LEGUMES, BERRIES AND SMALL FRUITS 



189 



The eastern wild varieties seldom produce large enough berries 

 to be of economic importance. 



The blackberry genus includes raspberries and black- 

 berries. They have coarse prickly stems or "canes" and form 

 bushy growths which often become impenetrable thickets. The 

 fruits are of the aggregate type, i.e., each fruit is really a composite 

 fruit resulting from a number of small fruits being united on the 

 same receptacle. In the blackberry the fruit cluster remains at- 

 tached to the receptacle, while in the raspberry it separates from 



Fig. 126.— The pistils of the 

 strawberry flower are seated on a 

 conical receptacle which, after 

 fertilization, enlarges to form the 

 edible portion of the fruit. 



A B 



Fig. 127.— In the blackberry (A) 

 the aggregate fruit remains attached to 

 the receptacle, while in the raspberry 

 (B) it separates from it leaving a de- 

 pression in the bottom of the fruit. 



it, leaving a depression in one side of the fruit (fig. 127). Black- 

 berries are a distinctively American fruit, though species occur in 

 Europe also. Our garden varieties are thought to have been 

 derived from a cross between two eastern American species. A 

 European species is the stock from which the Oregon everbearing 

 variety has been secured. The cultivated red raspberry, on the 

 other hand, is a European species which was grown and prized 

 by the Romans; black raspberries are descended from native 

 northeastern United States species. Raspberries are exceedingly 

 hardy fruits, being capable of cultivation as far north as Alaska. 

 Raspberries and blackberries have been crossed several times; 



