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of the zone will be discussed, therefore, without an attempt to 
assign them to definite floral districts. 
Interior valleys —In the San Fernando, the San Bernardino, 
and the San. Jacinto Valleys, the fan-like footslopes that spread 
over the valleys from the bases of the steep mountain slopes, and 
the dry washes leading from the mouths of the canyons give rise 
on their semi-arid gravelly slopes to a low shrubby type of vege- 
tation resembling that of the desert in its xerophytic habit. The 
upper parts of the footslopes, as has been previously stated, are 
intermediate between the Upper and the Lower Sonoran, but the 
dry washes produce a typical Lower Sonoran flora, that often 
spreads over the greater part of the footslopes. 
Following is a list of characteristic Lower Sonoran trees and 
shrubs of the interior valleys: 
Salix vallicola 
Populus Fremontii 
*Strombicarpus pubescens 
*Prosopis glandulosa 
Opuntia bernardina 
Opuntia Covillei 
*Chilopsis linearis 
Gutierrezia divergens 
Ericameria pintfolia 
* Encelia farinosa 
Vigutera Parish 
Bebbia juncea 
Lepidospartum squamatum 
Tetradymia comosa 
The species designated by an asterisk (*) occur only in the 
eastern end of the San Bernardino Valley or in the San Jacinto 
Valley, and of these only Encelia farinosa is common. 
San Diego district—A large number of peninsular species of 
shrubs and herbaceous plants extend into southwestern San Diego 
County which give a floral aspect quite unlike that of other parts 
of the coastal slope. 
The following is a list of peninsular or desert species recorded 
from the vicinity of San Diego: 
Ephedra californica 
Yucca mohavensis 
Atriplex canescens 
Isomeris arborea 
Opuntia prolifera 
Opuntia californica 
Lycium Richit 
Lycium Andersonu Wrightir 
Prosopis velutina 
Cneoridium dumosum 
Acalypha californica 
Tricherostigma miserum 
Simmondsia californica 
Adolphia californica 
Lycium californicum 
Hymenoclea monogyra 
Gaertneria chenopodifolia 
Iva Hindsiana 
Viguiera laciniata 
