81 
tion of about 3000 feet, in the midst of large granite boulders, we found 
ourselves in an open stand of desert bushes, cacti of several types, and 
conspicuous blooming plants of Nolina bigelovii. Throughout the south- 
west the finest displays of cacti, and the richest vegetation and flora in 
general, are to be found in just such situations as this, rocky and shehtly 
above the general level of the desert valleys. Here at our camp were 
to be seen the columnar Echinocactus cylindraceus, often six feet in 
height, the much-branched Opuntia acanthocarpa, a similar form close- 
ly related to O. bernardina, the low, flat-jointed O. occidentalis (2), 
the tall O. chlorotica, low clusters of Echinocereus engelmannii, and a 
single species of Mamillaria. 
Down the long grade to Mountain Springs the cacti and Nolina 
continued to be the most conspicuous elements of the vegetation, to- 
gether with the white-leaved Encelia farinosa (incienso), Simmondsia 
californica, Hyptis emoryt, and the green-stemmed almost leafless Tham- 
nosma montanum. In the narrow canon below Mountain Springs we saw 
the first plants of Fouquieria splendens (ocotillo, or candle-tree), a bizarre 
desert plant which is often supposed to be a cacius merely because it is 
spiny. In the sandy bed of the cahon we now saw Chilopsis saligna 
(desert willow), Hymenoclea monogyra,—a fine-leaved composite,— and 
Dalea spinosa (smoke-tree), the most beautiful tree of the Colorado 
desert. On emerging from the canon onto the great fan of sandy 
alluvium which stretches down to the Imperial Valley, we found our- 
selves in an extremely open stand of Covillea and Fouquieria, with a 
poor display of cacti and an extremely scanty number of herbaceous 
plants——a few individuals of Eriogonuwm and the gray and prostrate 
Psathyrotes annua being the only frequent ones. 
We returned from the desert to our camping site, and on the fol- 
lowing morning had a short time in which to enjoy that locality again. 
The return to San Diego was made by a different route, through Buck- 
man Springs, Descanso and Alpine. This detour brought us to the edge 
of the pine forest, where Pinus ponderosa (yellow pine) and P. jeffreyi 
were seen growing together, accompanied by a very open stand of the 
chaparral shrubs. In this immediate region it is very difficult to dis- 
tinguish the yellow and Jeffrey pines, which appear to be much more 
distinct in the northern and central part of California. The one for- 
ester of our party gave an interesting demonstration of his ability to 
differentiate these pines by their manner of branching and by a differ- 
ence in the odor of their leaves, apparently due to the presence of a 
charactristic oleoresin in each of the species. Between Buckman Springs 
and Descanso we were treated to the sight of virgin mountain parks, 
gray with a uniform stand of sage-brush and surrounded by pines. This 
