LENGTH OF ROOTS 



So far nothing has been said about the roots themselves, 

 which penetrate, explore, and exploit all these layers of dead 

 leaves, soil, and subsoil. 



The length of roots produced is very much greater than 

 any one would suppose. A one-year-old Scotch fir seedling 

 when grown in sand produced in a season a total length 

 (branches, etc.) of no less than thirty-six feet of root. The 

 total surface of this root system was estimated to be about 

 twenty-three square inches. This little Scotch fir after six 

 months' growth was laying under contribution a cone of 

 earth twenty to thirty inches deep and with a surface of 222 

 square inches. In certain kinds of corn the same author 

 estimated the total length of the roots as from 1500 to 1800 

 feet. S. Clark estimated the length of the roots of a large 

 cucumber plant as amounting to 25,000 yards (fifteen miles), 

 and made out that it was occupying a whole cubic yard of 

 ground. 



Clover roots are said to go down to depths of six or nine 

 feet, but many weeds go deeper still. Coltsfoot, for instance, 

 may be found, according to a friend of mine, living at a 

 depth of twenty spades. In Egypt and other places the roots 

 of acacias go down to twenty feet or even further, so that 

 they can tap the water supplies, which are at a great depth. 



But a still more extraordinary fact is the manner in which 

 the root-branches arrange to grow in such a way that they 

 search every part of the soil. 



The main root in many plants grows straight down, or as 

 nearly as it can do so. Its branches are inclined downwards 

 at a quite definite angle which is often 30"'-45° to the surface. 

 Moreover, these branches come off in quite a regular way. 

 Each keeps growing in its own special direction to the east, 

 south-east, or west, or whatever it may be, of its parent root. 



87 



