Book III. Deviations from the Ordinary Number of Organs

To a certain extent the number of the organs of a plant is of even greater consequence for purposes of classification than either their form or their arrangement; for instance, the number of cotyledons in the embryo is made the chief basis of separation between the two great groups of flowering plants, the monocotyledons and the dicotyledons. In the one group, moreover, the parts of the flower are arranged in groups or whorls of five; in the other the arrangement is ternary. In mosses the teeth of the peristome are arranged in fours, or in some multiple of that number. So far as the larger groups are concerned, and also in cases where the actual number of parts is small, the numerical relations above described are very constant; on the other hand, in the minor subdivisions, and especially where the absolute number of parts is large, considerable variation may occur, so that descriptive botanists frequently make use of the term indefinite, and apply it to cases where the number of parts is large and variable, or, at any rate, not easy to be estimated.

Considered teratologically, the changes, as regards the number of organs, are readily grouped into those consequent on a decreased and into those resulting from an increased development. The alteration may be absolute or relative. There may be an actual deficiency in the number of parts or an increase in their number, but in either case the change may be simply a restoration of the primitive number, a species of peloria, in fact. An increased number of parts, moreover, may depend not so much on the formation of additional parts as on the subdivision of one.

It seems also desirable to treat separately those cases in which there is an increased number of buds either leaf-buds or flower-buds, as the case may be, as happens in what is termed prolification. This formation of buds occurring, as it does, often in unwonted situations is treated of under the head of alterations of arrangement, the mere increase in number being considered of subordinate importance as contrasted with the altered disposition (see p. 100).

Part 1. Increased Number of Organs.

An augmentation in the number of parts may arise from several causes, and may sometimes be more apparent than real. True multiplication exists simply as a result of over-development; the affected organs are repeated sometimes over and over again each in their proper relative position, and without any transmutation of form.

Metamorphy, on the other hand, often gives rise to the impression that parts are increased in number, when it may be that the stamens and pistils, one or both, are not so much increased in number as altered in appearance. The double anemones and ranunculus of gardens, amongst many other analogous illustrations, may be mentioned. In these flowers, owing to the petalody of the stamens and pistils, one or both, an impression of exaggerated number is produced, which is by no means necessarily a true one. Fission or lateral subdivision also gives rise to an apparent increase in number; thus, some so-called double flowers, the elements of which appeared to be increased in numbers, owe the appearance merely to the laciniation or subdivision of their petals.

The French botanists, following Dunal and Moquin, attribute an increase in the number of whorls in the corolla, and other parts of the flower, to a process which they call chorisis, and they consider the augmentation to be due to the splitting of one petal, for instance, into several;—somewhat in the same manner as one may separate successive layers of talc one from the other.

English botanists, on the other hand, have been slow to admit any such process, because, in most instances, no alteration in the law of alternation takes place in these double flowers, and in those few cases where the law is apparently infringed, the deviation is explained by the probable suppression of parts, which were they present would restore the natural arrangement of the flower; and, that this is no imaginary or purely theoretical explanation, is shown by some of the Primulaceæ, wherein a second row of stamens is occasionally present in the adult condition, and renders the floral symmetry perfect.

The double daffodil, where there are from forty to fifty petaloid organs instead of fifteen, and wherein each piece exhibits a more or less perfect coronal lobe at the junction of the claw and the limb, has been cited as an objection to chorisis, though it is difficult to see on what grounds.

In Delphinium, as shown by Braun, the stamens and carpels are members of a continuous spiral series, and in the double balsam an extra corolline whorl is produced, without the suppression of the stamens, in the following manner: the ordinary stamens are replaced by petals, the carpels by stamens, while an additional whorl of carpels is produced at the summit of the axis. In this instance, therefore, the doubling is distinctly referrible to an absolute increase in the number of whorls, and not to chorisis.

On the other hand, it must be admitted that there are many cases which are not to be explained in any other way than that suggested by the French botanists before alluded to. Probably, the main difficulty in the way of accepting the doctrine of chorisis is the unfortunate selection of the word used to designate the process; this naturally suggests a splitting of an organ already perfectly formed into two or more portions, either in the same plane as the original organs, "parallel chorisis;" or at right angles to it "collateral chorisis." Indeed, before so much attention had been paid to the way in which the floral organs are developed, it was thought that an actual splitting and dilamination did really take place; Dunal and Moquin both assert as much. The truth would rather seem to be that, in the so-called parallel chorisis at least, the process is one of hypertrophy and over-development rather than of splitting. The adventitious petal or scale is an excrescence or an outgrowth from the primary organ, and formed subsequently to it.

In the case of "compound stamens" the original stamens are first developed each from its own cellular "mamelon," or growing point; and, after a time, other secondary growing points emerge from the primary one, and in this way the stamens are increased in number, without reference, necessarily, to the so-called law of alternation. Outgrowths from leaves, multiplying the laminar surface, are alluded to under the head of hypertrophy, and it is probable that some of the cases of duplication of the flower, or of the formation of adventitious segments outside the ordinary corolla as alluded to in succeeding paragraphs (see Pleiotaxy of the corolla), are due to a similar process.

The formation of parts in unwonted numbers may be merely a reversion to what is supposed to have been the original form, and in this way there may be a restoration of parts that are usually undeveloped or suppressed. There can be little or no doubt that there are in reality six stamens in Orchidaceæ, of which one only, under ordinary circumstances, is developed. When the numerical symmetry is restored, as it sometimes is, it is obvious that the augmentation that occurs is of a different character from that arising from a repetition or renewed development of organs. When the increased number arises from multiplication proper, or from repetition, the ordinary laws of alternation are not interfered with, but if from chorisis or "dédoublement," it may happen that the normal arrangement is disturbed.

Without studying the mode of development, it is not in all cases possible to tell under which of the above categories any particular instance should be placed; hence, in the following sections, except where otherwise stated, the cases are grouped according to the appearance presented in the adult condition, rather than to the way in which the changes from the typical condition are brought about. With reference to the foliar organs it is necessary to distinguish those cases in which there is, from any cause, an augmentation in the number of component parts of a whorl, from those in which the increase takes place in the numbers of the whorls themselves.

Chapter I. Multiplication of Axile Organs, Inflorescence, Etc.

By Linné an undue number of branches was designated as "plica," from the analogy with the disease of the hair known as plica polonica: "Plicata dicitur planta, cum arbor vel ramus excrescit minimis intertextis ramulis, tanquam plica polonica ex pilis, ceu instar nidi Picæ, quod vulgo a genio ortum arbitratur; frequens apud nos in Betula, præsertim Norlandiæ, in Carpino Scaniæ, nec infrequens in Pinu."

By some of the older authors this condition was called polyclady. In some cases, it would seem to be due to fungi as in the witches' brooms (hexenbesen) of the German forests; in other instances, it is a result of mutilation as after the operation of pollarding.

Moquin-Tandon mentions a case in a grafted ash in the botanic garden of Toulouse, where below the graft there was a large swelling, from which proceeded more than a thousand densely-packed, interlacing branches.

This must have been similar to the condition so commonly met with in the birch, and frequently in the hornbeam and the thorn, and which has prompted so many a schoolboy to climb the tree in quest of the apparent nest. It is probable that some of the large "gnaurs" or "burrs," met with in elms, &c., also in certain varieties of apples, are clusters of adventitious buds, some of which might, and sometimes do, lengthen out into branches.

An increased number of branches also necessarily arises when the flower-buds are replaced by leaf-buds.

Occasionally, a great increase in the number of pedicels, or flower-stalks, may be met with in conjunction with a decreased number of flowers, as in the wig-plant (Rhus Cotinus), or the feather-hyacinth (Bellevalia comosa). In these cases the supernumerary pedicels are often brightly coloured. To this condition Morren gave the name mischomany, from μἱσχος, a pedicel, a term which has not generally been adopted.

M. Fournier describes a case in the butcher's broom (Ruscus aculeatus), wherein from the axil of the minute leaf subtending the flower a secondary flattened branch proceeded.

Duchartre cites the case of a hyacinth which, in addition to the usual scape, had a second smaller one by its side terminated by a solitary flower; indeed, such an occurrence is not uncommon.

Some tulips occasionally present three or four, or more, flowers on one inflorescence, but whether from a branching of the primary scape, or from the premature development of some of the axillary bulbils into flowering stems which become adherent to the primary flower-stalk, cannot, in all cases, be determined. Certainly, in some cases examined by me the latter was the case.

Under this head, too, may be included those cases wherein an ordinarily spicate inflorescence becomes paniculate owing to the branching of the axis and the formation of an unwonted number of secondary buds. Instances of this kind may be met with in willows, hazels, alders, and other amentaceous plants. In the case of the hazel the unusual development of male catkins sometimes coincides with an alteration in their position, instead of being placed near the axil of a leaf; they become terminal. Jaeger figures and describes a bunch of Pinus sylvestris bearing in one case seventy minute cones, and in another fifty-nine. These cones preserved the same spiral arrangement among themselves which is proper to the leaves. These latter, indeed, replaced the strobili above.

M. Reichardt describes an analogous case in the same species, and attributes the inordinate number of cones to a fungus (Peridermium pini). In this case there were no less than 227 cones, but each one half the size of the ordinary cones.

