MAMMALS OF THE MEXICAN BOUNDARY. 45 



the photographer of the International Boundary Commission, ob- 

 tained an excellent photograph,- measured 2.34 meters in circumfer- 

 ence, and was estimated to be from 12 to 15 meters in height. This 

 tree was on the bank of the Santa Cruz River, a few miles above 

 Monument No. 118, at an altitude of about 1,300 meters (4,300 feet). 



On the San Jose Mountains the largest walnut tree seen was about 

 1.5 meters in circumference and 12 meters in height. This tree grew 

 beside a small spring at 2.210 meters (7,250 feet) altitude. At 2,240 

 meters (7,350 feet) there Avere several trees about a meter in circum- 

 ference and 10 meters in height. The highest one, a small tree, grew 

 at the altitude of 2,255 meters (7,400 feet). 



The lowest walnut tree in Turkev Canyon, on the west side of the 

 San Luis Mountains, is at 1.700 meters (5,575 feet). On the east side 

 of the San Luis Mountains, in the foothills near White Water, a tree 

 was found at 1,054 meters (5,425 feet). In the canyons of the Mule 

 Mountains, in Arizona, walnuts are numerous, extending downward 

 as far as Monument Xo. DO (altitude 1,390 meters, or 4,501 feet). 



HICORIA PECAN (Marshall) Britton. 

 PECAN. 



This, one of the largest, most beautiful, and most valuable trees in 

 western Texas, is found east of Devils River, on which stream it also 

 occurs. It is one of the most abundant trees along streams in the 

 vicinity of Fort Clark. Texas. 



SALIX NIGRA Marshall. 

 BLACK WILLOW. 



This is a connnon willow along streams everywhere in the South- 

 west, though it is least abundant in the California section of the 

 Boundary Line. I do not remember a stream of Xcav Mexico or Ari- 

 zona that lacks it. Its vertical range was not determined accurately, 

 owing to the difficulty of following up the streams, to which its 

 habitat is restricted. It was usually found as far up as there were 

 any fish. On the Pacific slope of the Coast Range it was collected 

 in the zone of Pinus saJnniana, at 4,300 feet (1,310 meters) altitude. 

 It is usually a small or medium-sized tree, with rough gray bark. 

 The largest ones seen were about .6 meter (2 feet) in diameter and 

 18 meters (60 feet) in height. 



SALIX OCCIDENTALIS LONGIPES (Andersson) Bebb. 

 LONGSTALK WILLOW. 



This is a small tree, from 20 to 40 feet (6 to 12 meters) in height, 

 found in wet soil in the mountains of the Elevated Central Tract. 

 On the Boundary it was common in all suitable places from the Dog 



