Salix humboldtiana |
Salix calcicola |
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Humboldt's willow |
limestone willow, woolly willow |
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Habit | Plants 0.05–1.3 m, (gnarled, sometimes forming clones by layering). | |||||
Stems | branches yellow-brown, gray-brown, orred-brown, not to weakly glaucous (dull or slightly glossy), villous to glabrescent; branchlets yellow-brown or red-brown, moderately densely to sparsely villous, (buds caprea- or arctica-type, scale inner membranaceous layer free, separating from outer layer in var. calcicola). |
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Leaves | stipules (sometimes marcescent), foliaceous, (1–6–14 mm, 1.1–2–4.4 times as long as wide, usually ovate, oval, or narrowly elliptic, flat when pressed), apex acute, convex, or rounded; petiole shallowly grooved, or convex to flat adaxially, 1.5–3.8–9 mm, villous or pilose adaxially; largest medial blade (sometimes hemiamphistomatous), narrowly to broadly elliptic or subcircular, 16–31.5–61 × 10–21.8–44 mm, 0.7–1.5–2.6 times as long as wide, base rounded or convex, sometimes cordate or cuneate, margins (sometimes purplish), flat, entire or serrulate, apex acuminate, acute, or rounded, abaxial surface glaucous, sparsely villous or pilose to glabrescent, hairs straight, adaxial dull or slightly glossy, sparsely villous or pilose; proximal blade margins entire; juvenile blade reddish or yellowish green, moderately densely villous abaxially, hairs white. |
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Staminate flowers | adaxial nectary oblong or narrowly oblong, 0.5–1.2 mm; filaments distinct, glabrous; anthers purple turning yellow, ellipsoid or shortly cylindrical, 0.5–0.7 mm. |
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Pistillate flowers | adaxial nectary oblong, 0.2–1.1 mm, longer than or equal to stipe (rarely shorter); stipe 0.2–1.2 mm; ovary pyriform or obclavate, beak gradually tapering to styles; ovules 13–20 per ovary; styles 0.9–3 mm; stigmas broadly cylindrical, 0.2–0.56 mm. |
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Capsules | 4–8 mm. |
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Salix | humboldtiana Willdenow: Humboldt willow is not known to occur in the flora area. |
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It | is characterized by: trees, 4–25 m; branches highly brittle at base, bud-scale margins distinct and overlapping adaxially; stipules on late leaves rudimentary or foliaceous; largest medial leaf blade usually linear, abaxial surface not glaucous, adaxial dull; pistillate bract deciduous after flowering; stamens 3–7; capsules with distinct, often raised, white veins.; it occurs throughout much of Mexico to central Chile. |
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Catkins | flowering before leaves emerge; staminate (no data on var. glandulosior) stout, 18–45 × 13–21 mm, flowering branchlet 0 mm; pistillate (no data on var. glandulosior except flowering branchlet length) densely flowered, stout, 32–75(–100 in fruit) × 12–25 mm, flowering branchlet 0–5 mm; floral bract brown or black, 1.2–3.2 mm, apex rounded or acute, abaxially hairy, hairs straight. |
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Salix humboldtiana |
Salix calcicola |
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Distribution |
Mexico to central Chile |
CO; AB; MB; NU; ON; QC |
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Discussion | Salix humboldtiana is closely related to S. nigra in its generally narrow leaf blades, which are not glaucous abaxially. The two differ in the following characters: S. humboldtiana has leaf blades linear to sometimes narrowly oblong (10–28.6 times as long as wide), ovaries usually ovoid to ellipsoid, ovary walls often stomatiferous and with raised, white veins, and capsule valves relatively thick, slightly recurved. S. nigra has leaf blades usually narrowly lanceolate (6–13 times as long as wide), ovaries pyriform to obclavate, ovary walls neither stomatiferous nor notably veined, and capsule valves relatively thin and strongly recurved. Both species occur in Chihuahua, Mexico. The report by R. I. Lonard et al. (1991) that specimens identified as Salix nigra from the lower Rio Grande, Texas, resemble S. humboldtiana in having strongly veined capsules suggests that S. humboldtiana, or intergrades with that species, may occur in Texas. Attempts to locate a voucher specimen were unsuccessful; because strongly veined capsules are diagnostic, further field study is indicated. An earlier name, Salix chilensis Molina, has been applied to this species; it does not seem to pertain to this taxon (C. K. Schneider 1918). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Varieties 2 (2 in the flora). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Key |
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Source | FNA vol. 7, p. 34. | FNA vol. 7, p. 143. | ||||
Parent taxa | Salicaceae > Salix > subg. Protitea > sect. Humboldtianae | Salicaceae > Salix > subg. Vetrix > sect. Lanatae | ||||
Sibling taxa | ||||||
Subordinate taxa | ||||||
Synonyms | S. richardsonii var. macouniana, S. lanata subsp. calcicola | |||||
Name authority | Willdenow | Fernald & Wiegand: Rhodora 13: 251. (1911) | ||||
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