22 UNITED STATES AND MEXICAN BOUNDARY. 



to the traveller. 



assume a com 



new Jllnimnaceoiis shrub {Zmjphus Parryiy Terr.) makes its appearance. Upon the hill sides 



here grows a species of Agave ^ the ^^ Mezcal'' of this region. The root of this, when prepared 



hy a kind of underground roasting, serves as an important article of food for the Indians, Here 



we also find the ^^ Spanish Bayonet/' a species of yucca^ which presents its spine-armed leaves 



jlete desert-like character. The 

 ^^ creosote bush'^ (Larrea 3Iexicana) makes its first appearance, to be our constant companion 



for the remainder of the journey. Perhaps the most striking plant of these wastes is the 

 Fouquieria splendens. This grows in clumps, consisting of from twelve to twenty long wand- 

 like branches, which, springing from the main stem close to the ground, rise to the height of 

 from ten to fifteen feet; the stems are beset with rows of spines, from the axils of which grow 

 small fassicles of leaves. Its bright scarlet flowers only appear at the time when the stalk 

 is destitute of leaves, and hence the whole plant has too naked an appearance to exhibit much 

 beauty. 



The well-known mezquite, {Algarohia glandulosa^) which we shall notice more particularly 

 hereafter, now becomes a common shrub ; and near the base of the mountains a species of pal- 

 metto is seen growing in the clefts of the rocks. Its appearance in these localities invariably 

 indicates the presence of water, though this is frec[uently found to be too saline for use. 



As we advance upon the desert'plain a very distinct character of vegetation presents itself. On 

 all the gravelly ridges near the mountains we find the stiff stalks of Foiiquiericu In the fur- 

 rowed rain-water courses there is usually a growth of shrubbery larger than in other portions 

 of the desert. In such situations a small tree of graceful outline occurs — the Dalea spinescens^ 

 (Gray, PL Thurb.) The finely divided branches of this plant are all terminated by sharp 

 points, and are covered with a silvery pubescence. It bears a few abortive leaves, and an abund- 



ance of bright blue flowers. Further on in the desert the vegetation is chiefly composed of 



Larrea mexicana and Olione canescens. Near the borders of the lakes and gullies which mark 

 the position of^*^ New river'' we find a greater variety among the plants. A very rank growth 

 of a species of Amaranilius borders the lakes in wet seasons^ and on the upper clay borders of 

 '^ New river.'' The annual ^^ Gramma grass" yields, after the rains or the overflows of the 

 rivers, a rapid growth of evanescent but highly nutritious fodder. We find in these situations 

 a species of Boerhavia and one of Kallstroemia. The mezquite trees near these places attain 

 a considerable size, and frequently bear upon their branches a vigorous growth of a peculiar 

 misletoe. 



As we descend from the table land of the desert, by the steep bluff which bounds the alluvial 

 bottoms of the Colorado river, the vegetation consists almost entirely of dense thickets of mez- 

 quite, but it assumes a more varied character when we reach the alluvial tracts. On all places 

 liable to overflow the cotton-wood and willow abound, the latter forming a thicket along the imme- 

 diate margin of the river. The higher grounds near the river seem especially favorable for the 

 mezquite, and we find it growing with greater luxuriance than we have seen it elsewhere. In 

 some situations it forms thorny and impervious thickets, but it is usually sufficiently scattered 

 to permit an easy passage for man or beast. The irregular gro-^*""*^ ^^ this tree renders it unfit 

 for most of the uses for which timber is needed. As an article ^^ »* ' «* is scarcely inferior to 

 hi^Vnrv, and the wood is very durable. The fruit of the mezqui*^^- " ^^*^ greatest value to the 



< 



in these regions. It is a long bean-shaped pod, which " ^\ Uly devoured by cattle 



id to be highly nutritious. A gum exudes from tL: t r* which closely resembles 



' 'c in its chemical characters. The production of the ^^am ^'^ evidently increased by 



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