_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.
Although the vegetation of this area is scattered and sparse, presenting
a barren and sterile aspect, the area supports a rather high population
of rodents. The soil at the bases of many large box-thorn- and
creosote-bushes is perforated by burrow systems of _Dipodomys
panamintinus_ or _Dipodomys merriami_, and those burrows abandoned by
kangaroo rats are used as retreats by _Onychomys torridus_ and
_Peromyscus maniculatus_. The mammals of this association are all
characteristic of the fauna of the Mojave Desert, with the ranges of
such species as the coyote and jack rabbit extending well up the desert
slope of the mountains.
The mammals listed below were taken in 1948 in roughly 400 trap nights
in the Joshua belt, at an elevation of 3500 feet, one mile below the
mouth of Graham Canyon.