402 



ROSACEA 



central raised part of the receptacle. Each carpel has a lateral 

 style, and contains a single ovule. As the calyx, corolla, and 

 androecium are inserted on the receptacle surrounding and free 

 from the centrally placed gynsecium the flower is perigynous. 



The flowers are protogynous, and cross-pollination is usually 

 effected by insects. In some cultivated varieties the flowers 

 possess no stamens ; neither the fruits proper, nor the receptacles 

 of such pistillate flowers develop unless pollen is brought from 

 another flower. 



After fertilisation the gynsecium develops into the fruit, which 

 is composed of small one-seeded achenes, and the receptacle 



Fig. 125. — At Vertical section of a strawberry ower. a Sepal; /' petal; s stamens: 

 c carpel. 



jB, Section of the ' spurious fruit ' developed from the flower A : the corresponding 

 parts of the flower and fruit * are connected by lines. 



grows to a large size, becoming at the same time succulent. The 

 succulent growth of the receptacle appears to depend on the 

 fertilisation of the ovules within the carpels ; should any of the 

 carpels be injured and fertilisation be prevented, the part of the 

 receptacle on which such carpels are situated does not develop, 

 and the result is a deformed strawberry. The achenes, which 

 at first are crowded together, become much separated from each 

 other by the growth of the receptacle. 



It is the receptacle or terminal part of the flower-stalk which 



