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Humboldt's willow

Pacific willow, shining willow

Habit Shrubs or trees, 1–9(–11) m. Stems: branches flexible to highly brittle at base, yellow-brown, gray-brown, or red-brown, slightly to highly glossy, glabrous or pilose to glabrescent; branchlets yellow-brown, gray-brown, or red-brown, glabrous, pilose, villous, or velvety, hairs spreading, straight, wavy, or crinkled, (inner membranaceous bud-scale layer free and separating from outer layer).
Leaves

stipules usually foliaceous, apex convex or rounded;

petiole deeply grooved adaxially, (1–)4–30 mm, with pairs or clusters of spherical or foliaceous glands distally, glabrous or pilose adaxially;

largest medial blade hypostomatous, hemiamphistomatous, or amphistomatous, narrowly oblong, very narrowly to narrowly elliptic, narrowly lanceolate to lanceolate, or oblanceolate, 53–170 × 9–31 mm, 3.1–9.8 times as long as wide, base convex or rounded, margins flat, serrulate, apex caudate to acuminate, abaxial surface glaucous or not, glabrescent or pilose, hairs white, sometimes also ferruginous, straight, wavy, or curved, adaxial slightly or highly glossy, glabrous, pilose, or long-silky, hairs white and ferruginous;

proximal blade margins entire and glandular-dotted or shallowly serrulate;

juvenile blade reddish or yellowish green, moderately to very densely villous, long-silky, or glabrous abaxially, hairs white and ferruginous.

Staminate flowers

abaxial nectary (usually present), (0–)0.4–0.8 mm, adaxial nectary square or ovate, 0.2–0.6 mm, nectaries distinct or connate and shallowly cup-shaped;

stamens 3–6;

filaments distinct, hairy on proximal 1/2 or basally;

anthers ellipsoid, shortly cylindrical, obovoid, or globose, 0.6–1 mm.

Pistillate flowers

adaxial nectary square or ovate, 0.2–0.6 mm, shorter than stipe;

stipe 0.8–4 mm;

ovary pyriform, beak slightly bulged below or gradually tapering to styles;

ovules 16–30 per ovary;

styles connate, 0.2–0.8 mm;

stigmas broadly cylindrical or 2 plump lobes, 0.2–0.4 mm.

Capsules

4–11 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

(fruiting in summer, persistent); staminate 21–78 × 8–15 mm, flowering branchlet 3–27 mm; pistillate moderately to very densely flowered, slender, stout, or subglobose, 18.5–103 × 6–17 mm, flowering branchlet 6–56 mm;

floral bract 1.7–4 mm, apex rounded, entire, toothed, or erose, abaxially hairy throughout or proximally, hairs wavy.

Salix humboldtiana

Salix lasiandra

Distribution
from USDA
Mexico to central Chile
[BONAP county map]
from FNA
AK; AZ; CA; CO; ID; MT; NM; NV; OR; SD; UT; WA; WY; AB; BC; MB; NT; SK; YT
[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.)

Varieties 2 (2 in the flora).

Varieties of Salix lasiandra at the south end of Kootenay Lake, British Columbia, are sympatric. In that area, they differ not only in the usual characteristics, leaf glaucescence and presence of stomata in adaxial epidermis, but plants of var. lasiandra are heavily infested with sawfly galls, whereas var. caudata are not, and leaves of var. lasiandra are stiffer than those of var. caudata.

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

Key
1. Largest medial blades hypostomatous or hemiamphistomatous (rarely amphistomatous), surfaces usually glaucous abaxially (rarely not glaucous), bases convex to rounded; staminate flowers: nectaries distinct; petioles with clusters of spherical or foliaceous glands distally.
var. lasiandra
1. Largest medial blades amphistomatous, surfaces not glaucous abaxially, bases convex; staminate flowers: nectaries usually distinct, sometimes connate and shallowly cup-shaped; petioles with pairs or clusters of spherical glands distally.
var. caudata
Source FNA vol. 7, p. 34. FNA vol. 7, p. 47.
Parent taxa Salicaceae > Salix > subg. Protitea > sect. Humboldtianae Salicaceae > Salix > subg. Salix > sect. Salicaster
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. 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
Subordinate taxa
S. lasiandra var. caudata, S. lasiandra var. lasiandra
Synonyms S. lucida subsp. lasiandra
Name authority Willdenow Bentham: Pl. Hartw., 335. (1857)
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