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INTRODUCTION. 
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The region of countr ediately adjoining tl I boundary of Mexico, 
including the western part of Texas, cot the greater part of New Mexico, Arizona, 
and southern California, is one of remarkable heat and aridity. It is mainly a 
region of elevated plains, called mesas, intersected by mountain ranges which occa- 
sionally run into high peaks, and is drained by comparatively few streams, which, 
on account of the limited rain-fall, cease to flow during a good part of the year, or 
convey only the waters obtained from distant portions of the country. 
Most of the region lies north of the thirty-second parallel of latitude, and ir in the 
western part reaches into Utah and Nevada. It is with great propriety called the 
desert belt: The country northward, and east of the Rocky Mountains, as far as 
the one-hundredth meridian, is an elevated arid plain, but with more abundant 
grasses, although rarely forming a continuous and connected sod. 
Inthe desert belt, however, the grasses become scanty, not in variety of species, 
but in distribution, some of them being short-lived, springing up suddenly after the 
summer rains and rapidly maturing ; others perennial, growing in bunches, and 
- having deeply penetrating roots which enable them to endure the long droughts of 
the country. Nowhere do the native grasses form a continuous sod, but grow in 
scattered bunches in connection with the low bushes which prevail on the mesas or 
among the chaparral. 
The country embraced in this desert belt is an extension northward of the 
great plateau of northern Mexico, as is shown in the similar character of its vege- 
tation. The grasses are largely the same, or of the same genera. But the grasses, 
like the rest of the vegetatiow, are peculiar to the region. Here one never sees the 
common grasses of the Eastern States. The vegetation is as different from that 
of the Eastern States as is that of the northern portion of the Sahara. Hence 
arises the utility of bringing to the notice of the public, and especially of the 
residents of this region, the information contained in this work. It is not a manual 
or description of all the grasses of the region, but it furnishes illustrations and de- 
scriptions of some of the more interesting and some of the commoner grasses of the 
country. Many of them were observed and specimens collected by the naturalists 
of the Mexican Boundary Survey, and by those of the Pacific Railroad Survey, but 
few or none of these have heretofore been illustrated or fully described. True, the 
descriptions here given are mostly in technical language, but accompanied by the 
illustrations they afford the best possible means of recognition. Probably the most 
important agricultural question before the people of this region is how to increase 
the production of grasses and forage plants on the arid lands. It is the opinion of 
many that this can be done by bringing under cultivation some of the native species. 
Experiments are about to be undertaken in this direction by the Agricultural Ex- 
periment Stations and by individuals. The first step in such an enterprise is a 
knowledge of or an acquaintance with the native species. Nothing can be better 
adapted to this object than the work here undertaken, and in this way the know]l- 
edge of the scientist can be made helpful to the practical economist. In this first 
part of the work fifty plates of grasses are given. A second part of an equal num- 
ber of plates is now in preparation, after which it is proposed to publish an analyti- 
cal synopsis of all the grasses of the desert region. The drawings of the grasses 
have been made chiefly by Mr. William R. Scholl, and in the description of the 
species I wish to acknowledge important aid from Mr. Frederick V. Coville, Assist- 
ant Botanist. z 
