BOTANICAL REPORT. 287 
_ moorish growths of ‘‘ wild sage” ae Sarcobatis, and Obione, or grease- 
F wood, well known to all Western explore 
_ The conditions essential for timber growths ., superficial moisture, and 
shelter from fierce winds, are here confined to the dope valleys and constant 
4 large water-courses, where cotton-wood an tain a variable ex- 
__ istence, occasionally occurring in extensive tracts sola ¢ the Arkansas and the 
ton Fork, while elsewhere the country presents a treeless and open 
i "The idea frequently suggested by those unacquainted with the true physical 
_ features of this section of country, of planting trees, and thus securing shelter 
and an increased precipitation of moisture, will by no means stand the test of a 
common-sense view, where the objects to be gained are precisely such as the 
4 pesntry does not naturally admit of; and furthermore, its perfect ton ne = 
q ng is so manifest, that any one view of its application to useful p 
prese 
= “meat in the form of summer rains and winter snows. ‘These memset 
give rise to perennial streams and springs, which send their watery tributes to 
the arid plains below, and maintain verdure in the lower yalleys, which are 
in nib peer eon s districts 
a sufficient elevation is attained to insure a constantly cool atmo- 
sphere, huhets abound, consisting mainly of evergreen pines, spruce, and fir, 
but also in << scattered growth of scrubby oak, maple, birch, cotton- 
wood, and willow The principal wears that penetrate this mountain district, 
rm, compri ; ral ‘ 
watered, an oonveanaily located for supplying adjoining mining 
With their lus agricultural products. Hence they represent the main 
Populous districte, which, combining all the agreeable accessories of & fine 
Salubrious climate, and anna for building and fu at - 
retain a permanent population devoted to the mixed pursuits of agriculture an: 
In the accompanying list of plants, those referred to as occurring in the 
“onl of the Huerfano and Sangre de © prone serye to represent the 
= vegetation of this peculiar m ountain 
7 In passing do rar valley of the Upper Rio gene we encounter 
Pea very distinct in its general features, Patio neluding an 
strange shrubbery, having a Mexican type. 
hemmed in along a great portion of its upper acon by dark, Se oa 
- basaltic tocks, flows in deep inaccessible cafons, which open out 
basins, 
