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mountain willow, Scouler willow, Scouler's willow

Pacific willow, shining willow

Habit Shrubs or trees, 1–10(–20) m. Stems: branches gray-brown, yellow-brown, or red-brown, not glaucous, glabrous or tomentose; branchlets yellow-green or yellow-brown, sparsely to densely villous, tomentose, or velvety. 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 absent, rudimentary, or foliaceous on early ones, foliaceous on late ones, (1–16 mm), apex acute or acuminate;

petiole convex to flat adaxially, 2–13 mm, velvety or villous adaxially;

largest medial blade usually oblanceolate, sometimes narrowly elliptic, elliptic or obovate, 29–100 × 9–37 mm, 1.7–3.9 times as long as wide, base cuneate or convex, margins strongly to slightly revolute or flat, entire, remotely serrate, crenate, or sinuate, (glands submarginal or epilaminal), apex acuminate, convex, or rounded, abaxial surface glaucous, sparsely to densely short- to long-silky or woolly, hairs (white, sometimes also ferruginous), wavy or straight, adaxial slightly glossy, pilose or moderately densely short-silky, midrib velutinous or villous, (hairs white, sometimes also ferruginous);

proximal blade margins entire, serrulate, or crenulate;

juvenile blade reddish or yellowish green, sparsely to densely villous, short- or long-silky abaxially, hairs white, sometimes also ferruginous.

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

adaxial nectary oblong or square, 0.4–0.9 mm;

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

anthers purple turning yellow, ellipsoid to shortly cylindrical, 0.7–1.2 mm.

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 oblong or square, 0.2–0.8 mm, shorter than stipe;

stipe 0.8–2.3 mm;

ovary pyriform or obclavate, densely long-silky, beak slightly bulged below styles;

ovules 10–18 per ovary;

styles 0.2–0.6 mm;

stigmas slenderly cylindrical, 0.4–0.82–1.04 mm.

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

4.5–11 mm.

4–11 mm.

Catkins

flowering before leaves emerge; staminate stout or subglobose, 18–40.5 × 8–22 mm, flowering branchlet 0–4 mm; pistillate very densely flowered, slender or stout, 18–60(–90 in fruit) × 10–22 mm, flowering branchlet 0–8 mm;

floral bract brown, black, or bicolor, 1.5–4.5 mm, apex rounded or acute, abaxially hairy, hairs straight.

(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.

2n

= 76.

Salix scouleriana

Salix lasiandra

Phenology Flowering late Feb-mid Jun.
Habitat Dry conifer forests, mature woods on edges of streams and lakes, treed bogs, meadows, subalpine slopes, springs, pine barrens, openings in old burns, arroyos and disturbed sites, sandy, silty-clay, or gravelly, igneous substrates
Elevation 0-3500 m (0-11500 ft)
Distribution
from FNA
AK; AZ; CA; CO; ID; MT; NM; NV; OR; SD; UT; WA; WY; AB; BC; MB; NT; SK; YT; Mexico (Chihuahua, Sonora)
[WildflowerSearch map]
[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

Western Salix scouleriana and eastern S. humilis are closely related and are sometimes difficult to separate. Although there is an apparent range disjunction between them in western Manitoba, it may be a collecting gap. In general, S. scouleriana differs from S. humilis in being a taller shrub, sometimes even tree-like, with broader leaves and longer catkins, floral bracts, stigmas, and styles, but these quantitative characteristics all overlap. The apparent difference in anther length (S. scouleriana 0.7–1.2 mm; S. humilis 0.4–0.6 mm) may be correlated with a difference in chromosome number. Salix scouleriana is tetraploid (Y. Suda and G. W. Argus 1968); S. humilis has been reported to be both diploid (Suda and Argus; L. Zsuffa and Y. Raj, unpubl.) and tetraploid (R. D. Dorn 1976). The latter count was from the same population as the one by Suda and Argus. Further chromosome counts are indicated.

See 77. Salix hookeriana for comparative descriptions.

Hybrids:

Salix scouleriana forms natural hybrids with S. hookeriana, S. planifolia, and S. pulchra.

(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. 131. FNA vol. 7, p. 47.
Parent taxa Salicaceae > Salix > subg. Vetrix > sect. Cinerella 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. 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. 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. 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. scouleriana var. poikila S. lucida subsp. lasiandra
Name authority Barratt ex Hooker: Fl. Bor.-Amer. 2: 145. (1838) Bentham: Pl. Hartw., 335. (1857)
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