23 



heavily thau at preseDt. For this purpose either native or valuable 

 introduced forms (discussed elsewhere in this report) may be used. 



The native grasses also are worthy of trial. The writer has seen 

 wonderful results from seeding the ground to sojne of these, especially 

 the wheat-grasses, and this, too, where the water used for irrigation 

 was far from the best and the ground strong with alkali. Further- 

 more, the increase in the water supply is not quite hopeless. The 

 region contains many natural basins in which, by the expenditure of 

 a little labor in the construction of dams, much of the water from the 

 accumulated winter snowdrifts might be saved for use later in the 

 season. 



On the outskirts of the desert, the problem is much the same as in 

 the greater arid west. Those measures which may be successfully 

 introduced in other localities will be equally successful here. 



CHARACTERISTIC DESERT PLANTS. 



A question needing full investigation is the relation of plants to 

 alkali or other salts in the soil. Practically all that we know is that 

 some species have adapted themselves to endure or even thrive in soil 

 containing greater or less amounts of various salts. Different species 

 even in the same genus behave very differently in this respect; ibr 

 example, Cheiiopodium albion L. seeks a soil free from salts, while for 

 C. (jlauciim L. there can hardly be too much. If alkali affects a plant 

 injuriously it seems to do so throughout its entire development. It has 

 been shown that alkali retards germination or entirely prevents it in 

 most seeds in direct proportion to the amount of the salt present.' Some 

 families of plants have adapted themselves to saline soil more tiian 

 others. Easily first in this respect is the goose-foot family {Clicnopo- 

 diace(v). To this belong a large number of distinctively alkali plants, 

 such as the Salt-sages, White Sage, Grease- wood, Russian Thistle, and 

 Australian Saltbush. 



In regard to the question of largest representation by species of the 

 families of plants found in the desert, the writer found on examining 

 the collections that the family represented by the largest number of 

 species is not necessarily the most characteristic of the region. The 

 obvious vegetation, that which gives character to the landscape, can 

 be included in a half dozen genera, Artemisia, Tetradymia, Chri/so- 

 thaniHUs, Atrijdex, Sarcohatm, and Ar/ropyron. Kemove all the plants 

 belonging to the three families, Gompositcc, Chenopodiacew, and Chutnii- 

 new, and the region w^ould look like a true desert. Many other families 

 are better represented in number of species, but the individuals are 

 either small or scattering, and bear the same relation to the great mass 

 of vegetation that the occasional weed in a well-tilled field bears to 

 the main crop. 



The plants of the following list are worthy of special note. It is 



'Bull. 29, Wyoming I'xperiiuent Stition. 



