180 



TREES OF NORTH AMERICA 



below, persistent. Flowers: aments erect, cylindrical, slightly flexuose, densely 

 flowered, nearly sessile, on short tomentose brauchlets, !' long, the staminate ' thick, 

 and nearly twice as thick as the pistillate; their scales oblong-obovate, rounded or 

 acute at the apex, dark-colored, clothed with long crisp white hairs, persistent under 

 the fruit; stamens 2, with elongated glabrous filaments more or less united below 

 the middle; ovary narrow, cylindrical, acute and long-pointed, dark green, glabrous, 

 with a short style and broad nearly sessile stigmas. Fruit oblong, cylindrical, light 

 reddish brown, about \' long. 



A tree, 20-30, or occasionally 50 high, with a trunk 12'-18' in diameter, slender 

 erect branches forming a loose open head, and stout branchlets coated at first with 

 hoary tomentum, bright yellow or dark reddish brown and puberulous or pubescent 

 during their first year, becoming darker and glabrous in their second season; or often 

 at the north and at high elevations a low shrub. Winter-buds ovate, acute, com- 

 pressed, contracted laterally into thin wing-like margins, light brownish yellow, 

 glabrous or puberulous. Bark on young stems and on the branches thin, smooth, 

 light gray-brown, becoming on old trunks dark, about ^' thick, roughened by small 

 lenticels and broken into broad flat irregularly connected ridges. Wood light, soft, 

 close-grained, light brown, with thick nearly white sapwood; in southern California 

 often used as fuel. 



Distribution. Banks of streams in low moist ground; valley of the Klamath 

 River southward through western California to Lower California, and on the moun- 

 tains of southern Arizona; one of the commonest and most variable of the California 

 Willows, growing at the south at low altitudes as a large tree; on the western slopes 

 of the Sierra Nevada and in Arizona reduced to a many-stemmed shrub. 



13. Salix cordata, var. Mackenzieana, Hook. Willow. 



Leaves involute in the bud, lanceolate to oblanceolate, gradually narrowed or 

 wedge-shaped or rounded at the base, long-pointed, occasionally slightly falcate 



above the middle, finely and obscurely crenately serrate or entire, reddish and 

 pilose with caducous pale hairs when they unfold, at maturity thin and firm in 

 texture, dark green above, pale below, 2'-3' long, about ' wide, with slender yellow 

 midribs, arcuate veins, and obscure reticulate veinlets; their petioles thin, yellow, 



