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Humboldt's willow

dark sandbar willow, dusky willow

Habit Shrubs, 0.8–4 m. Stems: branches gray-brown or red-brown, glabrous or hairy; branchlets gray-brown to dark red-brown, glabrous, puberulent, densely long-silky, or villous to glabrescent.
Leaves

stipules absent, rudimentary, or foliaceous on early ones, foliaceous on late ones (apex acuminate);

petiole 1.5–8 mm, glabrous adaxially;

largest medial blade lorate, narrowly oblong, narrowly elliptic, narrowly oblanceolate, or linear, 30–133 × 5–20 mm, 3.4–8–15 times as long as wide, base cuneate or convex, margins flat, spinulose-serrulate or entire, apex acute, acuminate, or convex, abaxial surface glaucous or not, pilose, villous, or long-silky to glabrescent, hairs appressed or spreading, wavy, adaxial slightly glossy, villous to glabrescent;

proximal blade margins entire or serrulate;

juvenile blade reddish or yellowish green, densely villous abaxially.

Staminate flowers

abaxial nectary 0.3–0.9 mm, adaxial nectary narrowly oblong, oblong, or flask-shaped, 0.4–1.2 mm, nectaries distinct;

filaments densely hairy on proximal 1/2;

anthers 0.55–0.7–0.9 mm.

Pistillate flowers

adaxial nectary ovate, oblong, or flask-shaped, 0.4–1.1 mm, longer than stipe, nectaries distinct or connate and cup-shaped;

stipe 0–0.7 mm;

ovary obclavate or pyriform, glabrous, beak abruptly tapering to styles;

ovules 13–22 per ovary;

styles 0–0.14–0.5 mm;

stigmas slenderly cylindrical or 2 plump lobes, 0.2–0.5 mm.

Capsules

4–5 mm.

Salix

humboldtiana Willdenow: Humboldt willow is not known to occur in the flora area.

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.

Catkins

staminate 18–48 × 5–13 mm, flowering branchlet 3–15 mm;

pistillate moderately densely flowered, slender or stout, 22–58 × 4–9 mm, flowering branchlet 4–12 mm;

floral bract (sometimes brown), 1.3–2.8 mm, apex rounded (sometimes truncate), entire or erose, abaxially hairy mainly proximally, hairs wavy.

Salix humboldtiana

Salix melanopsis

Phenology Flowering early May-mid Jul.
Habitat Riparian, floodplains, stream banks, subalpine meadows, coarse-textured substrates, silt
Elevation 600-3100 m (2000-10200 ft)
Distribution
from USDA
Mexico to central Chile
[BONAP county map]
from FNA
CA; CO; ID; MT; NV; OR; WA; WY; AB; BC
[WildflowerSearch map]
[BONAP county map]
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.)

Salix fluviatilis Nuttall, long used for a Columbia River endemic (see 22. S. columbiana), is a rejected name.

Hybrids:

Salix melanopsis forms natural hybrids with S. exigua var. exigua, S. sessilifolia, and S. sitchensis (R. D. Dorn 1998).

