. 68, fig. 29,

may also be explained on the supposition that the two lateral

lobes of the labellum in this flower were the representatives

of stamens.

In Fig. 193 is shown the arrangement of parts in a flower of

_Ophrys aranifera_. Here there were three sepals, two lateral

petals, one of which was adherent to the side of the column;

the central labellum was seemingly deficient, but there were

two pseudo-labella placed laterally in the position of the two

antero-lateral stamens of the outer series (A 2, A 3). Within

these was another perfect stamen occupying the position of the

anterior stamen of the inner series (_a_ 3). In another flower

of the same species, gathered at the same time (fig. 194),

there were three sepals not at all different from those of the

normal flower. The three petals next in succession were also,

in form and position, in their ordinary state. In colour,

however, the two upper lateral petals differed from what is

customary, in having the same purplish-brown tint which

characterises the lip. Within these petals, at the upper part

of the flower, there was the ordinary column, and at the

opposite side, alternating with the petals before mentioned,

two additional lip-like petals, one provided with a half-anther

containing a single perfectly formed pollen-mass (A 2, A 3). It

is, perhaps, worthy of notice that the arrangement of the

coloured spots on the true labellum, and that on the

adventitious lips, replacing the two lower of the outer

stamens, were not of a similar character. The supernumerary

lips had the [Greek: pi]-shaped marking which is so common in

this species, while the true lip was, as to its spots, much

more like _O. apifera_. Alternating with this last whorl were

three columns, all apparently perfectly formed and differing

only from the ordinary one in their smaller size and

corresponding to _a_ 1, _a_ 2, _a_ 3. The ovary in this flower

was two-celled, with four parietal placentas, thus giving an

appearance as though there had been a fusion of two or more

flowers associated with suppression and other changes. The

position of the supernumerary organs and the absence of any

positive sign of fusion in the bracts or other part of the

flower, seemed, however, to negative the idea of fusion.[451]

[Illustration: FIG. 193.--Diagram showing the arrangement of

parts in a malformed flower of _Ophrys aranifera_ (see p.

384).]

[Illustration: FIG. 194.--Malformed flower of _Ophrys

aranifera_ with two supernumerary lips and three additional

stamens.]

A similar illustration, for a knowledge of which the writer is

indebted to the kindness of Professor Asa Gray and Mr. Darwin,

occurred in some specimens of _Pogonia ophioglossoides_

collected by Dr. J. H. Paine in a bog near Utica, New York. It

will be seen from the following description that these flowers

presented an almost precisely similar condition to those of the

_Ophrys aranifera_ just mentioned. "The peculiarities of these

flowers," writes Professor Gray, "are that they have three

labella, and that the column is resolved into small petaloid

organs. The blossom is normal as to the proper perianth, except

that the labellum is unusually papillose, bearded almost to the

base. The points of interest are, first, that the two accessory

labella are just in the position of the two suppressed stamens

of the outer series, viz. of A2 and A3, as represented in the

diagram, fig. 192; and there is a small petaloid body on the

other side of the flower, answering to the other stamen, A1.

Secondly, in one of the blossoms, and less distinctly in

another, two lateral stamens of the inner series (_a_1 and

_a_2) are represented each by a slender naked filament. There

are remaining petaloid bodies enough to answer for the third

stamen of the inner series and for the stigmas, but their order

is not well to be made out in the dried specimens." It may here

be mentioned that _Isochilus_ is normally triandrous.

A tetrandrous flower of _Cypripedium_ has also been recorded.

In _Isochilus_, according to Cruger, there are often five

stamens, and there are several, besides those already

mentioned, in which six more or less perfect stamens have been

seen--of these the following may be taken as illustrations. A

hexandrous flower of _Orchis militaris_ has been recorded by

Kirschleger,[452] and in the accompanying diagram (fig. 195),

from Cramer,[453] of a monstrous flower of _Orchis mascula_,

there is one perfect stamen of the outer row and two lip-like

stamens of the same series, while the inner verticil comprises

one perfect and two abortive stamens.

[Illustration: FIG. 195.--Diagram of flower of _Orchis mascula_

with two additional lips, two perfect and two imperfect stamens

(after Cramer).]

Morren[454] describes some flowers of _Orchis morio_ in which

there were three sepals, three petals, and within the latter

two other ternary series of petals; this would seem to be a

case of petalody of all six stamens. Morren, however, seems to

have considered the additional segments as repetitions of the

corolline whorl, though he describes a central mass as the

column bearing a "_souvenir_ of the anther." Nevertheless,

there is no decisive evidence either in his figure or his

description in support of his opinion as to the nature of the

central mass, which might be a distorted condition of the

styles, or, as is more probable, a rudimentary and irregular

flower. Morren also describes another flower of the same plant

in which there were three sepals, two lateral petals partially

lip-like in aspect, a third labellum normal, two additional

labella representing the two anterior stamens of the outer

whorl, while more or less developed rudiments of the remaining

four stamens also exist.

While, in most cases, the supernumerary stamens can, by reason

of their relative position, their complete or partial

antheriferous nature, be safely referred to one or other of the

six stamens, making up a typical orchid flower, there are other

specimens in which the additional stamens are altogether

adventitious, and do not admit of reference to the homologue.

Thus it was in a specimen of _Odontoglossum Alexandrae_ examined

by the writer, and in which, within a normally constructed

perianth, there were six columns, all polliniferous, but

arranged in so confused and complicated a manner that it was

impossible to make out any definite relation in their position.

There was nothing to indicate a fusion of flowers, but rather

an extension of the centre of the flower, and consequent

displacement of the stamens, &c. Again, the existence of

adventitious stamens does not necessarily imply the development

of organs usually suppressed, inasmuch as they may result from

the assumption by the lateral petals of staminal

characteristics.

Nevertheless, as far as teratology is concerned, specimens may

be found in which some or all of the usually suppressed stamens

of _Orchidaceae_ may be found. These stamens may be all perfect

(polliniferous), or, as is more frequently the case, more or

less petal-like. Moreover, when the stamens are petalodic, the

form assumed is usually that of the labellum.

The presence of stamens in undue numbers in orchids is very

generally, but not always, attended by some coincident

malformation, of which the most frequent is cohesion of two or

more sepals, and consequent displacement or adhesion of one

petal to the side of the column. Petalody of the styles and

median prolification are also sometimes found in association

with an augmented number of stamens.

[Illustration: FIG. 196.--Increased number of carpels, tulip.]

[Illustration: FIG. 197.--Fruit of St. Valery apple cut lengthwise.]

=Pleiotaxy of the gynoecium.=--An increase in the number of whorls of

which the pistil consists is not of very frequent occurrence. Generally

after the formation of the whorl of carpels, the energy of the growing

point ceases, or if by chance it be continued, the result is more

generally the production of a new flower-bud (median prolification) than

the repetition of the carpellary series. It is necessary also to

distinguish between the veritable augmentation of the pistil and the

semblance of it, brought about by the substitution of carpels for some

other organs, as pistillody of the stamens, and even of the segments of

the perianth, is not very unfrequent, as has already been stated under

the head of substitution. Again, the increased number of carpels which

is sometimes met with in such flowers, as _Magnolia_ or _Delphinium_,

where the ovaries are arranged in spiral series, is not strictly

referable to the present category.

The orange is one of the plants most frequently subject to an

augmentation in the number of carpellary whorls; sometimes this is due

to the stamens assuming the guise of carpels, but at other times the

increase occurs without any alteration in the stamens or other organs.

If the adventitious carpels be exposed, they are covered with yellow

rind, while those portions that are covered by the primary carpels are

destitute of rind. Some varieties of the double tulip are very subject

to a similar change, but, in this case, the petals and the stamens very

frequently become more or less carpellary in their nature. Fig. 196

represents an increased number of whorls of carpels in the variety

called "rex rubrorum," the segments of the perianth having been removed.

In the St. Valery apple, already referred to, there is a second whorl of

carpels above the first, a fact which has been made use of to explain

the similar structure of the pomegranate.

The tomato (_Lycopersicum esculentum_) is another plant in which an

adventitious series is frequently produced, and generally in combination

with the primary series.

In the Chinese primrose (_Primula sinensis_) a supernumerary whorl is

frequently met with, generally associated with other changes in the

construction and arrangement of the parts of the flower.

M. de Candolle[455] mentions a flower of _Gentiana purpurea_ with four

carpels in one series, and five others in the circle immediately above

them. Wigand[456] alludes to an instance wherein there was a second pair

of carpels above the first in _Vinca herbacea_. Dr. Sankey has forwarded

flowers of a _Pelargonium_ having a double series of carpels, eight in

the outer row, five in the inner, and this condition is stated to exist

in the flowers of the same plant for two years consecutively. In

_Aquilegia_ I have met with a similar increase in the whorls of

carpels.[457] Meissner records a similar augmentation in _Polygonum

orientale_.[458]

Wigand[459] describes and figures a flower of _Vinca minor_, in which

there were two carpels intervening between the ordinary pair, and a

similar illustration has been observed by the writer in _Allamanda

cathartica_. Eichler[460] has put on record a similar case in a

capparid.

Marchand[461] mentions a polycarpellary berberid (_Epimedium

Musschianum_). The supernumerary carpels in this flower were placed on a

short axis, which originated in the axils of the stamens, and as these

latter organs were present in their usual number and position, the

adventitious carpels could not be considered as resulting from a

transformation, or substitution of carpels for stamens.

Lastly, the instance cited by Dr. Allman[462] in _Saxifraga Geum_ may be

alluded to. Here there was a row of adventitious carpels between the

stamens and pistils, the backs of the carpels being turned towards the

axis of the flowers. Dr. Allman explains the presence of the

supernumerary parts by the supposed production of a whorl of secondary

axes between the stamens and the centre of the flower. These axes are

further supposed to bear imperfect flowers, of which the additional

carpels are the only traces, but this explanation seems forced.

In addition to the references already cited the following may be given:

Duchartre, 'Ann. Sc. Nat.,' 4 ser., vii, p. 23 (Tulip).

Ferrari, 'Hesperides,' pp. 271, 395, 405. Duchartre, 'Ann. Sc.

Nat.,' 4 ser., 1844, vol. i, p. 294. Maout, 'Lecons Element.,'

vol. ii, pp. 488-9. Clos, 'Ann. Sc. Nat.,' 1865, p. 317

(_Citrus Aurantium_).

Clos, 'Bull. Soc. Bot. Fr.,' vol. xiii; 'Rev. Bibl.,' p. 75.

Pasquale, 'Reddicont Accad. Sc. Fis. e Math. Napoli.' Octr.

1866 (_Solanum Lycopersicum_).

On the general subject of multiplication, in addition to previous

citations, the reader may be referred to A. P. de Candolle, 'Theorie

Element. Bot.,' ed. 3, p. 89.

=Increased number of flowers in an inflorescence.=--This happens

generally as a result of over luxuriant growth, and scarcely demands

notice here, being rather referable to variation than to malformation.

The increased number of florets in the spikelets of some grasses has

already been alluded to (p. 351). Thus spikelets of wheat occasionally

produce more than the three florets which are proper to them.[463] It

will be remembered that in this as in many other grasses there are

rudimentary florets, and it is no matter for surprise that these florets

should occasionally be fully developed.

FOOTNOTES:

[392] 'Bull. Soc. Bot. Fr.,' vol. vii, 1860, p. 587.

[393] 'Fragment. Phyt. Austral.,' part xx, p. 270.

[394] 'Bull. Acad. Belg.,' xvi, pt. i, p. 60, "Fuchsia," p. 125, c. ic.

[395] "Theorie de la feuille," 'Arch. des Sciences Bibl. Univers.,'

1868.

[396] See Engelmann, 'De Antholysi,' p. 16, section 12.

[397] Verhandl. des Botanisch. Vereins Brandenburg,' 1859, 1 heft.

[398] See Henslow. 'Mag. Nat, Hist.' 1832, vol. v, p. 429.

[399] 'Phytologist,' September, 1857.

[400] Seemann's 'Journal of Botany,' iv, p. 168, t. 47, f. 3.

[401] 'Illust. Hortic.,' 1866, misc., p. 97.

[402] See Fresenius, 'Mus. Senkenb.,' bd. 2, p. 43. Schlechtendal, 'Bot.

Zeit.,' iv, pp. 403, 492, _Veronica tetrandra_.

[403] 'Flora,' 1865, tab. 6, fig. 8.

[404] 'Org. Veget.,' t. i, p. 497, pl. 42, f. 3.

[405] 'El. Ter. Veg.,' p. 354.

[406] Cited in "Rev. Bibl." of 'Bull. Soc. Bot. Fr.,' 1866, p. 171.

[407] Loc. cit., 351.

[408] 'Mem. Acad. Toulous.,' vi, 1862, ex 'Bull. Soc. Bot. Fr.,' "Rev.

Bibl.," vol. ix, 1862. p. 127.

[409] 'Flora.' 1857. p. 289.

[410] L. c., p. 354.

[411] Giraud, 'Ed. Phil. Mag.,' Dec., 1839.

[412] See _Cerasus Caproniana_, D. C. 'Plant. Rar. Hort. Genev.,' tab.

18.

[413] Nees, 'Linnaea,' v, p. 679, tab. 11 (_Schoenodorus_).

[414] 'Gard. Chron.,' 1852, p. 452.

[415] See Cramer, 'Bildungsabweich.' pp. 16, 24.

[416] 'Linnaea,' 1842, p. 389, c. ic.

[417] Seemann's 'Journal of Botany,' 1867, vol. v, p. 158.

[418] Cramer, 'Bildungsabweich,' p. 66, _Astrantia major_, _Eryngium_,

to which may be added _Daucus_, _Heracleum_, &c.

[419] See also Reinwardt, 'Nov. Act. Acad. Nat. Cur.,' 12, 1, 37; and

Masters, 'Journ. Linn. Soc.,' vi, p. 24.

[420] 'Organog. Veget.,' tab. 53.

[421] 'Missbild.,' p. 206.

[422] Ehrenberg, 'Flora,' 1846, p. 704.

[423] 'Flora,' 1860, tab. 7.

[424] 'Ann. Sc. Nat.,' 3 ser., t. x, p. 207.

