374 FOREST TREES OF THE PACIFIC SLOPE. 



OCCURRENCE. 



Desert hill slopes ; in gravelly and rocky dry soils. Scattered singly and in small 

 groups. 



Climatic Conditions. — Similar to those of leather-leaf ash (Fraxinus coriacea). 



Fig. 173. — Parkinsonia microphylla: a, seed. 



Tolerance. — Decidedly intolerant of shade. 



Reproduction and other silvical characteristics undetermined ; fairly abundant seeder. 



