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rock willow

Labrador willow

Habit Plants 0.2–1.5 m. Stems erect; branches brownish or red-brown, (dull), glabrous, long-silky, or villous to glabrescent; branchlets yellow-brown or gray-brown, long-silky, pilose, or moderately densely villous. Plants sometimes forming clones by layering.
Stems

branches red-brown or brownish, not or weakly glaucous, (highly glossy), pubescent to glabrescent;

branchlets yellow-brown or red-brown, sparsely pubescent.

Leaves

stipules absent or rudimentary;

petiole (shallowly to deeply grooved adaxially), 2–8 mm, (with 2 spherical glands distally, dark brown, sometimes basilaminar, sparsely pubescent or glabrous adaxially);

largest medial blade hypostomatous, (veins strongly impressed-reticulate), broadly elliptic, subcircular, or obovate, 18–67 × 10–40 mm, 1.1–2.3 times as long as wide, base rounded, convex, or subcordate, margins strongly revolute, crenate or subentire, apex rounded, convex, retuse, or toothed, abaxial surface sparsely to densely villous or long-silky, veins often with long, straight hairs, adaxial slightly glossy, glabrous or sparsely long-silky;

proximal blade margins entire or crenate;

juvenile blade (yellowish green), abaxially very densely long-silky.

stipules absent or rudimentary on early ones;

petiole shallowly grooved adaxially, 3–8 mm, (sometimes glands present distally), pubescent adaxially;

largest medial blade narrowly elliptic, narrowly oblong, or oblanceolate 25–65 × 7–15 mm, base cuneate or convex, margins strongly revolute, entire or crenulate, (glands submarginal or epilaminal), apex acute, convex, or acuminate, abaxial surface glaucous (sometimes obscured by hairs), pilose or densely long-silky or villous, (midribs yellow, prominent, glabrous or pubescent), hairs (white, sometimes also ferruginous), straight or wavy, adaxial slightly glossy, glabrous or sparsely pubescent, especially midrib, (hairs white, sometimes also ferruginous);

proximal blade margins entire;

juvenile blade yellowish green, sparsely to moderately densely long-silky abaxially, hairs white.

Staminate flowers

abaxial nectary 0.6–0.8 mm, adaxial nectary narrowly oblong, 0.5–1.2 mm, nectaries connate and shallowly cup-shaped, or distinct;

filaments distinct, hairy on proximal 1/2;

anthers ellipsoid or globose, 0.3–0.5 mm.

(abaxial nectary 0–0.6 mm), adaxial nectary oblong, narrowly oblong, or square, 0.4–1 mm, (nectaries usually distinct, sometimes cupulate);

filaments distinct;

anthers purple turning yellow, 0.4–0.5 mm.

Pistillate flowers

abaxial nectary (0–)0.8–0.9 mm, adaxial nectary oblong, ovate, or narrowly oblong to almost filiform, 0.7–1.4 mm, shorter to longer than stipe, nectaries distinct or connate and cup-shaped;

stipe 0.4–1.2 mm;

ovary pyriform or obnapiform, densely short-silky, hairs cylindrical, beak abruptly tapering to styles;

ovules 13–15 per ovary;

styles connate 1/2 their lengths to almost distinct, 0.2–0.4 mm;

stigmas flat, abaxially non-papillate with rounded tip, slenderly cylindrical, or 2 plump lobes, 0.2–0.28–0.36 mm.

adaxial nectary narrowly oblong, oblong, or square, 0.3–1.1 mm;

ovary pyriform, beak gradually tapering to styles;

ovules 12–13 per ovary;

styles 0.4–0.9 mm.

Capsules

3–5 mm.

2–4 mm.

Catkins

staminate 13–48 × 4–6.5(–8) mm, flowering branchlet 3–31(–50) mm; pistillate densely flowered, slender or stout, 18–56 × 4–10 mm, flowering branchlet 3–27(–40) mm;

floral bract tawny, 0.8–1.6 mm, apex rounded, entire, abaxially densely hairy, hairs straight.

flowering as leaves emerge; staminate stout or subglobose, 10–21.5 × 6–10 mm, flowering branchlet 1–8 mm; pistillate densely to moderately densely flowered, stout to subglobose, 11–20.5(–25 in fruit) × 5.5–17 mm, flowering branchlet 1–13 mm;

floral bract tawny, brown, or bicolor, 0.7–1.2 mm, apex rounded, abaxially hairy, hairs straight.

2n

= 38.

= 76.

