CHAPTER II.

METAMORPHY OF THE FLORAL ORGANS.

One of the main arguments adduced by Goethe and others in support of the now generally received doctrine of the essential morphological identity of the various whorls of the flower is derived from the frequent appearance of one organ in the guise of another. The several parts of the flower become, as it is said, metamorphosed; sometimes the change is complete, while at other times there may be every conceivable intermediate condition between one form and another. The sense in which the terms metamorphosis, substitution, transformation, and the like, are herein used has already been explained. For the convenience of arrangement, metamorphosis of the parts of the flower may be divided into several subdivisions, according to the particular organ affected, and according to the special kind or degree of change manifested, the main subdivisions being here classed as Sepalody, Petalody, Staminody, and Pistillody.

=Sepalody of the petals.=--This change, spoken of by most authors as retrograde metamorphosis of the petals into sepals, or as a substitution of sepals for petals, is obviously a condition that is in most cases hardly distinguishable from virescence of the corolla, or from multiplication of the sepals. Nor is this of much consequence unless there are some special structural features which render the discrimination a matter of importance, in which case the difficulty is generally easily surmounted. The flower of the Saint-Valèry Apple may perhaps be cited under this head. In the flower in question there are neither stamens nor petals, unless the second or inner of sepals be considered as sepaloid petals (fig. 152).

M. Alph. de Candolle[295] describes an instance in _Primula Auricula_ in which the corolla had assumed the appearance of the calyx, but neither calyx nor corolla in this case possessed perfect stomata.

This malformation is much less common than the converse one of calycanthemy. Many of the recorded instances of so-called metamorphosis of the parts of the flower to sepals have occurred in monocotyledonous plants, or others in which the calyx and corolla are of the same colour, and constitute what is frequently termed the perianth; and as this is usually brightly coloured (not green) it is more convenient to group the metamorphoses in question under the general term Petalody, which thus includes all those cases in which the organs of the flower appear in the form of coloured petal-like organs, whether they be true petals or segments of a coloured perianth. As the morphological difference between the organs is one of position merely, there is little objection to be raised to this course, the less so as the term petalody merely conveys an idea of resemblance and not of absolute identity.

Petaloid coloration of the ordinary leaves, or of the bracts, is mentioned under the chapter relating to colour.

=Petalody of the calyx--Calycanthemy.=--As with the bracts, so the calyx in certain instances is naturally coloured, as in _Delphinium_, _Tropæolum_, and others. In _Mussænda_, _Calycophyllum_, _Usteria_, &c., one or more of the calyx lobes become enlarged normally. Considered teratologically, petaloid coloration of the sepals is either general or partial; in the latter case the nerves retain their green colour longest. There is in cultivation a variety of the primrose called _Primula calycanthema_, in which the upper part of the calyx becomes coloured, so that the flower seems to have two corollas placed one within the other; a similar thing happens in _Mimulus_, in which plant, as the calyx is permanent while the corolla is deciduous, the coloured calyx is a great advantage in a horticultural point of view. Morren[296] says that in order to produce the fine colour of the calyx of _Primula officinalis_ (var. _smaragdina_) the Belgian gardeners cut away the corolla in a very early stage, and that in consequence the colouring matter proper to the corolla is developed in the tube of the calyx, the edges of the limb remaining green, the middle of the limb being purple (_Primula tricolor_).

Under this head may be mentioned the occurrence of tubular sepals in place of the ordinary flat ones in _Helleborus olympicus_; only two of the sepals were thus affected in a specimen recently observed--a third exhibited an intermediate condition.

The normal coloration of the calyx occurs most frequently in polysepalous calyces; teratological coloration, on the other hand, occurs especially in gamosepalous flowers. This assertion is borne out by the frequency of the change in the plants already mentioned, and also in the following:--_Campanula persicifolia_, _Anagallis arvensis_, _Gloxinia_, _Syringa persica_,[297] _Calceolaria_, _&c. &c_. In the last-named plant one or more of the lobes of the calyx may frequently be seen replaced by a slipper-like petal.

Among polysepalous plants petaloid sepals have been observed in _Ranunculus auricomus_, _Rubus cæsius_, _&c._ Fleischer also describes a case of this kind in _Carum carui_.[298]

It will be seen from the above that in the majority of cases there is no real metamorphosis or substitution of petal for calyx, but simply an alteration in colour; nevertheless, a change in form may accompany a change of colour: this happens especially if there has been any displacement of organs. Thus, if, in an orchidaceous plant, a sepal be displaced from any cause, or a petal be twisted out of its natural position to occupy the place of an absent sepal, that petal will be sepal-like in form, and _vice versâ_.

=Petalody of the stamens.=--A petaloid condition of the stamens is one of the commonest of all malformations. A large number of so-called double flowers (flores pleni)[299] owe their peculiar appearance to this circumstance.

It is necessary to distinguish carefully this petaloid development of the stamens from the corresponding condition of the pistils, and from that kind of doubling which is a result of multiplication of the corolla, as in _Datura_, _Campanula_, _Primula_, &c. (flores duplices, triplices, &c.), or from that produced by true median prolification (flores geminati, &c.).

In cases of true petaloid development of the stamens there are usually numerous intermediate forms between that of the true petals and that of the perfect stamens; indeed, in _Nymphæa_, _Canna_, and in some other plants, such a transition occurs normally. Petalody of the stamens may occur either without material change in the flower or it may exist in combination or in conjunction with an increased development of parts (Multiplication), or with a similar change in the carpels, and it is either partial or complete.

Among the flowers in which petaloid development of the stamens happens most frequently may be mentioned those in which the calyx is normally coloured, as in _Nigella damascena_, _Aguilegia_, and _Delphinium_.