[425] 'Mem. Mus.,' xii. t. 17.

[426] 'Nov. Act. Acad. Nat. Cur.,' xv, tab. xxviii, f. 3; 'Bot. Mag.,'

t. 1622. "Caryophyllus spicam frumenti referens." A similar malformation

in _Dianthus barbatus_ is not uncommon. It has lately been introduced

into gardens under the name of _Dianthus_ "_mousseux_," but is not

likely to find favour with gardeners.

[427] 'Bull. Soc. Bot. France,' t. vi, 1859. p. 268.

[428] Weber, 'Verhandl. Nat. Hist. Vereins. Rhein. Pruss.,' 1860.

[429] 'Bot. Zeit.,' 1848, p. 217.

[430] 'De Anthol.,' p. 17, Sec. 12.

[431] 'Linnaea,' vol. ii, 1827, p. 85.

[432] 'De Antholysi,' p. 17, tab. iii, f. 15, 16; Weinmann, 'Phytanth.

iconogr.,' nro. 292.

[433] See Hildebrand, 'Bot. Zeit.,' 1862, p. 209, tab. viii; Cramer,

'Bildungsabweich.,' p. 7, tab. xiii; Engelmann, 'De Antholysi,' p. 18,

&c. For similar changes in _Gagea arvensis_ see Wirtgen, 'Flora,' 1838,

t. xxi. p. 350, and 'Flora.' 1846, p. 353. Some of these are cases of

synanthy.

[434] Schlechtendal, 'Bot. Zeit.,' xx, 1862, p. 301.

[435] 'Phil. Bot.,' Sec. 126.

[436] C. Morren, 'Bull. Acad. Belg.,' xix, part ii, p. 17.

[437] 'Seemann's Journal of Botany,' iii, p. 354.

[438] On this point the reader will find an excellent summary in

Lindley's 'Vegetable Kingdom,' cd. iii, p. 183_a_, and in Darwin,

'Fertilisation of Orchids,' p. 292. See also Crueger,'Journ. Linn. Soc.,'

t. viii, p. 134.

[439] 'Seemann's Journal of Botany,' vol. iv, p. 168, tab. 47.

[440] Ibid., t. iv. 1866, p. 168, t. xlvii, f. 1.

[441] 'Bildungsabweich,' p. 8; see also 'Bot. Zeit.,' 1852, p. 425.

[442] 'Journ. Linn. Soc.,' t. ii, p. 104. tab. 1, fig. B.

[443] Lindl., "Orchid. Ind.," 'Jour. Linn. Soc.,' iii, p. 9.

[444] 'Arch. Bot.,' ii, p. 300, tab. xvi, f. 11.

[445] 'Seemann's Journal of Botany,' v, p. 318, tab. lxxii, figs. A 4, 4

_a_.

[446] "Monstr. Veg.," in 'Neue Denkschrift,' p. 17, tab. vii.

[447] 'Flora,' t. viii, 1825, p. 736.

[448] 'Mem. Soc. d'Hist. Nat.,' ii, 1, p. 212, tab. iii.

[449] 'Bull. Soc. Bot. Fr.,' t. vii, 1860, p. 26.

[450] 'Beitr. Morphol. und Biol. Orchid.,' quoted by Cramer;

'Bildungsabweich,' p. 9.

[451] Masters, 'Journ. Linn. Soc.,' viii, p. 207. See also Rodigas,

'Bull. Soc. Bot. Belg.,' iv, p. 266, for similar changes in _Cypripedium

Hookerae_.

[452] Kirschleger, 'Flora,' 1844, p. 131.

[453] 'Bildungsabweich,' p. 11, tab. xiv, f. 3.

[454] 'Bull. Acad. Roy. Belg.,' t. xix, part 2, p. 171.

[455] 'Organogr. Veget.,' t. i, p. 509, tab. 40, figs. 6, 7.

[456] 'Flora,' 1856, p. 715.

[457] 'Linn. Trans.,' t. xxiii, p. 364, tab. 34, fig. 5.

[458] 'Monog. Polygon,' pl. 3, K. f. 12.

[459] 'Flora,' 1856, tab. viii.

[460] Ibid., 1865, tab. ix, f. 6.

[461] 'Adansonia,' vol. iv, 1864, p. 127.

[462] 'Ann. Nat. Hist.,' 1845, vol. xvi, p. 126.

[463] See Schlechtendal, 'Bot. Zeit.,' t. xviii, p. 381 (_Triticum_);

also 'Flora,' t. xiv, 1831, p. 5 (_Avena_).

PART II.

DIMINISHED NUMBER OF ORGANS.

A diminution in the number of parts is generally due to suppression,

using that word as the equivalent of non-development. It corresponds

thus in meaning with the _Fehlschlagen_ of the Germans, the _avortement

complete_ of Moquin and other French writers. It differs from atrophy,

or partial abortion, inasmuch as the latter terms apply to instances

wherein there has been a partial development, and in which evolution has

gone on to a certain extent, but has, from some cause or other, been

checked. These cases will be found under the head of diminished size of

organs. As the word abortion is used by different authors in different

ways, it is the more necessary to be as precise as possible in the

application of the term. In the present work abortion is used to apply

to cases wherein parts have been formed, but wherein growth has been

arrested at a certain stage, and which, therefore, have either remained

_in statu quo_, while the surrounding parts have increased, or have,

from pressure or other causes, actually diminished in size.

In practice, however, it is not always possible to discriminate between

those instances in which there has been a true suppression, an absolute

non-development of any particular organ, and those in which it has been

formed, and has grown for a time, but has afterwards ceased to do so,

and has been gradually obliterated by the pressure exercised by the

constantly increasing bulk of adjacent parts, or possibly has become

incorporated with them. In the adult flower the appearances are the

same, though the causes may have been different.

CHAPTER I.

SUPPRESSION OF AXILE ORGANS.

Absolute suppression of the main axis is tantamount to the non-existence

of the plant, so that the terms "acaulescent," "acaulosia," etc, must be

considered relatively only, and must be taken to signify an atrophied or

diminished size of the stem, arising from the non-development of the

internodes.

The absence of lateral branches or divisions of the axis is of frequent

occurrence, and is dependent on such causes as the following:--deficient

supply of nutriment, position against a wall or other obstacle, close

crowding of individual plants, too great or too little light, too rich

or too poor a soil, &c.

Probably the absence of the swollen portion below the flower in the case

of many proliferous roses, double-flowered apples, as already referred

to, may be dependent on the non-development of the extremity of the

peduncle or flower-stalk. Thus, in a double-flowered apple recently

examined, there was a sort of involucel of five perfect leaves, then

five sepals surrounding an equal number of petals, numerous stamens, and

five styles, but not a trace of an expanded axis, nor of any portion of

the carpels, except the styles. The views taken as to the nature of this

and similar malformations must depend on the opinion held as to the

nature of inferior pistils, and on the share, if any, that the expanded

axis takes in their production. As elsewhere said, the evidence

furnished by teratology is conflicting, but there seems little or

nothing to invalidate the notion that the end of the flower-stalk and

the base of the calyx may, to a varying extent, in different cases,

jointly be concerned in the formation of the so-called calyx-tube and of

the inferior ovary. Obviously it is not proper to apply to all cases

where there is an inferior ovary the same explanation as to how it is

brought about.

As these pages are passing through the press, M. Casimir de Candolle has

published a different explanation as to the nature of the hip of the

rose, having been led to his opinion by the conclusion that he has

arrived at, that the leaf is to be considered in the light of a

flattened branch, whose upper or posterior surface is more or less

completely atrophied.

According to M. de Candolle, the calyx-tube, in the case of the rose, is

neither a whorl of leaves, nor a concave axis in the ordinary sense in

which those terms are used, but is rather to be considered as a

ring-like projection from an axis arrested in its ulterior development.

The secondary projections from the original one correspond to an equal

number of vascular bundles, and develope into the sepals, petals,

stamens, and ovaries. If these organs remained in a rudimentary

condition, the tube of the calyx would be reduced to the condition of a

sheathing leaf. The rose flower, then, according to M. de Candolle, may

be considered as a sheathing leaf, whose fibro-vascular system is

complete, and from which all possible primary projections are

developed.[464]

If, as M. de Candolle considers, the leaf and the branch differ merely

in the fact that the vascular system is complete in the latter, and

partly atrophied in the former, it would surely be better to consider

the "calyx-tube" of the rose as a concave axis rather than as a leaf,

seeing that he admits the fibro-vascular system to be complete in the

case of the rose.

With reference to this point the reader is referred to Mr. Bentham's

account of the morphology and homologies of the _Myrtaceae_ in the

'Journal of the Linnean Society,' vol. x, p. 105. See also _ante_, pp.

71, 77.

Some doubts also exist as to the nature of the beak or columella of such

fruits as those of _Geraniaceae_, _Malvaceae_, _Umbelliferae_,

_Euphorbiaceae_, &c. The nature of the organ in question may probably be

different in the several orders named; at any rate the subject cannot be

discussed in this place, and it is mentioned here because, now and then,

it happens that the organ in question is completely wanting, and hence

affords an illustration of suppression.

FOOTNOTES:

[464] 'Theorie de la feuille.' p. 24.

CHAPTER II.

SUPPRESSION OF FOLIAR ORGANS.

This subject may be considered, according as the separate leaves of the

stem or of the flower are affected, and according as either the number

of members of distinct whorls, or that of the whorls themselves, is

diminished.

The terms aphylly, meiophylly, and meiotaxy may be employed, according

as the individual leaves are altogether wanting, or with reference to

the diminished number of parts in a whorl, or a decrease in the

verticils.

=Aphylly.=--Entire suppression of the leaves is a rare phenomenon. Under

ordinary circumstances it occurs in most _Cactaceae_, in some of the

succulent Euphorbias, and other similar plants, where the epidermal

layers of the stem fulfil the functions of leaves. But even in these

plants leaf-like organs are present in some stage or another of the

plant's life.

Partial suppression of the leaf occurs sometimes in compound leaves,

some or other of the leaflets of which are occasionally suppressed.

Sometimes, as Moquin remarks, it is the terminal leaflet which is

wanting, when the appearance is that of _Cliffortia_, at other times the

lateral leaflets are deficient, as in _Citrus_ or _Phyllarthron_.

_Ononis monophylla_ and _Fragaria monophylla_ may be cited as instances

of the suppression of the lateral leaflets. If the blade of the leaf

disappears entirely, we have then an analogous condition to that of the

phyllodineous acacias.

With reference to the strawberry just mentioned, Duchesne, 'Hist. Nat.

Frais.,' p. 133, says that this was a seedling raised from the _fraisier

des bois_, and the characters of which were reproduced by seed, and have

now become fixed. The monophyllous condition has been considered to be

the result of fusion of two or more leaflets, but however true this may

be in some cases, it is not the case with this strawberry. M. Paillot

states that he has found the variety in a wild state.[465]

In like manner varieties of the following plants occur with simple

leaves, _Rosa berberifolia_ (_Lowea_), _Rubus Idaeus_, _Robinia

pseudacacia_, _Fraxinus excelsior_, _Sambucus nigra_, _Juglans nigra_,

&c.

In one instance seen by the writer every portion of the leaf of a rose

was deficient, except the stipules and a small portion of the petiole.

(See abortion.)

=Meiophylly.=--A diminished number of leaves in a whorl occasionally

takes place; thus, in some of the _Stellatae_, and frequently in _Paris

quadrifolia_, the number of leaves in the verticil is reduced. Care must

be exercised in such instances that an apparent diminution arising from

a fusion of two or more leaves be not confounded with suppression.

=Meiophylly of the calyx or perianth.=--A lessened number of sepals is

not a very common occurrence among dicotyledonous plants. Seringe

figures a proliferous flower of _Arabis alpina_ with two sepals only,

and a similar occurrence has been noticed in _Diplotaxis tenuifolia_.

In _Cattleya violacea_ the writer has met with a flower in which the

uppermost sepal was entirely wanting, while two of the lateral petals

were fused together. Moquin records that in some of the flowers of

_Chenopodiaceae_, in which the inflorescence is dense, a suppression of

two or three sepals sometimes occurs. The species mentioned are _Ambrina

ambrosioides_, _Chenopodium glaucum_, and _Blitum polymorphum_.

=Meiophylly of the corolla.=--Suppression of one or more petals is of

more frequent occurrence than the corresponding deficiency in the case

of the sepals. Among _Caryophyllaceae_ imperfection as regards the

numerical symmetry of the flower is not uncommon, as in species of

_Cerastium_, _Sagina_, _Dianthus_, &c. In _Ranunculaceae_ the petals are

likewise not unfrequently partially or wholly suppressed. A familiar

illustration of this is afforded by _Ranunculus auricomus_, in which it

is the exception to find the corolla perfect.[466] Some varieties of

_Corchorus acutangulus_ in west tropical Africa are likewise subject to

the same peculiarity. Amongst _Papilionaceae_ absence of the carina or of

the alae is not uncommon, as in _Trifolium repens_, _Faba vulgaris_, &c.

Moquin relates a case of the kind in the haricot bean, in which the

carina was entirely absent, and another in the pea, where both carina

and alae were missing, thus reducing the flower to the condition that is

normal in _Amorpha_ and _Afzelia_. Suppression of the upper lip in such

flowers as _Calceolaria_ has been termed by Morren "apilary."

In _Orchidaceae_ entire absence of the labellum, frequently without any

other perceptible change, is of common occurrence. The writer has seen

numerous specimens of the kind in _Ophrys apifera_ and _O. aranifera_;

also in _Dendrobium nobile_, _AErides odoratum_, _Cypripedium villosum_,

_Listera ovata_, &c. Morren[467] mentions analogous deficiencies in

_Zygopetalum maxillare_, _Calanthe_ sp., and _Cattleya Forbesii_. In

most of these there was also a fusion of the two lower sepals, which

were so twisted out of place as to occupy the situation usually held by

the labellum. At the same time the column was partially atrophied. To

this deficiency of the lip the author just quoted proposed to apply the

term acheilary, [Greek: a-cheilarion]. Mr. Moggridge has communicated to

the author an account of certain flowers of _Ophrys aranifera_, in which

the petals were deficient, sometimes completely, at other times one or

two only were present.

