268 Part III. Chapter 3. 
*Juniperus occidentalis Hook. | *+Prunus emarginata Walp. 
Populus tremuloides Michx. *+Acer glabrum Torr. 
*+Alnus tenuifolia Nutt. 
The continuation of the forest south of the Sierra Nevada isto 
be sought in the Sierra Madre Mountains in southern California. The distin- 
guishing feature of the natural vegetation of southern California is the pre- 
valence of shrubs’). Over three-fourths of the surface shrubs form the prin- 
cipal growth. Scattered in open order over desert, plain and valley as 
chaparral, it is seldom that shrubs give way to meadow and forest. At low 
altitudes the arboreal vegetation is mostly riparian. The streams are scantily 
fringed with alder, sycamore, cottonwood and a few species of willow. Atan 
altitude of 4000 and 5000 feet the coniferous forest begins. The San Gabriel | 
and San Bernardino mountains form together a portion of the Sierra Madre 
range. The general course of these mountains is from west to east. The 
general aspect of these mountains is extremely broken and rugged. The erest 
line of the main back bone of the range is moderately winding and from it 
steep declivities descend on the south flanks and north flanks, the latter bang 
more abrupt than the former. “ 
On San Jacinto and Grayback mountains is found an alpine Kor 
which lingers on these summits along the banks of perpetual snow in the cool 
shaded canyons which descend the north side at altitudes between 10,000 and 
10,800 feet. A single species Ranunculus Eschscholtzii has been found on er 
peaks, Arenaria hirta var. verna and Antennaria alpina have been collected 2 
on Grayback, while from San Jacinto, Carex Preslü, Oxyria dıgyna and the 
alpine forms of Spraguea umbellata and Aguilegia truncata’). = 
€ conspicuous vegetation of these mountains, which rise to above 
10,000 feet, is however, of twotypes. ı. A brush or chaparral growth, more 
or less mixed with an open, thin or aggregated stand of trees, or W I 
composed of shrubby plants except where broken by patches of naked rocks; “ 
2. a forest growth, which, while generally heavy enough to deserve the designatio! e 
of forest, is mostly of a thin stand, and composed of low, scraggy individuals s 
The chaparral of the San Jacinto range (which has its northern terminatiol 
at San Gorgonio Pass, a gap 4 to 5 miles wide separating the San 
Mountains from the San Bernardino range), is similar to that mentioned ab0°“ 
with the addition of Adenostoma sparsifolium (25 per cent), Encelta fi arinosh, 
Lycium Andersonü, Pentstemon antirrhinoides, Pluchea sertcea, Rhus oval, 
Ribes sanguineum, Simondsia californica. ur, 
The forest in the three mountain systems, San Gabriel, San Bet 
nardino and San Jacinto, is given in the following list. 
nt I a a PER 
ı) ParısH, S. B.: Distribution of Southern California Trees: Zoe. IV: 332. 
2) Harz, Harvey M.: A botanical Survey of San Jacinto Mountain. University © 
Publications, Botany 1: 1—140. June 7, 1902; Parish, S. B.: A Sketch of the Flora 0 
California. Botanical Gazette XXXVI: 214. 
f Califormia 
f sontbert 