M. Alph. de Candolle, in the 'Neue Denkschriften,' 1841, described and figured a singular form of _Viola odorata_, known under the name of "Bruneau," in Switzerland, in which the stamens are absent, and their place supplied by a second row of petals, within which is a third series of petals, representing, says M. de Candolle, the inner row of stamens that theory suggests should exist in the natural condition. Moreover, the carpels in this variety are five in number instead of three. In _Erica Tetralix_ the corolla may not unfrequently be found divided to the base into its constituent petals, and the place of the stamens occupied by a series of petal-like structures entirely destitute of anther.

In monocotyledonous flowers, especially those with a coloured perianth, the substitution of segments of the perianth for stamens occurs not unfrequently. M. Seringe has observed this in the stamens of _Lilium Martagon_, and there is in cultivation a variety of the white lily, _Lilium candidum_, sometimes called the double white lily, in which the segments of the perianth, in place of being arranged in two rows, are greatly increased in number, and disposed in a spiral manner. In these flowers, not only are the stamens and pistils thus modified, but also the upper leaves of the stem. In so-called double tulips there is likewise a replacement of stamens by coloured segments of the perianth, but this happens generally in connection with an increase in the number of organs. Moquin-Tandon remarks having seen in a garden in the environs of Montpelier a tulip, the stamens of which showed all possible stages of transition between the form proper to them and that of the perianth. The pistil in this case was transformed into several small leaves. Similar appearances have been observed in Iris, Hyacinths, Narcissus, Colchicum, and Crocus. M. Fournier[300] describes a flower of _Narcissus Tazetta_ from within the normal perianth of which sprang a second one, equally provided with a cup and occupying the space usually filled by the stamens. Flowers of _Narcissus poeticus_ may also be met with in which the stamens are replaced by six distinct segments exactly resembling those of the perianth in miniature.[301]

From an examination of these flowers it becomes evident that petalification is brought about in different flowers in different ways; sometimes it is the filament which becomes petaloid, sometimes the anther-lobes, while at other times it is the connective which assumes the appearance of petals.[302] For instance, in _Solanum tuberosum_, _S. Dulcamara_, in _Anagallis_, in _Fuchsia_, and some other plants, the anther-lobes themselves become petaloid, while the filament remains unchanged.

In gardens two distinct varieties of Columbine are cultivated, the one in which the filaments are dilated into the form of flat petals almost entirely or quite destitute of anthers, while in the other the filament is present in its usual form, but the anther is developed in the shape of a tubular hood or spur.

De Candolle[303] observes that in the _Ranunculaceæ_ the species of _Clematis_ become double by the expansion of the filament, those of _Ranunculus_ by the dilatation of the anther, and those of _Helleborus_ by the petal-like development of both filament and anther. In some cases even on the same plant all three modifications may be seen, as in Camellias, some of which may be found with petaloid filaments with anthers on the top, others with the filaments unchanged, but supporting petaloid anthers, while in others it is the connective alone which is petal-like. Where the flower naturally contains a large number of stamens, as in Mallows, Roses, Magnolias, &c., petaloid expansion of the filament is most common, though it is by no means confined to such flowers, the change occurring in _Allamanda cathartica_, _Jasminum grandiflorum_, and many other flowers with few stamens. A similar change in the anther and connective takes place more frequently in flowers where the number of stamens is smaller, but there are of course numerous exceptions to this rule.

In those cases where there is more than one row of stamens, the outermost are most liable to this change: thus in _Saxifraga decipiens_, as shown by Ch. Morren,[304] the outer series of stamens--those opposite to the sepals--become first affected, and, at a more advanced stage, the inner row also; and this is the case in most flowers that have their stamens in two rows. Occasionally it happens that an outer series of stamens is abortive, or wholly suppressed, while the inner row becomes petalodic; this was the case in some flowers of _Lilium auratum_ lately exhibited by Messrs. Veitch.

Those flowers in which only a portion of the stamens undergo this change are called semi-double, while in other cases that will be hereafter mentioned, not only are the stamens thus rendered petaloid, but their number is also augmented, as in most double roses, pinks, anemones, poppies, &c.

In some double flowers, in which the stamens assume more or less completely the appearance of petals, a singular appearance is afforded by the presence of four wing-like processes emanating from the central filaments, two on each side, so that the arrangement may be compared to two sheets of paper folded in the centre and adherent in that situation, though perfectly separate elsewhere, except sometimes at the top, where they form a sort of hood. This change results from an imperfect petalody of the anther; the two wings on each side of the central vascular cord represent the front and back walls of an anther lobe, or rather of that portion of the anther which, under ordinary circumstances, produces pollen. In the malformed flowers no pollen is formed, at least in the more complete states of the malformation, but the walls of the anther lobe become preternaturally enlarged, and petaloid in texture and appearance. This change occurs in some semi-double rhododendrons and azaleas, in crocuses, and in a species of violet found at Mentone by Mr. J. T. Moggridge.

There are numerous intermediate forms wherein the wing-like processes may be traced all the way along the filament till they ultimately lose themselves in the anther-lobes, with which they become continuous. In some cases, as in _Crocus_ and _Rhododendron_, this is shown even more clearly by the existence of two perfect pollen-sacs or quarter-anthers, the remaining portions being petaloid and continuous with the dilated filament. Not unfrequently these semi-petaloid stamens adhere to the fronts of the petals, and then it appears, at a first glance, as if three organs were stuck together, one in front of another, while in reality there are but two.[305] (See _antè_, p. 35, fig. 12.)