=Meiophylly of the androecium.=--Suppression of one or more stamens,

independently of like defects in other whorls, is not uncommon, even as

a normal occurrence, _e.g._ in _Carlemannia_, where the flower, though

regular, has only two stamens, and other similar deficiencies are common

in Dilleniads.

Seringe relates the occurrence of suppression of some of the stamens in

_Diplotaxis tenuifolia_,[468] St. Hilaire in _Cardamine hirsuta_, others

in _C. sylvatica_.

In _Caryophyllaceae_ suppression of one or more stamens has been observed

in _Mollugo cerviana_, _Arenaria tetraquetra_, _Cerastium_, &c.[469]

Among violets the writer has observed numerous flowers in which two or

three stamens were suppressed. Chatin[470] alludes to a similar

reduction in _Tropaeolum_, while in flowers that are usually didynamous

absence of two or more of the stamens is not unfrequent, _e.g._ in

_Antirrhinum_, _Digitalis_, while in a flower of _Catalpa_ a solitary

perfect stamen, and a complete absence of the sterile ones usually

present, have been observed. This might have been anticipated from the

frequent deficiencies in the staminal whorl in these plants under what

are considered to be normal conditions. Reduction of the staminal whorl

is also not unfrequent in _Trifolium repens_ and _T. hybridum_, and has

been seen in _Delphinium_, &c.[471]

=Meiophylly of the gynoecium.=--Numerical inequality in the case of

the pistil, as compared with the other whorls of the flower, is of such

common occurrence, under ordinary circumstances, that in some text-books

it is looked on as the normal condition, and a flower which is isomerous

in the outer whorls is by some writers not considered numerically

irregular if the number of the carpels does not coincide with that of

the other organs.

But in this place it is only necessary to allude to deviations from the

number of carpels that are ordinarily found in the particular species

under observation. As illustrations the following may be

cited:--_Arenaria tetraqueta_, which has normally three styles, and a

six-valved capsule, has been seen with two styles, and a four or

five-valved capsule. Moquin relates an instance in _Polygala vulgaris_

where there was but a single carpel, a condition analogous to that which

occurs normally in the allied genus _Mozinna_. _Reseda luteola_

occasionally occurs with two carpels only, while Aconites, Delphiniums,

Nigellas, and Paeonies frequently experience a like diminution in their

pistil.

In a flower of _Papaver Rhaeas_ the writer has recently met with an ovary

with four stigmas and four parietal placentae only, and to Mr.

Worthington Smith he is indebted for sketches of crocus blooms with two,

and in one instance only a solitary carpel.

Moquin cites the fruit of a wild bramble (_Rubus_) in which all the

little drupes which go to make up the ordinary fruit were absent, except

one, which thus resembled a small cherry. In _Crataegus_ the pistil is

similarly reduced to a single carpel, as in _C. monogyna_.

The writer has on more than one occasion met with walnuts (_Juglans_)

with a single valve and a single suture.[472] If the ovary of _Juglans_

normally consisted of two valvate carpels, the instances just alluded to

might possibly be explained by the suppression of one carpel, but the

ovary in _Juglans_ is at first one-celled according to M. Casimir de

Candolle.

Among monocotyledons _Convallaria majalis_ may be mentioned as very

liable to suffer diminution in the number of its carpels, either

separately or in association with other changes.[473]

=Meiophylly of the flower as a whole.=--In the preceding sections a

reduction in the parts of each individual whorl has been considered

without reference to similar diminution in neighbouring verticils. It

more commonly happens, nevertheless, that a defect in one series is

attended by a corresponding imperfection in adjoining ones. Thus

trimerous fuchsias and tetramerous jasmines may frequently be met with,

and Turpin describes a tetramerous flower of _Cobaea scandens_. Perhaps

monocotyledonous plants are more subject to this numerical reduction of

the parts of several verticils than are other flowering plants. Thus, in

both _Lilium lancifolium_ and _L. auratum_ the writer has frequently met

with pentamerous flowers. In _Convallaria maialis_ a like deviation not

unfrequently occurs.[474] M. Delavaud has recorded a similar occurrence

in a tulip.[475]

Dimerous crocuses may also sometimes be met with. In one flower of this

nature the segments of the perianth were arranged in decussating pairs,

and the four stamens were united by their filaments so as to form two

pairs.

M. Fournier mentions something of the same kind in the flower of an

_Iris_.[476]

Orchids seem peculiarly liable to the decrease in the number of their

floral organs. Prillieux[477] mentions a flower of _Cattleya

amethystina_ wherein each whorl of the perianth consisted of two

opposite segments.

The same observer has put on record instances of a similar kind in

_Epidendrum Stamfordianum_. In one flower of the last-named species the

perianth consisted of one sepal only, and one lip-like petal placed

opposite to it.[478] Morren[479] describes a flower of _Cypripedium

insigne_, in which there were two sepals and two petals. Of a similar

character was the flower found by Mr. J. A. Paine, and described in the

following terms by Professor Asa Gray in the 'American Journal of

Science,' July, 1866:--"The plant" (_Cypripedium candidum_) "bears two

flowers: the axillary one is normal; the terminal one exhibits the

following peculiarities. The lower part of the bract forms a sheath

which encloses the ovary. The labellum is wanting; and there are two

sterile stamens, the supernumerary one being opposite the other, _i.e._

on the side of the style where the labellum belongs. Accordingly the

first impression would be that the labellum is here transformed into a

sterile stamen. The latter, however, agrees with the normal sterile

stamen in its insertion as well as in shape, being equally adnate to the

base of the style. Moreover, the anteposed sepal is exactly like the

other, has a good midrib and an entire point. As the two sterile stamens

are anteposed to the two sepals, so are the two fertile stamens to the

two petals, and the latter are adnate to the style a little higher than

the former. The style is longer than usual, is straight and erect; the

broad, disciform stigma therefore faces upwards; it is oval and

symmetrical, and a light groove across its middle shows it to be

dimerous. The placentae, accordingly, are only two. The groove on the

stigma and the placentae are in line with the fertile stamens.

Here, therefore, is a symmetrical and complete, regular, but dimerous

orchideous flower, the first verticil of stamens not antheriferous, the

second antheriferous, the carpels alternate with these; and here we have

clear (and perhaps the first direct) demonstration that the orchideous

type of flower has two stamineal verticils, as Brown always insisted."

[Illustration: FIG. 198.--Regular dimerous flower of _Calanthe

vestita_.]

[Illustration: FIG. 199.--Regular dimerous flower of _Odontoglossum

Alexandrae_.]

Dr. Moore, of Glasnevin, kindly forwarded to the writer a flower of

_Calanthe vestita_ (fig. 198), in which there were two sepals only,

anterior and posterior, and two petals at right angles to the two

sepals. The lip was entirely wanting, but the column and ovary were in

their usual condition. In _Odontoglossum Alexandrae_ a similar reduction

of parts has been observed by the author (fig. 199).

It is curious to observe in these flowers how precisely one sepal

occupies the position of the labellum, and how the lateral petals are

displaced from the position they usually occupy, so as to form a regular

flower, the segments of which decussate, thus giving rise to a species

of regular peloria.

The genus _Maelenia_ was established on a malformed flower of _Orchis_ of

similar character to those above mentioned.

=Meiotaxy of the calyx.=--As already mentioned, this term is here

employed to denote those illustrations in which entire whorls are

suppressed. Complete deficiency of the calyx in a dichlamydeous flower

seems seldom or ever to occur; the nearest approach to it would be in

those cases where the calyx is, as it is termed, "obsolete," but here it

is chiefly the limb of the calyx which is atrophied, the lower portion

being more or less adherent to the ovary. In what are termed

monochlamydeous flowers both calyx and corolla are wanting, as in

_Salicineae_ and many other orders.

=Meiotaxy of the corolla.=--Deficiency of the entire corolla occurs in

conjunction with similar reductions in other organs, or as an isolated

phenomenon in the many apetalous varieties of plants recorded in books.

Deficiency of the corolla was observed in _Campanula perfoliata_ and

_Ruellia clandestina_ by Linne, who calls such blooms _flores

mutilati_.[480] Drs. Hooker and Thomson relate a similar occurrence in

_Campanula canescens_ and _C. colorata_. Some plants seem as a normal

occurrence to produce flowers of different construction, and are hence

termed dimorphic, as in many _Malpighiaceae_, _Violaceae_, _Oxalidaceae_,

in some of the flowers of which the petals are altogether wanting, while

in others the corolla is developed as usual. This deficiency of the

corolla is frequently, but not invariably, associated with an increased

fertility. Thus, in some violets the flowers produced in summer, and in

which the petals are either entirely suppressed or are more or less

atrophied, are always fertile, while the blossoms developed in spring,

and in which the petals are always present, are much less fertile. In

_Oxalis Acetosella_ there are two forms of flower, the one with, the

other without, petals, but both seem equally fertile. Linne remarks that

many plants which, in warm latitudes, produce a corolla, do not do so

when grown in colder climates. Thus, certain species of _Helianthemum_

are apetalous in Lapland. In the Pyrenees, according to Bentham, the

flowers of _Ajuga iva_ are constantly deprived of their corolla.[481]

Apetalous flowers have been noted most frequently in the following

plants:

Aconitum, sp. pl.!

Cardamine impatiens.

Cheiranthus Cheiri!

Viola odorata!

Cerastium vulgatum!

Alsine media.

Stellaria.

Lychnis dioica!

Dianthus barbatus, and other Caryophylleae.

Helianthemum, sp.!

Oxalis Acetosella.

Balsamineae.

Malpighiaceae.

Rosa centifolia.

arvensis!

Crataegus!

Medicago lupulina.

Melilotus officinalis.

Ononis minutissima.

Saxifraga longifolia.

Verbascum Thapsus.

Ajuga iva.

Teucrium Botrys.

Lamium purpureum!

amplexicaule.

Polemonium caeruleum.

Campanula, sp. pl.!

Ruellia clandestina.

Lonicera Periclymenum!

Tradescantia, sp.!

Hymenocallis.

The following references apply some to apetalous and others to

dimorphic flowers, but it must be remembered that the latter

plants are not necessarily wanting in petals or stamens, &c.,

though the functional activity of the parts may be impaired:

A. de Jussien, 'Monogr. Malpigh.,' pp. 82, 334. Torrey, 'Fl.

New York,' i, p. 428. Hooker and Thomson, 'Journ. Linn. Soc.,'

ii, p. 7, Guillemin, 'Archiv. de Botan.,' i, p. 412. Michalet,

'Bull. Soc. Bot. Fr.,' vii. p. 465. Mueller, 'Bot. Zeit.,' 1857,

p. 729. 'Natural History Review,' July, 1862, p. 235.

=Meiotaxy of the androecium.=--Complete suppression of the stamens

occurs normally in the female flowers of unisexual plants, and, as an

accidental occurrence, is not very uncommon. _Erica Tetralix_ is one of

the plants in which this is said to happen. The variety _anandra_ is

said to have been known in France since 1635. Cornuti speaks of it in

his 'Enchiridion.' In 1860 M. du Parquet discovered it in peaty woods

near Nangis (Seine et Marne).

Many _Umbelliferae_, such as _Trinia vulgaris_, present a like

deficiency, while it is of common occurrence among _Rosaceae_ and

_Pomaceae_. In the latter group the St. Valery apple, so often referred

to, is an illustration. To obtain fruits from this variety it is

necessary to apply pollen from another flower, a proceeding made the

occasion of festivity and rejoicing by the villagers in some parts of

France. In some of the _Artemisias_, especially in _Artemisia

Tournefortiana_, all the florets have been noticed to be female, owing

to the suppression of the stamens, and this suppression is associated

with a change in the form of florets.[482] Mr. Moggridge has

communicated to the author flowers of _Thymus Serpyllum_ from a plant in

which all the stamens were deficient, the flower being otherwise normal.

M. Dupont has given a list of nineteen species of _Chenopodiaceae_ in

which female flowers are occasionally produced, owing to the entire

suppression of the staminal whorl.[483]

Flowers the subjects either of regular or irregular peloria, _q. v._,

are often destitute of some or all their stamens, _e.g._ _Calceolaria_,

_Linaria_, _Viola_, &c., while in cases of synanthy suppression of some

of the parts of the flower, and specially of the stamens, is of very

common occurrence.

Suppression of the androecium as a teratological occurrence has been

most frequently noticed in the following plants, omitting members of

those families whose floral construction is normally incomplete in the

majority of instances, and exclusive also of cases of substitution. See

also under Heterogamy.

Ranunculus Ficaria!

auricomus!

bulbosus!

Cruciferae, sp. pl.

Violaceae, sp. pl.

Honckenya peploides.

Stellaria.

Caryophyllaceae, sp. pl.

Malpighiaceae, sp. pl.

Tropaeolum majus!

Fragaria vesca!

Rubus, sp.

Pyrus Malus.

Agrimonia vulgaris.

Rosaceae, sp. pl.

Trifolium hybridum.

repens.

Umbelliferae, sp. pl.

Onagraceae, sp. pl.

Hippuris vulgaris.

Callitriche vernalis.

autumnalis.

Lonicera Periclymenum.

Erica Tetralix.

Thymus Serpyllum.

Calceolaria.

Compositae, sp. pl.

Chenopodiaceae, sp. pl.

Stratiotes aloides.

=Meiotaxy of the gynoecium.=--Complete suppression of the pistil is of

more frequent occurrence than that of the stamens, hence more flowers

become accidentally unisexual by suppression of the pistil than by

deficiency of the stamens.

In many _Umbelliferae_, e.g. _Torilis Anthriscus_, _Cicuta virosa_, the

central flowers are often male, owing to the suppression of the pistil.

In many double flowers, owing to the excessive multiplication of

petaloid stamens, the pistil is suppressed, in which cases it often

happens that the flower is depressed in the centre, as in some garden

varieties of _Ranunculus_. Schlechtendal, in describing a flower of

_Colchicum autumnale_, in which the perianth was virescent, says that,

although the stamens were present, the pistil was absent.

In proliferous flowers the pistil is often completely defective, its

place being occupied by the adventitious bud or axis.

