136 



THE DESERT 



Tap roots. 



Under- 

 ground 

 structure. 



Feeding the 

 top growth. 



conserving it in tanks and reservoirs. The 

 roots of the grease-wood and the mesquite are 

 almost as powerful as the arms of an octopus, 

 and they are frequently three times the length 

 of the bush or tree they support. They will 

 bore their way through rotten granite to find a 

 damp ledge almost as easily as a diamond drill ; 

 and they will pry rocks from their foundations 

 as readily as the wistaria wrenches the ornamen- 

 tal wood-work from the roof of a porch. They 

 are always thirsty and they are always running 

 here and there in the search for moisture. A 

 vertical section of their underground structure 

 revealed by the cutting away of a river bank or 

 wash is usually a great surprise. One marvels 

 at the great network of roots required to sup- 

 port such a very little growth above ground. 



Yet this network serves a double purpose. 

 It not only finds and gathers what moisture 

 there is but stores it in its roots, feeding the 

 top growth with it economically, not wastef ully. 

 It has no notion of sending too much moisture 

 up to the sunlight and the air. Cut a twig and 

 it will often appear very dry ; cut a root and 

 you will find it moist. 



The storage reservoir below ground is not an 

 unusual method of supplying water to the plant. 



