622 SALICACE^E salix 



POPULUS 



of thie, it said to be nearly related to the preceding, differing in the narrow 

 oblanceolate leaves, few-flowered aments and much shorter capsule : it 

 grows on the high mountains of Washington to California, Utah and 

 Montana. 



S. saximontana Rydb. 1. c. 161. S. reticulata Bebb, not L. A dense- 

 ly cespitose and intricately branched shrub 1-3 inches long above ground, 

 with light yellow glabrous branches: leaves oblong or elliptic-oblong, com- 

 monly acutish at both ends, glabrous both sides, light green above, rather 

 strongly veined and glaucous beneath, 9-12 lines long; petioles about 6 

 lines long, aments 6-12 lines long, somewhat loosely many-flowered : bracts 

 cuneate oblong, truncate, light yellow, glabrous: capsule conical, sessile, 

 densely and finely white-tomentose: stigma nearly sessile. On high 

 mountains, eastern Oregon to the Rocky Mountains. 



S. vestita Pursh Fl. 610. A low shrub with 4-sided green twigs : leaves 

 obovate, thick, mostly retuse or emarginate at the apex slightly crenulate, 

 narrowed or rounded at base, dark green and glabrous above, persistently 

 silky beneath, 1-2 inches long, shortly petioled : aments terminal, ap- 

 pearing after the leaves, peduncled: stamens 2, : filaments distinct: capsule 

 narrowly ovoid-conic, sessile, densely eilky-tomentose, about 3 lines long. 

 Eastern Oregon to Quebec and Labrador. 



3 POPULUS L. Sp. 1034. 



Trees or shrubs with scaly resinous buds, broad or narrow 

 usually long-petioled leaves with minute fugacious stipules and 

 small dioecious flowers in bracted aments. Bracts of the aments 

 fimbriate or incised. Disk cup-shaped, oblique, lobed or entire. 

 Calyx none. Staminate aments dense, pendulous, the flowers, 

 with from 4-60 stamens, their filaments distinct. Pistillate a- 

 ments sometimes raceme-like by the elongation of the pedicels. 

 Ovary sessile. Style short. Stigmas 2-4, entire or 4-lobed. 

 Capsule 2-, 3- or 4-valved. 



P. alba L. Sp. 1034. A large tree with smooth light gray bark, 50-120 

 feet high and 2-6 feet in diameter : leaves broadly ovate or nearly orbicular 

 in outline, acute or somewhat acuminate, truncate or subcordate at base, 

 3-5-lobed or irregularly dentate, 2-4 inches broad, densely white-tomentose 

 when young, becoming glabrate and dark green above, persistently white- 

 tomentose beneath, on terete petioles shorter than the blade. Escaped 

 from cultivation in the Willamette valley. 



P. balsamifera L. Sp. 1034. A large tree 50-80 feet high and 3-7 feet 

 in diameter, the branches stout and spreading : leaves glabrous, broadly 

 ovate, dark green and shining above, pale beneath, acute or acuminate, 

 rounded or subcordate at base, crenulate, 3-5 inches long: petioles terete: 

 aments and bracts somewhat pubescent: stamens 18-30: lobes of the 

 stigma broad : capsule ovoid, 2-valved. In moist or dry soil, eastern 

 Oregon to Alaska, Hudson Bay and the Eastern States. 



P. ang'ustifolia James Long's Exp. i, 497. A slender tree 40-70 feet 

 high and 1-2 feet in diameter, the crown narrowly pyramidal with ascend- 

 ing branches and terete gray twigs : leaves glabrous, lanceolate, ovate-lan- 

 ceolate or ovate, gradually acuminate or acute, narrowed, rounded or 

 rarely subcordate at base 2-5 inches long, finely crenulate: petioles not 

 flattened laterally, 3-6 lines long: staminate aments oblong-cylindrical, 

 1-3 inches long : lobes of the stigma broad : capsules ovoid, 2-valved. Eas- 

 tern Oregon to Dakota and Arizona. 



P. trichocarpa T. & G. Hook. Incon. t. 878. A large tree 50-200 feet 