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Source FNA vol. 7, p. 34. FNA vol. 7, p. 58.
Parent taxa Salicaceae > Salix > subg. Protitea > sect. Humboldtianae Salicaceae > Salix > subg. Longifoliae
Sibling taxa
S. alaxensis, S. alba, S. amygdaloides, S. arbusculoides, S. arctica, S. arctophila, S. argyrocarpa, S. arizonica, S. athabascensis, S. atrocinerea, S. aurita, S. babylonica, S. ballii, S. barclayi, S. barrattiana, S. bebbiana, S. bonplandiana, S. boothii, S. brachycarpa, S. breweri, S. calcicola, S. candida, S. caprea, S. caroliniana, S. cascadensis, S. chamissonis, S. chlorolepis, S. cinerea, S. columbiana, S. commutata, S. cordata, S. daphnoides, S. delnortensis, S. discolor, S. drummondiana, S. eastwoodiae, S. elaeagnos, S. eriocephala, S. euxina, S. exigua, S. famelica, S. farriae, S. floridana, S. fuscescens, S. geyeriana, S. glauca, S. gooddingii, S. hastata, S. herbacea, S. hookeriana, S. humilis, S. interior, S. irrorata, S. jejuna, S. jepsonii, S. laevigata, S. lasiandra, S. lasiolepis, S. lemmonii, S. ligulifolia, S. lucida, S. lutea, S. maccalliana, S. melanopsis, S. monochroma, S. monticola, S. myricoides, S. myrsinifolia, S. myrtillifolia, S. nigra, S. niphoclada, S. nivalis, S. nummularia, S. orestera, S. ovalifolia, S. pedicellaris, S. pellita, S. pentandra, S. petiolaris, S. petrophila, S. phlebophylla, S. planifolia, S. polaris, S. prolixa, S. pseudomonticola, S. pseudomyrsinites, S. pulchra, S. purpurea, S. pyrifolia, S. raupii, S. reticulata, S. richardsonii, S. rotundifolia, S. scouleriana, S. sericea, S. serissima, S. sessilifolia, S. setchelliana, S. silicicola, S. sitchensis, S. sphenophylla, S. stolonifera, S. taxifolia, S. thurberi, S. tracyi, S. triandra, S. turnorii, S. tweedyi, S. tyrrellii, S. uva-ursi, S. vestita, S. viminalis, S. wolfii, S. ×fragilis, S. ×jesupii, S. ×pendulina, S. ×sepulcralis, S. ×smithiana
S. alaxensis, S. alba, S. amygdaloides, S. arbusculoides, S. arctica, S. arctophila, S. argyrocarpa, S. arizonica, S. athabascensis, S. atrocinerea, S. aurita, S. babylonica, S. ballii, S. barclayi, S. barrattiana, S. bebbiana, S. bonplandiana, S. boothii, S. brachycarpa, S. breweri, S. calcicola, S. candida, S. caprea, S. caroliniana, S. cascadensis, S. chamissonis, S. chlorolepis, S. cinerea, S. columbiana, S. commutata, S. cordata, S. daphnoides, S. delnortensis, S. discolor, S. drummondiana, S. eastwoodiae, S. elaeagnos, S. eriocephala, S. euxina, S. exigua, S. famelica, S. farriae, S. floridana, S. fuscescens, S. geyeriana, S. glauca, S. gooddingii, S. hastata, S. herbacea, S. hookeriana, S. humboldtiana, S. humilis, S. interior, S. irrorata, S. jejuna, S. jepsonii, S. laevigata, S. lasiandra, S. lasiolepis, S. lemmonii, S. ligulifolia, S. lucida, S. lutea, S. maccalliana, S. monochroma, S. monticola, S. myricoides, S. myrsinifolia, S. myrtillifolia, S. nigra, S. niphoclada, S. nivalis, S. nummularia, S. orestera, S. ovalifolia, S. pedicellaris, S. pellita, S. pentandra, S. petiolaris, S. petrophila, S. phlebophylla, S. planifolia, S. polaris, S. prolixa, S. pseudomonticola, S. pseudomyrsinites, S. pulchra, S. purpurea, S. pyrifolia, S. raupii, S. reticulata, S. richardsonii, S. rotundifolia, S. scouleriana, S. sericea, S. serissima, S. sessilifolia, S. setchelliana, S. silicicola, S. sitchensis, S. sphenophylla, S. stolonifera, S. taxifolia, S. thurberi, S. tracyi, S. triandra, S. turnorii, S. tweedyi, S. tyrrellii, S. uva-ursi, S. vestita, S. viminalis, S. wolfii, S. ×fragilis, S. ×jesupii, S. ×pendulina, S. ×sepulcralis, S. ×smithiana
Synonyms S. bolanderiana, S. exigua var. gracilipes, S. exigua subsp. melanopsis, S. exigua var. tenerrima, S. fluviatilis var. tenerrima, S. longifolia var. tenerrima, S. melanopsis var. bolanderiana, S. melanopsis var. gracilipes, S. melanopsis var. kronkheitii, S. melanopsis var. tenerrima, S. parksiana, S. sessilifolia var. vancouverensis, S. tenerrima
Name authority Willdenow Nuttall: N. Amer. Sylv. 1: 78, plate 21. (1842)
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