Of a similar character is the many-headed pineapple. Among grasses such a branching of the inflorescence is exceedingly common,—which is the more readily understood as the normal inflorescence is in so many cases paniculate. Cultivators have, in some instances, availed themselves of this peculiarity, as in the Egyptian wheat or corn of abundance (Triticum compositum), certain varieties of Maize, etc. Similar exuberant growths occur in Orchidaceæ, in Cyperaceæ, e.g. Carex, in Restiaceæ, and indeed they may be found in any plant with a similar form of inflorescence. In all these cases the branching begins at the lower part of the spike, and extends from below upwards in an indefinite manner, even although the primary inflorescence be definite.

Among the Equisetaceæ a similar plurality of spikes occurs often as a result of mutilation. The deviation in question might in some instances be turned to good account, as in the Triticum before mentioned or as in the broccoli shown at fig. 182, though it must be added that the apparent advantages are often counterpoised by some undesirable qualities or by some circumstance which prevents us availing ourselves of the new condition.

Multiplication of Bulbs.—This occurrence has been briefly alluded to previously (see p. 84). The most curious cases are those in which one bulb is placed on the top of another as happened in some bulbs of Leucoium æstivum described by M. Gay. Irmisch described a similar phenomenon in L. vernum; and Mr. Moggridge has communicated drawings of a similar formation in the same species grown in the neighbourhood of Mentone.

From the instances cited it is clear that branching of the inflorescence occurs most frequently in those plants naturally characterised by a dense compact mode of growth, whether that be definite or indefinite, as in spikes, umbels, capitula, &c.; so that compound spikes, umbels, &c., are formed in the place of simple ones (see also prolification of the inflorescence, p. 102).

Increased number of florets in the individual spikelets of grasses is also met with under some circumstances. I have seen this in Hordeum and Lolium, and an instance is figured in Avena by Dr. Wiegmann. M. Duval Jouve records a similar occurrence in Catabrosa aquatica, the spikelets of which contained from two to seven flowers.

Chapter II. Multiplication of Foliar Organs.

The cases referrible to this head may be ranged under two sections according as the increase is due to plurality of ordinarily single organs, or to an increase in the number of verticils or whorls.

When, in place of a single leaf organ two or more are really or in appearance present the occurrence may be due to one of several causes; among them may be mentioned an actual formation of parts in unwonted number, hypertrophy or enation, chorisis or fission, disjunction, adhesion of one leaf to another or to the stem, as in some of the leaves called "geminate," wherein the two leaves, though apparently in juxtaposition, yet originate from different parts of the stem, but by coalescence or lack of separation produce the impression as if they sprang from the same node. In the adult state it is not always possible to ascertain with certainty to which of these causes the increase in the number of leaves is due, though a clue to the real state of things may be gained from attention to the distribution of the veins, to the arrangement or phyllotaxy of the leaves, the size and position of the supernumerary organs, &c.

The term "phyllomania," as ordinarily used, is applied to an unwonted development of leafy tissue, as in some begonias where the scales or ramenta are replaced by small leaflets, or as in some cabbage leaves, from the surface of which project, at right angles to the primary plane, other secondary leafy plates; but these are, strictly speaking, cases of hypertrophy (see Hypertrophy).

Those instances in which the actual number of leaves is increased, so that in place of one there are more leaflets, may be included under the term "pleiophylly," which may serve to designate both the appearance of two or more leaves in the place usually occupied by a single one, and also those normally compound leaves in which the number of leaflets is greater than usual.

The increased number of leaves in a whorl may well be designated as "polyphylly," using the word in the same sense as in ordinary descriptive botany, while "pleiotaxy" may be applied to those cases in which the number of whorls is increased.

Pleiophylly.—As above stated, this term is proposed to designate those cases in which there is an absolute increase in the number of leaves starting from one particular point, as well as those in which the number of leaflets in a compound leaf is preternaturally increased. The simplest cases are such as are figured in the adjacent cuts, wherein, in place of a single leaf, two are produced in the elm. In the one case the new leaflet springs from the apex of the petiole and partially fills the space consequent on the obliquity of the base of the leaf. In the other it would seem as if two distinct leaves emerged from the stem in juxtaposition. This is probably due to a lateral chorisis or subdivision of the primitive tubercle or growing point, followed by a like subdivision of the vascular bundle supplying it. There are certain varieties of elm that very generally present this anomaly on their rank, coarse, growing shoots. In these cases the new growths have the same direction as the primary one, but in other cases the supplementary production is exactly reversed in direction. Thus, in the common hazel (Corylus) a second smaller leaf proceeding from the end of the leaf-stalk at the base of the primary one may frequently be seen. M. Germain de Saint Pierre records an instance in a mulberry leaf, from the base of which proceeded a large leafy expansion divided into two tubular, horn-like projections, and in the centre a thread-like process representing the midrib and terminated by a small two-lipped limb. Dr. Ferdinand Müller speaks of a leaf of Pomaderris elliptica as bearing a secondary leaf on its under surface.

The leaves of Heterocentron macrodon have likewise been observed occasionally to produce leaflets from their upper surface.

To this production of leaves from leaves the late Professor Morren applied the term "autophyllogeny." The Belgian botanist figures a small perfect leaf springing from the nerves of the upper surface of the primary leaf in a species of Miconia. As in the hazel, the direction of the adventitious leaf is inversely that of the primary one, the upper surface of the supernumerary leaflet being turned towards the corresponding surface of the normal leaf. A similar occurrence took place in Gesnera zebrina, but the new growth in this case sprang from the lower face of the leaf. Morren explains the appearances in question by supposing that the supplementary leaf is one of a pair belonging to a bud borne on a slender stalk. This stalk and one of the bud-leaves are supposed to be inseparably united with the primary leaf. But there is no reason at all for supposing the existence of adhesion in these cases; no trace of any such union is to be seen. A much more natural explanation is that, from some cause or another, development at the apex of the petiole or on the surface of the nerves, instead of taking place in one plane only, as usual, takes place in more than one, thus showing the close relationship, if not the intrinsic identity, between the leaf-stalk and its continuation, the midrib, with the branch and its subdivisions. The form of the leaf-stalk and the arrangement of the vascular bundles in a circle in the case of the hazel, before alluded to, bear out this notion. Such cases are significant in reference to the notion propounded by M. Casimir de Candolle, that the leaf is the equivalent of a branch in which the upper portion of the vascular circle is abortive.

Compound leaves, as has been stated, occasionally produce an extra number of leaflets; one of the most familiar illustrations of this is in the case of the four-leaved shamrock (Trifolium repens), which was gathered at night-time during the full moon by sorceresses, who mixed it with vervain and other ingredients, while young girls in search of a token of perfect happiness made quest of the plant by day. Linné, who in this matter, at any rate, had less than his usual feeling for romance, says of the four-leaved trefoil that it differs no more from the ordinary trefoil than a man with six fingers differs from one provided with the ordinary number. It should be stated that five and six adventitious leaflets are found almost as frequently as four.

Walpers describes a case where the leaf of T. repens bore seven leaflets. Schlechtendal alludes to a similar increase in number in Cytisus Laburnum, and many other instances might be cited.

For figures or descriptions of four-leaved shamrocks the reader is referred to Lobel, 'Stirp. Advers.,' Nov., p. 382. Tabernæmontanus 'Krauterbuch,' S. 222. Schlechtendal, 'Bot. Zeit.,' ix, p. 583, xiv, p. 71. Maugin, 'Bull. Soc Bot. Fr.,' 1866, t. xiii, p. 279. See also Cramer, 'Bildungsabweich,' p. 92. Walpers, 'Linnæa,' 1840, p. 362 (7-leaved). Schlechtendal, 'Bot. Zeit.,' 1844, p. 457, Cytisus. Wigand, 'Flora,' 1856, p. 706.

Frondiferous leaves have much the appearance of branches provided with leaves, and they may be compared with those instances in which an adventitious bud is placed on the surface or edges of the leaves, as in Gesnera, Cardamine, &c. In truth, the two conditions merge one into the other, as in some begonias, where the ramenta often become leaf-like and bear small bulbils in the axil.

When frondiferous leaves die the appendages die also, but when a true bud has been formed on a leaf it does not of necessity die with the leaf that bears it, but separates from it and continues to grow independently.

Increased number of stipules, spathes, &c.—Seringe relates the occasional presence of two or three additional stipules upon the leaf-stalks of Salix fragilis, and even makes a variety (Salix pendula, var. multistipulata).

An increase in the number of the spathes has been often noticed in Arads. Prof. Alex. Braun has studied this subject in some detail. In Calla palustris the shoot which continues the growth of the plant proceeds from the axil of the last leaf but one; the very last leaf producing no bud, but if accidentally a shoot is developed in this latter situation it produces flowers at once. No leaves are formed, but, on the contrary, two or three spathes surround the spadix, so that the presence of an increased number of spathes in this plant is associated with the development of a side shoot from the axil of the last leaf, the situation whence, under natural circumstances, no shoot at all issues. The supernumerary spathes are not always on the same level, but may be separated by a considerable interval. They vary very much in size, and sometimes assume the form and appearance of leaves. Similar anomalies occur in other Arads as Arum maculatum, Richardia æthiopica, and Anthurium Scherzerianum, frequently combined with a leaf-like appearance of the spathes and sometimes with a subdivision of the spadix into two or three branches.

