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mountain willow, Scouler willow, Scouler's willow

arctic willow, northern 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 0.03–0.15 m, (dwarf), forming clones by layering.
Stems

prostrate, long-trailing;

branches yellow-brown, red-brown, or green-brown, glabrous;

branchlets yellow-green or yellow-brown to red-brown, (sometimes weakly glaucous), glabrous, (inner membranaceous bud-scale layer free, not 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 rudimentary, absent, or foliaceous on early ones, foliaceous or rudimentary on late ones;

petiole 3–7.8–15 mm;

largest medial blade hypostomatous or hemiamphistomatous, elliptic, obovate, broadly elliptic, broadly obovate, subcircular, or oblanceolate, 15–31–60 × 6.5–16–35 mm, 1.2–3–4.3 times as long as wide, base cuneate, convex, or rounded, margins slightly revolute, inconspicuously crenulate or entire, apex usually acute or convex, sometimes rounded, abaxial surface glaucous, glabrous, adaxial slightly or highly glossy, glabrous;

proximal blade margins entire or serrulate;

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 absent, adaxial nectary oblong, square, narrowly oblong, or ovate, 0.4–1 mm;

filaments distinct or connate less than 1/2 their lengths, glabrous, or hairy on proximal 1/2;

anthers ellipsoid or long-cylindrical, 0.5–0.7 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 absent, adaxial nectary oblong or narrowly oblong, 0.5–0.9 mm, shorter than stipe;

stipe 0.8–1.4 mm;

ovary pyriform or obclavate, pubescent or short-silky, (refractive), hairs (white, grayish, or ferruginous), crinkled, often refractive, ribbonlike, beak gradually tapering to styles;

ovules 8–16 per ovary;

styles connate or distinct 1/2 their lengths, 0.6–1.4 mm;

stigmas slenderly or broadly cylindrical, 0.24–0.47–0.72 mm.

Capsules

4.5–11 mm.

5–9 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.

staminate 19–54 × 7–16 mm, flowering branchlet 4–20 mm; pistillate densely to moderately densely flowered, slender to subglobose, 30–79(–130 in fruit) × 10–20 mm, flowering branchlet 8–57 mm;

floral bract brown, black, or bicolor, 0.8–2.4 mm, apex rounded or acute, entire, abaxially densely hairy, hairs straight.

2n

= 76.

= 76.

Salix scouleriana

Salix arctophila

Phenology Flowering late Feb-mid Jun. Flowering late May-late Jul.
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 Arctic-alpine, subarctic, hummocks in wet, mossy, grass or sedge meadows, margins of streams or ponds, among granite boulders, on alluvial plains, sometimes in snowbeds
Elevation 0-3500 m (0-11500 ft) 40-600 m (100-2000 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; ME; MB; NL; NT; NU; ON; QC; SK; YT; Greenland
[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.)

Salix arctophila occurs in western Greenland.

Hybrids:

Salix arctophila forms natural hybrids with S. arctica, S. glauca var. cordifolia, and S. uva-ursi.

Salix arctophila × S. glauca var. cordifolia: Plants with villous leaves and moderately densely hairy branchlets and branches suggest this hybrid. Putative hybrids are rare but have been seen from Kuujjuaq and Ivujivik, Quebec (G. W. Argus, unpubl.), and are reported to be common in West Greenland (T. W. Böcher 1952).

Salix arctophila × S. uva-ursi is a rare hybrid. The plants often have ovaries with patches of hairs, some of which are ribbonlike, as in S. arctophila, but their habit is compact, as in S. uva-ursi, rather than long-trailing as in S. arctophila. Some specimens are infertile and are evidently hybrids, but there is little to confirm S. uva-ursi as the second parent. N. Polunin (1940b) also expressed some uncertainty about plants intermediate between S. arctophila and S. uva-ursi, and A. K. Skvortsov (1971) discounted this hybrid but noted that there were a few somewhat doubtful specimens.

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

Source FNA vol. 7, p. 131. FNA vol. 7, p. 73.
Parent taxa Salicaceae > Salix > subg. Vetrix > sect. Cinerella Salicaceae > Salix > subg. Chamaetia > sect. Myrtosalix
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. 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. 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 S. arctophila var. lejocarpa, S. groenlandica var. lejocarpa
Name authority Barratt ex Hooker: Fl. Bor.-Amer. 2: 145. (1838) Cockerell ex A. Heller: Cat. N. Amer. Pl. ed. 3, 89. (1910)
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