The change in the anther, above alluded to, must not be mistaken for that far more common one in which only a small portion of the anther becomes petaloid, forming a sort of lateral wing or appendage to the polliniferous portion, as happens normally in _Pterandra_, and is common in some double fuchsias. In this latter instance there is but a single wing, and the nature of the case is obvious.

Double flowers of _Orchidaceæ_ generally arise from petalification of the filaments, with or without other coincident changes. What makes double flowers in this order the more interesting is the development, in a petaloid condition, of some or all of those stamens which under ordinary circumstances are wholly suppressed, so that the morphological structure of the flower, at first a matter of theory, becomes actually realised. Fig. 156 is a diagram showing the presence of two additional labella within the ordinary one in a species of _Catasetum_, and representing two petaloid stamens, thus evidently completing the outer staminal whorl, of which there is usually but a single representative (see Peloria, Multiplication, Prolification). In some of these double orchids it is, however, necessary not to confound a petaloid condition of the existing column with the development of usually suppressed stamens in a petaloid form. Thus, in _Lycaste Skinneri_ the column is frequently provided with two petal-like wings, which might readily be supposed to be two stamens of the inner whorl adherent to the column; a little attention, however, to the relative position of these adventitious wings is generally sufficient to enable the observer to ascertain the true nature of the appearance.[306]

Some forms of duplicate or hose in hose corollas are apparently due, not so much to the formation of a second corolla within the first, as to the presence of an inner series of petal-like stamens, which, by their cohesion, form a second pseudo-corolla within the first. The staminal nature of this pseudo-corolla is inferred from the occasional presence of anthers on it.[307] In _Datura fastuosa_, as well as in _Gloxinia_, a pseudo-corolla of this kind sometimes occurs with the addition of a series of petaloid stamens attached to its outer surface.[308]

When the petalody specially affects the anther-lobes, as in _Arbutus_, _Petunia_, _Fuchsia_, _&c._, the venation of the petal-like portion is very frequently laminar, thus tending to show that the anther is in such cases really a modification of the blade of the leaf; but as, on the other hand, we often find petal-like filaments bearing pollen-sacs on their sides, it is clear that we must not attribute the formation of pollen to the blade of the leaf only, but we must admit that it may be formed in the filament as well.[309]

Petalody of the connective is of less frequent occurrence than the corresponding change in the other portions of the stamen. It may be seen in some forms of double columbine,[310] in which the connective forms a tubular petal or nectary, and in double petunias and fuchsias. When it occurs, the true anther-lobes are usually atrophied, and little or no pollen is formed.

An occurrence of this nature in _Tacsonia pinnatistipula_, in conjunction with the partial detachment of the stamens from the gynophore, led Karsten to establish a genus which he called _Poggendorffia_.[311]

From the subjoined list of genera in which petalody of the stamens, in some form or other, has been observed, it will be seen that it happens more often in plants with numerous distinct organs (Polypetalæ, Polyandria, Polygynia, &c.) than in other plants with a smaller number of parts, and which are more or less adherent one to the other. The tendency to petalification is, moreover, greater among those plants which have their floral elements arranged in spiral series, than among those where the verticillate arrangement exists; and in any given flower, if the stamens are spirally arranged while the carpels are grouped in whorls, the former will be more liable to petalody than the latter, and _vice versâ_. It has been before remarked, that this condition is far more common in plants whose petals, &c., have straight veins, like those in the sheath of a leaf, than in those the venation of which is reticulate, as in the blade of the leaf. It must also be remembered that in the same genus, even in the same species, different kinds of doubling occur. Familiar illustrations of this are afforded in the case of anemones, columbines, fuchsias, and other plants.

The existence of "compound stamens" in some flowers, as pointed out by Payer, and others, and the researches of Dr. Alexander Dickson, confer additional importance on the subject of petalody, and necessitate the examination of double flowers with special reference to these compound stamens, and to the order of their development.[312] The presence of these compound stamens affords a satisfactory explanation of the appearance in some double _Malvaceæ_, wherein the tufts of adventitious petals are very liable to be mistaken for buds, produced by axillary prolification in the axils of the petals, but which are in reality compound and petaloid stamens. At other times, however, true axillary prolification exists in these flowers; but then the supplemental florets have always a calyx, which is wanting in the other instances.

Petalody of the stamens has been met with most frequently in the following genera:

*Ranunculus! *Anemone! *Papaver! *Clematis! *Hepatica! *Ficaria! Thalictrum. *Caltha! *Trollius! *Nigella! *Aquilegia! *Delphinium! *Adonis! *Pæonia! *Nelumbium! *Nymphæa! *Berberis! *Papaver! *Chelidonium! Sanguinaria. Podophyllum. *Mathiola! *Cheiranthus! *Iberis! *Cardamine! *Hesperis. *Barbarea! *Sinapis! *Brassica! *Helianthemum! *Viola! *Dianthus! *Saponaria! *Lychnis! *Silene! *Sagina! *Hibiscus! *Althæa! *Malva! Æsculus! *Geranium! *Pelargonium. *Tropæolum! Oxalis! *Impatiens! *Camellia! Thea! Trifolium! Medicago! *Ulex! Spartianthus. Clitoria. Pisum! Orobus! Genista! Spartium! Cytisus! Anthyllis. Coronilla. Lotus! *Rosa! *Kerria! *Spiræa! *Fragaria! *Potentilla! *Cratægus! Cydonia. *Pyrus! Eriobotrya! *Amygdalus! *Prunus! *Myrtus! *Punica! *Philadelphus! *Deutzia! *Fuchsia! Godetia! Clarkia! Portulaca! Ribes! Saxifraga! Daucus. Ixora. Serissa! Gardenia! Lonicera! Sambucus. Viburnum. Scabiosa. *Campanula! Platycodon! Calluna! Azalea! Rhododendron! *Arbutus! *Erica! *Anagallis! *Primula! *Jasminum! Syringa! *Vinca! *Nerium! Allamanda! Tabernæmontana. *Calystegia! Convolvulus! Ipomoea. *Datura! *Petunia! Solanum! Orobanche. Gentiana. Mimulus. *Antirrhinum! Gratiola! *Digitalis! *Linaria! Veronica! Calceolaria! Achimenes. Gloxinia! Clerodendron! Bignonia. Cyclamen! Mirabilis. Laurus! Gladiolus! Crocus! Iris! *Galanthus! Leucojum! Sternbergia! Hippeastrum. *Narcissus! *Orchis! Catasetum! Hydrocharis. Asphodelus. *Tulipa! Scilla. *Convallaria! Fritillaria! *Lilium! *Hyacinthus! *Polianthes! *Hemerocallis! *Colchicum! *Sagittaria! *Tradescantia! Commelyna! Tofieldia.

