18-i TKEES OF NORTH AMERICA 



ovate or oblong, rounded at the apex, broader on the stanilnate than on the pistillate 

 plant, yellow below, rose color at the apex, villose, witli long pale silky hairs, per- 

 \ sistent under the fruit; staniinate cylindrical, obovate, narrowed at the base, densely 

 Howered, |'-1' long, ^-4' broad; i)i.stillate oblong-cylindrical, loosely flowered, about 

 1' long; stamens 2, with free glabrous filaments; ovary cylindrical, villous, with long 

 silky white hairs, gradually narrowed at the apex into broad sessile entire or emar- 

 ginate spreading yellow stigmas. Fruit elongated-cylindrical, gradually narrowed 

 into a long thin beak, and raised on a slender stalk sometimes ^' long. 



A bushy tree, occasionally 25 high, with a short trunk G'-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. "Winter-buds 

 oblong, gradually narrowed and rounded at the apex, full and rounded on the back, 

 bright light chestnut-brown, nearly 1' long. Bark thin, reddish or olive-green or 

 gray tinged with red, and slightly divided by shallow fissures into appressed plate- 

 like scales. 



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 inclin- 

 ing stems; common in all the northern states, ranging southward to Pennsylvania 

 and westward to Minnesota, through the Rocky Mountain region from western 

 Idaho and northern Montana to the Black Hills of Dakota and western Nebraska, 

 and southward through Colorado to northern Arizona; ascending as a low shrub in 

 Colorado to elevations of 10,000. 



17. Salix Nuttallii, Sarg. Black Willow. 



Leaves involute in the bud, oblong-obovate, gradually Jiarrowed and wedge- 

 shap'ed at the often unequal base, acute or abruptly acuminate, with short or long 

 points, or broad and rounded at the apex, entire or remotely and irregularly cre- 

 nately serrate, pilose above and coated below with pale pubescence or tomentum 

 when they unfold, at maturity thin and firm, dark yellow-green and lustrous above, 

 pale and glabrous or pilose below, l^'-4' long, ^'-1^' wide, with broad yellow pubescent 

 midribs and slender veins forked and arcuate within the slightly thickened and revo- 

 lute margins and connected by conspicuous reticulate veinlets, their petioles slender, 

 puberulous, \'-^' long; stipules foliaceous, semilunar, glandular-serrate, ^'-^ long, 

 caducous. Flovsrers: aments oblong-cylindrical, erect, nearly sessile, on short tomen- 

 tose branches, the staniinate about 1' long and rather more than ^' thick, the pistillate 

 1^' long, about |' thick, their scales oblong, narrowed at the ends, acute at the apex, 

 dark-colored, covered with long white hairs, persistent under the fruit; stamens 2, 

 with free glabrous filaments; ovary cylindrical, short-stalked, long-pointed, coated 

 with hoary pubescence, with broad nearly sessile emarginate stigmas. Fruit light 

 reddish brown, covered with pale pubescence, about |' long. 



A tree, occasionally 30 high, with a short trunk rarely exceeding 1 in diameter, 

 slender pendulous branches forming a rather compact round-topped shapely head, 

 and stout branchlets marked by scattered yellow lenticels, coated at first with pale 



