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* Leaves closely serrate with inflered teeth: scales entire: pods glabrous: stcrile catkins 
elongaled: rough trees. 
1. S. nigra Marsh. (BLACK WILLOW.) Leaves narrowly lanceolate, very long 
attenuate from near the roundish or acute base to the usually curved tip, becoming 
green and glabrous (except the petiole and midrib); stipules large, semicordate, 
pointed and persistent: fruiting aments (3 to 7.5 em, long) more or less dense: pods 
ovate-conical, short-pediceled.—On banks, bending over the water of most streams 
of western Texas. Var, Wricutu Anders., of the upper Rio Grande and westward, 
has shorter more densely flowered thicker aments, long-pediceled pods, and lanceo- 
late-linear leaves. 
2. S. amygdaloides Anders. Leaves lanceolate or ovate-lanceolate (5 to 10 em. 
long), attenuate-cuspidate, pale or glaucous beneath, on long slender petioles; 
stipules 1ainute, early deciduous: fertile aments becoming very loose in fruit from 
the lengthening of the slender pedicels.—Common on the Rio Grande, from El Paso 
to old Fort Quitman. . 
* * Leaves remotely denticulate with projecting teeth: stamens 2: pod glabrous or silky: 
shrubs. 
3. S. longifolia Muhl. Clumpy shrubs, rooting in alluvial deposits: leaves 
linear-lanceolate (7 to10 cm. long, 2 to 10 mm. broad), tapering at each end, nearly 
sessile, more or less silky when young, at length smooth and green on both sides: 
stipules small, lanceolate, deciduous: aments linear-cylindric, often clustered at 
the ends of the branchlets: pod short-pedicelled: stigma large, sessile.—Common 
along the water courses, from the Pecos to the lower Rio Grande and northward. 
Var. ARGYROPHYLLA Anders., of western Texas and northwestward, has leaves and 
pods clothed with a lustrous silky tomentum (8S. argyrophylla Nutt.) Var. EXIGUA 
Bebb, of western Texas and westward, has narrowly linear leaves 5 to 7.5 em. long 
and less than 2 mm. wide. (S. exigua Nutt.) 
4. S. taxifolia HBK. Shrub 15 to 18 dm, high, with short divaricate branches 
thickly set with numerous distichous yew-like leaves, which are 6 to 12 mm. long 
and 2 mm. wide, acute, obsoletely denticulate and silky-pubescent: aments oblong, 
densely flowered, terminating the branchlets, usually clustered; scales obovate, 
ciliate on the margins: pod sessile, ovate-conical: stigma bifid.— Extending from 
the west into western Texas. 
2. POPULUSL. (PoriarR. ASPEN.) 
Trees, with broad and more or less cordate or ovate-toothed leaves, 
scaly buds covered with resinous varnish, long drooping catkins: 
appearing before the leaves, flowering disk obliquely lengthened in 
front, 8 to 60 stamens with distinct filaments, 2 to4 elongated stigmas, 
and a 2 to 4-valved pod. 
* Styles 2, with 2 or & narrow or jiliform lobes: pod small, thin, oblong-conical, 2-valved : 
seeds very small: leaves ovate. 
1, P. tremuloides Michx. (AMERICAN ASPEN.) Small tree 6 to 15m. high, with 
smooth greenish-white bark: leaves roundish-cordate, with a sharp point and small 
somewhat regular teeth, smooth on both sides, with downy margins, on slender 
petioles (flattened laterally): scales cut into 3 or 4 deep linear divisions, fringed 
with long hairs: bracts silky: stamens 7 to 10.— Along water courses, throughout 
the State. 
