Salix scouleriana |
Salix humilis |
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mountain willow, Scouler willow, Scouler's willow |
gray or small pussy or upland willow, prairie willow |
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Habit | Shrubs or trees, 1–10(–20) m. Stems: branches gray-brown, yellow-brown, or red-brown, not glaucous, glabrous or tomentose; branchlets yellow-green or yellow-brown, sparsely to densely villous, tomentose, or velvety. | Shrubs, 0.3–3 m, (forming clones by layering). | ||||
Stems | branches dark red-brown, not or weakly glaucous, tomentose to glabrescent; branchlets red-brown, yellow-brown, or greenish brown, moderately to very densely villous, tomentose, or velvety-tomentose to glabrescent. |
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Leaves | stipules absent, rudimentary, or foliaceous on early ones, foliaceous on late ones, (1–16 mm), apex acute or acuminate; petiole convex to flat adaxially, 2–13 mm, velvety or villous adaxially; largest medial blade usually oblanceolate, sometimes narrowly elliptic, elliptic or obovate, 29–100 × 9–37 mm, 1.7–3.9 times as long as wide, base cuneate or convex, margins strongly to slightly revolute or flat, entire, remotely serrate, crenate, or sinuate, (glands submarginal or epilaminal), apex acuminate, convex, or rounded, abaxial surface glaucous, sparsely to densely short- to long-silky or woolly, hairs (white, sometimes also ferruginous), wavy or straight, adaxial slightly glossy, pilose or moderately densely short-silky, midrib velutinous or villous, (hairs white, sometimes also ferruginous); proximal blade margins entire, serrulate, or crenulate; juvenile blade reddish or yellowish green, sparsely to densely villous, short- or long-silky abaxially, hairs white, sometimes also ferruginous. |
stipules absent or rudimentary on early ones, absent, rudimentary or foliaceous on late ones, apex acute; petiole convex to flat, or shallowly grooved adaxially, 0.5–7(–12) mm, velvety, pilose, or villous adaxially; largest medial blade (sometimes hemiamphistomatous), narrowly oblong, narrowly elliptic, elliptic, oblanceolate, obovate, or broadly obovate, (13–)20–90(–135) × 3–23(–35) mm, 2.3–9 times as long as wide, base cuneate or convex, margins revolute or flat, entire, crenate, or sinuate, (glands submarginal), apex acuminate or convex, abaxial surface glaucous, sparsely to densely tomentose or woolly, hairs erect or spreading, wavy, adaxial slightly or highly glossy, glabrous, pubescent, tomentose, or pilose; proximal blade margins entire or serrulate; juvenile blade green, densely tomentose to glabrescent abaxially, hairs white, sometimes also ferruginous. |
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Staminate flowers | adaxial nectary oblong or square, 0.4–0.9 mm; filaments distinct, glabrous or hairy on proximal 1/2; anthers purple turning yellow, ellipsoid to shortly cylindrical, 0.7–1.2 mm. |
adaxial nectary oblong or square, 0.2–0.7 mm; filaments distinct, glabrous or hairy basally; anthers purple turning yellow, ellipsoid or cylindrical, 0.4–0.6 mm. |
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Pistillate flowers | adaxial nectary oblong or square, 0.2–0.8 mm, shorter than stipe; stipe 0.8–2.3 mm; ovary pyriform or obclavate, densely long-silky, beak slightly bulged below styles; ovules 10–18 per ovary; styles 0.2–0.6 mm; stigmas slenderly cylindrical, 0.4–0.82–1.04 mm. |
adaxial nectary square, 0.4–0.8 mm, shorter than stipe; stipe 1–2.5 mm; ovary obclavate or pyriform, moderately densely to sparsely short-silky-villous (hairs refractive), beak slightly bulged below styles, (valves recurving in fruit); ovules 6–12 per ovary; styles (sometimes slightly distinct distally), 0.2–0.4 mm; stigmas slenderly to broadly cylindrical, 0.2–0.56 mm. |
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Capsules | 4.5–11 mm. |
