280 



TREES OF NORTH AMERICA 



thin cup yellow-green and pubescent on the inner surface and covered by ovate- 

 oblong scales slightly thickened on the back, coated with hoary tonientum and ending 

 in thin acute bright red tips ciliate on the margins and sometimes forming a minute 

 fringe to the rim of the cup. 



A tree, rarely more than 30 high, with a short trunk 18'-20' in diameter, many 

 stout spreading often contorted branches forming a handsome round-topped symmet- 

 rical head, slender rigid branchlets coated at first with pale or fulvous tomentum. 



N. 22J 



light red-brown, dark brown or dark orange color in their first winter, becoming 

 ashy gray in their second or third year. "Winter-buds subglobose, obtuse, y&'-\' 

 long, with thin light chestnut-brown scales. Bark f '-1^' thick, ashy gray, and broken 

 into small nearly square or oblong close plate-like scales. Wood very heavy, hard, 

 strong, brittle, dark brown or nearly black, with thick brown sap wood; sometimes 

 used as fuel. 



Distribution. Chisos Mountains, western Texas, through southern New Mexico 

 and Arizona, and southward into northern Mexico; comparatively rare in Texas; 

 abundant on the foothills of all the mountain ranges of New Mexico and Arizona 

 south of the Colorado plateau at elevations of about 5000, and dotting the upper 

 slopes of the mesa where narrow cailons open to the plain. 



42. Quercus Arizonica, Sarg. White Oak. 



Leaves oblong-lanceolate to broadly obovate, generally acute or sometimes 

 rounded at the apex, rounded or cordate at the base, repandly spinose-dentate usu- 

 ally, except on vigorous shoots, only above the middle or toward the apex, or entire, 

 and sometimes undulate on the margins, when they unfold light red clothed with 

 bright fulvous tomentum and furnished with dark dental glands, at maturity thick, 

 firm and rigid, dark blue-green and glabrous or stellate pubescent above, yellow- 

 green or pale blue and covered with thick fulvous or pale pubescence below, l'-4' 

 long, y-2' broad, with broad yellow midribs, slender primary veins, arcuate and 

 united near the thickened revolute margins, and coarsely reticulate veinlets, falling 

 in the early spring just before the appearance of the new leaves; their petioles 

 stout, tomentose, \'-^' long. Flowers: staminate in tomentose aments 2'-3' long; 

 calyx pale yellow, pubescent, and divided into 4-7 broad acute ciliate lobes; anthers 



