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 symmetrical head, and slender rigid branchlets coated at first with pale or fulvous tomentum, 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, 1/16′—⅛′ long, with thin light chestnut-brown scales. Bark ¾′—1¼′ 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 sapwood; sometimes used as fuel.
Distribution. Chisos Mountains, western Texas, southeastern New Mexico, southern Arizona, and southward into northern Mexico; comparatively rare in Texas; abundant on the foothills of the mountain ranges of southern New Mexico and Arizona at altitudes of about 5000°, and dotting the upper slopes of the mesa where narrow cañons open to the plain.
34. [Quercus Engelmannii] Greene. Evergreen Oak.
Leaves oblong to obovate, usually obtuse and rounded or sometimes acute at apex, gradually or abruptly cuneate or rounded or cordate at base, entire, often undulate, or sinuate-toothed with occasionally rigid teeth, or at the ends of sterile branches frequently coarsely crenately serrate with incurved teeth, or rarely lobed with acute oblique rounded lobes, when they unfold bright red and coated with thick pale rufous tomentum, at maturity thick, dark blue-green and glabrous or covered with fascicled hairs above, pale, usually yellow-green and clothed with light brown pubescence, or puberulous or often glabrous below, 1′—3′ long, ½′—2′ wide; deciduous in the spring with the appearance of the new leaves; petioles slender, tomentose, becoming pubescent, ¼′—½′ in length. Flowers: staminate in slender hairy aments 2′—3′ long; calyx light yellow, pilose, with lanceolate acute segments; pistillate on slender peduncles, clothed like their involucral scales with dense pale tomentum. Fruit sessile or on slender pubescent peduncles sometimes ¾′ long; nut oblong, gradually narrowed and acute or broad rounded and obtuse at apex, broad or narrow at base, dark chestnut-brown more or less conspicuously marked by darker longitudinal stripes, turning light chestnut-brown in drying, ¾′—1′ long, about ½′ thick, inclosed for about half its length in a deep saucer-shaped, cup-shaped or turbinate cup light brown and puberulous within, and covered by ovate light brown scales coated with pale tomentum, usually thickened, united and tuberculate at the base of the cup, and near its rim produced into small acute ciliate tips.
A tree, 50°—60° high, with a trunk 2°—3° in diameter, thick branches spreading nearly at right angles and forming a broad rather irregular head, and stout rigid branchlets coated at first with hoary tomentum, light or dark brown tinged with red and pubescent during their first winter, becoming glabrous and light brown or gray in their second or third year. Winter-buds oval or ovoid, about ⅛′ long, with thin light red pubescent scales. Bark 1½—2′ thick, light gray tinged with brown, deeply divided by narrow fissures and separating on the surface into small thin appressed scales. Wood very heavy, hard, strong, close-grained, brittle, dark brown or nearly black, with thick lighter brown sapwood; used only for fuel.
Distribution. Low hills of southwestern California west of the coast range, occupying with Quercus agrifolia Née, a belt about fifty miles wide, and extending to within fifteen or twenty miles of the coast, from the neighborhood of Sierra Madre and San Gabriel, Los Angeles County, to the mesa east of San Diego; in northern Lower California.
35. [Quercus Douglasii] Hook. & Arn. Blue Oak. Mountain White Oak.
Leaves oblong, acute or rounded at apex, gradually narrowed and cuneate or broad and rounded or subcordate at base, divided by deep or shallow, wide or narrow sinuses acute or rounded in the bottom into 4 or 5 broad or narrow acute or rounded often mucronate lobes, 2′—5′ long, 1′—1¾′ wide, or oval, oblong or obovate, rounded or acute at apex, equally or unequally cuneate or rounded at base, regularly or irregularly sinuate-toothed with rounded acute rigid spinescent teeth, or denticulate toward the apex, 1′—2′ long, ¼′—1′ wide, when they unfold covered by soft pale pubescence, at maturity thin, firm and rather rigid, pale blue, with scattered fascicled hairs above, often yellow-green and covered by short pubescence below, with a hirsute or puberulous prominent midrib and more or less conspicuous reticulate veinlets; petioles stout, tomentose, ¼′—½′ in length. Flowers: staminate in hairy aments 1½′—2′ long; calyx yellow-green, coated on the outer surface with pale hairs, deeply divided into broad acute laciniately cut segments; pistillate in short few-flowered spikes coated like the involucral scales with hoary tomentum. Fruit sessile or short-stalked, solitary or in pairs; nut ellipsoidal, sometimes ventricose, with a narrow base, gradually narrowed and acute at apex, ¾′—1′ long, ½′—1′ thick, or often ovoid and acute, green and lustrous, turning dark chestnut-brown in drying, with a narrow ring of hoary pubescence at apex, inclosed only at base in a thin shallow cup-shaped cup light green and pubescent on the inner surface, covered on the outer by small acute and usually thin or sometimes, especially in the south, thicker tumid scales coated with pale pubescence or tomentum and ending in thin reddish brown tips.