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mountain willow, Scouler willow, Scouler's willow

polar 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 0.01–0.09 m, (dwarf), forming clones by rhizomes.
Stems

erect;

branches red-brown, (often glaucous, dull), glabrous;

branchlets brownish, 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 or rudimentary;

petiole (deeply grooved), 1.3–10 mm, (glabrous adaxially);

largest medial blade (deciduous in autumn, 2 pairs of secondary veins arising at or close to base, arcing toward apex), elliptic, broadly elliptic, obovate, or subcircular, 5–32 × 7–18 mm, 1.1–2.8 times as long as wide, base convex, rounded, or cuneate, margins slightly revolute or flat, entire, ciliate, apex usually rounded or convex, sometimes retuse, abaxial surface (rarely glaucous), glabrous or pilose, adaxial slightly glossy, glabrous;

proximal blade margins entire;

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 0.3–0.7 mm, adaxial nectary oblong, narrowly oblong, square, or ovate, 0.5–1.4 mm, nectaries distinct;

filaments usually distinct, sometimes connate proximally, glabrous;

anthers ellipsoid or ovoid, 0.4–0.6 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 nectaries absent, adaxial nectary narrowly oblong, oblong, or ovate, 0.8–1.8 mm, longer than stipe;

stipe 0.2–0.7 mm;

ovary obclavate or pyriform, densely villous to pilose, hairs flattened, beak gradually tapering to or slightly bulged below styles;

ovules 12–17 per ovary;

styles connate to distinct 1/2 their lengths, 0.7–1.2 mm;

stigmas flat, abaxially non-papillate with pointed tip, or slenderly to broadly cylindrical, 0.3–0.6(–0.7) mm.

Capsules

4.5–11 mm.

4.8–8.25 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.

sometimes from subterminal buds; staminate 9–34 × 6–12 mm, flowering branchlet 1.5–14 mm; pistillate densely or moderately flowered (more than 15 flowers), stout to globose, 10–50 × 7–13 mm, flowering branchlet 1–12 mm;

floral bract brown, black, or bicolor, 1.5–2.5 mm, apex rounded or convex, entire, abaxially sparsely hairy, hairs straight or wavy, (exceeding bract by 0.6–1.12–1.8 mm).

2n

= 76.

= 76, 114.

Salix scouleriana

Salix polaris

Phenology Flowering late Feb-mid Jun. Flowering mid Jun-early 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 Arctic-alpine, moist late snowbed and snowflush areas, talus and scree slopes, sides of depressed center frost polygons, sedge meadows, and mud boils, calcareous tills, sandy marine silts
Elevation 0-3500 m (0-11500 ft) 0-1800 m (0-5900 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; BC; NT; NU; YT; Eurasia (Chukotka, Novaya Zemlya, Russian Far East, arctic Siberia, Spitzbergen, and Sweden)
[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.)

The sectional placement of Salix polaris is uncertain. It was placed in sect. Myrtosalix (G. W. Argus 1997) but more recently Argus et al. (1999) placed it in sect. Herbella. This polyploid species may be an intersectional hybrid.

Hybrids:

Salix polaris forms natural hybrids with S. arctica and perhaps S. rotundifolia.

Salix polaris × S. rotundifolia: This putative hybrid occurs in Alaska and the Yukon. Many plants previously identified as S. rotundifolia but that have ovaries with hairs on the beaks or in patches, leaves not commonly marcescent, and catkins with fewer flowers than in S. polaris may be this hybrid.

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

Source FNA vol. 7, p. 131. FNA vol. 7, p. 69.
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. 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. 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. polaris subsp. pseudopolaris, S. polaris var. selwynensis
Name authority Barratt ex Hooker: Fl. Bor.-Amer. 2: 145. (1838) Wahlenberg: Fl. Lapp., 261, plate 13, fig. 1. (1812)
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