Engelmann relates the occurrence of an increased number of glumes in Bromus velutinus associated with suppression of the flowers.

Polyphylly.—As previously explained, this term is here applied to those cases in which the members of any particular whorl are increased in number, the whorls themselves not necessarily being augmented.

The simplest cases of this kind are those in which we meet with an unusual number of leaves in a whorl.

Increased number of leaves in a whorl.—This may arise from actual multiplication, or from lateral chorisis, or fission. The true nature of the case may usually be ascertained by an examination of the distribution of the veins of the leaves, or of the fibrous cords of the stem, by the relative position of the supernumerary organs, &c.

Among plants with normally opposite leaves the following occasionally produce them in whorls of three:—Lonicera brachypoda, L. Xylosteum, Weigela rosea, Cornus mas, Vinca minor, &c.

Paris quadrifolia may frequently be met with five leaves in its whorl, or even six.

Increased number of bracts.—This is not of infrequent occurrence; one of the most curious instances is that recorded by Mr. Edwards in Cerastium glomeratum, where, in place of the usual pair of bracts at the base of the head of flowers, there was a whorl of six or eight, forming an involucre. The flowers in this case were apetalous and imperfect.

Polyphylly of the calyx.—This may occur without any other perceptible change, while at other times the number of the other parts of the flower is proportionately increased. In a flower of a plum six sepals in place of five sometimes exist; a precisely similar occurrence in the flowers of the elder (Sambucus), the Fuchsia, and of Œnanthe crocata, may occasionally be met with. In the latter case, indeed, there are sometimes as many as ten segments to the calyx, and this without the other parts of the flower being correspondingly augmented. Among monocotyledons a similar increase is not uncommon, as in Tulipa, Allium, Iris, Narcissus, &c.

In some plants there seems to exist normally much variation in the number of parts; thus in some species of Lacistema in adjacent flowers the calyx may be found with four, five, or six segments.

Most of these cases of polyphylly affecting the calyx may be explained by lateral chorisis or fission.

Polyphylly of the corolla.—This may happen in connection with similar alterations in the calyx and stamens, or sometimes as an isolated occurrence. In the latter case it may be due to lateral chorisis, to substitution, or to the development of organs usually suppressed; thus, when in aconites we meet with four or five horn-like nectaries (petals) instead of two only, as usual, the supernumerary ones are accounted for by the inordinate development of parts which ordinarily are in an abortive or rudimentary state only. This is borne out by what happens in Balsamineæ. In the common garden balsam the fifth petal is occasionally present, while in Hydrocera triflora this petal is always present.

In a flower of a Cyclamen recently examined there were ten petals in one series, the additional five being evidently due to the subdivision of the five primary ones; the natural circular plan of the flower was here replaced by an elliptical one. A similar occurrence takes place in the flowers of maples (Acer), which sometimes show an increased number of parts in their floral whorls and an elliptical outline. Whether the additional organs in this last case are the result of complete lateral chorisis or of multiplication proper I do not know.

Orchids are very subject to an increase in the number of their labella. As illustrations may be cited an instance recorded by Mr. J. T. Moggridge in a flower of Ophrys insectifera, and in which there were two labella without any other visible deviation from the ordinary conformation.

I am indebted to Mr. Hemsley for the communication of a similar specimen in O. apifera, in which there were two divergent lips, each with the same peculiar markings. One of the sepals in this flower was adherent to one of the lateral petals. This augmentation of the labella depends sometimes on the separation, one from the other, of the elements of which the lip is composed, at other times on the development, in the guise of lips, of stamens which are usually suppressed (see p. 380).

The following enumeration will suffice to show the genera in which an increased number of petals or perianth-segments in any given whorl most frequently occurs.

• Anemone!
• Ranunculus!
• Aconitum!
• Raphanus.
• Bunias.
• Saponaria.
• Dianthus!
• Pelargonium!
• Hibiscus.
• Fuchsia.
• Sarothamnus!
• Lotus!
• Ulex!
• Prunus!
• Trifolium.
• Œnanthe and Umbellif. pl.!
• Sambucus!
• Bryonia.
• Campanula.
• Solanum.
• Veronica.
• Cyclamen!
• Primula!
• Anagallis!
• Plumbago.
• Jasminum.
• Syringa!
• Tradescantia.
• Iris.
• Tigridia.
• Narcissus.
• Tulipa.
• Convallaria!
• Paris!
• Hyacinthus!
• Allium!
• Ornithogalum.
• Orchideæ, sp. pl.!

For other illustrations see multiplication of whorls, petalody; see also Moquin, loc. cit., p. 350. Engelmann, loc. cit., p. 20, § 18. Cramer, loc. cit., p. 25.

Polyphylly of the andrœcium.—An increased number of stamens frequently accompanies the corresponding alterations in other whorls, and seems, if anything, to be more frequent among monocotyledonous plants than among dicotyledonous ones; thus, we occasionally find tetramerous flowers in Crocus, Hyacinthus, Tulipa, Iris, Tigridia, &c., and more rarely in Yucca (Y. flexilis).

The increased number of stamens in a single whorl may result from a development of organs usually suppressed, and constitute a form of regular peloria as in Linaria, wherein a fifth stamen is occasionally met with. Among normally didynamous plants such numerical restitution, so to speak, is not unusual; thus, in Veronica four and five stamens occur. Fresenius has seen five stamens in Lamium, Mentha, Chelone; Bentham in Melittis, and other instances are cited under the head of peloria. Chorisis may also serve to account for some of these cases; thus, Eichler figures a flower of Matthiola annua with five long stamens instead of four; one of the long pairs of stamens has here undergone a greater degree of repetition than usual. De Candolle cites and figures a curious form of Capsella Bursa-pastoris sent him by Jacquin, and which was to some extent reproduced by seed. In the flowers of this variety there were no petals, but ten stamens; hence De Candolle inferred that the petals were here replaced by stamens, but Moquin objects, and with justice, to this view, as the ten stamens are all on the same line; he considers the additional stamens to be the result of chorisis. Buchenau mentions the presence of seven stamens in another Crucifer, Ionopsidium acaule. Here the supernumerary organ was placed between two of the long stamens. The effect of chorisis in producing an augmentation of parts is well seen in some plants that have some of their flowers provided with staminodes or abortive stamens, and others with clusters or phalanges of perfect stamens. Thus, in the female flowers of Liquidambar there are five small staminodes without anthers, whereas in the male flower the stamens are numerous and grouped together in phalanges, so that the relation of simple to compound stamens is in this case readily seen, as also in many Malvaceæ, Sterculiaceæ, Byttneriaceæ, Tiliaceæ, and Myrtaceæ. It is probably the idea of splitting or dilamination involved in the word chorisis that has led many English botanists to hesitate about accepting the notion. Had they looked upon the process as identical with that by which a branched inflorescence replaces an unbranched one, or a compound leaf takes the place of a simple one, the objections would not have been raised with such force. The process consists, in most cases, not so much in actual cleavage of a pre-existing organ as in the development of new-growing points from the old ones.

An illustration given by Moquin from Dunal goes far to support the notion here adopted. The majority of the stamens of laurels (Laurus) have, says M. Dunal, on each side of the base of their filaments a small glandular bifid appendage; these excrescences are liable to be changed into small stamens. The male flowers have a four-leaved calyx, and sometimes eight stamens, each with two glands, four in one row, opposite to the sepals, four in a second series alternating with the first. More generally two of the stamens are destitute of glands, but have in their place a perfectly developed stamen, so that in these latter flowers there are twelve stamens.

M. Clos mentions a flower of rue (Ruta) wherein there were two stamens joined together below and placed in front of a petal, as in Peganum.

Buchenau mentions a flower of Lotus uliginosus in which there were eleven stamens, namely, two free and nine monadelphous; and Hildebrand describes an analogous increase in a flower of Sarothamnus scoparius in which, in conjunction with a seven-toothed calyx, there were two carinas and fourteen stamens. It would seem probable in this case that there was a coalescence of two flowers at an early date and consequent suppression of some of the parts of the flower. Whether this was the case or not in this particular illustration, it is nevertheless certain that many of the recorded instances of increased number in the organs of a flower are really the results of a fusion of two or more flowers, though frequently in the adult state but few traces of the coalescence are to be seen.

Polyphylly of the gynœcium.—Moquin remarks that, as the pistils are, generally speaking, more or less subject to pressure, owing to their central position, and it may be added owing to their later development, than the other parts of the flower, they are more subject to suppression than to multiplication; nevertheless, augmentation in the number of carpels does occasionally take place, especially when the other parts of the flower are also augmented in number. Sometimes this increase in the number of carpels is due to pure multiplication, without any other change. At other times the increase is due to a substitution of stamens or other organs for carpels (see Substitutions). In other cases the augmentation seems to be due to the development of parts usually suppressed; for instance, in Antirrhinum, where there are usually only two carpels present, but where, under peculiar circumstances, five may be found—thus rendering the symmetry complete. In Papilionaceæ, wherein usually only one carpel is developed, we occasionally find two, or even more, as in Wistaria, Gleditschia, Trifolium, &c. In Prunus and Amygdalus from two to five carpels are occasionally to be found, in Mimosa five, in Umbelliferæ three to five; in some composites, e.g. Spilanthes, five carpels have also been noticed; in Cruciferæ three and four, in grasses three. The double cocoa-nut affords an illustration of the development of two carpels out of three, one only generally arriving at perfection. Triple nuts (Corylus) also owe their peculiarity to the equal development of all three carpels which exist in the original flower, but of which, under ordinary circumstances, two become abortive. It is necessary, however, to distinguish these cases from those in which two embryos are developed in one seed.

