DEVELOPMENT OF PLANTS 



435 



the flower is strictly epigynous. In the rose family, which is 

 very closely connected with the preceding group, this story of 

 change in the evolution of the flower is repeated. In the simpler 

 forms the receptacle adheres to the calyx, forming a cup-like 

 structure that may be rather broad and shallow as in the straw- 

 berry, cinquefoil and blackberry (Fig. 312), but in higher types 

 the receptacle more or less completely surrounds the pistils as 

 in the spiraea, avens, rose, agrimony (Fig. 313). In the apple 

 family, including the apple, peach, quince, shadbush, thornapple, 



Fig. 312. 



Fig. 313. 



Fig. 312. A member of the rose family with the simple structure of the 

 saxifrages: A, flower of the strawberry (Fragaria). B, section of flower, 

 showing slight adhesion of receptacle to calyx and the spiral arrangement of 

 the sporophylls. C, the fruit, akenes spirally arranged on the enlarged and 

 fleshy receptacle. 



Fig. 313. Higher forms of the rose family: A, flower of the rose. B, 

 section of flower, showing the cup-like receptacle surrounding the pistils. 

 C, flower of Agrinionia. D, section of flower, showing the bristle-covered 

 receptacle completely surrounding the pistils. 



hawthorn, the ovules are completely enveloped by the receptacle 

 (Fig. 314, A-C) as in the currants, while in the plum family, 

 with its plum, prune, cherry, peach, almond, apricot members, 

 the pistils are reduced to one and do not adhere to the cup-like 

 receptacle (Fig. 314, D-F). 



