DISTRIBUTION OF SEEDS 285 



only a single seed, to travel considerable distances 

 with the wind (Plate XLIII, Fig. 2, and Plate V.). 



In a few plants the seeds are thrown out by the 

 agency of the fruit itself, as has been already explained 

 in the case of the Violets (p. 162), In other cases, 

 such as the Geranium, the ovary divides into five 

 fruitlets, which are shot off from the plant to a 

 considerable distance by the sudden splitting of the 

 fruit. 



The fruits, distributed by the agency of animals, 

 are of two kinds. The first are succulent and edible 

 and attract animals, especially birds. The second 

 possess some form of clinging apparatus, such as hooks, 

 by which they become attached to passing animals, 

 and are thus carried to a distance from the parent 

 plant. 



We have in an earlier chapter (p. 220) com- 

 mented on the number of plants producing berries in 

 the Alps. The other types of succulent fruits are 

 few in number. In the Wild Strawberry {Fragaria) 

 the receptacle of the flower becomes fleshy, and the 

 fruits, each of which only contains a single seed, are 

 the little black bodies scattered over the red flesh of 

 the ripe fruit. The " hips " of the Eoses {Rosa) are 

 complicated structures, in which the persistent and 

 flesh-coloured calyx tube of the flower grows 

 round and encloses the true fruits, each of which 

 also contains a single seed. 



Hooked fruits are comparatively few in the Alps. 

 We have already noticed (p. 158) the hooked style of 