The following list may serve to show in what genera this change has been most frequently noticed, and it may be said in general terms that Cruciferæ, Umbelliferæ, and Liliaceæ, are the orders most frequently affected. Cases of peloria are not included in the subjoined list.

• Nigella.
• Aquilegia.
• Pæonia!
• Delphinium!
• Iberis.
• Diplotaxis.
• Lunaria.
• Ricotiana.
• Octadenia.
• Draba!
• Lepidium.
• *Cheiranthus!
• Dianthus.
• Brassica!
• Parnassia.
• *Acer!
• Ptelea.
• Citrus!
• Philadelphus.
• Prunus!
• Amygdalus!
• Cratægus!
• Fuchsia!
• Trapa!
• Cassia.
• Cercis.
• Medicago.
• *Phaseolus!
• Wistaria.
• Gleditschia.
• Affonsea.
• Trifolium!
• Archidendron.
• Mimosa.
• Robinia.
• Diphaca.
• Cœsalpinia.
• Vicia.
• Anthyllis.
• Cucurbita.
• Passiflora!
• Sambucus!
• *Œnanthe!
• Daucus!
• Angelica!
• Heracleum!
• Silaus.
• Carum.
• Thysselinum.
• Campanula!
• Spilanthes.
• Chrysanthemum.
• Anagallis.
• Primula!
• Fraxinus!
• Lycium.
• Cobæa.
• Datura!
• Solanum!
• Sesamum.
• Sideritis.
• Coleus.
• Veronica!
• *Digitalis!
• Antirrhinum!
• Linaria.
• Gloxinia!
• Symphytum.
• Anchusa.
• Polygonum.
• Euphorbia.
• Cneorum.
• Mercurialis!
• Chenopodium.
• Suæda.
• Beta.
• Corylus!
• Lambertia.
• Cocos!
• Tigridia.
• Tulipa!
• Iris!
• Narcissus!
• Allium!
• Ornithogalum.
• Gagea!
• Tradescantia!
• Schœnodon.
• Bambuseæ.

A few additional references may here be given to papers where an increased number of carpels is described:—Engelmann, 'De Antholys,' § 17, p. 19. Bernhardi, 'Flora,' 1838, p. 129. Schkuhr., 'Bot. Handb.,' t. 179. Godron, 'Ann. Sc. Nat.,' ser. 5, vol. ii, p. 280, tab. xviii, pluricarpellary Crucifers. Weber, 'Verhandl. Nat. Hist. Vereins. Rhein. Pruss.,' &c., 1860, Cerasus, &c., &c. Baillon, 'Adansonia,' iv, p. 71, Trifolium. Schlechtendal, 'Bot. Zeit.,' xv, p. 67, Datura, three-celled fruit; 'Bot. Zeit.,' xiii, p. 823, Phaseolus, double pistil—a common case. Cramer, 'Bildungsabweich,' p. 99, reference to several leguminous plants with polycarpellary pistils. Munro, Gen., 'Linn. Trans.,' vol. xxvi, p. 26, Bambuseæ. Alph. de Candolle, 'Neue Denkschrift,' Cheiranthus. Schimper, 'Flora,' 1829, ii, p. 433. Wigand, 'Bot. Untersuch.' Fleischer, 'Missbild. Cultur Pfl.' Cramer, 'Bildungsabweich,' p. 65, Umbelliferæ.

Polyphylly of the flower in general.—Although, for the sake of convenience, multiplication has here been treated of as it affects the members of individual whorls of the flower, yet it must be remembered that, in general, the augmentation is not confined to one whorl, but affects several; thus, if the sepals are increased, the petals are likely to be so likewise, and so forth. One of the most curious illustrations of this is that recorded by Mr. Berkeley in a plum, wherein there was an increased number of sepals, a corresponding augmentation in the petals, while the pistil was composed of two and sometimes three carpels distinct from the calyx and from each other. In the flowers there did not appear to be any definite relation in the position of the parts either with reference one to another or to the axis.

In Primulaceæ this general augmentation has been frequently noticed.

Among Orchideæ the instance related by Dr. Seubert is worth alluding to here. This botanist observed and figured a flower of Orchis palustris with tetramerous arrangement of parts, that is to say there were four outer segments to the perianth, four petals, of which two were lip-like, four stamens, three of which were rudimentary, and an ovary with four parietal placentæ.

The following list will serve to show in what plants this general augmentation of parts has been observed most frequently:

• Ranunculus.
• Clematis!
• Delphinium.
• Brassica!
• Ruta.
• Acer!
• Prunus!
• Rosa!
• Rubus.
• Philadelphus!
• Chrysosplenium.
• Umbelliferæ, sp. pl.!
• *Fuchsia!
• Œnothera.
• Adoxa.
• Bryonia.
• Cucumis!
• Campanula!
• Sambucus!
• *Primula!
• Anagallis!
• Lycium.
• Solanum.
• Symphytum.
• Syringa!
• Linaria.
• Chenopodium.
• *Paris!
• Convallaria!
• Allium.
• *Lilium!
• *Tulipa!
• Ornithogalum.
• *Gagea!
• Tradescantia!
• Orchideæ, sp. pl.!

Increased number of ovules or seeds.—This appears not to be of very frequent occurrence, at least in those plants where the number of these organs is normally small; where, as in Primula, the ovules and seeds are produced in large quantities, it is not practicable to ascertain whether the number be augmented or not in any particular case. Very probably, the attachment or source of origin of the ovules determines, in some measure, their number. Thus, in the case of marginal placentation the number must be limited by the narrow space from which they proceed, whereas in parietal and free central placentation the ovules are generally numerous. In the latter case, however, it will be remembered that solitary ovules are not rare. An increased number of ovules is generally remarked in conjunction with some other change, such as a foliaceous condition of the carpel, in which the margins are disunited. In such cases the ovules may occupy the margin or may be placed a short distance within it, as in the case of some open carpels of Ranunculus Ficaria, and in which two ovules were borne in shallow depressions on the upper or inner surface of the open carpel and supplied with vascular cords from the central bundle or midrib. The outer coating of the ovule here contained barred or spiral fusiform vessels derived from the source just indicated.

In the very common cases where the pistil of Trifolium repens becomes foliaceous (see Frondescence), the outer ovules are generally two or more instead of being solitary. So, also, in the Rose with polliniferous ovules (see p. 274). Among Umbelliferæ affected with frondescence of the pistil a similar increase in the number of ovules takes place. It will be borne in mind that in most, if not all, these cases the structure of the ovule is itself imperfect.

What are called in popular parlance double almonds or double nuts (Corylus) are cases where two seeds are developed in place of one.

In the 'Revue Horticole,' 1867, p. 382, mention is made of a bush which produces these double nuts each year—in fact, it never produces any single-seeded fruit. The plant was a chance seedling, perhaps itself the offspring of a double-seeded parent. It would be interesting to observe if the character be retained by the original plant, and whether it can be perpetuated by seed or by grafting.

It is necessary to distinguish in the case of the nut between additional seeds or ovules, as just described, and the double, triple, or fourfold nuts that are occasionally met with, and which are the result either of actual multiplication of the carpels or of the continued development of some of the carpels which, under ordinary circumstances cease to grow (see ante, p. 364). In the case of a ripe nut with two seeds it might be impossible to tell whether the adventitious seed were the product of multiplication, or whether it belonged, in the first instance, to the same carpel as that producing the fellow-seed, or to a different and now obliterated ovary. In all probability, however, the second seed would be accounted for by the development of two seeds in one carpellary cavity.

There is still another condition occasionally met with in the almond, and which must be discriminated from the more common multiplication of the seed, and which is the multiplication of the embryos within the seed, and which furnishes the subject of the succeeding paragraph.

Increased number of embryos.—A ripe seed usually contains but a single embryo, although in the ovular state preparation is commonly made for more; and, indeed, in certain natural orders plurality of embryos in the same seed does occur, as in Cycadeæ and Coniferæ. In the seeds of the orange (Citrus), in those of some Euphorbiaceæ, &c., there are frequently two or more additional embryos. A similar occurrence has been recorded in the mango, for a specimen of which I am indebted to the Rev. Mr. Parish, of Moulmein.

Plurality of embryos has also been observed in—

• Raphanus sativus.
• *Citrus Aurantium!
• Diosma, sp.
• Hypericum perforatum.
• Triphasia aurantiaca.
• *Æsculus Hippocastanum!
• Euonymus latifolius.
• *Mangifera indica!
• Eugenia Jambos.
• Amygdalus vulgaris!
• Vicia, sp.
• Cassia, sp.
• *Viscum album!
• Daucus Carota.
• Ardisia serrulata!
• Cynanchum nigrum.
• fuscatum.
• Euphorbia rosea.
• Cœlebogyne ilicifolia.
• Allium fragrans.
• Funckia, sp.
• Carex maritima.
• Zea Mays.