5–12 mm. |
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Catkins | flowering before leaves emerge; staminate stout or subglobose, 18–40.5 × 8–22 mm, flowering branchlet 0–4 mm; pistillate very densely flowered, slender or stout, 18–60(–90 in fruit) × 10–22 mm, flowering branchlet 0–8 mm; floral bract brown, black, or bicolor, 1.5–4.5 mm, apex rounded or acute, abaxially hairy, hairs straight. |
flowering before leaves emerge; staminate 6.5–34 × 5–19 mm, flowering branchlet 0–1 mm; pistillate (and staminate) moderately to very densely flowered, stout, subglobose, or globose, 9–47(–55 in fruit) × 5.5–19 mm, flowering branchlet 0–4 mm; floral bract brown, black, or bicolor, 0.8–2 mm, apex rounded or acute, abaxially moderately densely hairy, hairs (white), straight or wavy. |
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2n | = 76. |
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Salix scouleriana |
Salix humilis |
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Phenology | Flowering late Feb-mid Jun. | |||||
Habitat | Dry conifer forests, mature woods on edges of streams and lakes, treed bogs, meadows, subalpine slopes, springs, pine barrens, openings in old burns, arroyos and disturbed sites, sandy, silty-clay, or gravelly, igneous substrates | |||||
Elevation | 0-3500 m (0-11500 ft) | |||||
Distribution |
AK; AZ; CA; CO; ID; MT; NM; NV; OR; SD; UT; WA; WY; AB; BC; MB; NT; SK; YT; Mexico (Chihuahua, Sonora)
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AL; AR; CT; DC; DE; FL; GA; IA; IL; IN; KS; KY; LA; MA; MD; ME; MI; MN; MO; MS; NC; ND; NE; NH; NJ; NY; OH; OK; PA; RI; SC; SD; TN; TX; VA; WI; WV; MB; NB; NS; ON; PE; QC
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Discussion | Western Salix scouleriana and eastern S. humilis are closely related and are sometimes difficult to separate. Although there is an apparent range disjunction between them in western Manitoba, it may be a collecting gap. In general, S. scouleriana differs from S. humilis in being a taller shrub, sometimes even tree-like, with broader leaves and longer catkins, floral bracts, stigmas, and styles, but these quantitative characteristics all overlap. The apparent difference in anther length (S. scouleriana 0.7–1.2 mm; S. humilis 0.4–0.6 mm) may be correlated with a difference in chromosome number. Salix scouleriana is tetraploid (Y. Suda and G. W. Argus 1968); S. humilis has been reported to be both diploid (Suda and Argus; L. Zsuffa and Y. Raj, unpubl.) and tetraploid (R. D. Dorn 1976). The latter count was from the same population as the one by Suda and Argus. Further chromosome counts are indicated. See 77. Salix hookeriana for comparative descriptions. Hybrids: Salix scouleriana forms natural hybrids with S. hookeriana, S. planifolia, and S. pulchra. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Varieties 2 (2 in the flora). Varieties humilis and tristis are almost sympatric. In Maine they occur in the same populations without evident intermediate forms, while in other places, e.g., Florida, Georgia, and Nebraska, they apparently intergrade. Usually, they are distinct in habit, leaf and catkin size, and, most conspicuously, the presence of foliaceous stipules in var. humilis and their absence in var. tristis. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Key |
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Source | FNA vol. 7, p. 131. | FNA vol. 7, p. 129. | ||||
Parent taxa | Salicaceae > Salix > subg. Vetrix > sect. Cinerella | Salicaceae > Salix > subg. Vetrix > sect. Cinerella | ||||
Sibling taxa | ||||||
Subordinate taxa | ||||||
Synonyms | S. scouleriana var. poikila | |||||
Name authority | Barratt ex Hooker: Fl. Bor.-Amer. 2: 145. (1838) | Marshall: Arbust. Amer., 140. (1785) | ||||
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