194 BRITISH PLANTS 
becomes fleshy, bearing a huge number of small achenes 
—‘‘ seeds ’’—on its inner 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 Classification 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 
«4 
te) 
ese 
RS 
ty 
——» 
Fig. 102.—Frvir or Fia. 
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 