=Petalody of the pistils.=--Taken by itself, this is much less common than the corresponding change in the stamens. It generally affects the style and stigma only, as happens normally in _Petalostylis_, _Iris_, &c., but this is by no means always necessarily the case. In some of the cultivated varieties of _Anemone_ and _Ranunculus_ all the parts of the flower remain in their normal state, except the pistils, which latter assume a petaloid appearance.

Many of the double flowers owe their peculiar appearance to the combination of the following appearances--a petal-like form of the stamens, increase in the number of these organs and similar changes affecting the pistils, and is applied to several distinct conditions. If in any given flower all the stamens and all the pistils become wholly petaloid, no pollen is formed, and of course no seeds can be produced, but this very rarely happens, as usually some pollen is produced, and some ovules capable of being fertilised are developed.

In double flowers of _Primula sinensis_ it frequently happens that the capsule is either partially leafy or partly petal-like; in either case the fruit is open at the extremity, and often destitute of the style and stigma. It is, however, doubtful if the ovules can be fertilised in these flowers.

The following list comprises the names of those genera in which this change has been most frequently observed, independently of corresponding alterations in the stamens, but it is more usual for both sets of organs to be similarly affected.

*Ranunculus! *Anemone! Nigella. *Papaver! *Dianthus! Saponaria! Viola! Camellia! Alcea. Hibiscus! Amygdalus! Lonicera! Scabiosa. Æschynanthus! Primula!

=Petalody of the ovules.=--The principal changes which occur in the ovule have already been alluded to at pp. 262-272; it may here be stated, however, that the ovules are occasionally represented by small stalked petal-like structures. This happens with especial frequency among _Cruciferæ_.[313]

=Petalody of the accessory organs.=--A petaloid condition of the disc, of the scales, or other excrescences from the axis or from the lateral portions of the flower, is of frequent occurrence, though it is but rarely that the change is of any great importance in a morphological point of view. C. Morren has given the name adenopetaly to a case wherein one of the glands at the base of the petals in _Lopezia_ was replaced by a petal.[314] A similar change may be seen in the double Oleander.

=Staminody of the bracts.=--An instance of this has been already alluded to in _Abies excelsa_, as observed by Prof. Dickson, and in which some of the bracts were seen assuming the form and characteristic of the stamens see _ante_: p. 192. Signor Licopoli met with a similar substitution of anthers for bracts in _Melianthus major_.[315]

=Staminody of the sepals and petals.=--In the first named this is of very rare occurrence. M. Gris has recorded an instance in _Philadelphus speciosus_[316] which appears to be the only case on record. The corresponding change in the case of the petals is far more common. De Candolle cites in illustration of this occurrence flowers of the common haricot, in which the alæ and carina of the corolla were thus changed.[317] There is in cultivation a form of _Saxifraga granulata_ wherein the petals are replaced by stamens, so that there are fifteen stamens. A similar change has been observed in _Capsella bursa-pastoris_.

Cramer figures and describes a stamen occupying the place of a petal in _Daucus Carota_.[318] Turpin[319] describes a similar occurrence in _Monarda fistulosa_, in which the lower lip terminated in an anther, but this may have been a case of adhesion. Moquin cites from Chamisso, _Digitalis purpurea_, and from Jussieu, _Asphodelus ramosus_, as having presented this change, and Wiegmann[320] has seen anthers developed on the awns of _Avena chinensis_. In semi-double flowers of _Ophrys aranifera_ and _Orchis mascula_, the lateral petals are occasionally partially antheroid, and others occur in which two of the outer series of stamens, which are ordinarily suppressed, are present, but in a petaloid state. Reichenbach[321] figures an illustration of this change, and also Moggridge.[322]

=Staminody of the pistils.=--The existence of this change has been denied by several authors, nevertheless, it is of sufficiently common occurrence. Alexander Braun notices the transformation of pistils into stamens in Chives (_Allium Scorodoprasum_), and in which three stamens appeared in the place of as many pistils, and had extrorse anthers, while the six normal anthers are introrse. In the horse-radish (_Armoracia rusticana_), two of the carpels are frequently converted into stamens, while two other organs absent from the normal flower make their appearance as carpels. Roeper has observed this phenomenon in _Euphorbia palustris_,[323] and in _Gentiana campestris_.[324] In these examples one of the carpels was apparently absent, and its place supplied by an anther. Roeper has also mentioned a balsam with a supernumerary stamen occupying exactly the position of a carpel.[325]

Agardh has observed a similar thing in a hyacinth, one half of the fruit of which contained seeds, and the other half, anthers. B. Clarke mentions an instance in _Mathiola incana_ in which the carpels were disunited, and antheriferous at the margin.[326]

The passage of pistils to stamens in willows has been frequently remarked, as in _Salix babylonica_, _silesiaca_, _cinerea_, _Caprea_ and _nigricans_. One of the most curious illustrations of this transformation in this genus is given by Henry and Macquart (Erst. Jahrb. des bot. Vereines am m. et n. Rhein., 1837). In the flowers in question the series of changes were as follows:--first, the ovary opened by a slit, and then expanded into a cup; next, anther-cells were developed on the margin of the cup, with stigmas alternating with them, the ovules at the same time disappearing; lastly, the margin became divided, and bore three perfect anthers, which in the more perfect states were raised on three filaments.