See Schauer's translation of Moquin-Tandon, 'El. Terat. Veget.,' p. 245, adnot., and 'Al. Braun Polyembryonie.'

Increased number of the cotyledons.—Although the presence of one or of two cotyledons in the embryo is generally accepted as a valuable means of separating flowering plants into two primary groups, yet, like all other means of discrimination, it occasionally fails, and, indeed, almost always requires to be taken in conjunction with some other character. There are cases among flowering plants where the embryo is homogeneous in its structure, there are others in which the number of the cotyledons is more than two. Thus, in some seeds of Cola acuminata the cotyledons vary in number from two to five. I have not been able to ascertain precisely whether this multiplication of the cotyledons is characteristic of all the seeds of particular trees, or whether some only are thus affected. Some fruits that I examined bore out the latter view, as in the same pod were seeds with two, three, and four cotyledons respectively.

I have also seen three cotyledons present in embryo-plants of Correa, Cratægus Oxyacantha, Dianthus sinensis, Daucus Carota, Cerasus Lauro-cerasus. De Candolle alludes to a case of the kind in the bean, and figures a species of Solanum with three cotyledons. Jaeger alludes to a similar instance in Apium Petroselinum; Ehrenberg to one in the marigold (Calendula); 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. This fusion seems frequently to accompany increase in the number of cotyledons. It was so in the Correa, and in the Cratægus previously mentioned. Some of these cases may be accounted for by chorisis or by a cleavage of the original cotyledons, as happens, according to Duchartre, in some Coniferæ, which he considers to be improperly termed polycotyledonous. Whether this holds good in the Loranths, where (Nuytsia, Psittacanthus) an appearance of polycotyledony exists, is not stated. In the case of the rue (Ruta) figured by M. A. de Jussieu this splitting of one cotyledon into two is sufficiently evident, as is also the case in the sycamore (Acer pseudo-platanus), seedlings of which may often be met with divided cotyledons.

In other instances a fusion of two embryo plants may give rise to a similar appearance, as in the Euphorbia and Sinapis found by M. Alph. de Candolle (see ante, p. 56).

Pleiotaxy or multiplication of whorls.—In the preceding section notice has been taken of the increased number of parts in a single whorl, but an augmentation of the number of distinct whorls is still more frequently met with. Many of the so-called double flowers owe their peculiarity to this condition. The distinction between the two modes in which the parts of the flower are increased in number has been pointed out by Engelmann, Moquin, and others, and the two seem to require distinctive epithets; hence the application of the terms polyphylly and pleiotaxy, as here proposed.

Pleiotaxy in the bracts.—An increase in the number of bracts has been met with very constantly in a species of Mæsa, and in a peculiar variety of carnation, called the wheat-ear carnation. 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.

It has been noticed also in the common pea, Pisum sativum, and M. Lortet 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.

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. Irmish 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 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 Rœper observed a calyx consisting of a double series, each of five sepals, in conjunction with other changes. It is also common in double columbines, delphiniums, nigellas, &c.

In the 'Revue Horticole,' 1867, p. 71, fig. 9, is described and figured by M. B. Verlot a curious variety of vine grown for years in the Botanic Garden at Grenoble, under the name of the double-flowered vine. The place of the flower is occupied by a large number of successive whorls of sepals disposed in regular order, and without any trace of the other portions of the flower. It is, in fact, more like a leaf-bud than a flower. The outermost whorls of this flower open at the time when the ordinary flowers of vines do; the second series are gradually produced, and expand about the time when the ovaries of the normal flowers begin to swell; a third series then gradually forms, and so on, until frost puts a stop to the growth. This malformation, it appears, is produced annually in certain varieties of vine, and may be perpetuated by cuttings.

The flower of the St. Valèry apple, already alluded to under the head of sepalody, might equally well be placed here. It is not very material whether the second whorl of organs be regarded as a repetition of the calyx or as a row of petals in the guise of sepals.

Engelmann 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.

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.

Pleiotaxy of the corolla.—With reference to double flowers, it was remarked by Linné that polypetalous flowers were, as he said, multiplied, while monopetalous flowers were duplicated, or triplicated, as the case may be, a statement that is true in the main, though it requires modification. In the case of polypetalous, or rather dialypetalous flowers, the petals may be very largely increased by multiplication, as in roses, anemones, pinks, &c. In the last-named genus the number is often so much increased that the calyx splits from the tension exercised on it by the increasing mass within. This multiplication may happen without any metamorphy or substitution of petals for stamens, though, in the majority of cases, it is associated with such a change. It is curious to observe in some of these flowers that the total number of parts is not greatly increased; thus, in some of the double-flowered Leguminosæ, such as Ulex europæus and Lotus corniculatus, the petals are repeated once or twice, the stamens are petalodic, but reduced in number, while the carpels are usually entirely wanting. Thus, owing to the diminished number of parts in the inner whorls of the flower, these very double-looking blooms do not contain any greatly increased number of parts.

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.

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, 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 andrœcium.—An increase in the number of whorls in the stamens is very common, especially in cases where the number of circles of stamens is naturally large. The augmentation of the number of stamens is still more frequent where these organs are arranged, not in verticils, but in one continuous spiral line.

In Cruciferæ there is always an indication of two whorls of stamens, and this indication is rendered even more apparent in some varieties accidentally met with. So in Saponaria, in Dianthus, and other Caryophylleæ, three and four verticils of stamens have been met with. In Lonicera Periclymenum a second whorl of stamens more or less petalodic sometimes occurs.

Moquin mentions a variety of Rubus fruticosus in which nearly 900 petaloid organs existed in the place of the twenty-five or thirty stamens natural to the plant, the other organs of the flower being in their ordinary condition, with the exception of the pistil, which did not attain its full size. Baillon records the occasional existence of two rows of stamens in Ditaxis lancifolia.

Increased number of stamens in orchids, &c.—Various deviations from the ordinary type of orchid structure have been already alluded to under the head of displacement, fusion, peloria, substitution, &c., but the alterations presented by the andrœcium 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 andrœcium 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.

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. 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). 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.

Rœper is stated by Cramer to have seen a specimen of Orchis morio with two stamens.

In a flower of Habenaria chlorantha, described by the late Professor Henslow, 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, the three stamens (according to the diagram of its structure given by Lindley) pertaining to the outer row.

In a specimen of Dendrobium hœmoglossum 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. 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." 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 figures a flower of Maxillaria in exactly the same condition, so far as the stamens are concerned, as in the Ophrys flowers just mentioned. It is curious to observe that in many of these cases the two lateral petals are suppressed.

Von Martius mentions the occurrence of three anthers (naturaliter conformatæ) in Orchis morio. Richard, as cited by Moquin-Tandon, Lindley, and others, describes and figures a peloria of Orchis latifolia with regular triandrous flowers.

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 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.

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 π-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.

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 (a1 and a2) 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, and in the accompanying diagram (fig. 195), from Cramer, 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.

Morren describes some flowers of Orchis morio in which there were three sepals, three petals, and within the latter two other ternary series of petals; this would seem to be a case of petalody of all six stamens. Morren, however, seems to have considered the additional segments as repetitions of the corolline whorl, though he describes a central mass as the column bearing a "souvenir of the anther." Nevertheless, there is no decisive evidence either in his figure or his description in support of his opinion as to the nature of the central mass, which might be a distorted condition of the styles, or, as is more probable, a rudimentary and irregular flower. Morren also describes another flower of the same plant in which there were three sepals, two lateral petals partially lip-like in aspect, a third labellum normal, two additional labella representing the two anterior stamens of the outer whorl, while more or less developed rudiments of the remaining four stamens also exist.

While, in most cases, the supernumerary stamens can, by reason of their relative position, their complete or partial antheriferous nature, be safely referred to one or other of the six stamens, making up a typical orchid flower, there are other specimens in which the additional stamens are altogether adventitious, and do not admit of reference to the homologue. Thus it was in a specimen of Odontoglossum Alexandræ examined by the writer, and in which, within a normally constructed perianth, there were six columns, all polliniferous, but arranged in so confused and complicated a manner that it was impossible to make out any definite relation in their position. There was nothing to indicate a fusion of flowers, but rather an extension of the centre of the flower, and consequent displacement of the stamens, &c. Again, the existence of adventitious stamens does not necessarily imply the development of organs usually suppressed, inasmuch as they may result from the assumption by the lateral petals of staminal characteristics.

Nevertheless, as far as teratology is concerned, specimens may be found in which some or all of the usually suppressed stamens of Orchidaceæ may be found. These stamens may be all perfect (polliniferous), or, as is more frequently the case, more or less petal-like. Moreover, when the stamens are petalodic, the form assumed is usually that of the labellum.

The presence of stamens in undue numbers in orchids is very generally, but not always, attended by some coincident malformation, of which the most frequent is cohesion of two or more sepals, and consequent displacement or adhesion of one petal to the side of the column. Petalody of the styles and median prolification are also sometimes found in association with an augmented number of stamens.

Pleiotaxy of the gynœcium.—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 mentions a flower of Gentiana purpurea with four carpels in one series, and five others in the circle immediately above them. Wigand 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. Meissner records a similar augmentation in Polygonum orientale.

