REPRODUCTION IN PLANTS 



95 



(see Fig. 40) ; hence each of these so-called berries is composed 

 of a number of separate fruits. Sometimes the end of the 

 stem which bears the pistils becomes pulpy and juicy and the 

 dry pistils are embedded in 

 its outer surface, as is the 

 case with strawberries (see 

 Fig. 42). In other fruits 

 the ovary may form a hard 

 woody wall, as in the nuts 

 like the chestnut (Fig. 39) 

 and acorn, or the wall may 

 be like a tough paper, as in 

 the pods of peas and locusts 

 (Fig. 43). In still other 

 forms the whole ovary may 

 become fleshy, as in the true 

 berries, such as the cran- 

 berry, grape, and tomato. 

 Or we may find a combina- 

 tion of a tough wall and a fleshy interior, as in the pumpkin, 

 squash, and cucumber. In cherries, plums, and peaches the 

 ovary forms two kinds of material, the inner very hard and 



stone-like and the outer pulpy. 

 In fruits like the corn grain 

 and the wheat kernel the ovary 

 wall is so closely united with 

 the coats of the single seed that 

 these grains are commonly con- 

 sidered as seeds. 



The facts just stated with 

 regard to different kinds of fruits suggest a simple form of 

 classification, based largely on the characteristics of the ovary 

 walls. Thus, for instance, all those fruits, such as bean pods, 



FIG. 39. Chestnut fruits inside the 

 chestnut bur. (Bailey.) 



FIG. 40. Raspberry fruits. 



