CH. Xl] ANDRCEC1UM. 151 



Within the keel are contained the androecium and the 

 gynoecium. The stamens show a remarkable arrangement 



FIQ. 69. 

 FLOWER OF THE SWEET PEA. 



S, the standard viewed from behind. 



C, the calyx. W, one of the wings. 



which is described by the technical term diadelphous. The 

 horizontal bases of the filaments of nine of the stamens 

 are united into a broad plate which, being longitudinally 

 folded, makes a trough, while the tenth filament is free 

 and roofs in the trough above. The nine stamens are not 

 coherent throughout their entire lengths, their free apical 

 parts bend upwards and terminate in anthers. 



The gyncecium is contained in the .trough of the 

 united filaments; it consists of a single carpel, of which 

 the horizontal part (in the trough) is the ovary, while the 

 vertical part is the style which bears the stigma. The 

 ovary of the pea differs from that of the buttercup in 

 containing several ovules, as may be seen in fig. 70, where 

 however only part are shown. The cavity of the ovary is 

 made by the folding of the carpellary leaf, and the ovules 



