Salix humboldtiana |
Salix nigra |
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Humboldt's willow |
black willow |
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Habit | Trees, 5–20+ m. Stems: branches highly brittle at base, red-brown to yellow-brown, glabrous; branchlets gray-brown to red-brown, glabrous or pilose to villous. | |
Leaves | stipules rudimentary or foliaceous on early ones, usually foliaceous on late ones, (glands few or absent adaxially), apex acuminate, acute, or rounded; petiole (margins covering groove, with spherical glands distally), (2–)3–10(–15) mm, glabrous or pilose adaxially; largest medial blade (sometimes amphistomatous), very narrowly elliptic, lanceolate to narrowly lanceolate, or linear to lorate, (50–)70–103(–190) × (6–)7.5–17(–23) mm, 6–13 times as long as wide, base cuneate to convex, margins serrulate, apex acuminate, acute, or caudate, abaxial surface (not glaucous), glabrous or pilose, hairs white or ferruginous, wavy, adaxial slightly glossy, glabrous or pilose (especially on midribs); proximal blade margins serrulate; juvenile blade glabrous or pilose abaxially, hairs white and/or ferruginous. |
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Staminate flowers | abaxial nectary 0.3–1 mm, adaxial nectary oblong to ovate, 0.2–0.6 mm, nectaries distinct or connate and shallowly cup-shaped; stamens 4–6; filaments hairy on proximal 1/2 or basally; anthers 0.4–0.6 mm, (axes strongly recurved). |
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Pistillate flowers | adaxial nectary oblong, (swollen), 0.2–0.5 mm; stipe 0.5–1.5 mm; ovary pyriform to obclavate, (rarely pilose), beak slightly bulged below styles; ovules 12–16 per ovary; styles 0.1–0.3 mm; stigmas (sometimes 2 plump lobes), 0.2–0.28–0.36 mm. |
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Capsules | 3–5 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 | staminate 35–83 × 7–13 mm, flowering branchlet 5–35 mm; pistillate 23–74(–80 in fruit) × 5–10 mm, flowering branchlet 6–35 mm; floral bract 1–3 mm, apex acute or rounded, entire, abaxially sparsely hairy, hairs wavy; pistillate bract deciduous after flowering. |
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2n | = 38. |
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Salix humboldtiana |
Salix nigra |
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Phenology | Flowering (south) early Feb-early May, (north) late Mar-early Jul. | |
Habitat | Floodplains, edges of ponds and lakes, swamps, marshes, white cedar bogs, wet meadows, open fields, roadside ditches, mixed upland deciduous woods along streams | |
Elevation | 10-1400 m (0-4600 ft) | |
Distribution |
Mexico to central Chile |
AL; AR; CT; DC; DE; FL; GA; IA; IL; IN; KS; KY; LA; MA; MD; ME; MI; MN; MO; MS; NC; NE; NH; NJ; NY; OH; OK; PA; RI; SC; TN; TX; VA; VT; WI; WV; NB; ON; QC; Mexico (Chihuahua)
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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.) |
Hybrids: Salix nigra forms natural hybrids with S. alba, S. amygdaloides, S. caroliniana, S. gooddingii, and S. lucida. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 7, p. 34. | FNA vol. 7, p. 36. |
Parent taxa | Salicaceae > Salix > subg. Protitea > sect. Humboldtianae | Salicaceae > Salix > subg. Protitea > sect. Humboldtianae |
Sibling taxa | ||
Synonyms | S. nigra var. falcata, S. nigra var. lindheimeri | |
Name authority | Willdenow | Marshall: Arbust. Amer., 139. (1785) |
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