PLANT FAMILIES: POMACES. 277 



are at first perigynous, but become epigynous (upon the gynoe- 

 cium) by the fusion of the receptacle with the carpels. The floral 



Fig. 366. 



Choke-cherry (Prunus virginiana). Leaves, 

 flower raceme, and section of flower at right. 



formula is thus Ca5, Co 5, A 10-5-5 or IO ~ I -5Gi-5. The carpels 



Fig. 367. 

 Flower of pear. (After Warming.) 



are united, but the styles are free. In fruit the united carpels fuse 

 more or less with the receptacle. 



