BOTANY. 15 
mules, horses, and cattle, preparatory to crossing the desert of a part of the Salt Lake valley ; 
before the California gold excitement, animals were sent from the valley of Los Angeles, and its 
vicinity, to Santa Fé, with profitable returns. Large herds were annually brought out to this 
place and grazed for that purpose. Since the revolution, stock of all kinds is in great demand, 
at very high rates, in California ; and New Mexico, in her turn, now sends out large flocks of 
sheep, to supply, in part, those demands. Sometimes they are sent by the way of Salt Lake 
valley, and from thence, up this valley, to California. After crossing the desert of Salt Lake 
valley, they are generally permitted to stop here, and at the Cajon to recruit, so as to render 
them saleable on arriving at the settlements of California. At other times they are sent by the 
way of the valley of the Gila, and thence across the desert to San Diego. Our route is much 
more direct than either of the others, and better, too, if we may judge from our own explorations 
and the accounts of travellers. The enterprising Captain Aubrey would have taken his sheep 
over this route the present season, but for the hostility of the Mojave and other tribes of 
Indians who infest this region. 
The stream of the Mojave is not continuous, but sinks and rises every few miles, after the 
manner of Bill Williams' fork, and the Rio Mimbres, in New Mexico. In some places the 
stream is large and bold, running with a swift current, like the Mimbres. The soil in the 
widened valleys is rich, and appears to be capable of cultivatior without irrigation. In such 
case it will make a valuable territory, well suited to settlements and military posts. 
The timber of the valley is much like that of the Colorado, consisting of cotton-wood, (Populus 
monilifera,) mezquite, (Algarobia glandulosa,) curly mezquite, (Strombocarpa pubescens,) and 
willow, (Salix,) of several species. On arriving at the Cajon Pass, two kinds of cedars occur ; 
pines, three or four kinds—Oregon pine, ( Pinus Douglassit,) piñon, or nut pine, (P. monophylla, 
Torr.;) and on the neighboring mountains, the sugar pine, (P. Lambertiana,) and one other 
species, somewhat resembling, but different from, the New Mexican yellow pine. All of these 
occur in great abundance, and of the best quality. Immediately on passing the crest of the 
Cajon, the vegetation changes like magic. Many of the shrubs being such as we had never 
before seen, the mountains and hills were covered and green with their perennial foliage. 
Among the most beautiful we found several species of Ceonothus, (represented at home chiefly 
by the New Jersey tea,) ornamented with bright, cerulean blue flowers, in charming contrast 
with the leafless waste that we had just left. We collected at this place specimens of the new 
remarkable genus Fremontia, which is described and figured in Plante Fremontiane, (p. 6, pl. 2: 
1850,) by Dr. Porrey. The whole tree has very much the habit of Hibiscus syriacus, or common 
Althea shrub ? but, according to Dr. Torrey, it belongs to the family of Bombaceæ, and is very 
closely allied to the celebrated hand-tree of Mexico, (Cheirostemon of Humboldt.) A species of 
Yucca, different from the five or six other Texan and New Mexican species that we had seen 
before, was collected at this place. A beautiful evergreen oak, with very large cups and acorns, 
was first found at this pass. Not having proper books of reference at hand, it is impossible at 
this time to determine the species. But the acorn is the one on which the Digger Indians, of 
California, are known to subsist for a great portion of the year. When standing in an open 
space, it forms one of the most beautiful and graceful trees of the forest. 
The Cactus tribe in this valley is not so plentiful in species or numbers as in some of the 
regions just described ; yet we found an Echinocactus here that had not been seen before. Tt 
may be the E. viridescens, Nutt. Var? cylindraceus, collected by Dr. Parry “near San Felipe, 
on the eastern slope of the California mountains ;" but in the absence of the fruit, or flower, or 
even a good description of the original plant itself, it is impossible to decide with certainty. 
Dr. Engelmann's Mamillaria tetrancistra, collected by Dr. Parry on the desert between San 
Diego and the junction of the Gila with the Colorado, was collected here, as also on Bill 
Williams’ fork ; but the long, hooked central spines vary from one to four in number. 
SECTION XI. Los Angeles Valley.—From Cajon Pass to the sea, at San Pedro, is a distance of 
about eighty miles through a beautiful valley, requiring very little description, in consequence 
