298 FORREST SHREVE 



After reaching the slopes of the mountain proper we find 

 a typical encinal 6 in which Quercus emoryi and Q. arizonica occur 

 along with the components of the scrub just mentioned. Com- 

 munities of this general composition occupy the south-facing 

 slopes up to 7000 feet, and a scrub of similar appearance clothes 

 the steepest slopes of southern outlook to elevations of slightly 

 more than 8000 feet. Cercocarpus and Robinia are among the 

 few shrubs that range throughout the vertical extension of the 

 encinal and its high-altitude analogue. Above 7000 feet this 

 shrubby vegetation is made up chiefly of Quercus reticulata, Q. 

 submollis, Q. hypoleuca and Ceanothus fendleri. At its highest 

 limit it is sometimes found to merge into young thickets of 

 Populus tremuloides. 



On the southwestern side of the Pinaleno Mountains the 

 vegetation is much more simple in its distributional features, 

 owing to the greater simplicity of the topography. The grass- 

 land of the Bonita valley becomes very open as it is followed up 

 the slopes immediately adjacent to the base of the mountain, 

 and Yucca radiosa is the most conspicuous of the woody plants, 

 with Opuntia spinosior and Prosopis playing a secondary role. 

 Open encinal covers the lowest slopes of the mountain, here 

 somewhat more than 5000 feet in elevation, and descends in 

 many places onto the gentle alluvial aprons over which the 

 principal streams find their way to the plain. The courses of 

 the largest streams, as those from Grant, Goudy and Jesus 

 canons, can be traced from a distance by their trees. These are 

 chiefly Quercus emoryi, Fraxinus velutina, Platanus occidentalis 

 and Juglans major. Near Fort Grant a running stream ten feet 

 wide may be found at all seasons of the year, shaded by its fring- 

 ing grove of trees. On following this stream down the very 

 gentle slope toward Bonita the amount of water is found to 

 become rapidly less and the riparian grove to become more and 

 more open. Within less than two miles from the mouth of the 

 canon the water has vanished and the dry streamway has 



6 Encinal is an open or closed community in which evergreen oaks are domi- 

 nant. From the Spanish encina, evergreen oak; encinal, evergreen oak forest. 

 (Pronounced with accent on the last syllable.) 