_Campanula persicifolia_, _C. rapunculoides_, and _C. glomerata_ have been observed to present an anther surmounting the pistil.[327] Double tulips often present this change, and a like appearance has been observed in _Galanthus nivalis_, and _Narcissus Tazetta_.

Moquin mentions the existence of this condition in a female plant of maize, some of the pistils of which were wholly or partially converted into anther-like organs. Mohl has recorded an analogous malformation in _Chamærops humilis_, and in which the three carpels were normally formed, and only differed from natural ovaries in this, that along the two edges of the ventral suture there was a yellow thickening, which a cross section of the ovary showed to be an anther-lobe filled with pollen.[328]

In _Tofieldia calyculata_ a similar substitution of a stamen for a carpel has been observed by Klotsch,[329] and Weber[330] gives other instances in _Prunus_ and _Pæonia_. Corresponding alterations may be met with in cultivated tulips, in the cowslip and other plants. In most of the above cases the transmutation has been perfect, but in quite an equal number of cases a portion only of the carpel is thus changed, generally the style or the stigma; thus Baillon describes the stigmas of _Ricinus communis_ as having been in one instance antheriferous.[331] Moggridge figures a flower of _Ophrys insectifera_ in which the rostellate process was replaced by an anther.[332]

Mohl remarks that the change of pistils into stamens is more common in monocarpellary pistils than it is in those which are made up of several carpels. It seems clear that in this transformation the lobes of the anther and the development of pollen have no relation to the production of ovules.

=Staminody of the accessory organs of the flower.=--The scales that are met with in some plants, either as excrescences from the petals, or as imperfect representatives of stamens or other organs, are occasionally staminoid; thus the scales of _Saponaria officinalis_, of _Silene_, _Nerium Oleander_, the rays of _Passiflora_, the corona of _Narcissus_, have all been observed occasionally to bear anthers.[333] In the case of _Narcissus_ the loose spongy tissue of the corona seems to have the nearest analogy to the anther-lobes, while the prolonged connective is more like the ordinary segments of the perianth in texture. The species in which this change may most frequently be observed are, _N. poeticus_, _N. incomparabilis_, and _N. montanus_.

M. Bureau found in some flowers of _Antirrhinum majus_ two petal-like bodies standing up in front of, or opposite to the two petals of the upper lip,[334] and similar developments in which each of the two adventitious segments are surmounted by an anther may be met with frequently. It does not follow because these organs bear anthers that they are morphologically true stamens. They are really scales, &c., taking on themselves accidentally the characters proper to stamens.

=Pistillody of the perianth.=--The passage of the segments of the perianth into carpels has been observed frequently in _Tulipa Gesneriana_, the change in question being generally attended by a partial virescence. M. Gay is said by Moquin to have observed a flower of _Crocus nudiflorus_ in which the segments of the perianth were cleft and fringed at the same time, so that they presented the appearance of the stigmas.

=Pistillody of the sepals.=--In some double flowers of the garden pea communicated by Mr. Laxton, among other peculiarities was a supernumerary 5-6-leaved calyx, some of the segments of which were of a carpellary nature, and bore imperfect ovules on their margins, while at their extremities they were drawn out into styles.[335]

=Pistillody of the stamens.=--This change whereby the stamens assume more or less the appearance of pistils is more commonly met with than is the metamorphosis of the envelopes of the flower into carpels. In some cases the whole of the stamen appears to be changed, while in others it is the filament alone that is altered, the anther being deficient, or rudimentary; while, in a third class of cases, the filament is unaffected, and the anther undergoes the change in question. In those instances in which the filament appears to be the portion most implicated, it becomes dilated so as to resemble a leaf-sheath rather than a leaf-stalk, as it does usually.

One of the most curious cases of this kind is that recorded in the 'Botanical Magazine,' (tab. 5160, f. 4) as having occurred in _Begonia frigida_ already alluded to, and in which, in the centre of a male flower, were four free ovoid ovaries alternating with as many stamens. In the normal flowers of this plant, as is well known, the male flowers have several stamens, while in the female flowers the ovary is strictly inferior, so that, in the singular flower just described, the perianth was inferior instead of being superior, as it is usually. It should be added also that the perianth in these malformed flowers was precisely like that which occurs ordinarily in the male flowers.

In some varieties of the orange, called by the French "bigarades cornues," the thalamus of the flower, which is usually short, and terminated by a glandular ring-like disc, is prolonged into a little stalk or gynophore, bearing a ring of supernumerary carpels. These carpels are isolated one from another, and are formed by the transformation of the filaments of the stamens.[336]

The additional carpels in the case of the apple of St. Valéry, in which the petals are of a green colour, like the sepals, are by some attributed to the transformation of the stamens into carpels. These adventitious carpels frequently contain imperfect ovules and form a whorl above the normal ones. (See _Pyrus dioica_ of Willdenow.)[337] A similar change occasionally happens in the stamens of _Magnolia fuscata_, while in double tulips this phenomenon is very frequent, and among them may be found all stages of transition between stamens and pistils, and many of the parts combining the characters of both.[338] Dunal and Campdera have described flowers of _Rumex crispus_, with seven pistils, occupying the place of as many stamens.

