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mountain willow, Scouler willow, Scouler's willow

snow-bed 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. Plants 0.005–0.05 m, (dwarf), forming clonal mats by rhizomes.
Stems

erect;

branches red-brown to violet, (sometimes weakly glaucous), glabrous;

branchlets yellow-brown or red-brown, glabrous.

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 absent;

petiole (convex or flat to deeply grooved adaxially), 1.5–6(–7) mm;

largest medial blade (2 pairs of secondary veins arising at or close to base, arcing) circular, subcircular or broadly elliptic, 6–21(–34) × 6–17(–31) mm, 0.9–1.4 times as long as wide, base usually subcordate or cordate, sometimes convex or rounded, margins flat, crenulate or crenate, apex rounded, convex, retuse, or toothed, abaxial surface (not glaucous), glabrous, adaxial slightly glossy to almost dull, glabrous;

proximal blade margins crenulate;

juvenile blade glabrous.

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 0.5–0.8 mm, adaxial nectary oblong or ovate, 0.6–1.1 mm, nectaries distinct, or connate and shallowly cup-shaped;

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

anthers shortly cylindrical or globose, 0.3–0.6 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.

abaxial nectary (0–)0.2–0.3 mm, adaxial nectary narrowly oblong or oblong, 0.3–1.1 mm, longer or shorter than stipe, nectaries distinct or connate and shallowly cup-shaped;

stipe 0.3–1.1 mm;

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

ovules 11–18 per ovary;

styles connate to distinct, 0.2–0.4 mm;

stigmas broadly cylindrical or 2 plump lobes, 0.08–0.24–0.32 mm.

Capsules

4.5–11 mm.

2.2–7.5 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.

from subterminal buds; staminate 3–7.5 × 1.5–5 mm, flowering branchlet 0.3–2 mm; pistillate loosely flowered (2–11 flowers), stout to globose, 3.3–13 × 2–10 mm, flowering branchlet 0.8–3.5 mm;

floral bract tawny, light rose, or brown, 0.5–1.5 mm, margins ciliate, apex rounded, retuse, or truncate, entire, abaxially glabrous.

2n

= 76.

= 38.

Salix scouleriana

Salix herbacea

Phenology Flowering late Feb-mid Jun. Flowering late Jun-mid Aug.
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 Snowbeds and places with good snow protection, well-drained riverbanks, sandy beaches, granite boulder ridges, steep bouldery slopes, or in marshes, usually on non-calcareous substrates, places exposed to sea-spray
Elevation 0-3500 m (0-11500 ft) 0-1700 m (0-5600 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
ME; NH; MB; NL; NT; NU; QC; Greenland; Europe (British Isles, Russia, Scandinavia, Spitzbergen); Atlantic Islands (Iceland)
[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.)

Salix herbacea is the only willow with an amphi-Atlantic distribution. Disjunct populations occur as far west as Great Bear and Great Slave lakes, Northwest Territories. Macrofossils show that, during the late-Wisconsinan period, it occurred in North America along the glacial margin between Minnesota (R. G. Baker et al. 1999) and Cambridge, Massachusetts (G. W. Argus and M. B. Davis 1962). D. J. Beerling (1998) provided a comprehensive review of its biology and ecology.

Hybrids:

Salix herbacea forms natural hybrids with S. arctica, S. argyrocarpa, S. fuscescens, and S. uva-ursi.

Salix herbacea × S. uva-ursi (S. ×peasei Fernald) was described from Mt. Washington, New Hampshire, but occurs also in northern Quebec (G. W. Argus, unpubl.). It is morphologically intermediate between the parents. Its distinctly crenulate, broadly obovate leaves are similar to those of S. herbacea, its catkins are smaller and have fewer flowers than those of S. uva-ursi but more flowers than those of S. herbacea, its leaves are sparsely glaucous abaxially, and it has stems stouter than those of S. uva-ursi.

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

Source FNA vol. 7, p. 131. FNA vol. 7, p. 67.
Parent taxa Salicaceae > Salix > subg. Vetrix > sect. Cinerella Salicaceae > Salix > subg. Chamaetia > sect. Herbella
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. 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. 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. scouleriana var. poikila
Name authority Barratt ex Hooker: Fl. Bor.-Amer. 2: 145. (1838) Linnaeus: Sp. Pl. 2: 1018. (1753)
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