PRINCIPLE OF METAMORPHOSED SYMMETRY -171 



that the members of each of these whorls are in their nature identical, 

 and the same as if they were whorls of ordinary leaves, brought 

 together by the shortening their common axis, and modified in form 

 by the successive elaboration of their nutriment. Further, according 

 to this view, a whcrl of leaves itself is to be considered as identical with 

 several detached leaves dispersed spirally along the axis, and brought 

 together because the axis is shortened. Thus all the parts of a plant 

 are, or at least represent, the successive metamorphoses of the same 

 elementary member. The root-leaves thus pass into the common 

 leaves ; these into bractece ; these into the sepals ; these into the 

 petals ; these into the stamens with their anthers ; these into the 

 ovaries with their styles and stigmas ; these ultimately become tie 

 fruit ; and thus we are finally led to the seed of a new plant. 



Moreover the same notion of metamorphosis may be applied to 

 explain the existence of flowers which are not symmetrical like those 

 we have just referred to, but which have an irregular corolla or calyx. 

 The papilionaceous flower of the pea tribe, which is so markedly irre- 

 gular, may be deduced by easy gradations from the regular flower, 

 (through the mimosecej) by expanding one petal, joining one or two 

 others, and modifying the form of the intermediate ones. 



Without attempting to go into detail respecting the proofs of that 

 identity of all the different organs, and all the different forms of plants, 

 which is thus asserted, we may observe, that it rests on such grounds 

 as these ; the transformations which the parts of flowers undergo by 

 accidents of nutriment or exposure. Such changes, considered as mon- . 

 strosities where they are very remarkable, show the tendencies and 

 possibilities belonging to the organization in which they occur. For 

 instance, the single wild-rose, by culture, transforms many of its nume- 

 rous stamens into petals, and thus acquires the deeply folded flowei 

 of the double garden-rose. We cannot doubt of the reality of this 

 change, for we often see stamens in which it is incomplete. In other 

 cases we find petals becoming leaves, and a branch growing out of the 

 centre of the flower. Some pear-trees, when in blossom, are remark- 

 able for their tendencies to such monstrosities. 3 Again, we find that 

 flowers which are usually irregular, occasionally become regular, and 

 conversely. The common snap-dragon (Linaria vulyaris) affords a 

 curious instance of this." The usual form of this plant is " personate," 

 the corolla being divided into two lobes, which differ in form, and 



Lindley, Nat. Syst. p. 84. 4 Henslow, Principles of Botany, p. 116. 



