12 VEGETATION OF A DESERT MOUNTAIN RANGE. 
mmunities which may be seen in southern Texas and in California, as 
well as in similar cae in Arizona and New Mexico; the last is 
essentially like the great body of yellow pine forest which stretches 
from southern Jalisco to British Columbia, or like the fir and Douglas 
spruce forests of the Rocky Mountains. These three major regions 
FEET 
9,000 
8,000} 
7,000 
6,000 
5,000 
4,000 
3,000 
9,000/- + 4 
8,000; + 4 
7,0007 T 4 
6000}- + 4 
5,000}- + 7 
4,000}- + 4 
3,000 Paes T ike : 7 
Fouquieria splendens Dasylirion wheeleri 
9,000 / i = 
8,000 F + =] 
7,000F + “ 
6,000; + 7 
5,000- + =] 
4,000} + 4 
3,000F + 4 
Quercus emory! Quercus hypoleuca 
Fig. 1.—Diagram showing vertical distribution of Desert, Encinal, Pine 
Forest, and Fir Forest in relation to slope exposure, together with dia- 
grams showing effect of slope exposure on vertical distribution of Fou- 
quieria splendens, Dasylirion wheelert, Quercus emoryi, and Quercus 
hypoleuca. 
constitute the most natural and easily distinguished subdivisions of 
the vegetation, and depend for their distinctness on the radical dis- 
similarity of the dominant types of plants in each. They may best be 
designated by the simple terms Desert, Encinal,* and Forest. The 
* The Spanish word “‘encinal’’ signifies a grove or forest of evergreen oaks, being derived from 
encina, evergreen oak. The suitability of the word was suggested by Prof. J. W. Harshberger. 
