ORGANS OF REPRODUCTION. 



269 



the circumference of the flower ; the former is called the ventral 

 suture {fig. 570. vs), the latter the dorsal {fig. 570 ds). 



Nature of the Carpel. — That the carpel is analogous to the 

 leaf is proved in various ways, some of which will be more 

 particularly mentioned hereafter, when treating of the General 

 Morphology of the Flower ; we shall here only allude to 

 the proofs of its nature which are afforded by tracing its 

 development, and by the appearance it sometimes presents in 

 double or cultivatedflowers Thus in the double flower of the 

 Cherry, the carpels do not present a distinct ovary, style, and 

 stigma, as in their normal condition in the single flower {fig. 

 574), but they, either become flattened into green expansions, 

 each of which resembles the blade of a leaf {fig. 571), or into 

 organs intermediate in their nature between carpels and leaves 

 {figs. 572 and 573). Here the lower portion representing the 



Fig, 571. Fig. 572. 



Fig. 573. Fig. 574. 



Figs. 571, 572, and 573. Carpellary leaves from the double flowers of the 

 Cherry tree, h Lamina; s. Prolonged portion corresponding to the style 



and stigma of a perfectly formed carpel Fig. .574. Carpel from the 



single flower of the Cherry, o. Ovary; t. Style; s. Stigma. 



lamina of the leaf, is clearly analogous to the ovary of a com- 

 plete carpel, and the prolonged portion to the style and stigma. 

 The carpels of the single-flowering Cherry being thus con- 

 vertible into leaves, afford at once an evidence of their being 

 analogous structures. A second proof of the nature of the car- 

 pels is affbrded by tracing theii* development. Thus when 

 first examined, they appear as little shghtly concave bodies 

 of a green colour like young leaves {fig. 575), in a short 

 time they become more and more concave {fig. 576), till ulti- 

 mately the two margins of the concanty in each unite, and 