As in other cases of like nature, suppression of the pistil is very

frequently consequent on fusion of flowers or other changes. Thus Morren

relates an instance of synanthy in the flowers of _Torenia scabra_,

accompanied by resorption or disappearance of some parts and spiral

torsion of others. The pistil was entirely absent in this instance.[484]

M. Gaetano Licopoli places on record an instance where the petals and

carpels of _Melianthus major_ were suppressed.[485]

On the whole, the pistil seems less subject to changes of this character

than the androecium.

Suppression of the pistil has been most frequently recorded in flowers

(normally bisexual) of--

Ranunculus!

Aconitium!

Delphinium!

Paeonia.

Caryophylleae!

Umbelliferae.

Trifolium repens.

hybridum.

Compositae, sp. pl.

Datura.

Torenia asiatica.

Colchicum autumnale.

=Suppression of ovules,--abortion of seeds.=--The two cases are taken

together, as the effects are similar, though it must be remembered that

in the one case the ovules at any rate have been formed, but their

development has been arrested, while in the other they have never

existed. The precise cause that has determined the absence of seed

cannot in all cases be ascertained in the adult condition, hence it is

convenient to treat the two phenomena under one head.

Many plants in other than their native climates either produce no fruit

at all, or the fruits that are produced are destitute of seed, _e.g._

_Musa_, _Artocarpus_, &c. Some of the cultivated varieties of the grape

and of the berberry produce no seeds.

Suppression or abortion of the seed is frequently associated with the

excessive development either in size or number of other portions of the

plant, or with an altered condition, as when carpels become foliaceous

and their margins detached. Hybridisation and cross fertilisation are

also well-known agents in diminishing the number and size of seeds.

=Meiotaxy of the parts of the flower in general.=--In the preceding

sections suppression has been considered as it affected individual

members of a whorl or separate whorls. It rarely happens, however, that

the suppression is limited in this way. More generally several of the

parts of the flower are simultaneously affected in the same manner.

A few illustrations are all that is necessary to give as to this point.

One of the most familiar instances is that of the cauliflower or

broccoli, where the common flower-stalk is inordinately thickened and

fleshy, while the corolla and inner parts of the flower are usually

entirely suppressed; the four sepals can, however, generally be

detected.

Maximowicz describes a _Stellaria_ (_Kraschenikovia_) in which the upper

flowers are male only, while the lower ones, which ultimately become

buried in the soil, have neither petals, stamens, nor styles, but the

walls of the capsule are fleshy, and enclose numerous seeds.[486]

Kirschleger[487] mentions a variety of _Lonicera Caprifolium_, which was

not only destitute of petals but of stamens also.

In some species of _Muscari_ and _Bellevalia_ the uppermost flowers of

the raceme show more or less complete suppression of almost all the part

of which the flower normally consists. In those cases where an imperfect

perianth exists, but in which the stamens and pistils are entirely

suppressed, Morren applies the term Cenanthy, [Greek: kenos], empty.

=Complete suppression of the flower.=--It is not necessary in this place

to allude to that deficient production of flowers characteristic of what

is termed by gardeners a "sky bloomer." In such plants often the

requisite conditions are not complied with, and the skill of the

gardener is shown in his attempt to discover and allow the plant to

avail itself of the necessary requirements. We need here only allude to

those instances in which provision is made for the production of

flowers, and yet they are not produced. A good illustration of this is

afforded by the feather-hyacinth, _Hyacinthus comosus_, in which the

flowers are almost entirely suppressed, while the pedicels are

inordinately increased in number, and their colour heightened. Something

similar occurs in several allied species, and in _Bowiea volubilis_. The

wig plant (_Rhus Cotinus_) affords another illustration of the same

thing. Some tendrils also owe their appearance to the absence of

flowers, being modified peduncles; proofs of this may frequently be met

with in the case of the vine.

In _Lamium album_ I have seen one of the verticillasters on one side of

the stem completely wanting, the adjacent leaf being, however, as fully

formed as usual.

=General remarks on suppression.=--On comparing together the various

whorls of the flower in reference to suppression, and, it may be added,

to atrophy, we find that these phenomena occur most rarely in the calyx,

more frequently in the corolla, and very often in the sexual

organs and seeds; hence it would seem as if the uppermost and most

central organs, those most subject to pressure and latest in date of

development--formed, that is, when the formative energies of the plant

are most liable to be exhausted--are the most prone to be suppressed or

arrested in their development. When the plants in which these

occurrences happen most frequently are compared together, it may be seen

that partial or entire suppression of the floral envelopes, calyx, and

corolla, is far more commonly met with in the polypetalous and

hypogynous groups than in the gamopetalous or epigynous series.

The orders in which suppression (speaking generally) occurs most often

as a teratological occurrence are the following:--_Ranunculaceae_,

_Cruciferae_, _Caryophyllaceae_, _Violaceae_, _Leguminosae_, _Onagraceae_,

_Jasminaceae_, _Orchidaceae_. It will be observed that these are all

orders wherein suppression of the whole or part of the outer floral

whorls takes place in certain genera as a constant occurrence.

Again, it may be remarked that many of these orders show a tendency

towards a regular diminution of the assumed normal number of their

parts; thus, among _Onagraceae_, _Circeia_ and _Lopezia_ may be referred

to, the former normally dimerous, the latter having only one perfect

petal. So in fuchsias, a very common deviation consists in a trimerous

and rarely a dimerous symmetry of the flower.

Although, if the absolute number of genera or orders be counted, there

appears to be little difference in the frequency of the occurrence of

suppression in irregular flowers as contrasted with regular flowers, yet

if the individual instances could be counted in the two groups

respectively it would be found that suppression is more common among

irregular than in regular flowers. Thus, the number of individual

instances of flowers in which the perianth is defective is comparatively

large among _Violaceae_, _Leguminosae_, and _Orchidaceae_. This statement

hardly admits of precise statistical proof; still, it is believed that

any observer who pays attention to the subject must come to the same

conclusion. This is but another illustration of the fact that conditions

which are abnormal in one plant constitute the natural arrangement in

others.

As to the suppressions that occur in the case of the sexual organs, and

the relations they bear to dimorphism, diclinism, &c., but little stress

has been laid on them in this place, because their chief interest is in

a physiological point of view, and is treated of in the writings of

Mohl, Sprengel, Darwin, Hildebrand, and others. All that need be said

here is, that teratology affords very numerous illustrations of those

intermediate conditions which are also found, under natural

circumstances, between the absolutely unisexual flowers, male or female,

and the structurally hermaphrodite ones. Rudimentary stamens or pistils

are of very common occurrence in monstrous flowers. See Chapter on

Heterogamy, &c.

FOOTNOTES:

[465] 'Rev. Hortic.,' 1866, p. 467.

[466] De Rochebrune, 'Bull. Soc. Bot. Fr.,' ix, p. 281. The author

points out seven grades between complete absence of petals and their

presence in the normal number in this plant. See also Gaudin, in 'Koch.

Fl. Helv.;' Koch. 'Synops. Fl. Germ.;' Cramer, 'Bildungsabweich,' p. 85.

[467] 'Bull. Acad. Belg.,' t. xix, part 1, p. 255.

[468] 'Bull. Bot.,' i, p. 7, tab. i, f. 7.

[469] See Gay, 'Ann. Sc. Nat.,' iii, p. 27.

[470] 'Ann. Sc. Nat.,' 4 ser., v, p. 305.

[471] Cramer, 'Bildungsabweich,' p. 90.

[472] See also Clos, 'Bull. Soc. Bot. Fr.,' xiii, p. 96, adnot.

[473] See Cramer, 'Bildungsabweich,' p. 7. Hildebrand, 'Bot. Zeit.,' xx,

1862, p. 209.

[474] See Hildebrand, 'Bot. Zeit.,' xx, 1862, p. 209.

[475] 'Bull. Soc. Bot. Fr.,' viii, p. 287.

[476] 'Bull. Soc. Bot. Fr.,' vol. viii, 1861, p. 152.

[477] Ibid., ix, p. 275.

[478] Ibid., 1861, vol. viii, p. 149.

[479] 'Lobelia,' p. 55.

[480] 'Phil. Bot.,' p. 119.

[481] 'Cat. Plant. Pyr,' p. 58.

[482] Moquin-Tandon, loc. cit., p. 328.

[483] For other instances see Chatin in 'Ann. Sc. Nat.,' 4 ser., vol. v,

p. 305.

[484] See also Morren. 'Bull. Acad. Belg.,' xv, Fuchsia, p. 67.

[485] Cited in 'Bull. Soc. Bot., France,' t. xiv ("Rev. Bibl."), p. 253.

[486] 'Primit. Flor. Amurens.' p. 57.

[487] 'Flora.' 1848. p. 484.

BOOK IV.

DEVIATIONS FROM THE ORDINARY SIZE AND CONSISTENCE OF ORGANS.

In the animal kingdom the entire adult organism, as well as each of its

separate parts, has certain dimensions, beyond which, under ordinary

circumstances, it does not pass, either in the one direction or the

other. It may not be easy or possible to state what the limits are, but,

practically, this inability to frame a precise limitation is productive

of no inconvenience. It is universally admitted that a certain animal

attains such and such dimensions, and that one organ has a certain

proportionate size as contrasted with another. The same rules hold good

in the case of plants, though in them it is vastly more difficult to

ascertain what may be called the normal dimensions or proportions.

Nevertheless observation and experience soon show what may be termed the

average size of each plant, and any disproportion between the several

organs is speedily detected.

When there is a general reduction in size throughout all the organs of a

plant, or throughout all the nutritive organs, stem, leaves, &c., and

the several portions participate in this diminished size, we have what

are generally termed "dwarf varieties," dwarf in comparison, that is,

with the ordinary condition of the plants; on the other hand, if the

entire plant, or, at least, if the whole of one set of organs be

increased in size beyond the recognised average, we have large

varieties, often qualified by such terms as _macrophylla_, _longifolia_,

_macrantha_, &c. &c. In all these cases either the entire plant or whole

series of organs are alike increased or diminished beyond average

limits; and such variations are often very constant, and are transmitted

by hereditary transmission. It may be supposed that such deviations may

have originated, in the first instance, either from excessive use, or

from disuse, or from the agency of certain conditions promoting or

checking growth, as the case may be; but whether or no, it is certain

that these variations often persist under different conditions, and that

they often retain their distinctive characters side by side with plants

presenting the normal average dimensions. In other cases the variations

in size are of a less general character, and affect certain organs of a

whorl in a relative manner, as, for instance, in the case of didynamous

or tetradynamous stamens, where two or four stamens are longer than

their fellows, the long or short stamens and styles of di- and

tri-morphic flowers, &c. These differences are sometimes connected with

the development of parts in succession, and not simultaneously.

Teratological deviations of size differ from those of which mention has

just been made chiefly in this, that they are more limited in their

manifestations. It is not, as a rule, the whole plant, or the whole

series of nutritive or of reproductive organs, that are affected, but it

is certain parts only; the alteration in size is more a relative change

than an absolute one.

For convenience sake the teratological alterations of size may be

divided into those which are the result of increased growth and those

which arise from diminished action. It will be seen, therefore, that in

these instances it is the bulk of the organs that is increased, not

their number; moreover, their development or metamorphosis is not

necessarily altered. In connection with increased size an alteration of

consistence is so frequent that the two phenomena are here taken

together. It will be borne in mind that the changes of consistence from

membranous to succulent or woody are very frequent in the ordinary

course of development. They may also occur as accidental phenomena, or

the normal conditions of any particular flower or fruit may be exactly

reversed, the usually succulent fruit becoming dry and capsular, and so

forth.

PART I.

HYPERTROPHY.

The term hypertrophy may serve as a general one to comprise all the

instances of excessive growth and increased size of organs, whether the

increase be general or in one direction merely. General hypertrophy is

more a variation than a deformity, unless indeed it be caused by insect

puncture or the presence of a fungus, in which case the excessive size

results from a diseased condition. For our present purpose hypertrophy

may be considered as it affects the axile or the foliar organs, and also

according to the way in which the increased size is manifested, as by

increased thickness or swelling--intumescence, or by augmented

length-elongation, by expansion or flattening, or, lastly, by the

formation of excrescences or outgrowths, which may be classed under the

head of luxuriance or enation.

As size must be considered in this place relatively, it is not possible

to lay down any precise line separating what are considered to be the

normal dimensions from those which are abnormal.

In practice no inconvenience will be found to accrue from this inability

to establish a fixed rule, and we may say that an hypertrophied organ is

one which, from some cause or other, attains dimensions which are not

habitual to the plant in its usual, healthy, well-formed state.

It will be seen that under this general head of hypertrophy, increase of

size, however brought about, is included; thus, not only increase in

length, but also in thickness; alterations of substance or consistence,

no less than of dimensions, are here grouped together. The alterations

of consistence resulting from an inordinate development of cellular,

fibrous, or ligneous tissue, are, of course, strictly homologous with

the similar changes which occur, under ordinary circumstances, during

the ripening of fruits or otherwise.

Hypertrophy, whatever form it may assume, may be so slight as not

perceptibly to interfere with the functions of the part affected, or it

may exist to such an extent as to impair the due exercise of its office.

It may affect any or all parts of the plant, and is generally coexistent

with, if not actually dependent on, some other malformation. Thus, the

inordinate growth of some parts is most generally attended by deficiency

in the size and number of others, as in the peripheral florets of

_Viburnum_ or _Hydrangea_, where the corollas are relatively very large,

and the stamens and pistils abortive.

CHAPTER I.

ENLARGEMENT.

A swollen or thickened condition (_renflement_) is usually the result of

a disproportionate formation of the cellular tissue as contrasted with

the woody framework of the plant. We see marked instances of it in

cultivated carrots and turnips, the normal condition of the roots or

root-stocks in these plants being one of considerable hardness and

toughness, and their form slender, tapering, and more or less branched.

