THE PLANT AS A PARENT 63 



altogether. In a slightly different way enormous 

 numbers of seeds which are eaten by birds rely 

 for their dispersal on the fact that whilst feasting 

 the winged creatures will almost certainly pick 

 up a few on their feet. In this manner they will, 

 of course, be carried to great distances. 



A very interesting group of plants are those 

 which, by sheer force, expel their seeds from the 

 cases. One of the most curious examples in the 

 world is certainly the Sand Box tree, the seed 

 case of which, as it dries, becomes in a state of 

 considerable tension. At a certain stage of its 

 development the large capsule bursts, hurling the 

 hard seeds with great force in all directions. It 

 is said that passers-by have not infrequently been 

 injured by the flying seeds. In much the same 

 way the Para Rubber tree scatters its seeds afar, 

 and when these are ripening in a plantation the 

 sound resembles the constant firing of pistols. 

 To come to more homely instances, the common 

 Balsams of our gardens possess seed vessels which 

 are veritable popguns. When the seeds are ripe 

 for ejectment the five divisions of the capsule burst 

 open and throw out the contents with a good 

 deal of violence. The pretty little English Wood 

 Sorrel offers another example of those plants 

 which scatter their seeds with force. As soon as 