In _Papaver bracteatum_ a considerable number of the stamens sometimes become developed into pistils, especially those which are nearest to the centre of the flower, and in these flowers the filaments are said to become the ovaries, while the anthers are curled so as to resemble stigmas. A similar change is not infrequent _Papaver somniferum_. Goeppert, who found numerous instances of the kind in a field near Breslau, says the peculiarity was reproduced by seed for two years in succession.[339] Wigand ('Flora,' 1856, p. 717) has noticed among other changes the pistil of _Gentiana Amarella_ bearing two sessile anthers. _Polemonium cæruleum_ is another plant very subject to this change. Brongniart[340] describes a flower of this species in which the stamens were represented by a circle of carpels united to each other so as to form a sheath around the central ovary. By artificial fertilization M. Brongniart obtained fertile seeds from the central normal ovary as well as from the surrounding metamorphosed stamens.

_Cheiranthus Cheiri_ has long been known as one of the plants most subject to this anomaly. De Candolle even mentions it in his 'Prodromus' as a distinct variety, under the name of _gynantherus_. Brongniart (loc. cit.) thus refers to the _Cheiranthus_:--"Sometimes these six carpellary leaves are perfectly free, and in this case they spread open, presenting two rows of ovules along their inner edges, or these edges maybe soldered together, forming a kind of follicle like that of the columbine; at other times, these staminal pistils are fused into two lateral bundles of three in each bundle, or into a single cylinder which encircles the true pistil. In a third set of cases these outer carpels are only four in number, two lateral and two antero-posterior, all fused in such a manner as to form around the normal pistil a prism-shaped sheath, with four sides presenting four parietal placentæ, corresponding to the lines of junction of the staminal carpels."

In the accompanying figures (fig. 163, _a-d_) the nature of this change is illustrated. In some of the specimens it is easy to see that the two shorter stamens undergo the change into carpels later and less perfectly than the four longer ones, and not infrequently the outer pair are altogether absent. In most of the flowers of this variety the petals are smaller and less perfectly developed than usual.[341]

In _Lilium tigrinum_, some specimens of which were gathered by Mr. J. Salter, in addition to various degrees of synanthy and other changes, some of the stamens were developed in the form of carpels, adherent by their edges so as to form an imperfect tube or sheath around the normal pistil. Fig. 164 shows one of the intermediate organs from these flowers, in which half the structure seems devoted to the formation of ovules, while the other half bears a one-celled anther. Lindley[342] has also described a case of this kind in a species of _Amaryllis_.

In _Saxifraga crassifolia_ it sometimes happens that mixed with the stamens, and originating with them, are a number of distinct and perfectly formed carpels, wholly separated from the normal carpels, in the centre of the flower. In this particular instance there is usually no intermediate condition between the stamen and the pistil. Guillemin[343] also describes a transformation of the stamens into carpels in _Euphorbia esula_.

When the anther is involved it may be only partially so, or almost the whole organ may be transformed. As instances of very partial change may be cited the passage of the connective into a stigma in _Thalictrum minus_, or the passage of the points of the anthers into imperfect styles in some species of bamboo.[344]

In _Rosa arvensis_ similar transformations have been observed of a slightly more complex character than those just mentioned, and passing into more important changes, especially to the formation of pollen within ovules, formed on the edges of an open carpellodic anther (see p. 186).

Mr. Berkeley has recorded an analogous case in a gourd in which the stamens bore numerous ovules (p. 200), and Baillon describes another gourd in which certain fleshy appendages surrounding the androecium were provided with ovules.[345]

Payer, in his 'Organogénie,' p. 38, mentions a stamen of _Dionæa_ bearing not only an anther, but likewise an ovule.

_Sempervivum tectorum_ and _S. montanum_, have long been noticed as being very prone to present this change. Mohl[346] remarks that, in the transformation of the stamens to the pistil in the common houseleek, the filament of the stamen generally preserves its form, the anthers alone undergoing change. At other times, however, the transformation takes place at the same time, both in the filament and in the anther. When the stamens are numerous some of them remain in their normal state, while others, and especially the inner ones, undergo a change. Sometimes all the stamens are changed simultaneously, while at other times some of these organs may be found in which the anther is partially filled with ovules, and partially with pollen.

In the accompanying figures (fig. 165, _a-h_) a series of intermediate stages is shown between the ordinary stamen of _Sempervivum tectorum_ and the ordinary carpel, from which it will be seen that the filament is little, if at all, affected, and that in those cases where there is a combination of the attributes of the stamen and of the pistil in the same organ the pollen is formed in the upper or inner surface of the leaf-organ, while the ovules arise from the opposite surface from the free edge, (_b_, _c_, _d_, _e_, _f_, _g_).

In a drawing made by the Rev. G. E. Smith of a malformed flower of _Primula acaulis_, and which the writer has had the opportunity of examining, the stamens are represented as detached from the corolla, and their anthers replaced by open carpels, with ovules arising, not only from their edges, but also from their surfaces, while the apex of the carpellary leaf was drawn out into a long style, terminated by a flattened spathulate stigma.