The disproportionate development of cellular tissue is also seen in

tubers and bulbs, and in the swollen stems of such plants as

_Echinocactus_, _Adenium obesum_, some species of _Vitis_, &c. So, too,

the upper portion of the flower-stalk occasionally becomes much

dilated, so as ultimately to form a portion of the fruit. But it is not

necessary to give farther illustrations of this common tendency in some

organs to become hypertrophied. As a result of injury from insects or

fungi, galls and excrescences of various kinds are very common, but

their consideration lies beyond the scope of the present work.

[Illustration: FIG. 200.--_Pelargonium_, one branch of which was

hypertrophied.]

=Enlargement of axile organs.=--All the species of _Pelargonium_,

_Geranium_, _Mirabilis,_ as well as those of _Caryophylleae_ and other

orders, have tumid nodes as a normal occurrence. In the genus

_Pelargonium_ this swelling is sometimes not confined to the nodes, but

extends to the interspaces between them, _e.g._ _P. spinosum_. This

condition, which happens as a natural feature in the species just named,

may also occur as an exceptional thing in others. The author is indebted

to Dr. Sankey for a branch of _Pelargonium_ which was thus thickened,

the remaining branches not being in any way affected. The leaves on the

swollen branch were smaller than the others, and their stalks more

flattened. There was, in this instance, no trace of fungus or insect to

account for the swelling of a single branch, which might, therefore, be

due to bud-variation, perhaps to reversion to some ancestral form. The

repeated cross fertilisations to which Pelargoniums have been subjected

render this hypothesis not an improbable one.

As an accompaniment to a spiral torsion of the woody fibres, this

distension of the stem is frequently met with, as in _Valeriana_,

_Dipsacus,_ &c. (See Spiral Torsion.)

=Knaurs.=--On certain trees, such as the oak, the hornbeam, some species

of _Crataegus_, &c., hard woody lumps may occasionally be seen

projecting, varying greatly in size, from that of a pea to that of a

cocoa-nut. They are covered with bark, and consist in the interior of

very hard layers of wood disposed irregularly, so as to form objects of

beauty for cabinet-makers' purposes. From the frequent presence of small

atrophied leaf-buds on their surface, it would seem as if the structures

in question were shortened branches, in which the woody layers had

become inordinately developed, as if by compensation for the curtailment

in length.[488] The cause of their formation is not known, but it has

been ascertained that they are not due to insect agency. Knaurs may

occasionally be used for purposes of propagation, as in the case of the

"uovoli of the olive" and the "burrs" that are formed on some varieties

of apple, from which both roots and leaf-shoots are produced in

abundance.

A distinction must be drawn between those instances in which the

swelling is solid throughout from the excessive formation of cellular

tissue, and those wherein it is hollow from the more rapid growth of the

outer as contrasted with the inner portions. These latter cases might be

classed under the head of distension.

[Illustration: FIG. 201.--Formation of tubers or hypertrophied buds in

the axils of leaves in the potato.]

=Enlargement of the buds= may be seen in the case of bulbs and tubers.

Occasionally these organs are developed in the axils of leaves, when

their nature becomes apparent. A swollen bud or bulbil in this

situation is not uncommon in some cultivated tulips and lilies. The

presence of small tubers in the axils of the leaves in the potato, as

shown in fig. 201, is also not unfrequent.

[Illustration: FIG. 202.--Inflorescence of ash (_Fraxinus_), with

hypertrophied pedicels, flowers absent.]

=Enlargement of the flower-stalk.=--The cauliflower and broccoli afford

familiar illustrations of hypertrophy of the flower-stalk, accompanied

by a corresponding defective development of the flowers. In the case of

the ash the terminal pedicels occasionally become swollen and distorted,

while the flowers are completely deficient, as shown in the adjacent cut

(fig. 202).

In grapes a similar condition may occasionally be met with in which the

terminal pedicels become greatly swollen and fused into a solid mass. It

would seem probable that this change is due to insect puncture, or to

the effect of fungus growth at an early stage of development, but as to

this point there is at present no evidence.[489]

[Illustration: FIG. 203.--Monstrous pear, showing extension and

ramification of the succulent floral axis. The bases of the sepals are

also succulent.]

In the apple a dilatation of the flower-stalk below the ordinary fruit

may occasionally be observed, thus giving rise to the appearance of two

fruits superposed and separated one from the other by a constriction.

(See fig. 176, p. 327.) The lower swelling is entirely axial in these

cases, as no trace of carpels is to be seen. M. Carriere[490] mentions

an instance wherein from the base of one apple projected a second

smaller one, destitute of carpels, but surmounted by calyx-lobes as

usual. The direction of this supernumerary apple was the exact opposite

of that of the primary fruit.

[Illustration: FIG. 204.--Monstrous pear, showing extension and swelling

of axis, &c.]

In pears, quinces, and apples, a not uncommon deviation is one in which

the axis is prolonged beyond the ordinary fruit, like which it is much

swollen. Occasionally the axis is not only prolonged, but even ramifies,

the branches partaking of the succulent character of the ordinary pome.

Such instances are frequently classed under the head of prolification,

but they have in general no claim to be considered in this light, for

the reasons already given in the chapter relating to that subject. (See

p. 135.)[491]

A very curious illustration of hypertrophy of the flower-stalk is

recorded and figured by M. Carriere[492] in the cherry. The calyx in

these fruits was completely superior, the succulent portion of the fruit

being made up of the dilated extremity of the peduncle, and possibly in

part of the base of the calyx. The general appearance was thus that of a

crab-apple. There was no stone in the interior, but simply a rudimentary

kernel or seed.[493]

Moquin-Tandon records an instance in which the stamens of each

individual flower in the inflorescence of a vine were hypertrophied, the

sepals, petals, and other organs of the flower, being proportionately

diminished.[494]

In this place may also be mentioned the hypertrophied condition of the

placenta observed by Alphonse de Candolle in a species of _Solanum_, and

also in a species of _Melastoma_. Not only was the placenta unusually

large in these flowers, but it also protruded beyond the ovary.[495] A

similar state of things in _Lobelia_ and _Cuphea_ has already been

alluded to under the head of Alterations of Direction (p. 210).

The following singular growth in a tomato is described by the Rev. M.

J. Berkeley in the 'Gardeners' Chronicle' for 1866, p. 1217, and appears

to have been an extension of the placenta:--"On the first glance it

seemed as if an unusually large grape-stone had accidentally fallen on

the upper surface of the fruit, and was attached by the narrow base. The

process was, however, five lines long, and much narrowed below, besides

which, though it was pale green above, the base was coral-red, like the

tomato itself. It grew on a narrow and shallow crack on the surface of

the fruit, and was found below to communicate directly with a

fibro-vascular bundle, which entered into the composition of a portion

of the placenta. On making a vertical section, instead of being

succulent, as I expected, it was white and spongy within, with several

lacunae, and one or two irregular fibro-vascular bundles, with highly

developed spiral vessels threading the centre. These vessels, moreover,

were tinged with brown, as in many cases of diseased tissues. There was

not the slightest appearance of placentae or anything indicating an

abortive fruit. On closer examination the cuticle was found to consist

of thick-walled cells, exactly like those of the tomato, while the

spongy mass consisted of a similar tissue to the fleshy portion of the

fruit, but with far less wrinkled walls, and more indistinct

intercellular spaces. The most striking point, however, was the immense

quantity of very irregular and unequal starch-grains with which they

were gorged, which gave a peculiar sparkling appearance to them when

seen _en masse_. I am inclined to regard the body rather as an abortive

axis than an undeveloped fruit. In almost all, if not all, these cases

of abnormal growth, whether from leaves, petioles, fruit, or other

portions of the plant, we find an immediate connection with one or more

spiral vessels, which if not existent at first are developed sooner or

later. In the present case the connection of the fibro-vascular tissue

of the fruit and abnormal growth was plain enough, but whether it

existed when the body was first given off I am unable to say, as it was

fully developed when the fruit was brought to me."

=Enlargement of the leaves.=--Increase in the size or substance of

leaves takes places in several ways, and affects the whole or only

certain portions of them. The simplest form of this malformation is met

with in our cabbages, which, by the art of the gardener, have been made

to produce leaves of greater size and thickness than those which are

developed in the wild form. In such instances the whole substance of the

leaf is increased in bulk, and the increase affects the fibrous

framework of the leaves as well as the cellular portions, though the

exaggerated development of the latter is out of proportion to that of

the former.

In some species of _Podocarpus_ there may occasionally be seen at the

base of the branchlets a dozen or more fleshy scales, of a rose colour,

passing gradually into the ordinary leaves of the plant, and evidently

analogous to the three fleshy confluent bracts which surround the ripe

fruit.

In other instances, while the fibrous framework of the leaf retains its

usual degree of development, the cellular parenchyma is developed in

excess, and, if the increase is so arranged that the number of

superposed layers of the cellular tissue is not increased, or their

thickness exaggerated, then we get such leaves as those of the "kail,"

or of the "Savoys" leaves, which are technically called by descriptive

botanists "folia bullata." In such leaves the disc of the leaf, rather

than the margin, is increased and its surface is thrown up into little

conical projections, which are hollow on the under side.

But leaves may increase beyond their usual size without such grave

alterations of form as those to which allusion has just been made. It is

well known that if a tree be cut down and new shoots be sent out from

the stump, the leaves formed on these shoots very often greatly exceed

the ordinary ones in dimensions. Such cases as this hardly come under

the head of malformations. But where one part only of the leaf is

excessively developed, the other portion remaining in its ordinary

condition, there can be no hesitation in ranking the phenomenon as

teratological.

Thus, Moquin says that the median nerve may be prolonged beyond the

blade of the leaf in the form of a short strap or ribbon-like

excrescence, while, at other times, the lateral parts of the leaf are

subjected to undue development. He refers to a case cited by

Schlotterbec[496] in which each side of the leaves of a yellow "violier"

(wallflower) was dilated into a kind of projecting lobe on either side

of the true apex of the leaf, thus rendering it in appearance

three-lobed. M. Delavaud[497] puts on record a case of hypertrophy in

the leaves of the common elm, resulting in the formation of an

additional lobe and a return to the tricostate type. A leaf so affected

is stated to have presented the appearance of a fusion of two leaves.

(See also Multiplication of leaves, p. 353.)

The hypertrophied and coloured leaf of _Gesnera_ occupying the place of

the absent inflorescence has been previously alluded to under the head

of displacement (p. 88).

In some instances hypertrophy is the opposite of suppression; as in the

case previously mentioned, where the stipule in the inflorescence of a

pea, which is usually undeveloped and rudimentary, was developed in the

form of a leafy cup or pitcher.

Another instance of the development of parts usually suppressed, is

afforded by the bud-scales of _Magnolia fuscata_, which may sometimes be

found with small but perfect leaves projecting from them, the leaf in

this case being the lamina which is ordinarily abortive, while the

scales are the representatives of the stipules. This condition is said

by Hooker and Thomson ('Flora Indica,' p. 73) to be constant in

_Magnolia Campbelli_.

=Enlargement of the perianth, &c.=--One or all the segments of the

perianth may be subjected to hypertrophy; thus, the utricle of _Carex

vulpina_ may frequently be observed to attain four or five times its

usual size, the contained ovary remaining unaffected. This condition is

generally the result of insect puncture. The growth of parasitic fungi

will produce a similar result, as is often seen in the common shepherd's

purse, _Thlaspi bursa pastoris_, and other _Cruciferae_. The perianth of

_Rumex aquaticus_ has been also observed to be occasionally

hypertrophied in conjunction with a similar condition of the pistil and

with atrophy of the ovules.

Moquin relates having found flowers of _Salsola Kali_ and of

_Chenopodium murale_ in which some of the segments of the perianth were

five or six times larger than they should be.

[Illustration: FIG. 205.--Hypertrophy of the perianth in _Cocos

nucifera_.]

The adjoining woodcut represents a singular condition of some cocoa-nuts

in the Kew Museum, the appearance of which is due apparently to an

hypertrophied condition of the segments of the perianth, which have not

only increased in length as the central nut has ripened, but have

developed in their tissues that fibrous tissue which ordinarily is found

in the pericarp only. This view of the structure of these nuts is borne

out by the fact that, under normal circumstances, the base of the

perianth contains a considerable amount of fibrous material. In the

present case this has increased to such an extent that the fruit appears

surrounded by a double husk, by an inner one as usual, and by an outer

six-parted one.

It will be remembered that in some of the _Cinchonaceae_, e.g.

_Mussaenda_, _Pinckneya_, _Calycophyllum_, one or more of the calycine

lobes are normally dilated and petaloid, the others remaining small and

comparatively inconspicuous. Inequality in size is, indeed, a common

occurrence in the sepals of many natural orders--_Polygalaceae_,

_Leguminosae_, _Labiatae_, &c. The flowers of a rose are mentioned by

Moquin as having presented an enlargement of the calyx without any other

alterations in form. Schlechtendal has noticed the same thing in

_Papaver Rhoeas_, Reichenbach in _Campanula persicifolia_, and A. de

Candolle in _C. Rapunculus_. M. Brongniart also has recorded[498] a

remarkable variety of _Primula sinensis_ cultivated in the Jardin des

Plantes at Paris, wherein the calyx is enormously developed. MM.

Fournier and Bonnet have described flowers of _Rubus_ with hypertrophied

calyx in conjunction with atrophy and virescence of the petals and other

changes.[499]

The corolla may be hypertrophied in some cases, though the change is

more rare than in most other organs. Moquin-Tandon mentions as subject

to this anomaly species of _Galeopsis_, _Prunella_, _Scabiosa_, and

_Dipsacus_, and also mentions a remarkable variety of _Viola odorata_

cultivated in the neighbourhood of Toulouse. The same learned author

also alludes to the so-called double Composites, viz. those in which the

usually tubular florets of the disc assume the form and proportions of

those of the ray, but these are hardly cases of hypertrophy.

=Enlargement of the androecium.=--Dunal[500] alludes to a curious

instance in a species of _Verbascum_, the lower flowers of which had

hairy stamens as usual, but the filaments of the topmost flower were

quite destitute of hairs, and dilated like a flat ribbon.

Moquin relates having found in the neighbourhood of Toulouse a plant of

_Solanum Dulcamara_ in which all the upper flowers had two or three

stamens of larger dimensions than the others. This happens habitually in

_Solanum tridynamum_ and _S. Amazonicum_, and to a less extent in _S.

vespertilio_ and _S. cornutum_; also in some species of _Hyoscyamus_.

