HOW PLANTS DEINK. 59 



adapted by natural selection for special purposes. 

 If you sow a pea or bean you will find at once 

 that the young seedling begins from the very 

 first to distinguish carefully between two main 

 parts of its body. In one direction, it pushes 

 downward, forming a tiny root, which insinuates 

 itself with care among the stones and soil ; in 

 the other direction, it pushes upward, forming a 

 baby stem, which gradually clothes itself with 

 leaves and flowers. 



The tip of the root is the part of the plant 

 which exercises the greatest discrimination and 

 ingenuity, so much so that Darwin likened it to 

 the brain of animals. For it goes feeling its 

 way underground, touching here, recoiling there, 

 insinuating little fingers among pebbles and 

 crannies, and trying its best by endless offshoots 

 to fix the plant with perfect security. Large 

 trees, in particular, need very firm roots, to moor 

 them in their places, and withstand the force of 

 the winds to which they are often subject. After 

 every great storm, as we know, big oaks and 

 pines may be seen uprooted by the power of 

 this invisible but very dangerous enemy. 



The root, however, does not serve merely to 

 anchor the plant to one spot, and secure it a 

 place in which to grow and feed ; it also drinks 

 water. The hairs and tips of the root absorb 

 moisture from the soil ; and this water circulates 

 freely as sap through the entire plant, dissolving 

 and carrying with it the starches and other 

 materials which each part requires for its growth 

 find nourishment (Figs. 7, 8, and 9), Without 



