Salix glauca var. cordifolia
Salix glauca
glaucous willow, gray willow, gray-leaf willow, grey-leaf willow
erect or decumbent;
branches brownish, yellow-brown, gray-brown, or red-brown, villous or pilose to glabrescent;
branchlets yellow-brown or red-brown, sparsely to densely villous or tomentose to glabrescent.
stipules not marcescent, rudimentary or foliaceous on early and late ones, usually inconspicuous, oblong to elliptic or ovate, 1–2.1–4 mm, apex acute to caudate;
petiole 2–9 mm, pilose adaxially;
largest medial blade (sometimes hemiamphistomatous), sometimes broadly obovate, 17–63 × 6–28 mm, 1.4–3.5 times as long as wide, base sometimes rounded, rarely subcordate, apex sometimes rounded, abaxial surface pilose, moderately densely villous or long-silky to glabrescent, hairs straight or wavy, adaxial (sometimes dull), pilose or villous to glabrescent;
proximal blade margins entire or serrulate;
juvenile blade sparsely to densely villous or tomentose.
stipules (marcescent or not), foliaceous or rudimentary on early and late ones;
petiole (usually deeply to shallowly grooved adaxially), 1–27 mm, (much longer than subtended bud);
largest medial blade usually hypostomatous, sometimes hemiamphistomatous or amphistomatous, usually narrowly elliptic, elliptic, usually oblanceolate or obovate, sometimes narrowly oblong or obovate, 27–82 × 6–39 mm, 1.4–4.8 times as long as wide, base usually cuneate or convex, sometimes rounded, rarely subcordate, margins slightly revolute or flat, usually entire, apex acute, acuminate, convex, or rounded, abaxial surface densely villous or villous-silky, tomentose, short- or long-silky, or pilose, hairs usually wavy or straight, sometimes curved, adaxial usually slightly glossy, sometimes dull, moderately densely villous, pilose, or long-silky to glabrescent;
proximal blade margins entire or serrulate;
juvenile blade sparsely or densely villous, tomentose, or long-silky abaxially.
abaxial nectary 0.3–1 mm, adaxial nectary narrowly oblong, oblong, ovate, or flask-shaped, 0.5–1.3 mm;
filaments distinct or slightly connate, glabrous, or hairy on proximal 1/2.
abaxial nectary 0.1–1 mm, adaxial nectary narrowly oblong, oblong, square, ovate, or flask-shaped, 0.5–1.3 mm, nectaries distinct, or connate and cup-shaped;
filaments distinct or slightly or partly connate, glabrous, or hairy on proximal 1/2;
anthers 0.4–0.8 mm.
adaxial nectary 0.4–1.4 mm;
stipe 0.3–1.3 mm;
ovary pyriform, densely villous or tomentose, beak gradually tapering to styles;
ovules 10–18 per ovary;
styles connate to distinct 1/2 their lengths or more, 0.7–1.6 mm;
stigmas slenderly cylindrical, 0.36–0.48–0.72 mm.
abaxial nectary absent, adaxial nectary usually narrowly oblong, oblong, or ovate, sometimes flask-shaped, 0.4–1.8 mm, shorter to longer than stipe;
stipe 0.3–2.8 mm;
ovary pyriform or obclavate, densely villous, tomentose, short-silky, or pubescent, beak usually gradually tapering to styles, sometimes gradually tapering to or slightly bulged below styles;
ovules 6–22 per ovary;
styles connate to distinct 1/2 their lengths or more, 0.3–1.6 mm;
stigmas flat, abaxially non-papillate with rounded tip, or slenderly or broadly cylindrical, 0.2–0.8 mm.
6–7.5 mm.
4.5–9 mm.
staminate 10–48 × 5–14 mm, flowering branchlet 2–25 mm;
pistillate subglobose or globose, 18–56(–60 in fruit) × 7–21 mm, flowering branchlet 2–26 mm;
floral bract tawny, brown, or bicolor, 2–3 mm, apex rounded, hairs wavy or straight.
staminate 14–53 × 5–17 mm, flowering branchlet 1–25 mm;
pistillate densely to sometimes loosely flowered, slender, stout, subglobose, or globose, 15–83 × 7–21 mm, flowering branchlet 2–37 mm;
floral bract tawny, brown, bicolor, or greenish, 1–3.4 mm, apex convex or rounded, entire, abaxially hairy, hairs wavy, crinkled, or straight.
= 76, 95, 114, 152.
Salix glauca var. cordifolia
Salix glauca
The taxonomy of var. cordifolia in the Canadian arctic islands and Greenland is confusing. T. W. Böcher (1952) noted what he thought were two ecologically and morphologically different types of Salix glauca occurring in western Greenland: a glabrous type corresponding to S. glauca subsp. callicarpaea and a hairy one corresponding to S. cordifolia var. intonsa. G. W. Argus (1965) proposed that all Greenland material belonged to the eastern phase of S. glauca (corresponding to S. glauca var. cordifolia). Böcher later recognized two taxa on Greenland, S. glauca subsp. callicarpaea (including var. intonsa) and subsp. glauca, which he thought resembled the European S. glauca (Böcher et al. 1968). A. K. Skvortsov (1971) did not agree that European S. glauca occurs on Greenland. He pointed out that the Greenland plants differ by their usually shorter, broader, more obtuse leaves, adaxial leaf surfaces bare and even somewhat slightly glossy, flowering branchlets as long as the catkins themselves, bracts often brownish, stamens often with glabrous filaments, and a more spreading growth form.
