MAMMALS OF THE MEXICAN BOUNDARY. 49 



the Verde Valley showed any foliage by March 25 ; but on descend- 

 ing to Ash Creek. March 2(), we found a beautiful grove of cotton- 

 woods in full foliage; and March 27, on reaching New Kiver, 

 the foliage of the cottonwood here, and farther on along New 

 River near its junction with the Agua Fria, had assumed the dark, 

 rich tint of green, characteristic of the fully developed leaf. The 

 trees Avere feathery with '• cotton,'' which hung in festoons from the 

 drooi)ing branches. I gathered a quantity of it at Huston's Kanch 

 for stuffing and packing specimens. 



ALNUS OREGONA Nuttall. 

 RED ALDER. 



Small trees were found on the San Diego River in California. 

 Alders were not seen elsewhere on the Mexican Boundary, but on the 

 headwaters of the Verde River, in central Arizona, Alniis acuminata 

 grows commonly along streams, and has the proportions of a medium- 

 sized tree. 



QUERCUS GAMBELII Nuttall, 

 GAMBEL OAK. 



This is a deciduous white oak, growing only at or near the sum- 

 mits of the higher mountains. It occupies the Canadian or lowest 

 division of the Boreal Zone, and is often associated with the Mexican 

 white pine, Douglas spruce, and aspen. In good soil it reaches 

 a height of 20 to GO feet, with a trunk from 1 to 3 feet in diameter. 

 Some trees seen on the JNIogollon Mountains, Arizona, probably 

 exc(^eded these dimensions. At the base of San Francisco Mountain, 

 near Flagstaff, Arizona, in 1886 and 1887, I camped in a handsome 

 grove of these trees, Avhich had long ago excited the admiration of 

 the members of Captain Sitgreaves's party, but which was over- 

 looked by Dr. C. Hart Merriam, who observed : " 



There is something remarkable respecting the history of this tree in the San 

 Francisco Mountain region. Sitgreaves and other early explorers speak of it 

 as abundant about the mountain, while we did not find it at all in the very 

 places where it was formerly connnon. Its absence explains the absence of 

 several species of birds which might be expected at the mountain, but which 

 are rarely found except in oak scrub. 



On the higher peaks of the ]Mexican Boundaiy region this oak 

 usually becomes reduced to a scrubby bush from 2 to 4 feet in height; 

 but on the Animas Mountains, close to the summit of next to the 

 highest peak of the range, a tree was seen which was 2 feet in di- 

 ameter and 30 feet in height, with rough, whitish bark, resembling 

 that of the eastern Avhite oak {Quercus aWa). Large examples 



North American Fauna, No. .S, p. 119, September 11, 1890. 

 30G.S9— No. ,50—07 m i 