These cases show the close affinity between the _Solanaceae_ and the

_Scrophulariaceae_.

=Enlargement of the gynoecium.=--In some flowers which have become

accidentally female the pistil becomes unusually large, and even to such

an extent as to prevent the passage of the pollen. Moquin remarks having

seen this enlargement in the pistils of _Suaeda fruticosa_ and _Kochia

scoparia_. The flowers of these Chenopods, under these circumstances,

resemble the female flowers of some nettles. The styles of _Anemone_ are

also much enlarged as the result of cultivation, and from their petaloid

appearance resemble those of the _Iris_ (Goethe). MM. Seringe and

Heyland[501] have figured some anomalous flowers of _Diplotaxis

tenuifolia_ in which the pistil, more or less distended and deformed,

was considerably elongated below, so that it seemed to be borne upon a

long stalk, analogous to that of fruits of Capparids. Dr. Klinsman[502]

mentions an instance of a similar kind combined with hypertrophy of the

sepals and pistils; indeed, the alteration is not uncommon among

Crucifers. _Pyrethrum inodorum_ is very subject to hypertrophy. The

styles of its radial florets become elongated without any other

alteration; at the same time the small corollas become green, and show a

tendency to assume a foliaceous condition. Sometimes the hypertrophy

affects also the styles of the central florets, and these also become

enlarged to double or treble their usual dimensions.

Linne has remarked that the ovary of _Tragopogon_ sometimes assumes very

large dimensions, as also does the pappus. He mentions a double-flowered

variety, the ovaries of which become ten or twelve times larger than

ordinary. M. Clos[503] records an instance in _Rumex scutatus_ wherein

the pistil was hypertrophied or club-shaped, and open at the top, or in

other cases funnel-shaped, three-lobed at the summit, each lobe

terminated by a style. One of the most frequent causes tending to the

hypertrophy of the pistil is attributable to the puncture of insects;

thus, when the ovary of _Juncus articulatus_ is thus punctured, it

acquires a size two or three times larger than ordinary, becoming at the

same time sterile.[504]

Occasionally the enlargement may be due to a fusion or incorporation of

other elements; thus, M. Lemaire describes an instance in which the

style of _Sinningia purpurea_ was much larger than ordinary, tubular,

bearing three small lobes, and altogether bearing much resemblance to

the column or "gynosteme" of Orchids. This appearance was due to the

cohesion and intimate union of the styles with three abortive

stamens.[505]

=Enlargement of the fruit.=--Most cultivated fruits are in a state of

true hypertrophy. Girod de Chantrans, after many trials, succeeded in

producing a peculiar variety of pea with pods double the ordinary

size.[506] M. Clos[507] mentions a case wherein the carpels of

_Delphinium dictyocarpum_ were hypertrophied. The change in size may or

may not be attended by a difference in form; thus, in certain

_Leguminosae_, as _Medicago lupulina_, _Melilotus leucantha_, the carpels

are sometimes hypertrophied and elongated, so as to resemble a claw or

hook.[508]

The fruit of the common groundsel (_Senecio vulgaris_) is in its normal

condition two or three times shorter than the involucre, and cylindrical

for its whole length, but it frequently happens that the fruits become

as long as the involucre itself, and taper from the base upwards, so as

to become beaked. Under this head may also be mentioned the fleshy

bulbils that are found in the capsules of _Crinum_, _Amaryllis_, and

_Agave_. These are true seeds enormously dilated.[509] In these seeds

the outer coating becomes very thick and fleshy, and is traversed by

spiral vessels.

It is obvious that very important results in a practical point of view

may be and have been arrived at by cultivators availing themselves of

this tendency of plants to increase in dimensions under certain

circumstances. It is needless to do more than refer to the many fruits,

vegetables, and cereals, which have thus become enlarged and improved by

careful selection and rearing.

=Alterations of consistence= often accompany changes in size. The change

may be one whereby the tissues become unusually hardened, by the

excessive formation of secondary woody deposits, or softer and more

succulent than ordinary, from the formation of an inordinate amount of

loose cellular tissue. Generally speaking, the appearances presented in

such cases are not sufficiently striking to demand notice other than as

regards their size. One illustration, however, may be cited from its

singularity. This was the case of a dahlia, in which the centre of the

flower was occupied by a projecting knob as large as a walnut, brown in

colour, and very hard in texture. This knob was nothing but the enlarged

and indurated extremity of the common receptacle, destitute of the

scales and florets which usually spring from it. No insect-puncture

could be detected, and no other reason for this peculiarity could be

ascertained.

FOOTNOTES:

[488] On the subject of knaurs, the reader is referred to Trecul, 'Ann.

Sc. Nat.,' 3 ser., vol. xx, p. 65; Lindley, 'Theory of Horticulture;'

Rev. M. J. Berkeley, 'Gardeners' Chronicle,' 1855, p. 756.

[489] Jaeger, 'Flora.' 1860. p. 49, tab. i.

[490] 'Revue Horticole,' 1868, p. 110, figs. 12, 13.

[491] The reader may also refer for further information on the subject

of malformed pears to Irmisch. 'Flora,' 1858, p. 38, tab. i; Lindley,

'Theory of Horticulture'; Caspary, 'Bull. Soc. Bot. France,' vol. vi,

1859 (Rev. Bibl.), p. 235; Duhamel, 'Phys. Arbr.,' liv. iii, cap. 3. p.

393, fig. 308; Bonnet, 'Recherch. Us. feuilles,' tab. xxvi, fig. 2;

Moquin-Tandon, 'El. Ter. Veg.,' p. 384, &c. Some of the cases recorded

are, however, instances of true prolification.

[492] 'Revue Horticole' 1868, p. 310.

[493] The interest of this accident is great, as showing how an

habitually superior ovary may become inferior--a change so rare in its

occurrence that its existence has been denied, and thus forming a marked

contrast with the frequency with which the converse change of an

inferior ovary to a superior one, from want of union with the calyx or

from imperfect development of the peduncle, may be observed. It is also

interesting as showing how the peduncle may become swollen, and at the

same time how the woody deposit of the endocarp may, as if by

compensation, be deficient. And, again, the malformation is not without

significance in regard to the relationship between the drupaceous and

the pomaceous subdivisions of _Rosaceae_. The case would fitly be

included under alterations of position, but the sheets relating to that

subject were printed off before the publication of M. Carriere's notice.

[494] 'Bull. Soc. Bot. France,' 1860, vol. vii, p. 881.

[495] "Monstr. Veget.," in 'Neue Denkschrift.'

[496] "Sched. de Monst. Plant." in 'Act. Helvet.,' t. ii, pl. ii, f. 14.

[497] 'Bull. Soc. Bot. France,' vol. viii, 1861, p. 144.

[498] 'Ann. Sc. Nat.,' ser. 2, t. i, p. 308, pl. ix _c_, fig. 1.

[499] 'Bull. Soc. Bot. France,' 1862, t. ix, p. 37.

[500] 'Consid. org. Fleur.,' Montpell., 1829, 25, 26, pl. ii, f. 18 and

19.

[501] 'Bull. Bot.,' t. i, p. 7, tab. 1.

[502] 'Linnaea,' vol. x, p. 604, tab. 5.

[503] 'Mem. Acad. Sc. Toulouse,' 5 ser., vol. iii.

[504] 'Re. nosol. Veget.,' pp. 342.

[505] 'Illustr. Hortic.,' 1868, Misc., p. 62.

[506] 'Ann. Soc. Linn.,' Paris, t. i, p. 139.

[507] 'Mem. Acad. Toulouse,' t. 6, 1862.

[508] 'D. C. Prod.,' ii, pp. 172, 187.

[509] Richard, "Obs. sur les bulbilles des Crinum;" 'Ann. Sc. Nat.,' t.

ii, p. 12. pl. i, fig. 1, 2. See also A. Braun, "Memoire sur les graines

charnues des Amaryllidees," &c.; 'Ann. Sc. Nat.,' 1860, vol. xiv, p. 1,

tab. 1.

CHAPTER II.

ELONGATION.

The class of cases coming under this head are sufficiently indicated by

the name. There are many instances of this phenomenon occurring under

different conditions, which, though unusual, can hardly be called

abnormal, such, for instance, as the great lengthening of roots in their

search for water, the excessive elongation that takes place in plants

when grown at a distance from the light, in their endeavour to attain to

which they become, as gardeners phrase it, "drawn." A similar result is

brought about in forests or plantations, where long spars are required,

by allowing the trees to grow very close to each other, so as to prevent

the lateral extension of the branches. When plants grow in running

water their roots, stems, and sometimes their leaves, become excessively

elongated, as in _Ranunculus fluitans_, the flower-stalks of _Valisneria

spiralis_, &c. These are cases of variation rather than of malformation,

but are none the less curious, or sometimes perplexing; thus, Lapeyrouse

described, in his 'Supplement a la flore des Pyrenees,' p. 27, under

the name _Potamogeton bifolium_, a plant which Mr. Bentham subsequently

discovered to be nothing but a flowerless variety of _Vicia Faba_

distorted by its growth in water.[510]

=Elongation of the root.=--This, as already remarked, is more often a

variation than a malformation, and is usually due to the presence of

water at a distance necessitating growth at the extremities of the root,

or to the presence of some obstacle, such as a stone, to avoid which the

root elongates till it has passed the obstruction. Occasionally in

Crocus corms some of the fibrils may be met with much lengthened and

thickened, and invested with a fleshy sheath. It is not certain,

however, that these structures are roots; possibly, nay probably, they

may be processes from the stem thrust downwards into the soil, similar

to the formations already described in the tulip (p. 85, fig. 39).

=Elongation of the inflorescence.=--Under this heading it is necessary

to consider lengthening of the common rachis in the case of an aggregate

inflorescence, and lengthening of the individual flower-stalks, whether

they be solitary or portions of a multiple inflorescence. The two

phenomena may occur together, but they are quite as often independent

one of the other. Thus, among _Umbelliferae_ the umbels are occasionally

met with supported on unusually long stalks, while the pedicels of the

individual flowers may or not be increased in length; so also with some

of the Composites, or the heads of flowers of some _Leguminosae_,

_Trifolium repens_, &c. &c.

Another illustration of the sort is that recorded by M. Fournier,

wherein the usually umbellate inflorescence of _Pelargonium_ was,

through the lengthening of the main stalk, transformed into a raceme.

Among Composites a similar change may sometimes be met with.

MM. Clos and De Schoenefeld have recorded the existence of a variety of

the sweet chestnut (_Castanea_)in which the female catkins were as long,

and bore nearly as many flowers, as the male spikes. This is stated to

be of constant occurrence in some localities, and to be accompanied by a

diminished size of the fruits. A similar elongation has been observed in

the case of the walnut, catkins of which have been seen bearing thirty

to thirty-five large nuts.[511]

In the strobile of the hop, _Humulus Lupulus_, a like elongation may

sometimes be met with, generally in association with a more or less

leafy condition of some of the scales.

Of a similar character, but complicated with extrusion or eversion of an

ordinarily concave axis, is the fig described by Zuccarini,[512] and

from the appearances presented by which that author draws the inference

that the peculiar appearance of the fig is due to the formation of a

large number of small bracts blended together for the greater part of

their length, and accompanied by the suppression of the internodes, and

consequent shortening of the axis. In the monstrous fruit the axis is

prolonged, and forms a kind of raceme or catkin, surrounded at the base

by numerous bracts, as in many _Amentaceae_. (See p. 204, figs. 105,

106.)

A lengthening of the axis of the female strobiles of _Coniferae_ is not

of infrequent occurrence in _Cryptomeria japonica_, _Larie europaea_,

&c., and this is usually associated, as has been before stated, with a

leaf-like condition of the bracts, and sometimes even with the

development of leaf-bearing shoots in place of the scales. (See under

Prolification of Inflorescence and Phyllomorphy, and for references, p.

115.)

=Elongation of the secondary flower-stalks.=--In the previous section

the effect of elongation of the main rachis has been considered. A

corresponding deviation occurs in the peduncles or pedicels, and

sometimes alters the general character of the inflorescence very

considerably, converting a spike into a raceme, a raceme into a corymb,

a capitulum into an umbel, and so forth. A few such cases may here be

alluded to. Fig. 206 represents a specimen of _Ranunculus acris_, in

which the lower and lateral flower-stalks were not only increased in

number, but so much lengthened as to form a flat-topped inflorescence--a

corymbose cyme. In many leguminous plants, as in _Trifolium repens_,

_Lotus corniculatus_, &c., what is usually a compact spike, or head of

flowers, becomes a raceme from the elongation of the pedicels. In

_Umbelliferae_ a similar change occurs, by virtue of which sometimes the

umbels themselves, and at other times the florets, are raised on

unusually long stalks, as in _Angelica Razoulzii_, _Carum Carui_,

_Thysselinum palustre_.[513] In _Compositae_, when affected by an

analogous change, the capitulum assumes the appearance of a simple

umbel, as in _Hypochaeris radicata_, _Senecio vulgaris_, and other

plants.

[Illustration: FIG. 206.--Inflorescence of _Ranunculus acris_, with

secondary peduncles lengthened.]

In some of the double-flowered apples which have been previously alluded

to, the flower-stalk is inordinately long when compared with the

adjacent ones. Possibly in some of these cases the absence of the usual

swelling of the upper part of the peduncle may be connected with its

increased length. One of the most striking instances of lengthened

flower-stalk occurred in an apple flower, wherein there was no swelling

beneath the calyx, while the latter was represented by five perfect

stalked leaves.

=Elongation of the leaves.=--In the case of water plants this change

keeps pace with the corresponding growth of the stem, _e.g._

_Ranunculus fluitans_, and in terrestrial plants there are varieties

termed longifoliar, from the unusual length of the leaves. A similar

lengthening occurs in the involucral leaves of _Umbelliferae_ and

_Compositae_, changing very materially the general aspect of the

inflorescence. Occasionally, also, the leaf-lobes of parsley (_Apium

Petroselinum_) and other crested-leaved plants may be observed to lose

their ordinary wavy form, and to be lengthened into flat riband-like

segments, as shown in fig. 207.

