A bushy tree, occasionally 25° high, with a short trunk 6′—8′ in diameter, stout ascending branches forming a broad round head, and slender branchlets coated at first with hoary deciduous tomentum, varying during their first winter from reddish purple to dark orange-brown, marked by scattered raised lenticels and roughened by conspicuous elevated leaf-scars, growing lighter-colored and reddish brown in their second year; usually much smaller and often shrubby in habit. Bark thin, reddish or olive-green or gray tinged with red, and slightly divided by shallow fissures into appressed plate-like scales. Winter-buds oblong, gradually narrowed and rounded at apex, full and rounded on the back, bright light chestnut-brown, nearly ¼′ long.
Distribution. Borders of streams, swamps, and lakes, hillsides, open woods and forest margins, usually in moist rich soil; valley of the St. Lawrence River to the shores of Hudson’s Bay, the valley of the Mackenzie River within the Arctic Circle, Cook Inlet, Alaska, and the coast ranges of British Columbia, forming in the region west of Hudson’s Bay almost impenetrable thickets, with twisted and often inclining stems; common in all the northern states, ranging southward to Pennsylvania and westward to Minnesota and through the Rocky Mountain region from western Idaho and northern Montana to northern North Dakota, eastern South Dakota, northeastern and central Iowa, and western Nebraska, and southward through Colorado to northern Arizona; ascending as a low shrub in Colorado to an altitude of 10,000°.
21. [Salix discolor] Muehl. Glaucous Willow.
Leaves lanceolate to elliptic, gradually narrowed at the ends, remotely crenulate-serrate, as they unfold thin, light green often tinged with red, pubescent above and coated with a pale tomentum below, at maturity thick and firm, glabrous, conspicuously reticulate-venulose, bright green above, glaucous or silvery white below, 3′—5′ long, ¾′—1½′ wide, with a broad yellow midrib and slender arcuate primary veins; petioles slender, ½′—1′ long; stipules foliaceous, semilunar, acute, glandular-dentate, about ¼′ long, deciduous. Flowers: aments appearing late in winter or in very early spring, erect, terminal on short scale-bearing branchlets coated with thick white tomentum, oblong-cylindric, about 1′ long and ⅔′ thick, the staminate soft and silky before the flowers open and densely flowered; scales oblong-obovate, dark reddish brown toward the apex, covered on the back with long silky silvery white hairs; stamens 2, with elongated glabrous filaments; ovary oblong-cylindric, narrowed above the middle, villose, with a short distinct style and broad spreading entire stigmas; pedicel glabrous, about twice the length of the scale. Fruit cylindric, more or less contracted above the middle, long-pointed, light brown, coated with pale pubescence.
A tree, rarely more than 25° high, with a trunk about 1° in diameter, stout ascending branches forming an open round-topped head, and stout branchlets marked by occasional orange-colored lenticels, dark reddish purple and coated at first with pale deciduous pubescence; more often shrubby, with numerous tall straggling stems. Winter-buds semiterete, flattened and acute at the apex, about ⅜′ long, dark reddish purple and lustrous. Bark ¼′ thick, light brown tinged with red, and divided by shallow fissures into thin plate-like oblong scales. Wood light, soft, close-grained, brown streaked with red, with lighter brown sapwood.
Distribution. Moist meadows and the banks of streams and lakes; Nova Scotia to Manitoba, and southward to Delaware, southern Indiana and Illinois, eastern and southwestern Iowa, the Black Hills of South Dakota, and northeastern Missouri; common.
A form of Salix discolor with more densely flowered and more silvery pubescent aments is described as var. eriocephala Schn. and a form with loosely flowered aments with less tomentose fruits with longer styles and with narrower leaves as var. prinoides Schn.
22. [Salix Scouleriana] Barr. Black Willow.
Salix Nuttallii Sarg.