ITS THEORETICAL STRUCTURE. 



229 



should he a pistil into a leaf In the double Garden Cherry, either 

 comi:)letely (Fig. 345), or else incompletely, so that the resulting 

 t)rgan (as in Fig. 346) is something intermediate between the two. 

 The change of what should he stamens into petals is of common oc- 

 currence in what are called douhle and semi-double flowers of the 

 gardens ; as in Roses, Camellias, Carnations, &c. "VMien such flow- 

 ers have many stamens, these disappear as the supernumeraiy petals 

 increase in number ; and the various bodies that may be often ob- 

 served, intermediate between perfect stamens (if any remain) and 

 the outer row of petals, — from imperfect petals, with a small lamina 

 tapering into a slender stalk, to those which bear a small distorted 

 lamina on one side and a half-formed anther on the other, — plainly 

 reveal the nature of the transformation that has taken place; Car- 

 ried a step farther, the pistils likewise disappear, to be replaced by 

 a rosette of petals, as in fully double Buttercups. 



430. In full double Buttercups we may often notice a tendency 

 in the inner petals to turn 

 green, that is, to retro- 

 grade still farther into foli- 

 aceous organs. And there 

 is a monstrous state of the 

 Strawberry blossom, well 

 known in Europe, in which 

 all the floral organs revert 

 into green sepals, or imper- 

 fect leaves. Fig. 348 ex- 

 hibits a similar retrograde 

 metamorphosis in a flower 

 of the White Clover, where 

 the calyx, pistil, &c. are 

 still recognizable, althou";Ii 

 partially transformed into 

 leaves. And the ovary, 

 which has opened down one 

 side, bears on each edge a number of small and imperfect leaves ; 

 much as the ordinary leaves, or rather leaflets, of Br}'ophyllum are 

 apt to develop rudimentary tufts of leaves, or leaf-buds, on their 

 margins (Fig. 347), which may gi-ow into little plantlets, by which 

 the species is often propagated. This retrograde metamorjjhosis of 



FIG. 34S. A flower of the common White Clover reverting to a leafy branch; after Turpin. 



20 