The only further illustrations that it is requisite to give of such

changes in this place are those occurring in lobed or compounded leaves,

which, from a lengthening of the midrib or central stalk, convert a

digitate or palmate leaf into a pinnate one. In these instances the

lobes or leaflets become separated one from another by a kind of

apostasis. This change may be frequently seen in the horse-chestnut,

particularly in the young shoots formed after the trees have been pruned

or pollarded. In the adjoining cut the intermediate stages between a

palmate or digitate leaf to a pinnate one may be seen. The specimens

from which the drawing was made were taken from the same tree at the

same time.

[Illustration: FIG. 207.--Portion of leaf of parsley, showing the change

from short wavy to long flat leaf-lobes.]

In the white clover, _Trifolium repens_, a similar transition may often

be observed, as also in some species of _Potentilla_.[514]

=Elongation of the parts of the flower.=--The only circumstance that

needs especial mention under this section is the great lengthening that

sometimes takes place in the carpels, sometimes as a result of injury

from insects or fungus, at other times without assignable cause.

[Illustration: FIG. 208.--Leaves of horse-chestnut, _AEsculus_, showing

passage from digitate to pinnate leaves.]

In the case of inferior ovaries this lengthening is, perhaps, even more

common, as in _Umbelliferae_, _Compositae_, &c. The common groundsel

(_Senecio vulgaris_) is especially liable to this form of enlargement of

the pistil, either in association with a leafy condition of the pappus

or without any such change.

=Elongation of the thalamus, placenta, &c.=--In some plants, as in

_Magnolia_ or _Myosurus_, the thalamus becomes much elongated, and bears

the carpels disposed spirally around it. A similar lengthening occurs in

malformed flowers, usually in association with a similar change in the

lower or outer part of the flower, by virtue of which the whorls become

separated from each other (Apostasis). Elongation and protrusion of the

placenta have been already alluded to at p. 119, and also at p. 125. In

some of these cases the elongated placenta has taken the form of a

leaf-bearing shoot.[515]

=Apostasis.=--Engelmann made use of this term to express the separation

of parts one from another by the unusual elongation of the

internodes.[516] He drew a distinction between the separation of

individual organs one from the other, and the corresponding displacement

of whorls. The subject has already been, to a considerable degree,

treated of in these pages under the head of dialysis, displacement, and

prolification, and but little need here be added. With reference to the

distance between one whorl and another, it will be remembered that,

although in the majority of cases the floral whorls are packed closely

together, yet in other instances the floral axis becomes elongated, and

thus separates the whorls one from another, by structures such as the

gynophores, androphores, &c., of _Passifloreae_, _Caryophylleae_,

_Capparideae_, &c. &c.

A similar elongation of the thalamus, bringing about the separation of

the floral whorls, or of their constituent parts, is very commonly met

with in association with median prolification. Where the individual

floral elements are thus thrown out of their usual verticillate

arrangement, they naturally assume a spiral disposition, and are, in

some cases, united by their margins, so that a spiral sheet or tube is

formed, surrounding the axis. This frequently occurs in double flowers

of the Chinese primrose, _Primula sinensis_.

Engelmann[517] figures a case wherein the calyx of _Anagallis

phoenicea_ was separated by a rather long internode from the corolla,

and a like illustration in _Torilis Anthriscus_.

[Illustration: FIG. 209.--Flower of _Delphinium_, showing apostasis of

carpels, from lengthening of the thalamus, &c. (Cramer.)]

A frequent change in Crucifers is due to the formation of a long stalk

bearing the pod, and thus giving rise to the appearance met as a

constant occurrence in Capparids.

In _Tropaeolum majus_ a similar elevation of the pistil may occasionally

be seen.

The adjacent figure of a monstrous _Delphinium_ taken from Cramer

illustrates well the elongation of the floral axis and the apostasis of

the carpels. In this instance the axis is terminated by a second flower

(median prolification).

One of the best-marked illustrations of these changes occurs in a

permanent malformation of _Epilobium hirsutum_, specimens of which were

originally obtained from the late Professor Henslow. The several floral

parts are here, some virescent, others truly foliaceous, and each whorl

is separated from its neighbour by a rather long internode. In _Fuchsia_

and _Campanula_ a like change may occasionally be observed.

Engelmann, in addition to those previously mentioned, cites the

following plants as having manifested this change:

_*Convallaria majalis!_, _*Tulipa Gesneriana!_, _Veronica Chamaedrys_,

_Orobanche gracilis_, _Solanum Lycopersicum_, _Gentiana campestris_,

_Hypericum_, _Helleborus fetidus_, _Caltha palustris_, _Brassica

oleracea!_ and many _Rosaceae_, _Caryophylleae_, _Cruciferae_, and

_Ranunculaceae_. (See Dialysis, Median Prolification, &c.)

Apostasis of the sub-floral or involucral leaves is not of infrequent

occurrence in malformations affecting _Compositae_ and _Umbelliferae_. In

the following genera it has been observed with especial

frequency:--_Torilis Anthriscus_, _Eryngium_, _Athamanta Cervaria_,

_Leontodon_, _Tragopogon pratense!_, _Wedelia perfoliata!_ In garden

anemones, also, it is a common deviation.

FOOTNOTES:

[510] 'Cat. Plant.,' Lang., p. 113.

[511] 'Bull. Soc. Bot. France,' t. i, 1854, p. 173, and t. xiii, p. 96.

[512] 'Abhandl. Math. Phys. Class.,' Band. iv, Abhandl. i, tab. i.

[513] See Cramer, 'Bildungsabweich,' pp. 62-79, and Fleischer,

'Missbild, der Culturpflanzen.'

[514] Schlechtendal, 'Bot. Zeit.,' 1844, p. 457; 'Linnaea,' xi, p. 301,

xiv, p. 363; 'Bot. Zeit.,' 1856, p. 72; Masters, 'Rep. Brit. Assoc.,'

Manchester, 1861; Coultas, 'What may be learnt from a tree,' p. 118.

[515] For further details refer to the chapter on Displacements, p. 86.

[516] 'De Antholysi,' p. 42, Sec. 49.

[517] Loc. cit., tab. 2, f. 6.

CHAPTER III.

ENATION.

Under the above heading are included certain forms arising from excess

not of growth, but of development, and consisting in the formation of

supplementary lobes or excrescences from various organs.

The new formations are not due either to a repetition or to a partition

of any organ, but are out-growths from others previously formed.

In prolification and in multiplication the adventitious structures are

of independent origin. In fission the new developments grow

simultaneously with the older ones, of which, indeed, they are mere

repetitions. Moreover, in fission the supplementary lobes do not, in

general, project a plan different from that of the original structure,

at least in the first instance, though their direction may ultimately

become changed.

In enation the new growth projects from a previously formed organ after

it has attained to considerable size, or even after its ordinary

proportions have been attained, and it sprouts out from the beginning in

a plane which is at a considerable angle to that of the parent organ,

and it is sometimes of a different structure from it, and has different

functions to fulfil.

Many of the instances that occur of scales projecting from petals, as in

_Caryophylleae_, _Sapindaceae_, &c., the coronal filaments of

passion-flowers, the cup of _Narcissus_, the appendages that beset the

segments of the perianth in _Lilium lancifolium_, and other similar

growths, may be referred to a like process. In many cases this has been

proved by a study of the development of the flower, from which it

appears that the growths in question are developed subsequently to the

formation of the ordinary floral whorls. It is requisite, however, to be

cautious in pronouncing upon the exact nature of these bodies, in the

absence of a knowledge of their period and mode of formation. They may

be mere outgrowths from one or other of the customary whorls, or they

may represent abortive stamens or petals, &c. Where circumstances

prevent the course of development from being traced, something may be

inferred as to their real nature from their position in regard to the

other parts of the flower, from their anatomical structure, and from

analogy or comparison with like organs in other plants. The period of

their formation is, perhaps, of less importance than was at one time

supposed, since it is well ascertained that, in some cases, the

formation of the parts of the flower, _e.g._ the stamens of mallows,

follows a centrifugal rather than a centripetal order.

In the case of monstrous developments of this nature too much care can

hardly be exercised, and the observer should rarely venture on an

explanation of the nature of the case from the evidence afforded by the

monstrous growth apart from that to be derived from the study of the

development and organization of the normal flower and from analogous

formations in allied plants.

=Excrescences from axile organs--Warts.=--In a preceding paragraph the

formation of gnaurs has been alluded to. There are other outgrowths,

called warts, occasionally met with in trees, and which are more closely

connected with the central tissues of the stem, while at the same time

they are not provided with buds, in which two particulars warts differ

from gnaurs.

Excrescences of this kind often attain a very large size, and may be

seen on old elms and other trees, but, as their formation is probably

more pathological than teratological, no further notice of these

structures need here be given. No special notice need here be taken of

the tubercles on the roots of so many _Leguminosae_, nor of the peculiar

excrescences on the roots of _Taxodium distichum_, as these appear to be

normal formations. But it may be well to mention in this place an

anomalous development which occurs occasionally in _Ruscus aculeatus_,

and in which, from the upper surface of the ordinary flattened leaf-like

branch, projects at right angles a second similar branch, so that in

section the appearance would be like that of the inverted letter t;

thus, [Symbol: Inverted upper-case T].

=Enation from foliar organs--Leaves.=--The development of adventitious

lobes from leaves may take place either from their surfaces or their

margins. A few illustrations may be given of each. In cabbage leaves a

formation of adventitious laminae projecting at right angles from the

primary one may frequently be observed. In the instance figured (fig.

210) the new growths proceeded almost exclusively from the thick midrib,

which, in the figure, is shown cut through just above the base. Not only

is the ordinary semilunar band of vascular tissue to be here seen, but a

similar broken line of vessels exists on the upper side of the

leaf-stalk; thus the whole structure resembles that of a stem or a

branch as much as that of a true leaf.

[Illustration: FIG. 210.--Section through base of midrib of cabbage

leaf, showing supplementary laminae, &c.]

The development of secondary leaves from the surfaces of primary ones

(phyllomania, autophyllogeny) has already been alluded to at p. 355.

Some of the cases wherein a leaf seems to have a double lamina may be

alluded to here, though possibly they would more properly be referred to

fission. The appearance presented is as if four wings projected from the

midrib, so that a cross section would be nearly in the form of

[Symbol: )O( turned 90 degrees.]. In an orange leaf presenting this

appearance the lower surface of one lamina was, as usual, dull in

colour, while the upper surface of the subjacent lamina was likewise

dull; hence the impression might arise that this was an instance of the

adhesion of two leaves back to back, but the petioles were not twisted,

as they must have been had two leaves thus been united, and neither in

the petiole nor in the midrib was there the slightest indication of

fusion, the vascular bundles being arranged in a circular manner, not in

a horseshoe-like arrangement, as would have been the case had adhesion

taken place.[518] (See p. 33.)

Such leaves as those of the hedgehog holly, _Ilex Aquifolium_, var.

_feroae_, and, to a less extent, bullate leaves, may also be mentioned

here as illustrations of hypertrophy or enation.

[Illustration: FIG. 211.--_Nephrodium molle_. Ordinary frond and forked

and crested varieties of the same, the crest arising from the inordinate

development of the margins of the pinnules.]

When the increased development occurs at the margin of the leaves,

especially, the result is a wavy or crisped appearance, "folia undulata,

_vel_ crispa."[519] These conditions occur normally in such leaves as

those of _Rumex crispus_, _Malva crispa_, &c., and are developed to an

extreme degree in garden varieties of parsley, some kails, &c., as well

as in many ferns, but these are probably cases rather of fission than

enation as here understood.[520]

=Enation from the sepals.=--The basal lobes of the calyx in _Campanula

Medium_, under normal circumstances, may be referred to in illustration

of this occurrence, while the adventitious spurs on the calyx of some

monstrous flowers seem due also to a like cause. These have already been

alluded to at p. 315.

=Enation from the corolla.=--The instances of this are more frequent

than in the case of the calyx, and admit of classification according as

they occur in polypetalous or gamopetalous flowers, on the outer or

inner surface of the petals, &c. Under natural circumstances the

formation of scales, lobes, &c., from the petals, as in some

_Caryophylleae_, _Sapindaceae_, &c. &c., may be explained, as already

remarked, by this process, rather than by fission, chorisis, or by

substitution of petals for stamens, &c. Each case must, however, be

examined on its own merits, as it is not safe to decide upon the

arrangement of parts in one flower by simply referring to the analogy of

others. In the following illustrations the course of development has

not, in all cases, been observed, and hence the explanation here given

must be taken with some reserve; for should it prove that the

adventitious lobes, &c., are formed simultaneously with the ordinary

petals, the case will be one of chorisis rather than of enation, as here

understood. Again, it may be that the supernumerary organs really

represent petals or stamens in disguise, though this hypothesis demands

the further assumption (in order to account for the interference with

the law of alternation) that suppression of certain organs has taken

place.

Taking first those instances in which the supplementary petals appear on

the inner surface of the corolla, as being at once the most frequent,

and as presenting the closest analogy, with similar conformations, under

natural circumstances, certain double-flowered varieties of the Chinese

primrose, _Primula sinensis_, may be mentioned. In these flowers the

calyx is normal, the tube of the corolla is traversed by ten vascular

bundles, and the limb is divided into ten fimbriated lobes. About

halfway up the tube, on the inner surface, are given off five

supernumerary petals, opposite to as many lobes of the corolla. Some of

the supplementary petals have a stamen in front of them, in the same

relative position as in the normal flower. In some cases the back or

outer surface of the supplementary petal is turned towards the inner or

upper surface of the primary corolla, thus [Symbol: ((turned 90 degrees

cw]; while, in other instances, the front of the adventitious lobe is

directed towards the corresponding surface of the original petal, thus

[Symbol: () turned 90 degrees]. Whether these supernumerary petals are

formed by chorisis or by enation cannot, with certainty, be determined

without examining the early stages of development.

[Illustration: FIG. 212.--_Datura fastuosa._ True corolla turned back to

show the supernumerary corolla with the petal-like segments attached to

its outer surface (reduced).]