Wigand 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 has put on record a similar case in a capparid.

Marchand 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 in Saxifraga Geum may be alluded to. Here there was a row of adventitious carpels between the stamens and pistils, the backs of the carpels being turned towards the axis of the flowers. Dr. Allman explains the presence of the supernumerary parts by the supposed production of a whorl of secondary axes between the stamens and the centre of the flower. These axes are further supposed to bear imperfect flowers, of which the additional carpels are the only traces, but this explanation seems forced.

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

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

Ferrari, 'Hesperides,' pp. 271, 395, 405. Duchartre, 'Ann. Sc. Nat.,' 4 ser., 1844, vol. i, p. 294. Maout, 'Leçons Elément.,' vol. ii, pp. 488–9. Clos, 'Ann. Sc. Nat.,' 1865, p. 317 (Citrus Aurantium).

Clos, 'Bull. Soc. Bot. Fr.,' vol. xiii; 'Rev. Bibl.,' p. 75. Pasquale, 'Reddicont Accad. Sc. Fis. e Math. Napoli.' Octr. 1866 (Solanum Lycopersicum).

On the general subject of multiplication, in addition to previous citations, the reader may be referred to A. P. de Candolle, 'Théorie Elément. Bot.,' ed. 3, p. 89.

Increased number of flowers in an inflorescence.—This happens generally as a result of over luxuriant growth, and scarcely demands notice here, being rather referable to variation than to malformation. The increased number of florets in the spikelets of some grasses has already been alluded to (p. 351). Thus spikelets of wheat occasionally produce more than the three florets which are proper to them. 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.

Part II. Diminished Number of Organs.

A diminution in the number of parts is generally due to suppression, using that word as the equivalent of non-development. It corresponds thus in meaning with the Fehlschlagen of the Germans, the avortement complète of Moquin and other French writers. It differs from atrophy, or partial abortion, inasmuch as the latter terms apply to instances wherein there has been a partial development, and in which evolution has gone on to a certain extent, but has, from some cause or other, been checked. These cases will be found under the head of diminished size of organs. As the word abortion is used by different authors in different ways, it is the more necessary to be as precise as possible in the application of the term. In the present work abortion is used to apply to cases wherein parts have been formed, but wherein growth has been arrested at a certain stage, and which, therefore, have either remained in statu quo, while the surrounding parts have increased, or have, from pressure or other causes, actually diminished in size.

In practice, however, it is not always possible to discriminate between those instances in which there has been a true suppression, an absolute non-development of any particular organ, and those in which it has been formed, and has grown for a time, but has afterwards ceased to do so, and has been gradually obliterated by the pressure exercised by the constantly increasing bulk of adjacent parts, or possibly has become incorporated with them. In the adult flower the appearances are the same, though the causes may have been different.

Chapter I. Suppression of Axile Organs.

Absolute suppression of the main axis is tantamount to the non-existence of the plant, so that the terms "acaulescent," "acaulosia," etc, must be considered relatively only, and must be taken to signify an atrophied or diminished size of the stem, arising from the non-development of the internodes.

The absence of lateral branches or divisions of the axis is of frequent occurrence, and is dependent on such causes as the following:—deficient supply of nutriment, position against a wall or other obstacle, close crowding of individual plants, too great or too little light, too rich or too poor a soil, &c.

Probably the absence of the swollen portion below the flower in the case of many proliferous roses, double-flowered apples, as already referred to, may be dependent on the non-development of the extremity of the peduncle or flower-stalk. Thus, in a double-flowered apple recently examined, there was a sort of involucel of five perfect leaves, then five sepals surrounding an equal number of petals, numerous stamens, and five styles, but not a trace of an expanded axis, nor of any portion of the carpels, except the styles. The views taken as to the nature of this and similar malformations must depend on the opinion held as to the nature of inferior pistils, and on the share, if any, that the expanded axis takes in their production. As elsewhere said, the evidence furnished by teratology is conflicting, but there seems little or nothing to invalidate the notion that the end of the flower-stalk and the base of the calyx may, to a varying extent, in different cases, jointly be concerned in the formation of the so-called calyx-tube and of the inferior ovary. Obviously it is not proper to apply to all cases where there is an inferior ovary the same explanation as to how it is brought about.

As these pages are passing through the press, M. Casimir de Candolle has published a different explanation as to the nature of the hip of the rose, having been led to his opinion by the conclusion that he has arrived at, that the leaf is to be considered in the light of a flattened branch, whose upper or posterior surface is more or less completely atrophied.

According to M. de Candolle, the calyx-tube, in the case of the rose, is neither a whorl of leaves, nor a concave axis in the ordinary sense in which those terms are used, but is rather to be considered as a ring-like projection from an axis arrested in its ulterior development. The secondary projections from the original one correspond to an equal number of vascular bundles, and develope into the sepals, petals, stamens, and ovaries. If these organs remained in a rudimentary condition, the tube of the calyx would be reduced to the condition of a sheathing leaf. The rose flower, then, according to M. de Candolle, may be considered as a sheathing leaf, whose fibro-vascular system is complete, and from which all possible primary projections are developed.

If, as M. de Candolle considers, the leaf and the branch differ merely in the fact that the vascular system is complete in the latter, and partly atrophied in the former, it would surely be better to consider the "calyx-tube" of the rose as a concave axis rather than as a leaf, seeing that he admits the fibro-vascular system to be complete in the case of the rose.

With reference to this point the reader is referred to Mr. Bentham's account of the morphology and homologies of the Myrtaceæ in the 'Journal of the Linnean Society,' vol. x, p. 105. See also ante, pp. 71, 77.

Some doubts also exist as to the nature of the beak or columella of such fruits as those of Geraniaceæ, Malvaceæ, Umbelliferæ, Euphorbiaceæ, &c. The nature of the organ in question may probably be different in the several orders named; at any rate the subject cannot be discussed in this place, and it is mentioned here because, now and then, it happens that the organ in question is completely wanting, and hence affords an illustration of suppression.

Chapter II. Suppression of Foliar Organs.

This subject may be considered, according as the separate leaves of the stem or of the flower are affected, and according as either the number of members of distinct whorls, or that of the whorls themselves, is diminished.

The terms aphylly, meiophylly, and meiotaxy may be employed, according as the individual leaves are altogether wanting, or with reference to the diminished number of parts in a whorl, or a decrease in the verticils.

Aphylly.—Entire suppression of the leaves is a rare phenomenon. Under ordinary circumstances it occurs in most Cactaceæ, in some of the succulent Euphorbias, and other similar plants, where the epidermal layers of the stem fulfil the functions of leaves. But even in these plants leaf-like organs are present in some stage or another of the plant's life.

Partial suppression of the leaf occurs sometimes in compound leaves, some or other of the leaflets of which are occasionally suppressed. Sometimes, as Moquin remarks, it is the terminal leaflet which is wanting, when the appearance is that of Cliffortia, at other times the lateral leaflets are deficient, as in Citrus or Phyllarthron. Ononis monophylla and Fragaria monophylla may be cited as instances of the suppression of the lateral leaflets. If the blade of the leaf disappears entirely, we have then an analogous condition to that of the phyllodineous acacias.

With reference to the strawberry just mentioned, Duchesne, 'Hist. Nat. Frais.,' p. 133, says that this was a seedling raised from the fraisier des bois, and the characters of which were reproduced by seed, and have now become fixed. The monophyllous condition has been considered to be the result of fusion of two or more leaflets, but however true this may be in some cases, it is not the case with this strawberry. M. Paillot states that he has found the variety in a wild state.

In like manner varieties of the following plants occur with simple leaves, Rosa berberifolia (Lowea), Rubus Idæus, Robinia pseudacacia, Fraxinus excelsior, Sambucus nigra, Juglans nigra, &c.

In one instance seen by the writer every portion of the leaf of a rose was deficient, except the stipules and a small portion of the petiole. (See abortion.)

Meiophylly.—A diminished number of leaves in a whorl occasionally takes place; thus, in some of the Stellatæ, and frequently in Paris quadrifolia, the number of leaves in the verticil is reduced. Care must be exercised in such instances that an apparent diminution arising from a fusion of two or more leaves be not confounded with suppression.

Meiophylly of the calyx or perianth.—A lessened number of sepals is not a very common occurrence among dicotyledonous plants. Seringe figures a proliferous flower of Arabis alpina with two sepals only, and a similar occurrence has been noticed in Diplotaxis tenuifolia.

In Cattleya violacea the writer has met with a flower in which the uppermost sepal was entirely wanting, while two of the lateral petals were fused together. Moquin records that in some of the flowers of Chenopodiaceæ, in which the inflorescence is dense, a suppression of two or three sepals sometimes occurs. The species mentioned are Ambrina ambrosioides, Chenopodium glaucum, and Blitum polymorphum.

Meiophylly of the corolla.—Suppression of one or more petals is of more frequent occurrence than the corresponding deficiency in the case of the sepals. Among Caryophyllaceæ imperfection as regards the numerical symmetry of the flower is not uncommon, as in species of Cerastium, Sagina, Dianthus, &c. In Ranunculaceæ the petals are likewise not unfrequently partially or wholly suppressed. A familiar illustration of this is afforded by Ranunculus auricomus, in which it is the exception to find the corolla perfect. Some varieties of Corchorus acutangulus in west tropical Africa are likewise subject to the same peculiarity. Amongst Papilionaceæ absence of the carina or of the alæ is not uncommon, as in Trifolium repens, Faba vulgaris, &c.