Hybrids:
Variety cordifolia forms natural hybrids with Salix arctophila, S. ballii, S. brachycarpa, S. myricoides, and S. pedicellaris. Placement of specimens from Anticosti Island, Quebec, and North Point, James Bay, Ontario, with densely villous branchlets and relatively short petioles, sometimes thought to be hybrids with S. glauca var. cordifolia, is dubious. Hybrids with S. planifolia have been reported (C. K. Schneider 1921) but no convincing specimens have been seen.
Variety cordifolia × Salix myricoides (S. ×amoena Fernald, S. glauca var. tonsa) is a hybrid swarm characterized by buds with ferruginous hairs, leaves serrulate-crenulate and sparsely hairy, except on margins, and ovaries with flattened, refractive hairs. At the type locality on Ha-Ha Mountain, Newfoundland, it is growing in a population of var. cordifolia; S. planifolia, S. ×pedunculata Fernald, and S. candida were growing nearby. The second parent, S. myricoides, occurs some distance south along the coast. It is possible that the unusual vegetative characteristics were derived from S. planifolia, but they best fit S. myricoides.
Variety cordifolia × Salix pedicellaris occurs in northern Quebec. It has the general appearance of var. cordifolia, but the ovaries are mostly glabrous with patches or streaks of hairs, or, sometimes, mostly hairy, and with glabrous basal patches. These hybrids usually are fertile and evidently a cross between a species with hairy ovaries and one with glabrous ovaries. The identification of S. pedicellaris as the second parent is based on the hybrids having leaf surfaces glaucous adaxially, ovaries and capsules glaucous, and stipes as long as 1.6–1.8 mm. Plants without these diagnostic characteristics often have shorter styles (0.4–0.8 mm) and floral bracts (1.8–2.4 mm) than is usual for var. cordifolia.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Varieties 5 (4 in the flora).
Occurrence of Salix glauca is disjunct in western Siberia; var. glauca is known from Scandinavia.
Salix glauca is ubiquitous, highly polymorphic, and polyploid. It appears to have four major variations that are treated in different ways. European floras have treated it as an undivided polymorphic species(A. K. Skvortsov 1999), as several distinct species (K. H. Rechinger 1964b), or as comprising several subspecies (Rechinger 1993; G. W. Argus et al. 1999; B. Jonsell and T. Karlsson 2000+, vol. 1). In North America, Argus (1965) treated the four central tendencies as widely intergrading “phases” of a single species, later adopting varietal rank, whereas E. Hultén (1968) recognized them as subspecies. In view of the fact that the four elements are confluent over wide areas, there may be some merit in recognizing them as informal phases, but varietal rank is used here.
All specimens from Iceland named Salix glauca are S. arctica and those from Svalbard, Norway, are S. lanata Linnaeus.
The major reason for the high variability within Salix glauca seems to be high, and probably recurrent, polyploidy. Tetraploids, pentaploids, hexaploids, and octoploids are known in the species, and two of the subspecies include three ploidal levels. There also are intergrading geographical variations that are the basis for the recognition of infraspecific taxa.
Hybrids:
Salix glauca forms natural hybrids with S. arctica, S. arctophila, S. ballii, S. barclayi, S. boothii, S. brachycarpa, S. eastwoodiae, S. myricoides, S. niphoclada, S. pedicellaris, and S. planifolia.
The following key will help identify the varieties, but there are extensive areas of overlap among them and many intermediates.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
1. Stipules often marcescent, foliaceous on late leaves, usually prominent, linear, narrowly elliptic, or lanceolate, 2-17 mm; branches red-brown or gray-brown or brownish; branchlets densely villous to glabrescent; proximal blades: margins entire; floral bracts 1.2-2.5 mm; staminate flowering branchlets 1-14 mm; ovaries obclavate or pyriform; Alaska, Canada | → 2 |
1. Stipules sometimes marcescent or rudimentary, if foliaceous, usually inconspicuous, oblong, elliptic, or ovate, 1-8(-10) mm; branches usually yellow-brown or red-brown; branchlets usually sparsely villous or tomentose; proximal blades: margins entire or serrulate; floral bracts 1-3.4 mm; staminate flowering branchlets 1.5-25 mm; ovaries pyriform; northern Canada east of Mackenzie River, Greenland, Rocky Mountains | → 3 |
2. Shrubs, 0.3-1 m; branchlets densely villous; petioles 1-9 mm; largest medial blades: apex acute, sometimes acuminate, or convex, adaxial surface moderately densely villous, or long-silky to glabrescent; staminate catkins 14-26 mm; filaments distinct or partly connate, glabrous or hairy on proximal 1/2; pistillate catkins stout to subglobose, flowering branchlets 2-19 mm; stipes 0.4-1.8 mm; Alaska, Northwest Territories, w Nunavut, n Yukon. | var. stipulata |
2. Shrubs, 0.3-6 m; branchlets soon becoming pilose or glabrescent; petioles 4-27 mm; largest medial blades: apex acuminate to convex, adaxial surface often sparsely long-silky or pilose; staminate catkins 19-45 mm; filaments distinct, glabrous; pistillate catkins slender to stout, flowering branchlets 3-37 mm; stipes 0.5-2.8 mm; c Alaska, British Columbia, Northwest Territories, Yukon. | var. acutifolia |
3. Stipules 0.9-2.8-8(-10) mm, sometimes marcescent; floral bracts usually brownish; largest medial blades: petiole 3-14 mm; Alberta, British Columbia, Rocky Mountains, Saskatchewan to New Mexico. | var. villosa |
3. Stipules 1-2.1-4 mm, usually deciduous (in autumn); floral bracts usually tawny; largest medial blades: petiole 2-9 mm; c, e Canada, Greenland, St. Pierre and Miquelon. | var. cordifolia |
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