PRACTICAL POLLIXATIOX 243 



On one hand there are numerous gigantic 

 trees that no longer depend upon insects for the 

 fertihzation of their flowers. 



On the other hand there are httle cowering 

 plant waifs that nestle close to the earth and 

 which, in quite a different manner, also assert 

 their independence. 



The trees that have thus revoked the treaty of 

 alliance include such familiar forms as the pine, 

 the oak, and the walnut. 



These trees, and a goodly number of their 

 fellows, long ago declared against further co- 

 operation with the insect, and adopted the 

 method of producing large quantities of pollen 

 and scattering it in the air to be carried by the 

 wind to the pistillate flowers, which in some 

 cases grow on neighboring branches and in 

 other cases on quite different trees. 



The method is in one sense wasteful, inasmuch 

 as it involves the production of vast quantities of 

 pollen, only an infinitesimal portion of which will 

 ever come in contact with a receptive pistil. And 

 of course the production of this pollen must draw 

 heavily on the energies of the living substance of 

 the tree. 



But, on the other hand, the tree that thus 

 depends upon the wind rather than upon the 

 insects is under no necessity to develop large and 



