148 ELEMENTARY STUDIES IN BOTANY 



pulpy mass in which the seeds are imbedded, as in the grape, 

 currant, gooseberry, tomato, etc., all of which are berries. 

 In still other cases, the ovary wall may ripen into two layers, 

 the inner one being very hard and the outer one being fleshy, 

 as in the peach, plum, cherry, etc., which are called stone-fruits 

 (Fig. 120). Sometimes the changes extend beyond the 

 ovary. For example, the cup-like base of the flower sur- 

 rounding the ovary may become fleshy, as in the apple and 

 pear, in which the ovary is represented by the " core " con- 

 taining the seeds (Fig. 121). An extreme case is the pine- 

 apple, in which a whole flower cluster 

 has become an enlarged fleshy mass, in- 

 cluding the axis and the bracts (Fig. 

 122). 



All of these changes outside the seed 

 result in what is called the fruit. It 

 is evident that " fruit " is a very 

 indefinite thing. It may be dry or 



FIG. 120. Section of a . J 



peach, showing pulp and fleshy, and it may include only the 

 <H3, ovary, or it may extend to the base 



and inclosing the seed o f ^he flower, or it may involve a 



(kernel). After GRAY. 



whole cluster of flowers. 



90. Summary. The Angiosperms are far more varied 

 and abundant than are the Gymnosperms, and constitute 

 the conspicuous vegetation of the land surface, and also the 

 vegetation of greatest importance to man. Three features of 

 the group stand out conspicuously in contrast with Gym- 

 nosperms. 



The first feature is the inclosed ovule, the inclosing struct- 

 ure being the carpel. This means that the pollen grains, con- 

 taining the male gametophytes, cannot reach the ovule, but 

 are received by a special region of the surface of the carpel 

 (the stigma) . This means, further, that the pollen tube must 

 traverse the style, enter the cavity of the ovary, reach the 

 tip of an ovule (the position for the pollen grain in Gymno- 



