805 



METAMORPHOSIS. 



METAMORPHOSIS. 



806 



In Narcissus the cup is formed of three stamens of the first row, 

 become petaloid and united at their margins ; while the six which 

 form the second and third rows are in their usual state and within the 

 tube. This is shown, firstly, by the frequent divisions of this cup 

 into three lobes, which then alternate with the petals ; secondly, by a 

 distinct tendency in double Narcissi, particularly N. poeticus, to pro- 

 duce abortive anthers on the margin of the lobes of the cup ; and 

 thirdly, by the genus Brodicea and its allies. In that genus the crown 

 of the original species consists of three petaloid pieces, not united 

 into a cup, as in Narcissus, but wholly separate from each other : in 

 Leucocoryne ixioides these pieces are not petaloid, but clavate ; and in 

 L. odorata the species have the same figure as in L. ixioides, but 

 almost constantly bear more or less perfect anthers. That the anthers 

 are mere alterations of the margins of the petals there is no difiiculty 

 in demonstrating. In Nymyhaea the passage from the one to the other 

 may be distinctly traced. In double roses the precise nature of this 

 metamorphosis is shown in a very instructive way. If any double 

 rose is examined it will be seen that those petals which are next the 

 stamens contract their claw into the form of a filament, and a dis- 

 tortion of the upper part, or limb, also takes place ; the two sides 

 become membranous, and put on the colour and texture of the anther; 

 and sometimes the perfect lobe of au anther will be found on one side 

 of a petal, and the half-formed misshapen rudiment of another on the 

 opposite side. In A quilegia vulgaris this transformation is still more 

 curious, but equally distinct ; the petals of that plant consist of a long 

 sessile j, urple horn or bag, with a spreading margin ; while the stamens 

 consist of a slender filament, bearing a small oblong two-celled yellow 

 anther. In single and regularly-formed flowers nothing can be more 

 unlike than the petals and stamens ; but in double flowers the tran- 

 sition is complete ; the petals, which first begin to change, provide 

 themselves with slender ungues ; the next contract their margin, 

 and acquire a still longer unguis ; in the next the purple margin 

 disappears entirely ; two yellow lobes like the cells of the anther take 

 its place, and the horn, diminished in size, no longer proceeds from 

 the base, as in the genuine petal, but from the apex of the now 

 filiform unguis. In the last transition the lobes of the anther are 

 more fully formed, and the horn is almost contracted within the 

 dimensions of the connective, retaining however its purple colour : the 

 next stage is the perfect stamen. The conversion of stamens into green 

 leaves is far more uncommon : this indeed very rarely occurs. It was 

 seen by Roper in the Campanula. Rapunculus already referred to ; and 

 Du Petit Thouars found the stamens of Brassies, napus converted into 

 branches bearing verticillate leaves. In Plantago major and Sieversia 

 montana permanent instances are known of a conversion of the 

 stamens, with all the other floral organs, into leaves. Thus it appears 

 that the stamens, like the petals, calyx, and bractese, are merely 

 modified leaves. [STAMENS.] 



The Disc is so frequently absent, and is of so obscure a nature, that 

 few morphologistg take it into their consideration. It many plants it 

 consists of a mere annular fleshy ring encompassing the base of the 

 ovary ; in others it forms a sort of cup, in which the ovaries are 

 inclosed, as in certain Pceonies, and it very frequently makes its appear- 

 ance in the form of hypogynous glands or scales : it is almost always 

 between the stamens and pistil. That it is not an organ of a distinct 

 nature may be inferred from its having no existence in a large number 

 of flowers ; but if it is not an organ of itself it must be a modification 

 of something else, and in that view, from its situation, it would be 

 referrible either to the stamens or pistil. It has so little connection 

 with the latter, from which it always separates at maturity, that it can 

 scarcely belong to it. With the stamens it has a stronger relation : it 

 consists of the same cellular substance as the connective of the anthers, 

 is very often of the same colour ; whenever it separates into what are 

 called hypogynous glands or scales these always alternate with the 

 innermost series of stamens. In the Pceony the disc may in some 

 measure be compared to the inner row of scales which exist between 

 the stamens and pistil of the nearly-related genus A quUegia. Dunal 

 has noticed half the disc of a Cistus bearing stamens ; and a variety 

 of instances may be adduced of an insensible gradation from the 

 stamens to the most rudimentary state of the organ. 



The fifth and last series of the fructification is the Pistil. The 

 simple pistil, that of the pea for instance, consists of an ovary, bearing 

 its ovules on one side in two parallel contiguous rows, and at its 

 upper extremity tapering into a style, which terminates in a stigma. 

