Salix humboldtiana |
Salix pulchra |
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Humboldt's willow |
diamond-leaf willow, tealeaf willow |
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Habit | Shrubs, 0.1–3(–4.5) m. Stems: branches yellow-brown or red-brown, not or weakly glaucous, (slightly or highly glossy), villous in patches to glabrescent; branchlets yellow-green or brownish, glabrous, puberulent, or densely villous, (buds caprea- or arctica-type). | |
Leaves | stipules (usually marcescent), foliaceous, (linear or lanceolate, 2–9.8–23 mm), apex acuminate; petiole convex to flat adaxially, 2.8–10(–15) mm, glabrous or puberulent adaxially; largest medial blade narrowly elliptic, elliptic, or obovate, 22–75 × 8–26 mm, 1.7–4.7 times as long as wide, base cuneate, margins flat to slightly revolute, entire, crenate, or serrulate, apex acuminate, acute, or convex, abaxial surface glaucous, glabrous or pubescent, midrib pilose, hairs (white, sometimes also ferruginous), straight, adaxial highly to slightly glossy, midrib glabrous or sparsely pubescent; proximal blade margins entire; juvenile blade green, glabrous or pubescent abaxially, hairs white, sometimes also ferruginous. |
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Staminate flowers | adaxial nectary narrowly oblong to oblong, 0.6–1 mm; filaments distinct or connate less than 1/2 their lengths, glabrous; anthers purple turning yellow, ellipsoid to shortly cylindrical, 0.4–0.8 mm. |
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Pistillate flowers | adaxial nectary narrowly oblong to oblong, 0.4–1.6 mm, longer than stipe; stipe 0.2–0.8 mm; ovary pyriform, long-silky, beak slightly bulged below styles; ovules 12–16 per ovary; styles 1–1.8 mm; stigmas slenderly cylindrical, 0.44–0.63–0.96 mm. |
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Capsules | 3.2–5.6 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 stout or subglobose, 21–53 × 12–19 mm, flowering branchlet 0–3 mm; pistillate densely flowered, slender to stout, 27–82 × 8–20 mm, flowering branchlet 0–3(–8) mm; floral bract brown or black, 1.6–2.8 mm, apex acute or rounded, abaxially hairy distally, hairs straight. |
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2n | = 76. |
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Salix humboldtiana |
Salix pulchra |
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Phenology | Flowering mid Apr-late Jul. | |
Habitat | Arctic boreal and subalpine thickets, stream and lake margins, tundra, black spruce-lichen woodlands, open white spruce-dwarf birch woodlands | |
Elevation | 0-2000 m (0-6600 ft) | |
Distribution |
Mexico to central Chile |
AK; BC; NT; NU; YT; Asia (Chukotka, Kamchatka, Lena-Kolyma, Okhotia, Russia [Anadyr], Siberia) |
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.) |
Plants with branchlets densely villous with white, gray, or, sometimes, ferruginous hairs have been named var. yukonensis. This hairy variant occurs scattered throughout populations in both North America and Russia and does not seem to warrant taxonomic recognition. The closely related Salix planifolia shows similar variation. Hybrids: Salix pulchra forms natural hybrids with S. planifolia and S. scouleriana. Salix pulchra × S. scouleriana is known from Alaska. It resembles S. pulchra in its long, linear stipules, general leaf shape, and relatively long styles; and S. scouleriana in its juvenile leaves with abundant ferruginous hairs, petioles densely villous to velvety, and relatively short stigmas. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 7, p. 34. | FNA vol. 7, p. 138. |
Parent taxa | Salicaceae > Salix > subg. Protitea > sect. Humboldtianae | Salicaceae > Salix > subg. Vetrix > sect. Phylicifoliae |
Sibling taxa | ||
Synonyms | S. divaricata subsp. pulchra, S. phylicifolia subsp. pulchra, S. phylicifolia var. subglauca, S. planifolia subsp. pulchra, S. planifolia var. yukonensis, S. pulchra var. yukonensis | |
Name authority | Willdenow | Chamisso: Linnaea 6: 543. (1831) |
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