112 THE HUMAN SIDE OF PLANTS 



aerial navigation as a sort of chance or happening 

 of no special importance ; but it is vitally important, 

 not only for the success of the plant, but for man- 

 kind as well. 



Some plants send their seed-children out by 

 means of spines and hooks, others shoot them out to 

 places of safety, still others float upon the water, 

 as the cocoanut; again some roll and tumble to a 

 suitable home. All of these methods of dispersal 

 are used; to say nothing of the work of birds and 

 animals in aiding them to distribute the seeds in 

 places where competition is not too strong, and 

 where climatic conditions will be conducive to their 

 best growth; but there is a large group of plants 

 that have adopted by far the most ingenious method 

 of sending their children into the world that is, by 

 means of airships. Plants of this kind may be 

 grouped into several classes according to their 

 method of navigating the air. 



The seed-children of the elm-tree and those 

 of the maple and the ash have wings like Icarus of 

 old and fly somewhat like birds ; those of the hop- 

 tree are surrounded by a peculiar kite-like structure 

 with the seed in the centre of this thin membrane; 

 the sycamore keeps its children snugly rolled to- 

 gether in a ball until they are fully developed, when 

 each one flies forth by means of a winged-arm 