_Delphinium elatum_ is one of the plants in which this change has been most frequently noticed.[347]

In willows the change of pistils into staminal organs has been frequently observed. In _Salix babylonica_ Prof. Schnizlein has described various transition stages between the carpels and the stamens, and in one instance, in addition to this change, a perfect cup-shaped perianth was present, as happens normally in _Populus_[348]. Mr. Lowe also records the conversion of stamens into ovaries in _Salix Andersoniana_, and this by every conceivable intermediate gradation.[349]

The following list will serve to show what plants are most subject to this anomaly. It is difficult to draw any accurate inference from this enumeration, but attention may be called to the frequency of this occurrence in certain plants, such as the _Sempervivum_, the wallflower, the poppy, and the heath. Why these plants should specially be subject to these changes cannot be at present stated.

By the student of animal physiology such a change as above described--equivalent to the substitution of an ovary or a uterus for a testis--would be looked on as next to impossible; the simpler and less specialised structure of plants renders such a change in them far more easy of comprehension.

Thalictrum minus. Delphinium elatum. Magnolia fuscata. Bocconia cordata. *Papaver bracteatum! * somniferum! nudicaule. Dionæa muscipula! Barbarea vulgaris. *Cheiranthus Cheiri! Cochlearia Armoracia. Tropæolum majus. Citrus Aurantium. *Sempervivum tectorum! montanum. Begonia frigida! Cucumis, sp. Cucurbita Pepo. Pyrus Malus. Rosa arvensis! Saxifraga crassifolia! Myrtus, sp. Campanula rapunculoides. Polemonium cæruleum. Gentiana Amarella. *Erica Tetralix. Stachys germanica. Primula acaulis. Rumex crispus. *Salix, sp. plur.! Euphorbia esula. Glochidion. Asphodelus ramosus. Amaryllis. Lilium tigrinum! longiflorum. *Tulipa Gesneriana! var. cult. plurim.! Hemerocallis. Zea Mays. Bambusa, sp.

=Pistillody of the ovule.=--An instance of this extraordinary transformation in the carnation, as observed by the Rev. Mr. Berkeley, is given at p. 268.

FOOTNOTES:

[295] 'Neue Denkschrift. Schweiz. Gesellsch.,' band v, p. 9.

[296] 'Bull. Acad. Belg.,' xix, part 2, p. 93.

[297] Schlechtendal, 'Linnæa,' ix, p. 737.

[298] Misbilld., 'Cult. Gewachs.,' p. 32.

[299] Linn., 'Phil. Botan.,' § 120.

[300] 'Bull. Soc. Bot. France,' 1859, vol. vi, p. 199.

[301] Seemann's 'Journal of Botany,' vol. iii, p. 105; also Morren, 'Bull. Acad. Belg.,' vol. xx, part 2, p. 264.

[302] Morren, 'Bull. Belg.,' xviii, p. 503.

[303] 'Organ. Vég.,' t. i, p. 513.

[304] 'Bull. Acad. Roy. Belg.,' tome xvii; and Lobelia, p. 65.

[305] Masters, "On Double Flowers," 'Rep. Internat. Bot. Congress,' London, 1866. p. 127.

[306] See also C. Morren, "Sur les vraies fleurs doubles chez les Orchidées," 'Bull. Acad. Roy. Belg.,' vol. xix, part ii, 1852. p. 171.

[307] C. Morren, 'Bull. Acad. Belg.,' vol. xx, 1853, part ii, p. 284 (_Syringa_).

[308] 'Rep. Bot. Congress,' London, 1866, p. 135, t. vii, f. 14.

[309] Although it is generally admitted that the filament of the stamen corresponds to the stalk of the leaf, and the anther to the leaf-blade, yet there are some points on which uncertainty still rests. One of these is as to the sutures of the anther. Do these chinks through which the pollen escapes correspond (as would at first sight seem probable) to the margins of the antheral leaf, or do they answer to the lines that separate the two pollen-cavities on each half of the anther one from the other? Professor Oliver, 'Trans. Linn. Soc.,' vol. xxiii, 1862, p. 423, in alluding to the views held by others on this subject, concludes, from an examination of some geranium flowers in which the stamens were more or less petaloid, that Bischoff's notion as to the sutures of the anther is correct, viz., that they are the equivalents of the septa of untransformed tissue between the pollen-sacs. Some double fuchsias ('Gard. Chron.,' 1863, p. 989) add confirmation to this opinion. In these flowers the petals were present as usual, but the stamens were more or less petaloid, the filaments were unchanged, but the anthers existed in the form of a petal-like cup from the centre of which projected two imperfect pollen-lobes (the other two lobes being petaloid). Now, in this case, the margins of the anther were coherent to form the cup, and the pollen was emitted along a line separating the polliniferous from the petaloid portion of the anther. This view is also borne out by the double-flowered _Arbutus Unedo_, and also by what occurs in some double violets, wherein the anther exists in the guise of a broad lancet-shaped expansion, from the surface of which project four plates (fig. 157), representing apparently the walls of the pollen-sacs, but destitute of pollen; the chink left between these plates corresponds thus to the suture of the normal anther.

The inner or upper portion of the anther-leaf is that which is most intimately concerned in the formation of pollen; it comparatively rarely (query ever) happens that the back or lower surface of the antheral leaf is specially devoted to the formation of pollen. On the other hand, in cases like those of the common houseleek, where we meet with petaloid organs combining the attributes of anthers and of carpels, we find the inner layers devoted to the production of pollen, the outer to the formation of ovules.

