142 A MANUAL OF FARM GRASSES 



zona and New Mexico, where it is known by the Mexi- 

 can name of sacaton. This is a vigorous bunch grass 2 

 to 6 feet high, erect, with long tough leaves and a large 

 open oblong panicle i to 2 feet long. In the valleys to 

 the north, especially in the Great Basin, a species of 

 bluegrass {Poa nevadensis Vasey) is common. 'In alka- 

 line soil the dominant grass is likely to be salt grass 

 {Distichlis spicata (L.) Greene). This is a short tough 

 grass with extensively creeping stout wiry rootstocks, 

 short stiff distinctly 2-ranked leaves, and a short nar- 

 row whitish flower .head. Salt grass is of little value 

 for forage but in the absence of other grasses is grazed 

 by stock. Large areas of the grass are found in the 

 Salt Lake basin of Utah. 



DESERTS 



Under this heading are included the arid regions west 

 of the Great Plains. Much of the desert region is more 

 arid than the western part of the Great Plains, but even 

 in cases where the rainfall is about the same, the desert 

 differs from the plain in the lack of a continuous grass 

 covering. The vegetation of the desert varies from al- 

 most total absence to a covering of scattered shrubs 

 and small trees. Alkaline deserts may be so strongly 

 impregnated with salt or soda as to be totally lacking in 

 vegetation. These deserts are the basins of former lakes 

 and may still contain shallow lakes at least during the 

 wet season. Such deserts are colloquially known as 

 "slick deserts." Where the soil is less alkaline there 

 may be a growth of grease wood and salt bushes. The 

 later are of value as forage plants. If the soil is not 



