III.] 



VETCH. 



61 



(Fig. 43, f), the use of which I will not here stop to 

 discuss. As the result of all this complex mechanism 

 the seeds when ripe are flung to a distance which is 

 surprising when we consider how small the spring is. 

 In their natural habitat it is almost impossible to 

 find the seeds when once thrown. I therefore brought 



Diagram. 



FIG. 43. Geranium robertianum. 

 a, just before throwing the seed ; b, tha rod ; c, the seed inclosed in the capsule. 



some into the house and placed them on my billiard- 

 table. They were thrown from one end completely 

 beyond the other, in some cases more than twenty feet. 

 Some species of Vetch, again, and the common 

 Broom, throw their seeds, owing to the elasticity of 

 the pods, which, when ripe, open suddenly with a jerk. 