That the pollen-lobes are not to be taken as halves of a staminal leaf, but rather as specialised portions of it, not necessarily occupying half its surface, is shown also in the case of double-flowered _Malvaceæ_, in which the stamens are frequently partly petal-like, partly divided into numerous separate filaments, each bearing a one-, or it may be even a two-lobed anther. This circumstance is confirmatory of the opinion held by Payer, Duchartre, Dickson, and other organogenists, as to the compound nature of the stamens in these plants. The stamens are here analogues not of a simple entire leaf, but of a lobed, digitate, or compound leaf, each subdivision bearing its separate anther. On this subject the reader may consult M. Müller's paper on the anther of _Jatropha Pohliana_, _&c._, referred to at page 255.

[310] See C. Morren, "On Spur-shaped Nectarines," &c., 'Ann. Nat. Hist.,' March, 1841, p. 1. tab. 11.

[311] Karsten, 'Flor. Columb. Spec.,' tab. xxix.

[312] See Dickson, "On Diplostemonous Flowers," 'Trans. Bot. Soc. Edin.,' vol. viii, p. 100; and on the Androecium of _Mentzelia_, _&c_., in Seemann's 'Journal of Botany,' vol. iii, p. 209, and vol. iv (1866) p. 273 (_Potentilla_, _&c._).

[313] See Baillon, 'Adansonia,' iii, p. 351, tab. 12, _Sinapis_.

[314] 'Bull. Acad. Belg.,' xvii, part i, p. 516, c. tab., and '_Lobelia_,' p. 83.

[315] Cited in 'Bull. Soc. Bot. France,' xiv, p. 253 ('Rev. Bibl.').

[316] 'Bull. Soc. Bot. Fr.,' 1858, p. 331.

[317] 'Mem. Legum.,' p. 44.

[318] 'Bildungsabweich, 'Pflanz. Fam.,' tab. 8, f. 12.

[319] 'Atlas de Göthe' p. 55, t. 4, f. 18.

[320] Wiegmann, 'Bot. Zeit.,' 1831, p. 5, tab. i.

[321] 'Ic. Flor. Germ.,' xiii, tab. 112, cccclxiv, f. 2.

[322] Seemann's 'Journal of Botany,' 1867, p. 317, t. 72, A (_Ophrys_).

[323] 'Enum. Euphorb.' p. 53.

[324] 'Linnæa.' i, p. 457.

[325] 'De Balsam,' p. 17.

[326] B. Clarke, 'Arrangement of Phænog. Plants,' p. 23.

[327] See 'Engelmann,' p. 26, tab. 3, f. 10, 11, 14.

[328] 'Ann. Sc. Nat.,' ser. 2, t. viii, 1837, p. 58.

[329] 'Bot. Zeit.,' 4, 1846, 889.

[330] 'Verhandl. Nat. Hist. Ver. Preuss. Rheinl. und Westph.,' 1858, 1860, p. 381. Cramer also, 'Bildungsabweich,' p. 90, cites a case in _Pæonia_ where the carpel was open and petaloid, and bore an anther on one margin, and four ovules on the other.

[331] 'Euphorbiaceæ,' p. 205.

[332] Seemann's 'Journ. Bot.,' iv, p. 168, tab. 47, f. 1.

[333] Moquin-Tandon, l. c., 220, _Passiflora_. Masters, 'Journ. Linn. Soc.,' 1857, p. 159, _Saponaria_. Seemann's 'Journ. Botany,' vol. iii, p. 107, _Narcissus_.

[334] 'Bull. Soc. Bot. Fr.,' 1857, p. 452.

[335] 'Gardeners' Chronicle,' 1866, p. 897.

[336] Maout, 'Leçons Element.,' vol. ii, p. 488.

[337] Poiteau and Turpin, 'Arb. Fruit,' t. 37, and Trécul, 'Bull Soc. Bot. France,' vol. i. p. 307.

[338] Clos, 'Mem. Acad. Toulouse,' 5 ser., vol. iii.

[339] 'Bot. Zeit.,' 1850, t. viii, pp. 514, 664. 'Flora,' (B. Z.) 1832, t. xv, p. 252; also cited in 'Ann. des Serres et des jardins,' vi, pp. 241-5. See also Schlechtendal, 'Bot. Zeit.,' 1845, t. 3, p. 6.

[340] 'Bull. Soc. Bot. France,' t. viii, p. 453.

[341] See also Allmann, 'Rep. Brit. Assoc.,' July, 1851.

[342] 'Theory of Horticulture,' ed. 2, p. 82.

[343] 'Mém. Soc. Hist. Nat. Paris.' i, 16.

[344] Gen. Munro, 'Trans. Linn. Soc.,' xxvii, p. 7.

[345] 'Bull. Soc. Bot. Fr.,' 1857, p. 21.

[346] 'Ann. Scienc. Nat.,' t. viii, 1837, p. 50, and 'Bot. Zeit.' (R.), 1836, t. xix, p. 513, &c. See also MM. Sourd Dussiples and G. Bergeron, 'Bull. Soc. Bot. France,' viii, p. 349; Von Schmidel, 'Icon. plant. et Anal. part.' 1782, p. 210, fig. 54.

[347] Godron, 'Bull. Soc. Bot. Fr.,' xiii, p. 82, Rev. Bibl.

[348] Cited in Henfrey, 'Bot. Gazette,' iii, p. 12.

[349] 'Ann. Nat. Hist.,' September, 1856, p. 56. See also Kirschleger, 'Flora (Bot. Zeit.),' xxiv, 1841, p. 340, _Salix alba_. Henschel, 'Flora (Bot. Zeit.),' 1832, t. xv, p. 253, _S. cinerea_. Hartmann, 'Flora (Bot. Zeit.),' xxiv, p. 199, _S. nigricans_. Meyer, C. A., 'Bull. Phys. Math.,' t. x, _S. alba_.