FRUIT AND SEED DISTRIBUTION 



317 



the appearance of holes. The pods of the bean family and 

 of the evening-primrose family illustrate this dehiscence, and 

 the poppy is a good example of the formation of pores. 



Fleshy fruits often drop off, carrying the seeds with them, 

 and the seed escapes when the fleshy part of the fruit is eaten 

 by some animal or rots (that is, is eaten by some plant). 



Fig. 145. Seeds scattered by the wind 

 /, dandelion : 2, milkweed : ?, white maple ; 4, prickly lettr.ce ; j. thistle 



Many fruits, however, do not permit the seeds to escape ; 

 the fruit and the seed are so closely united that they constitute 

 a structure that acts as a whole — as in the grains, the nuts, 

 and the nutlets of the dandelion family (Fig. 145, i, 4, and 5). 



372. Seed distribution. In their dehiscence many fruits 

 open so suddenly that they shoot the seeds to a distance of 

 a yard or more. This shooting is commonly brought about 

 by the rapid twisting of the parts of the pod, as in the touch- 

 me-not and the lupine (see Fig, 144). 



Most plants depend upon outside agencies to scatter their 

 seeds for them. The wind is active in the case of species 

 whose seeds are either very small (the orchids) or have 



