1881. 



on FrnifH and Seeds. 



GO.' 



carpel springs away (Fig. 8 h and c). The eeod-chambcr (Fig. 8 r) 

 detaclies itself from the rod of the carpel (Fig. 8//), and wlicn tlic see(l 

 is flung away remains attached to it. Under these circumstances it is 

 unnecessary for the chamber to raise itself from the central pillar, to 

 which accordingly it remains close until the moment of disruption 

 (Fig. 6 e). The seed-chamber is moreover held in place by a short 

 tongue which projects a little way over its base ; while, on the other 

 hand, the lower end of the rod passes for a short distance between the 

 seed-capsule and the central pillar. The seed -capsule has also near 

 its apex a curious tuft of silky hair (Fig. 8 c), tlie use of which I will 

 not here stop to discuss. As the result of all this complex mechanism 



Fig. 8. 



Diagram. 



Geranium robertianum. 



a, just before throwing the eeed ; b, the rod ; c, the seed enclosed in the capsule. 



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 some into the house and placed them on my billiard-table. 

 They were thrown from one end completely over 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, oj^en 

 suddenly with a jerk. Each valve of the pod contains a layer of 

 woody cells, which, however, do not pass straight up the pod, but are 



