350 WATER MAKES A GARDEN OF THE DESERT 



to distribute the manufactured food to all parts of the plant. 

 Scarcity of rainfall means a parched, dry soil, and starvation 

 for plants. 



The rainfall of the East is sufficient to support plants in 

 abundance, from low grass to tall forest trees. The rainfall of 

 the middle West is less abundant, fine large trees are scarce, 

 _^_____^^^^^______^_^^__ and grasses cover the 



prairies (Fig. 215). In 

 the desert regions the 

 rainfall is meager and 

 the land is dotted here 

 and there with a scanty 

 plant growth totally 

 different from that of 

 well-watered regions. 

 There are two conspic- 

 uous desert regions in 

 the United States. One 

 consists of portions of 

 Utah, Nevada, Cali- 

 fornia, Arizona, and 

 neighboring states ; the 

 other includes portions 

 of Arizona and New 

 Mexico and extends into 

 the adjoining country of Mexico. In both of these regions there 

 are vast areas almost without plant life; but, generally, plants 

 are huddled together in scattered patches on the dry land (Fig. 

 214). Owing to the scarcity of water in the soil, each plant 

 needs a large space from which to draw its supply. For this 

 reason the vegetation is scattered and interrupted by stretches 

 of barren soil. To get sufficient water small shrubs like the 

 mesquite sometimes send roots 50 feet from the parent in search 



FIG. 216. Barrel cactus. 