Of more interest are those instances where the adventitious growth is on

the outside of the corolla; thus in a garden azalea there was

intermediate between the calyx and the corolla, both of which were

normal, a series of five petalodes, alternating with the sepals, and,

therefore, opposite to the lobes of the corolla, and adherent with them

at the very base, though elsewhere detached. These petalodes were

concave on the surface looking towards the calyx, and were there

brightly coloured, while the tint of the opposite surface looking

towards the corolla was of a duller hue, corresponding with that of the

outside of the corolla-tube. This arrangement of the colour was thus

precisely similar to that which occurred in the four-winged leaves

already referred to at p. 446. In some flowers of _Datura fastuosa_ a

similar series of excrescences was observed; the calyx and the corolla

were normal within the latter, intervening between it and the stamens

was a second corolla produced by duplication, and adherent to the inner

surface of this latter were five stamens. So far there was nothing very

peculiar; it remains to say, however, that on the outer surface of the

second corolla were five petal-like lobes closely adherent to it below,

but partially detached above. The colour of the adventitious segments

was paler on the outside than on the inner surface, as in the corolla

itself. The position of the several parts was such that they were

opposite one to the other; hence, while the lobes of the inner corolla

were opposite to those of the outer one, the intermediate petalodes were

opposite to both; thus:

S S S S S

--------------------------

P P P P P

X X X X X

--------------------------

P P P P P

st st st st st

The X indicating the position of the petalodes.

[Illustration: FIG. 213.--Gloxinia, with supernumerary segments on the

outside of the true corolla.]

A still more singular case is that of a variety of the Gloxinia,

described originally by Professor Edouard Morren,[521] but which is now

becoming common in English gardens. When first observed these flowers

were observed to produce petaloid segments outside the ordinary corolla,

and partially adherent to (or rather, not completely separated from it)

much as in the azalea before mentioned, the outer surface being brightly

coloured, like the inner surface of the corolla in ordinary gloxinias.

Being encouraged and tended by gardeners, in course of time, instead of

a series of petalodes, more or less distinct from one another, a second

corolla or "catacorolla" was formed outside the primary one, so that a

hose in hose flower was produced, but, in this case, the supplementary

flower was formed on the outside and not within the ordinary corolla.

Moreover, the disposition of the colour was reversed, for in the

outermost corolla the richest hues were on the outer surface, while in

the inner or true corolla they were on the inside.

Professor Morren considers the adventitious petalodes as rudiments of so

many supplementary flowers, axillary to the calyx, and adnate to the

corolla; each lobe then would, in this view, represent an imperfect

flower, and the completed catacorolla would be formed of a series of

confluent flowers of this description. But this view involves the

assumption of the suppression of all the parts of the flower, except the

lobes in question.

[Illustration: FIG. 214.--"Catacorolla" of _Gloxinia_, formed from the

union of adventitious petalodes on the outside of the true corolla

(after Morren).]

The view here propounded that the lobes in question are enations from

the true petals, which become confluent, so as to form the catacorolla,

is surely more simple, involves no assumptions of suppression of parts;

and moreover, is borne out by the examination of some flowers, where the

production of these adventitious lobes from the outside of the minute

partially developed petals could be distinctly seen.

=Enation from the stamens.=--An illustration of this process occurred in

some double-flowered rhododendrons, which presented the following

arrangement of parts:--calyx and corolla normal; within the latter eight

petal-like stamens, forming a pseudo-corolla. The appearance presented

by the petaloid filaments and anthers was as if they were adnate to the

centre of the petals, but, on closer examination, it appeared that the

petaloid expansion to which the dilated filament was apparently

attached, was equally a part of the stamens; in other words, that the

filament was provided with four petal-like wings, two on each side

[Symbol: 00 topped by (turned cw 90 deg., an o above and another ( turned cw

above that]. This disposition was well seen in the anther, half of which

was, in some cases, petaloid like the filament; in fact, the inner wing

of the latter was directly continuous with the petal-like expansion from

the anther. A section through the latter showed, going from within

outwards, the cut edges of two perfect polliniferous lobes in the

centre; and on either side the petaloid wing representing the remaining

anther-lobe; outside these were the edges of the remaining wings, one on

each side. (See p. 290, fig. 155.)

=Enation from the carpels.=--The only instances of this that need be

referred to are such cases as those in which spur-like projections,

horns, tubercles, or winged expansions, are formed from the surface of

the ovary during the course of its development. The extraordinary

cornute oranges described and figured by Ferrari, Gallesio, and other

writers on the genus _Citrus_, may be mentioned under this head. A

similar formation occurs in the fruit of some species of _Solanum_. (See

p. 316.)

FOOTNOTES:

[518] It is desirable in this place to allude to a singular case of

fissiparous division of a leaf of _Prunus Laurocerasus_ described by

Prof. Alexander Dickson ('Seemann's Journ. Botany,' vol. v, 1867, p.

323), and which did not come under the writer's notice till after the

sheet relating to fission, p. 61, had been sent to press. Dr. Dickson

thus speaks of this abnormal leaf:--"The petiole (unchanged) supported

two laminae, placed back to back, and united by their midribs (_i.e._ not

separated) to within about an inch from their extremities, which were

perfectly free from each other. These laminae stood vertically, their

edges being directed towards and away from the axis; and as they were

placed back to back, the shining surfaces, corresponding in structure to

the normal upper leaf-surface, were directed laterally outwards. In the

axil of this abnormal leaf were two axillary buds. The existence of two

leaf-apices and two axillary buds shows that this was not due to an

accidental exuberance of development, but to fissiparous division,

which, had it been complete, would have resulted in the replacement of a

single leaf by two leaves. The arrangement in Prof. Dickson's leaf may

be thus represented: [Symbol: )OO( with X above]. The nature of the case

may be even better seen by comparison with the normal arrangement, which

would be [Symbol: (OX turned 90 degrees ccw], while in those cases where

the fission of the leaf occurs in the same plane as that of the primary

lamina, as where a leaf splits into two lobes at the apex, with a midrib

to each, the arrangement is as follows: [Symbol: OX turned 90 degrees

ccw, with 2 arcs below forming a half circle], the X in all cases

representing the position of the axis, the O that of the axillary bud,

and the [Symbol: ( turned 90 degrees ccw] that of the laminae."

[519] Linn., 'Phil. Bot.,' Sec. 274. The term "_crispa_" is surely

preferable to that of Re, "phyllorhyseme."

[520] See C. Morren, "Consid. sur les deformations," &c., in 'Bull.

Acad. Belg.,' 1852, tom, xix, part 3, p. 444; and as to ferns, see

Moore, 'Nature-Printed British Ferns,' 8vo ed., where numerous

illustrations are given.

[521] 'Bull. Acad. Belg.,' t. xix, p. 224, tab. i; and 'Gardeners'

Chronicle,' 1865, p. 865.

PART II.

ATROPHY.

Under the head of atrophy are included those cases wherein the organs

affected are actually present, but in a dwarfed and stunted condition as

compared with surrounding parts.

The diminished size is, in such instances, obviously due to a partial

development and to an arrest of growth at a certain stage, from the

operation of various causes, either external or inherent to the

organization itself. It may affect any part of the plant, and exists, in

very varying degree, in different instances, being sometimes so slight

in amount as not to preclude the exercise of the functions of the part;

while in others, the structure is so incomplete that the office cannot

be performed. These differences depend, of course, upon the stage of

development which the organ had reached when its growth was checked. For

practical purposes atrophy may be distinguished from suppression by the

fact that in the latter case a certain element of the flower or plant

which, under ordinary circumstances, is present, is entirely wanting,

while, in the former class, it exists but in a rudimentary condition.

Again, atrophy is to be separated from that general diminution in the

size of the whole plant or of distinct parts of that plant which is

comprised under the term "nanism." Thus the several dwarf varieties of

plants (var. _nanae_), or those in which the leaves or flowers are

smaller than usual (var. _parvifoliae_, v. _parviflorae_), are truly

regarded as variations, and not as malformations properly so called.

Atrophy is partial and special in its operation, nanism is general.

Under ordinary circumstances atrophy is exemplified by the presence of

rudimentary or imperfect organs, as, for instance, in _Pentstemon_,

_Scrophularia_, &c., where one stamen is atrophied.

For convenience sake atrophy may be divided into abortion and

degeneration, the first including cases where, from arrest of

development occurring at an early stage, organs are present; but in a

much smaller and more rudimentary condition than usual, their form and

general appearance, except so far as regards their dimensions, not being

materially altered. On the other hand, in cases of degeneration,

development is not entirely checked, but rather perverted, so that not

only the dimensions are lessened, but the form is altered.

CHAPTER I.

ABORTION.

The sense in which this term is here understood has been explained in

the preceding paragraph. It is only necessary to say further, that cases

of abortion are to be distinguished from those of suppression, on the

one hand, and those of degeneration on the other. In suppression there

is from the first an absolute deficiency of a particular organ. In

degeneration the part is present, but in a diminished and perverted

condition. In abortion it exists, but in a stunted and dwarfed, but not

otherwise permuted state.

=Abortion of axile organs.=--When the main stem is arrested in its

growth, the habit and general appearance of the plant are materially

altered, as in the so-called stemless plants, _plantae acaules_. In these

the internodes are so slightly developed that the leaves are closely

crowded in tufts or rosettes. When this shortening of the stem

(acaulosia) occurs, without other considerable change in other organs,

the deviation is classed under the head of variation rather than of

monstrosity; and, indeed, in very many plants, this arrested growth of

the axis is the rule rather than the exception. When occurring in an

abnormal manner, atrophy of the stem is most frequently attended by

other more or less grave alterations in other structures; thus

Moquin-Tandon[522] cites an instance of _Camphorosma monspeliaca_,

wherein the stems presented the form of very short, hard, woody

tubercles, thickly clothed with deformed leaves, and invested by a vast

number of hairs, longer and more dense than usual. A similar deformity

sometimes occurs in an Indian species of _Artabotrys_; in these

specimens the branchlets are contracted in length, and bear numerous

closely packed scaly leaves, densely hairy, and much smaller than

ordinary.

Spines and thorns may he looked on as atrophied branches, and seem to

result from poorness of soil, as the same plants, which, in hungry land,

produce spines, develop their branches to the full extent when grown

under more favorable conditions.[523]

In the birch an arrest of development in some of the branches is of

common occurrence. The branch suddenly ceases to grow in length; at the

same time it thickens at the end into a large bulbous knob, from which

are developed a profusion of small twigs, whose direction is sometimes

exactly the reverse of that of the main branch. (See p. 347.)

The branches of the common spruce fir, especially the lateral ones, when

attacked by a particular species of aphis, are very apt to be developed

into a cone-like excrescence.[524]

A shortened condition of the flower-stalks occurs occasionally, greatly

altering the general character of the inflorescence. This has been

observed in pelargoniums and in the Chinese primrose, in both of which

the effect was to replace the umbellate form of inflorescence by a

capitate one.

=Abortion of the receptacle.=--Here may be mentioned those cases of

flowers with habitually inferior ovary (real or apparent), in which the

receptacle fails, from some cause or other, to dilate as usual. This has

already been alluded to under the head of Prolification, Displacements,

&c. (pp. 78, 130, &c., figs. 35-37, 64, &c.), and hence requires only

incidental comment in this place. There are, however, certain other

cases of a similar nature which may here be referred to; such as the

abortive condition of the inferior ovary, or rather of the receptacle,

that usually encircles the ovary in _Compositae_ and _Umbelliferae_. In

the former natural order the following plants have been met with in this

condition:--_*Tragopogon pratense!_, *_Cirsium arvense_, _Hypochaeris

radicata_, _Senecio vulgaris!_, _Coreopsis Drummondi_. In the latter

order, _Daucus Carota!_ _OEnanthe crocata!_ and _Thysselinum

palustre_, seem most frequently to have been observed in this

state.[525] In some gourds the receptacle may be seen partially

developed only, and forming a kind of cup, from which the true carpels

protrude.

=Abortion of the leaves.=--Arrest of growth in the leaves occurs in

different ways; sometimes the whole leaf is smaller than usual; at other

times certain parts only are reduced in size; while, in a third class of

cases, portions of the leaf are entirely suppressed.

Moquin[526] mentions having seen the leaves of _Chenopodium vulvaria_,

and of _Diplotaxis muralis_ reduced to a fourth of their natural size;

and he alludes to other cases of the same nature, seen by other

observers, in _Hypericum perforatum_ and _Blitum polymorphum_.

_Nicandra physaloides_[527] has also been met with in a similar

condition, which, indeed, is a common result of insect-puncture, and of

fungous growth in plants. Those instances in which the leaf is

diminished in size, without any attendant malformation in other organs,

may be regarded rather as variations than as monstrosities, as in the

case of the entire-leaved varieties of those plants which ordinarily

have cut or divided leaves, _e.g._ _Plantago Coronopus_, var.

_integrifolia_, _Papaver Rhoeas integrifolia_, &c. &c. The same remark

may be made of those specimens in which one part of the leaf is

developed to a less extent than another, as happens in the submerged

leaves of such plants as _Ranunculus aquatilis_, _Cabomba aquatica_, the

spiney leaves of _Berberis_, the fenestrated leaves of _Ouvirandra_, &c.

In the illustrations last cited the relative deficiency of one portion,

as contrasted with another, takes place as a constant occurrence, and is

uniform and regular throughout the whole leaf. When, on the other hand,

the deficiency in question happens accidentally and irregularly, the

change may be considered as a malformation. One side of the blade of the

leaf is frequently affected in this manner, the other portions remaining

unaffected. It would appear as if any plant might be thus altered, but

the following species appear to be particularly subject to this change:

_AEesculus Hippocastanum_, _Digitalis purpurea_, _Morus alba_, _Fagus

silvatica contracta_ (hort.), _Codiaeum variegatum_ var. _erosum_

(hort.), _Broussonettia papyrifera_, _Scolopendrium vulgare_, &c.

Frequently this irregular diminution in proportion is coexistent with an

unusual degree of cleavage or laciniation of the margin, as in _Acer

platanoides laciniatum_, _Tilia asplenifolia_, _Alnus imperialis_

(hort.), _Fagus silvatica_ var. (hort.), &c.