SKETCHES OF THE COLORADO DESERT 123 



of the plants usually to be found in the canyons of these deserts, 

 as Nicotiana trigonophylla, Gilia latifolia, Oenothera cardiophylla, 

 Mohavea viscida and Cladothrix oblongifolia. Here, too, was As- 

 ter Orcuttii, a rare and beautiful species, bearing large lilac-col- 

 ored flowers. It is endemic in the mountains of the Colorado 

 desert, replacing the allied Aster tortifolius of the Mojave desert. 

 On the talus, fallen from a cliff, was an abundance of slender 

 H offmanseggia mici'ophylla, and over a bush clambered the rare 

 cucurbit, Braridegea par vi flora. A commoner member of the 

 same family, Cucurhita palmata, trailed its vines, well set with 

 golden, globular fruits, over the sandy floor of the canyon. . 



In these sands grew a few large shrubs, Hyptis Emoryi, Acacia 

 Greggii, Chilopsis linearis and Parosela spinosa, the last two some 

 times almost small trees. The leafless branches of the Parosela 

 were hidden (June 27) beneath the abundance of its beautiful 

 blue-purple flowers, while the Acacia was laden with ripe and 

 ripening pods. 



In the shelter of these cliffs Acacia Greggii is a several-stemmed 

 shrub, with virgate branches 6 to 8 feet long. Further west, be- 

 tween Whitewater and Banning, where it grows in the open, 

 wind-swept desert, it forms patches hardly exceeding 1 foot in 

 height, dense with short, rigid intertangled branches. In the 

 same region Lycium Andersonii var, Wrightii takes a like con- 

 densed and depressed form, while in a neighboring canyon it 

 has long, vu-gate stems. They exemplify the opposite effects of 

 exposm'e and shelter in modifying the forms of plants. Encelia 

 farinosa affords a further example of the same thing. In the 

 desert this grows in very compact rounded clumps, each of a 

 single individual, but in sheltered canyons near San Bernardino 

 it is a gregarious shrub, straggling in habit, and 3 or 4 feet high. 



My driver had promised to take me to the summit of the 

 divide, where we were to find a spring of pure water, beneath a 

 grove of noble palms. But when we had ascended the canyon 

 some 4 miles we entered, through a passage scant 12 feet wide, 

 a little amphitheater, whose upper end was barred by a ledge 

 of granite, worn to the smoothness of glass by a trickle of water, 

 which sank at once in the sand at its foot. Far up on the summit 



