THE FLORA OF SOUTHWESTERN COLORADO. 



BY T. S. BRAXDEGEE. 



Attached to the division of the San Juan as assistant topographer, as 

 much time as possible was given to the botany of the country through 

 which our work obliged us to pass. Under such circumstances, it was 

 impossible to make a complete botanical collection of the district given 

 to our division ; therefore no plants were gathered excepting such as 

 seemed to be additions to the flora of Colorado, as published by the Survey 

 in Miscellaneous Publications, Xo. 4. The collections and notes were 

 almost all made while riding from one topographical station to another. 



Early in June we left Pueblo for Southwestern Colorado, via the Mosca 

 Pass, over the Sangre de Cristo. The country was alive with innumer- 

 able grasshoppers, busy eating every green thing excepting the leaves 

 of Juniperus occidentaUs and the cactus-plants. Opuntia Missouriensis 

 was in full bloom, and early in the morning, before the grasshoppers 

 had breakfasted upon the newly-opened flowers, presented a magnificent 

 sight. We rode over mile after mile of the Saint Charles and Huerfano 

 Plains, now covered /with the red or yellow flowers of Opuntia Missouri- 

 ensis. The mesas, variegated with the different-colored patches of this 

 cactus, presented a striking contrast to their generally dry, barren ap- 

 pearance. 



The thickets of Slicplierdia, aryentea on the banks of the Huerfano 

 and its tributary streams, and the abundance of-Abronia fragrans upon 

 the mesas, at once attract the attention of any one familiar with the 

 flora of Northern Colorado. Up the eastern slope of the Sangre de 

 Cristo we meet with Abies Douylasii, and at the very summit of the 

 pass find a long-leaved tree of Abies concolor. Pinus flexilis, scattered 

 here and there by its twisted branches, bears witness to the prevalent 

 direction of the winds. Some fine old trees of Abies concolor grow along 

 the little stream which runs down the pass, and near the base of the 

 mountain descend into the habitat of Pinus edulis. A camp at the foot 

 of the pass close to the dunes affords an opportunity for examining the 

 vegetation about those mountains of drifting sand. Nothing, not even 

 a blade of grass, grows upon them ; but along their base some Triticum 

 repens, Thermopsis, Astragalus pictus, Psoralea, have a foothold. The 

 willows continue along the creek until they are almost buried by the 

 sand which has collected about them. 



From here to the Rio Grande, the dry level country is very uninteresting 

 botauically. With the exception of the banks and alkaline flats of the 

 lakes, for thirty or forty miles we pass through a Liliputian forest of 

 Bigeloi'ia, Sarcolatus, and Atriplex. Beds of Heliotropium Curassai'icum, 

 with their pretty white flowers now in full bloom, are scattered over the 

 alkaline flats about the lakes. The sandy beaches of the lakes are the 

 favorite habitat of Nasturtium sinuatum. In September, the banks of 

 the streams were yellow with Bidens clirysantliemoides, and upon the 

 surrounding plains Cleome Sonorce, with Aplopappus lanceolatus, grew in 



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