MAMMALS OF THE MEXICAN BOUNDARY. 53 



2,133 meters (7,000 feet) this oak was reduced to a shrub, having 

 spiny angled instead of mostly entire leaves. 



On the San Luis Mountains this tree was not met with on the main 

 ridge north of Turkey Canyon below the altitude of 2,240 meters 

 (7,340 feet), and only spiny-leaved shrubs were seen; but in Turkey 

 Canyon trees were found as low as 2,133 meters (7,000 feet), having 

 mostly entire leaves and ranging from 6 to 9 meters (20 to 30 feet) in 

 height. The bark is usually rather smooth and blackish gray. The 

 acorn cups are very characteristic. 



In the Canelo Hills, between the Huachuca Mountains and the 

 Santa Cruz River, two handsome trees were seen. It was also found 

 on the highest peaks of the Coast Range Mountains, in California. 



QUERCUS AGRIFOLIA Nee. 

 CALIFORNIA LIVE OAK. 



A tall, handsome tree, bearing boat-shaped evergreen leaves. It 

 is the common oak tree of the low valleys of the Pacific Coast Tract. 

 We did not observe it on the east slope of the Coast Range Moun- 

 tains, though it appeared as soon as the divide was crossed, in the 

 vicinity of Jacumba Hot Springs. It again disappeared in the low 

 country bordering the Pacific Ocean, where it is replaced by the 

 scrub oak {Quercus dumosa). In San Diego County, California, 

 this tree sometimes reaches the height of 23 to 30 meters (75 to 100 

 feet), with the trunk 0.5 to 1.5 meters (2 to 5 feet) in diameter. 

 (Plate VII, fig. 1.) 



QUERCUS HYPOLEUCA Engelmann. 

 WHITELEAF OAK, 



A handsome evergreen oak, with medium-sized leathery leaves 

 covered on the under surface with whitish tomentum. It is usually 

 a small or medium-sized tree, but near the lower spring in Turkey 

 Canyon of the San Luis Mountain are several trees that reach nearly 

 30 meters (100 feet) in height, with straight trunks 1 meter (about 3 

 feet) in diameter. At the highest spring on the north side of the 

 San Jose Mountains at 2,297 meters (7,250 feet) altitude is a white- 

 leaf oak measuring 23 meters (75 feet) in height by 0.67 meter 

 (2 feet) in diameter. (Plate VII, fig. 2.) 



The extreme vertical range of this oak is from 1,775 meters or 

 5,825 feet (Turkej^ Canyon, San Luis Mountains, Chihuahua) to 

 2,877 meters or 9,440 feet (summit of Animas Peak, New Mexico). 

 As in the case of other species of oak, it becomes a shrub on the 

 mountain summits. On the east side of the San Luis Mountains the 

 lowest were noted at 1,865 meters (6,120 feet) ; on the west side at 

 1,775 meters (5,825 feet). In Millers Canyon of the Huachuca 



