ROOTS 223 



roots of ordinary plants are much larger than we 

 suppose. When a plant is pulled out of the ground, 

 the larger part of the root system is broken off and 

 left in the ground. The roots of trees ordinarily spread 

 much farther underground than their branches do above. 



Roots seem to be modified to suit their surroundings. 

 However, we must not fail to recognize the fact that 

 plants can not adapt themselves to conditions. In many 

 ways they are very well adapted or suited to the 

 conditions under which they live, but that is because 

 they are the only plants which have survived. On 

 the whole, large aerial stem systems are commonly 

 associated with extensive root systems. The roots of 

 plants along streams and shores are especially effective 

 for anchorage. The roots of these plants are frequently 

 matted together, thereby clinging firmly to the earth. 

 As a result, the water can not wear away the soil and 

 dislodge the plant. 



The size of the root varies greatly with the amount 

 of available water. The roots of water and of swamp 

 plants are usually short. Those of desert plants, on the 

 other hand, are often enormously developed. 



' ' One of the most notable examples of an enormously, 

 developed root system is found in the mesquite of the 

 far Southwest and Mexico. When this plant grows as 

 a shrub, reaching the height, even in old age, of only 

 two or three feet, it is because the water supply in 

 the soil is very scanty. In such cases the roots extend 

 down to a depth of sixty feet or more, until they reach 



