622 SALICACEZ SALIX 
POPULUS 
of this, 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, somewbat 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 silky-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 diccious 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. apa 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. angustifolia 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 tcrete gray twigs: leaves glabrous, lanceolate, ovate-lan- 
ceolate or ovate, gradually acuminate or acute, narrowed, rounded or 
rarely subcordate at base 2-6 inches long, finely crenulate: petioles not 
flattened laterallv, 3-6 lines long: staminate aments oblong-cylindrical, 
1-3 inches long: lobes of the stigma broad: capsules ovoid, 2-valved LEas- 
tern Oregon to Dakota and Arizona. 
P. trichocarpa T. & G. Hook. Incon. t: 878. A large tree 50-200 feet 