Moquin relates a case of the kind in the haricot bean, in which the carina was entirely absent, and another in the pea, where both carina and alæ were missing, thus reducing the flower to the condition that is normal in Amorpha and Afzelia. Suppression of the upper lip in such flowers as Calceolaria has been termed by Morren "apilary."

In Orchidaceæ entire absence of the labellum, frequently without any other perceptible change, is of common occurrence. The writer has seen numerous specimens of the kind in Ophrys apifera and O. aranifera; also in Dendrobium nobile, Ærides odoratum, Cypripedium villosum, Listera ovata, &c. Morren 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, α-χειλαριον. 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 andrœcium.—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, St. Hilaire in Cardamine hirsuta, others in C. sylvatica.

In Caryophyllaceæ suppression of one or more stamens has been observed in Mollugo cerviana, Arenaria tetraquetra, Cerastium, &c. Among violets the writer has observed numerous flowers in which two or three stamens were suppressed. Chatin alludes to a similar reduction in Tropæolum, while in flowers that are usually didynamous absence of two or more of the stamens is not unfrequent, e.g. in Antirrhinum, Digitalis, while in a flower of Catalpa a solitary perfect stamen, and a complete absence of the sterile ones usually present, have been observed. This might have been anticipated from the frequent deficiencies in the staminal whorl in these plants under what are considered to be normal conditions. Reduction of the staminal whorl is also not unfrequent in Trifolium repens and T. hybridum, and has been seen in Delphinium, &c.

Meiophylly of the gynœcium.—Numerical inequality in the case of the pistil, as compared with the other whorls of the flower, is of such common occurrence, under ordinary circumstances, that in some text-books it is looked on as the normal condition, and a flower which is isomerous in the outer whorls is by some writers not considered numerically irregular if the number of the carpels does not coincide with that of the other organs.

But in this place it is only necessary to allude to deviations from the number of carpels that are ordinarily found in the particular species under observation. As illustrations the following may be cited:—Arenaria tetraqueta, which has normally three styles, and a six-valved capsule, has been seen with two styles, and a four or five-valved capsule. Moquin relates an instance in Polygala vulgaris where there was but a single carpel, a condition analogous to that which occurs normally in the allied genus Mozinna. Reseda luteola occasionally occurs with two carpels only, while Aconites, Delphiniums, Nigellas, and Pæonies frequently experience a like diminution in their pistil.

In a flower of Papaver Rhæas the writer has recently met with an ovary with four stigmas and four parietal placentæ only, and to Mr. Worthington Smith he is indebted for sketches of crocus blooms with two, and in one instance only a solitary carpel.

Moquin cites the fruit of a wild bramble (Rubus) in which all the little drupes which go to make up the ordinary fruit were absent, except one, which thus resembled a small cherry. In Cratægus the pistil is similarly reduced to a single carpel, as in C. monogyna.

The writer has on more than one occasion met with walnuts (Juglans) with a single valve and a single suture. 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.

Meiophylly of the flower as a whole.—In the preceding sections a reduction in the parts of each individual whorl has been considered without reference to similar diminution in neighbouring verticils. It more commonly happens, nevertheless, that a defect in one series is attended by a corresponding imperfection in adjoining ones. Thus trimerous fuchsias and tetramerous jasmines may frequently be met with, and Turpin describes a tetramerous flower of Cobæa scandens. Perhaps monocotyledonous plants are more subject to this numerical reduction of the parts of several verticils than are other flowering plants. Thus, in both Lilium lancifolium and L. auratum the writer has frequently met with pentamerous flowers. In Convallaria maialis a like deviation not unfrequently occurs. M. Delavaud has recorded a similar occurrence in a tulip.

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.

Orchids seem peculiarly liable to the decrease in the number of their floral organs. Prillieux 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. Morren describes a flower of Cypripedium insigne, in which there were two sepals and two petals. Of a similar character was the flower found by Mr. J. A. Paine, and described in the following terms by Professor Asa Gray in the 'American Journal of Science,' July, 1866:—"The plant" (Cypripedium candidum) "bears two flowers: the axillary one is normal; the terminal one exhibits the following peculiarities. The lower part of the bract forms a sheath which encloses the ovary. The labellum is wanting; and there are two sterile stamens, the supernumerary one being opposite the other, i.e. on the side of the style where the labellum belongs. Accordingly the first impression would be that the labellum is here transformed into a sterile stamen. The latter, however, agrees with the normal sterile stamen in its insertion as well as in shape, being equally adnate to the base of the style. Moreover, the anteposed sepal is exactly like the other, has a good midrib and an entire point. As the two sterile stamens are anteposed to the two sepals, so are the two fertile stamens to the two petals, and the latter are adnate to the style a little higher than the former. The style is longer than usual, is straight and erect; the broad, disciform stigma therefore faces upwards; it is oval and symmetrical, and a light groove across its middle shows it to be dimerous. The placentæ, accordingly, are only two. The groove on the stigma and the placentæ are in line with the fertile stamens.

Here, therefore, is a symmetrical and complete, regular, but dimerous orchideous flower, the first verticil of stamens not antheriferous, the second antheriferous, the carpels alternate with these; and here we have clear (and perhaps the first direct) demonstration that the orchideous type of flower has two stamineal verticils, as Brown always insisted."

Dr. Moore, of Glasnevin, kindly forwarded to the writer a flower of Calanthe vestita (fig. 198), in which there were two sepals only, anterior and posterior, and two petals at right angles to the two sepals. The lip was entirely wanting, but the column and ovary were in their usual condition. In Odontoglossum Alexandræ a similar reduction of parts has been observed by the author (fig. 199).

It is curious to observe in these flowers how precisely one sepal occupies the position of the labellum, and how the lateral petals are displaced from the position they usually occupy, so as to form a regular flower, the segments of which decussate, thus giving rise to a species of regular peloria.

The genus Mælenia was established on a malformed flower of Orchis of similar character to those above mentioned.

Meiotaxy of the calyx.—As already mentioned, this term is here employed to denote those illustrations in which entire whorls are suppressed. Complete deficiency of the calyx in a dichlamydeous flower seems seldom or ever to occur; the nearest approach to it would be in those cases where the calyx is, as it is termed, "obsolete," but here it is chiefly the limb of the calyx which is atrophied, the lower portion being more or less adherent to the ovary. In what are termed monochlamydeous flowers both calyx and corolla are wanting, as in Salicineæ and many other orders.

Meiotaxy of the corolla.—Deficiency of the entire corolla occurs in conjunction with similar reductions in other organs, or as an isolated phenomenon in the many apetalous varieties of plants recorded in books. Deficiency of the corolla was observed in Campanula perfoliata and Ruellia clandestina by Linné, who calls such blooms flores mutilati. Drs. Hooker and Thomson relate a similar occurrence in Campanula canescens and C. colorata. Some plants seem as a normal occurrence to produce flowers of different construction, and are hence termed dimorphic, as in many Malpighiaceæ, Violaceæ, Oxalidaceæ, in some of the flowers of which the petals are altogether wanting, while in others the corolla is developed as usual. This deficiency of the corolla is frequently, but not invariably, associated with an increased fertility. Thus, in some violets the flowers produced in summer, and in which the petals are either entirely suppressed or are more or less atrophied, are always fertile, while the blossoms developed in spring, and in which the petals are always present, are much less fertile. In Oxalis Acetosella there are two forms of flower, the one with, the other without, petals, but both seem equally fertile. Linné remarks that many plants which, in warm latitudes, produce a corolla, do not do so when grown in colder climates. Thus, certain species of Helianthemum are apetalous in Lapland. In the Pyrenees, according to Bentham, the flowers of Ajuga iva are constantly deprived of their corolla.

Apetalous flowers have been noted most frequently in the following plants:

• Aconitum, sp. pl.!
• Cardamine impatiens.
• Cheiranthus Cheiri!
• Viola odorata!
• Cerastium vulgatum!
• Alsine media.
• Stellaria.
• Lychnis dioica!
• Dianthus barbatus, and other Caryophylleæ.
• Helianthemum, sp.!
• Oxalis Acetosella.
• Balsamineæ.
• Malpighiaceæ.
• Rosa centifolia.
• arvensis!
• Cratægus!
• Medicago lupulina.
• Melilotus officinalis.
• Ononis minutissima.
• Saxifraga longifolia.
• Verbascum Thapsus.
• Ajuga iva.
• Teucrium Botrys.
• Lamium purpureum!
• amplexicaule.
• Polemonium cæruleum.
• Campanula, sp. pl.!
• Ruellia clandestina.
• Lonicera Periclymenum!
• Tradescantia, sp.!
• Hymenocallis.