 If this organ be further examined, it will be found that there is a 

 suture running down each edge from the style to the base ; it will be 

 also seen that the ovules are attached to one of these sutures, and 

 that the style is an elongation of the other : further, it will be per- 

 ceived that the two sides of the ovary are traversed by veins 

 emanating from the suture that terminates in the style, and that these 

 veins take a slightly ascending direction towards the suture which 

 bears the ovules. Now if, when the pod of the pea is half grown, it 

 be laid open through the latter suture, all these circumstances will at 

 that time be distinctly visible ; and if it then be compared with one 

 of the leaflets of the plant, it will be apparent that the suture that 

 bears ovules answers to the two edges of the leaf, the suture without 

 ovules to the midrib, and the style to the mucro. Hence it might, 

 without further evidence, be suspected that the ovary is an alteration 

 of the leaf; but if the inquiry be carried further in other plants, this 



suspicion becomes converted into certainty. In the first place, the 

 suture without ovules, which has been said to be the midrib, is 

 always external with respect to the axis of fructification, as would be 

 the case with the midrib of a leaf folded up and terminating the 

 fructification. In the next place, nothing is more common than to 

 find the_pistil converted either into petals or into leaves. Its change 

 into pefels is to be found in numerous double flowers, as for example 

 double Narcissi, Hibiscus Rosa-sinensis, Wall-Flowers, Ranunculuses, 

 Saxifrages, and others. These however only show its tendency to 

 revert to petals as the representatives of leaves. The cases of its 

 reverting to other organs are much more instructive. In the double 

 Ulex Europceus the ovary is extremely like one of the segments of the 

 calyx ; its ovuliferous suture is not closed ; in the room of ovules it 

 sometimes bears little yellow processes like miniature petals, and its 

 back corresponds to what would be the back of the calyx ; no style 

 or stigma is visible ; sometimes two of these metamorphosed ovaries 

 are present : in that case the sutures which should bear ovules are 

 opposite to each other, just as the indexed margins of two opposite 

 leaves would be. In Kerria Japonica, which is only known in our 

 gardens in a double state, the ovaries are uniformly little miniature 

 leaves, with serrated margins corresponding to the ovuliferous suture 

 of the ovary, and an elongated poiut representing the style ; their 

 interior is occupied by other smaller leaves. Nothing is more common 

 among roses than to find the ovaries converted into perfect leaves ; in 

 such cases the margins uniformly occupy the place of the ovuliferous 

 suture, and the midrib that of the sterile suture. But the most 

 instructive and satisfactory proof of the pistil being merely a modified 

 leaf is to be found in the comnlou double cherry of the gardens. In 

 this plant the place of the ovary is usually occupied by a leaf alto- 

 gether similar to those of the branches, but much smaller : it is folded 

 together ; its margins are serrated, and, in consequence of the folding, 

 placed so as to touch each other ; and they occupy the place of the 

 ovuliferous suture of a real pistil. The midrib of this leaf corresponds 

 to the station of the sterile suture of the ovary, and is not only 

 lengthened into a process representing a style, but is actually termi- 

 nated by a stigma. There is thus a greater identity of function 

 between the pistil and the other series of the fructification than 

 would at first appear probable. The pistil is seldom indeed found 

 converted into stamens ; but it often takes upon itself the form of 

 petals, as has been shown above ; and although cases are very rare 

 of pistils bearing pollen, yet several instances are known of ovules 

 being borne by the stamens. This occurs continually in Sempvrmvwm, 

 tectorum. 



It appears then that there is not only a continuous uninterrupted 

 passage from the leaves to the bracts, from bracts to calyx, from calyx 

 to corolla, from corolla to stamens, and from stamens to pistil, from 

 which circumstance alone the origin of all these organs might have 

 been referred to the leaves, but that there is also a continual tendency 

 on the part of every one of them to revert to the form of a leaf. 



The pistil in a state of composition differs much in appearance 

 from its simple form. At section 78 of 'Die Metamorphose der 

 Planzen ' of Gb'the, are the following remarkable words : " Keeping 

 in view the observations that have now been made, there will be no 

 difiiculty in discovering the leaf in the seed-vessel, notwithstanding 

 the variable structure of that part and its peculiar combinations. 

 Thus, the pod is a leaf which is folded up and grown together at its 

 edges, and the capsule consists of several leaves grown together ; and 

 the compound fruit is composed of several leaves united round a 

 common centre, their sides being opened so as to form a communica- 

 tion between them, and their edges adhering together. This is obvious 

 from capsules, which, when ripe, split asunder, at which time each 

 portion is a separate pod. It is also shown by different species of 

 one genus, in which modifications exist of the principle on which 

 their fruit is formed : for instance, the capsules of Nigella orientalis 

 consist of pods assembled round a centre, and partially united ; in 

 Nigella damascena their union is complete." 



As it may thus be proved that all the parts of a flower are merely 

 modified leaves, the following propositions may be stated to constitute 

 the basis of Vegetable Morphology : 



" Every flower, with its peduncle and bracteolaa, being the develop- 

 ment of a flower-bud, and flower-buds being altogether analogous to 

 leaf-bxids, it follows as a corollary, that every flower, with its peduncle 

 and bracteolse, is a metamorphosed branch. 



" And further, the flowers being abortive branches, whatever the 

 laws are of the arrangement of branches with respect to each other, 

 the same will be the laws of the arrangement of flowers with respect 

 to each other. 



" In consequence of a flower and its peduncle being a branch in a 

 particular state, the rudimentary or metamorphosed leaves which con- 

 stitute bractex, floral envelopes, and sexes, are subject to exactly the 

 same laws of arrangement as regularly formed leaves." (Lindley, 

 ' Outline of the First Principles of Botany.') 



Engelmann has ('De Antholysi Prodromus') attempted to classify 

 the principal aberrations from normal structure, and has Collected a 

 very considerable number of cases under the following heads : 



1. Retrograde Metamorphosis (Regressus), when organs assume the 

 state of some of those on the outside of them, as when carpels change 

 to stamens or petals, hypogynous scales to stamens, stamens to petals 



