Major Plants
Bromus sp.
Artemisia tridentata
Chrysothamnus nauseosus
Purshia glandulosa
This association is found on only the crest and desert slope of the range between 5000 and 8000 feet elevation. There it characteristically occupies flats and clearings in the yellow pine forest and pinyon-juniper woodland. The dominant plant of the association is basin sagebrush, and in many places this plant forms mixed growths with snowbrush and Haplopappus. The low brush of this association is formed by closely spaced bushes with grasses growing between.
Because of its limited occurrence in the San Gabriel Mountains, this association there has relatively little effect on mammalian distribution. Locally, nevertheless, the presence of this association governs the distribution of certain mammals. For example, on Blue Ridge, islands of sagebrush amid the conifers provide suitable habitat for Dipodomys agilis perplexus and Perognathus californicus bernardinus; and in Swarthout Valley D. a. perplexus, Reithrodontomys megalotis longicaudus, and Lepus californicus deserticola are seemingly restricted to the sagebrush flats.
Joshua Tree Woodland Association
Major Plants
Yucca brevifolia
Lycium Andersonii
Eriogonum fasciculatum
Tetradymia spinosa
Ephedra sp.
Larrea divaricata
This association is on the piedmont that dips toward the Mojave Desert from the interior base of the San Gabriels. The widely spaced Joshua trees with low bushes between, and the dry washes breaking the level terrain below the mouths of canyons are typical of this area. Field work was extended no farther down into the desert than about the 3500 foot level, where this association was still dominant.