The following references apply some to apetalous and others to dimorphic flowers, but it must be remembered that the latter plants are not necessarily wanting in petals or stamens, &c., though the functional activity of the parts may be impaired:

A. de Jussien, 'Monogr. Malpigh.,' pp. 82, 334. Torrey, 'Fl. New York,' i, p. 428. Hooker and Thomson, 'Journ. Linn. Soc.,' ii, p. 7, Guillemin, 'Archiv. de Botan.,' i, p. 412. Michalet, 'Bull. Soc. Bot. Fr.,' vii. p. 465. Müller, 'Bot. Zeit.,' 1857, p. 729. 'Natural History Review,' July, 1862, p. 235.

Meiotaxy of the andrœcium.—Complete suppression of the stamens occurs normally in the female flowers of unisexual plants, and, as an accidental occurrence, is not very uncommon. Erica Tetralix is one of the plants in which this is said to happen. The variety anandra is said to have been known in France since 1635. Cornuti speaks of it in his 'Enchiridion.' In 1860 M. du Parquet discovered it in peaty woods near Nangis (Seine et Marne).

Many Umbelliferæ, such as Trinia vulgaris, present a like deficiency, while it is of common occurrence among Rosaceæ and Pomaceæ. In the latter group the St. Valery apple, so often referred to, is an illustration. To obtain fruits from this variety it is necessary to apply pollen from another flower, a proceeding made the occasion of festivity and rejoicing by the villagers in some parts of France. In some of the Artemisias, especially in Artemisia Tournefortiana, all the florets have been noticed to be female, owing to the suppression of the stamens, and this suppression is associated with a change in the form of florets. Mr. Moggridge has communicated to the author flowers of Thymus Serpyllum from a plant in which all the stamens were deficient, the flower being otherwise normal.

M. Dupont has given a list of nineteen species of Chenopodiaceæ in which female flowers are occasionally produced, owing to the entire suppression of the staminal whorl.

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 andrœcium as a teratological occurrence has been most frequently noticed in the following plants, omitting members of those families whose floral construction is normally incomplete in the majority of instances, and exclusive also of cases of substitution. See also under Heterogamy.

• Ranunculus Ficaria!
• auricomus!
• bulbosus!
• Cruciferæ, sp. pl.
• Violaceæ, sp. pl.
• Honckenya peploides.
• Stellaria.
• Caryophyllaceæ, sp. pl.
• Malpighiaceæ, sp. pl.
• Tropæolum majus!
• Fragaria vesca!
• Rubus, sp.
• Pyrus Malus.
• Agrimonia vulgaris.
• Rosaceæ, sp. pl.
• Trifolium hybridum.
• repens.
• Umbelliferæ, sp. pl.
• Onagraceæ, sp. pl.
• Hippuris vulgaris.
• Callitriche vernalis.
• autumnalis.
• Lonicera Periclymenum.
• Erica Tetralix.
• Thymus Serpyllum.
• Calceolaria.
• Compositæ, sp. pl.
• Chenopodiaceæ, sp. pl.
• Stratiotes aloides.

Meiotaxy of the gynœcium.—Complete suppression of the pistil is of more frequent occurrence than that of the stamens, hence more flowers become accidentally unisexual by suppression of the pistil than by deficiency of the stamens.

In many Umbelliferæ, e.g. Torilis Anthriscus, Cicuta virosa, the central flowers are often male, owing to the suppression of the pistil. In many double flowers, owing to the excessive multiplication of petaloid stamens, the pistil is suppressed, in which cases it often happens that the flower is depressed in the centre, as in some garden varieties of Ranunculus. Schlechtendal, in describing a flower of Colchicum autumnale, in which the perianth was virescent, says that, although the stamens were present, the pistil was absent.

In proliferous flowers the pistil is often completely defective, its place being occupied by the adventitious bud or axis.

As in other cases of like nature, suppression of the pistil is very frequently consequent on fusion of flowers or other changes. Thus Morren relates an instance of synanthy in the flowers of Torenia scabra, accompanied by resorption or disappearance of some parts and spiral torsion of others. The pistil was entirely absent in this instance.

M. Gaetano Licopoli places on record an instance where the petals and carpels of Melianthus major were suppressed.

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

Suppression of the pistil has been most frequently recorded in flowers (normally bisexual) of—

• Ranunculus!
• Aconitium!
• Delphinium!
• Pæonia.
• Caryophylleæ!
• Umbelliferæ.
• Trifolium repens.
• hybridum.
• Compositæ, sp. pl.
• Datura.
• Torenia asiatica.
• Colchicum autumnale.

Suppression of ovules,—abortion of seeds.—The two cases are taken together, as the effects are similar, though it must be remembered that in the one case the ovules at any rate have been formed, but their development has been arrested, while in the other they have never existed. The precise cause that has determined the absence of seed cannot in all cases be ascertained in the adult condition, hence it is convenient to treat the two phenomena under one head.

Many plants in other than their native climates either produce no fruit at all, or the fruits that are produced are destitute of seed, e.g. Musa, Artocarpus, &c. Some of the cultivated varieties of the grape and of the berberry produce no seeds.

Suppression or abortion of the seed is frequently associated with the excessive development either in size or number of other portions of the plant, or with an altered condition, as when carpels become foliaceous and their margins detached. Hybridisation and cross fertilisation are also well-known agents in diminishing the number and size of seeds.

Meiotaxy of the parts of the flower in general.—In the preceding sections suppression has been considered as it affected individual members of a whorl or separate whorls. It rarely happens, however, that the suppression is limited in this way. More generally several of the parts of the flower are simultaneously affected in the same manner.

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

One of the most familiar instances is that of the cauliflower or broccoli, where the common flower-stalk is inordinately thickened and fleshy, while the corolla and inner parts of the flower are usually entirely suppressed; the four sepals can, however, generally be detected.

Maximowicz describes a Stellaria (Kraschenikovia) in which the upper flowers are male only, while the lower ones, which ultimately become buried in the soil, have neither petals, stamens, nor styles, but the walls of the capsule are fleshy, and enclose numerous seeds.

Kirschleger 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, κενος, empty.

Complete suppression of the flower.—It is not necessary in this place to allude to that deficient production of flowers characteristic of what is termed by gardeners a "sky bloomer." In such plants often the requisite conditions are not complied with, and the skill of the gardener is shown in his attempt to discover and allow the plant to avail itself of the necessary requirements. We need here only allude to those instances in which provision is made for the production of flowers, and yet they are not produced. A good illustration of this is afforded by the feather-hyacinth, Hyacinthus comosus, in which the flowers are almost entirely suppressed, while the pedicels are inordinately increased in number, and their colour heightened. Something similar occurs in several allied species, and in Bowiea volubilis. The wig plant (Rhus Cotinus) affords another illustration of the same thing. Some tendrils also owe their appearance to the absence of flowers, being modified peduncles; proofs of this may frequently be met with in the case of the vine.

In Lamium album I have seen one of the verticillasters on one side of the stem completely wanting, the adjacent leaf being, however, as fully formed as usual.

General remarks on suppression.—On comparing together the various whorls of the flower in reference to suppression, and, it may be added, to atrophy, we find that these phenomena occur most rarely in the calyx, more frequently in the corolla, and very often in the sexual organs and seeds; hence it would seem as if the uppermost and most central organs, those most subject to pressure and latest in date of development—formed, that is, when the formative energies of the plant are most liable to be exhausted—are the most prone to be suppressed or arrested in their development. When the plants in which these occurrences happen most frequently are compared together, it may be seen that partial or entire suppression of the floral envelopes, calyx, and corolla, is far more commonly met with in the polypetalous and hypogynous groups than in the gamopetalous or epigynous series.

The orders in which suppression (speaking generally) occurs most often as a teratological occurrence are the following:—Ranunculaceæ, Cruciferæ, Caryophyllaceæ, Violaceæ, Leguminosæ, Onagraceæ, Jasminaceæ, Orchidaceæ. It will be observed that these are all orders wherein suppression of the whole or part of the outer floral whorls takes place in certain genera as a constant occurrence.

Again, it may be remarked that many of these orders show a tendency towards a regular diminution of the assumed normal number of their parts; thus, among Onagraceæ, Circeia and Lopezia may be referred to, the former normally dimerous, the latter having only one perfect petal. So in fuchsias, a very common deviation consists in a trimerous and rarely a dimerous symmetry of the flower.

Although, if the absolute number of genera or orders be counted, there appears to be little difference in the frequency of the occurrence of suppression in irregular flowers as contrasted with regular flowers, yet if the individual instances could be counted in the two groups respectively it would be found that suppression is more common among irregular than in regular flowers. Thus, the number of individual instances of flowers in which the perianth is defective is comparatively large among Violaceæ, Leguminosæ, and Orchidaceæ. This statement hardly admits of precise statistical proof; still, it is believed that any observer who pays attention to the subject must come to the same conclusion. This is but another illustration of the fact that conditions which are abnormal in one plant constitute the natural arrangement in others.

As to the suppressions that occur in the case of the sexual organs, and the relations they bear to dimorphism, diclinism, &c., but little stress has been laid on them in this place, because their chief interest is in a physiological point of view, and is treated of in the writings of Mohl, Sprengel, Darwin, Hildebrand, and others. All that need be said here is, that teratology affords very numerous illustrations of those intermediate conditions which are also found, under natural circumstances, between the absolutely unisexual flowers, male or female, and the structurally hermaphrodite ones. Rudimentary stamens or pistils are of very common occurrence in monstrous flowers. See Chapter on Heterogamy, &c.