194 BRITISH PLANTS 



becomes fleshy, bearing a huge number of small achenes 

 — " seeds " — on its umer surface. In the pineapple the 

 bracts of the inflorescence become fleshy and coalescent. 

 In this connection it may be noted that whenever the 

 bracts are persistent in the fruit, they are to be regarded 

 as part of it, biologically. They are usually concerned 

 only in its protection, but' in some cases they do more ; 

 in the lime, hornbeam, pineapple, and hop, they take a 

 prominent part in its dispersal. 



Biological Classiflcation of Fruits. 



The primitive and paramount purpose of the fruit is 

 the protection of the seed. The dispersal of the seed is a 

 derived function, but in the evolution of fruits this has 



Via. 102.— Fruit of Via. 

 a, succulent inflorescence-axis ; b, remains of flowers. 



gradually increased in importance, so that the specializa- 

 tion of the fruit is almost entirely directed to this end. 

 If the fruit is indehiscent, it is the fruit itself which is 

 dispersed. If it is dehiscent, the opening of the fruit is 

 dependent upon favourable atmospheric conditions — e.g., 

 dry air and wind — ^and in some cases the seeds themselves 

 are provided with mechanisms for further dispersal. In 

 this connection drupe-like fruits, whether true or false, 

 must be looked upon as indehiscent, since they are dispersed 

 whole, or practically whole — e.g., plums, apples — while 



