San Bernardino District. 629 
assume a spreading habit!). Elsewhere Adenostoma fasciculatum, Prunus ilieifolia, the bushy 
Pentstemon antirrhinoides, Calochortus Plummerae and Yucca Whipplei abound. 
Chaparral Formation. Interior southern California is covered with shrubs 
and trees scattered in open order over plain, hillside and valley. In 
places (San Diego County) the chaparral consists of Ouercus Engelmannii which 
stretches in belts across the hills with Oxereus agrifolia in park-like growths. 
The brush or chaparral is continuous about the base of the San Gabriel 
Mountains forming thickets far denser and higher than on any area in the 
neighborhood of the San Bernardino and San Jacinto ranges. In such localities 
Arctostaphylos manzanita and Ceanothus divaricatus form an arborescent growth. 
The common height of the chaparral at middle elevations on the slopes varies 
from 3 to 4 feet. In the canyons ı2 or ı4 feet and above the 6,000 feet 
contour line two feet is a common height. Above the 6,000 foot contour the 
brush occurs as an undergrowth in the forest. 
There is a zonal arrangement of the various species of shrubs. The composition of the 
chaparral on the southern, eastern and western slopes of San Gabriel Mountains?) below the 
5,000 foot contour is: Adenostoma faseiculatum (65 per cent), Arctostaphylos manzanita 
(3 per cent), A. tomentosa, Baccharis viminea, Ceanothus cerassifolius (1 per cent), C. cuneatus, 
C. divaricatus (16 per cent), C. hirsutus, C. integerrimus, C. vestitus, Cercocarpus betulaefolius 
(5 per cent), C. ledifolius (1 per cent), Chrysoma pinifolia, Eriodietyon californicum, E. tomen- 
tosum, Fraxinus dipetala, Fremontia californica, Garrya Veatchü, Prunus ilieifolia, Quercus undulata, 
Rhamnus ilieifolia, R. rubra, Rhus diversiloba, R. trilobata, Ribes cereum, R. hesperium, Salix 
lasiandra, $. lasiolepis, Aplopappus interior and Styrax californica. 
The composition of the chaparral on the southern, eastern and western slopes of the San 
Gabriel Mountains above the 5,000 foot contour is Adenostoma fasciculatum (40 per cent), 
Arctostaphylos manzanita (6 per cent), A. patula (10 per cent), A. tomentosa, Artemisia tridentata, 
astanopsis chrysophylla, Ceanothus divaricatus (20 per cent), Cercocarpus betulaefolius, C. ledi- 
folius, Fremontia (Fremontodendron) californica, Prunus ilieifolia, Quercus undulata (15 per cent). 
The chaparral on the northern declivities is very thin and scattered. 
In the San Bernardino Mountains?) the height of the chaparral varies 
from 3 to ı0 feet. It covers all the arid and semiarid lands excepting the 
areas of the pihon pines. On the Mohave Desert side the brush is in open 
formation. The chaparral above 4,800 feet exists mostly as underbrush in the 
forest. The chaparral on the southern and western slopes resembles that of 
San Gabriel Mountains. 
The following species occur in the brush thickets of the San Bernardino range on the eastern 
slopes below the 5,000 foot eontour: Adenostoma faseieulatum (5 per cent), Aratoetapbyios glanca, 
A. tomentosa, Ceanothus cuneatus (2 per cent), C. divaricatus (5 per cent), C. piReRITEN, C. vestitus, 
Cereocarpus betulaefolius (8 per cent), C. ledifolius (10 per cent), Juniperus ealitorniea a ur cent), 
Quereus undulata (3 per cent) and agaves, cacti and yuccas (530 per cent). If a division be we 
on the eastern slope at the 3,500 foot contour, the composition of the chaparral would stand: 
1) Mc Kenney, R. E. B.: loc. eit, | 
2) LEIBERG, Yopi B.: The San Gabriel forest Reserve. 2oth Report U. S. Geologiecal Bumen 
1900, Part V: 455—473. 
3) GrinNELL, Josern: The Biota i 
1—170 (1908); Parısı, S. B.: Notes on the Flora of Palm Springs 
of San Bernardino Mountains. Univ. Calif. Publ. in Zool. V: 
Muhlenbergia IH: 121—128- 
Di 