Salix vestita

Salix argyrocarpa

Phenology Flowering mid Jun-late Jul. Flowering early Jun-early Aug.
Habitat Moist to dry open forests and rocky streamsides, in upper montane and subalpine zones, rarely alpine Floodplains, lake and stream margins, wet snow flush areas, snowbeds, sedge meadows, treed bogs, shrubby tundra, subarctic and subalpine conifer forests, granitic, sandstone, or limestone substrates
Elevation 0-2400 m (0-7900 ft) 10-1800 m (0-5900 ft)
Distribution
from FNA
MT; OR; WA; AB; BC; MB; NL; NS; NU; ON; QC; Asia (China [Xinjiang], Mongolia, Russia, e, c Siberia)
[WildflowerSearch map]
[BONAP county map]
from FNA
ME; NH; NL; NU; QC
[BONAP county map]
Discussion

Salix vestita is an ancient amphiberingian species. Its distribution includes a series of isolated, disjunct populations in Central Siberia, the northern Rocky Mountains, the west coast of Hudson Bay, and the northeastern arctic and subarctic. Occurrence in Nunavut is on Akpatok Island in Ungava Bay and on the Belcher Islands in Hudson Bay. It may be extirpated in Washington.

The flowering and vegetative branchlets sometimes have relatively short internodes. In subsequent years, branches have the appearance of short shoots similar to those in Alnus. Short shoots do not appear on all branches or in all years. The formation of short shoots may be related to adverse growing conditions.

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

Salix argyrocarpa occurs in Nunavut on the Belcher Islands in Hudson Bay.

In the field, Salix argyrocarpa can be confused with S. glauca. They are not closely related but both have staminate flowers with both abaxial and adaxial nectaries, and tawny floral bracts. In subg. Vetrix, this characteristic occurs also in S. wolfii and sometimes in S. orestera, where it may be attributable to hybridization. See 54. S. wolfii for comment.

Vegetative specimens of Salix argyrocarpa and S. pellita are sometimes difficult to separate. There is no evidence that they hybridize.

Salix argyrocarpa is distinguished from S. pellita by having plants 0.2–1 m, stems delicate, largest medial blades 25–65 mm, 3.3–5.9 times as long as wide, branches highly glossy, not or weakly glaucous, flexible at base, and juvenile blades long-silky; S. pellita has plants 0.5–6 m, stems coarse, largest medial blades 40–123 mm, 4.2–11.3 times as long as wide, branches slightly glossy, often strongly glaucous, highly to ± brittle at base, and juvenile blades glabrous or pubescent, tomentose, or short-silky.

Hybrids:

Salix argyrocarpa forms natural hybrids with S. herbacea, S. pedicellaris, and S. planifolia.

Salix argyrocarpa × S. herbacea has leaf shape and margin dentition of S. herbacea but resembles S. argyrocarpa in having leaves glaucous abaxially, along with some white, silky hairs (especially on proximal leaves), juvenile leaves often revolute or infolded, and ovaries glabrous or with patches of hair, hairs appressed, short, straight or slightly curved, and flattened (having a saberlike appearance). These hybrids are sometimes misidentified as S. arctophila × S. herbacea, but ovary hair type and other characters suggest that S. argyrocarpa is the second parent. Occasional specimens with ferruginous hairs on the leaves suggest the influence of S. pellita or S. planifolia.

Salix argyrocarpa × S. pedicellaris (S. ×dutillyi Lepage) resembles S. pedicellaris in leaf shape and size and in having ovaries usually glabrous, although with patches or streaks of hair, and S. argyrocarpa in having leaves sparsely long-silky abaxially, in margins sparsely crenulate, and in proximal leaves with long-silky hairs abaxially. This hybrid is widespread in northern Quebec (G. W. Argus, unpubl.), where backcrosses seem to occur.

Salix argyrocarpa × S. planifolia (S. ×grayi C. K. Schneider): The collector, C. E. Faxon, noted that it could be distinguished at a distance from S. planifolia by its dull white color and upright branching, and from S. argyrocarpa by being taller. It resembles S. argyrocarpa in having juvenile leaves yellow-green, in catkins shorter and borne on longer flowering branchlets, and in stigmas purplish red. It resembles S. planifolia in having juvenile leaves with ferruginous hairs, and in the general appearance of the catkins (M. S. Bebb 1890).

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

Source FNA vol. 7, p. 64. FNA vol. 7, p. 151.
Parent taxa Salicaceae > Salix > subg. Chamaetia > sect. Chamaetia Salicaceae > Salix > subg. Vetrix > sect. Argyrocarpae
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. 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. 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. 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. leiolepis, S. vestita subsp. leiolepis, S. vestita var. psilophylla
Name authority Pursh: Fl. Amer. Sept. 2: 610. (1813) Andersson: Monogr. Salicum, 107, plate 6, fig. 60. (1867)
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