BOTANICAL GEOGRAPHY 335 
The Pacific Slope is characterized by cone-bearing ever- 
greens in great abundance in the mountains and along the 
foothills. Chief among these in point of size are the red- 
woods and the “big trees” (Sequoias) (Fig. 32). Oaks 
are represented by a good many species, several of them 
evergreen. There are many xerophytes, some of them 
characteristic of alkali regions; and in Southern California, 
on account of the long dry season, plants with large roots 
or rootstocks and bulb-bearing plants (many of them 
belonging to the lily family) are abundant. The tree 
yucca (Plate VIJ) is one of the largest and most inter- 
esting xerophytic plants of North America. 
