Salix hookeriana
Salix ballii
coastal willow, dune willow, Hooker's willow
ball's willow
branches (highly brittle at base), yellow-brown, gray-brown, red-brown, or violet, not or weakly glaucous, glabrous, tomentose, woolly, or sparsely villous to glabrescent (nodes hairy);
branchlets gray-brown, red-brown, or yellow-brown (sometimes color obscured by hairs), glabrous, pilose, moderately densely villous, tomentose, or woolly, scale with inner membranaceous layer free, (not separating from outer layer).
stipules rudimentary or absent on early ones, foliaceous (early deciduous) or rudimentary (sometimes obscured) on late ones, (2.5–7.8–18 mm), apex acuminate, acute, or rounded;
petiole convex to flat, or shallowly grooved adaxially, 4–29 mm, villous, woolly, pilose, or tomentose adaxially;
largest medial blade (sometimes hemiamphistomatous), narrowly to broadly elliptic, oblanceolate, or obovate to broadly obovate, 36–123 × 18–63 mm, 1.5–4.2 times as long as wide, base convex, rounded, subcordate, cordate, or cuneate, margins slightly revolute, crenate, serrate, shallowly serrulate, sinuate, or entire, apex acuminate, acute, or convex, abaxial surface glaucous, pilose, moderately densely tomentose, villous, or woolly, midrib hairy, hairs (white, sometimes also ferruginous), wavy or straight, adaxial highly or slightly glossy, glabrous, pilose, villous, or moderately densely tomentose, midrib and veins hairy (hairs white, sometimes also ferruginous);
proximal blade margins entire or shallowly serrulate;
juvenile blade yellowish, reddish green (sometimes obscured by hairs), pilose or sparsely to densely long-silky, tomentose, woolly, or villous abaxially, hairs white, sometimes also ferruginous, or yellowish.
stipules absent or rudimentary on early ones, foliaceous on late ones, apex acute or convex;
petiole shallowly to deeply grooved adaxially, 2.5–7.5 mm, pubescent;
largest medial blade elliptic to obovate, 23–63 × 10–35 mm, 1.4–2.8 times as long as wide, base convex or rounded, sometimes cordate or subcordate, margins flat, serrulate or sinuate, apex convex, rounded, acute, or acuminate, abaxial surface glaucous, glabrous, adaxial slightly glossy, glabrous or sparsely pubescent on midrib, (hairs white, sometimes also ferruginous);
proximal blade margins serrulate or crenulate;
juvenile blade sometimes reddish, glabrous, or midrib sparsely pubescent abaxially, hairs white, sometimes also ferruginous.
adaxial nectary oblong, ovate, or narrowly oblong, 0.5–1.4 mm;
filaments distinct or slightly basally connate, glabrous or hairy on proximal 1/2 or basally;
anthers yellow, cylindrical or ellipsoid, (0.5–)0.7–1 mm.
adaxial nectary oblong, square, or ovate, 0.3–1 mm;
filaments distinct, glabrous;
anthers yellow, 0.4–0.8 mm.
adaxial nectary narrowly oblong, oblong, or square, 0.5–1.4 mm, shorter than stipe;
stipe 0.5–1.8(–2.8) mm;
ovary obclavate or pyriform, glabrous, tomentose, villous, or woolly (hairs wavy), beak sometimes abruptly tapering to styles;
ovules 12–20 per ovary;
styles 0.6–2.3 mm;
stigmas broadly to slenderly cylindrical, 0.3–0.8 mm.
adaxial nectary square or oblong, 0.2–0.6 mm, shorter than stipe;
stipe 0.8–2 mm;
ovary pyriform, glabrous, beak gradually tapering to or slightly bulged below styles;
ovules 12–18 per ovary;
styles 0.4–1 mm;
stigmas flat, abaxially non-papillate with pointed tip, or broadly cylindrical, 0.2–0.3–0.36 mm.
5–10 mm.
3–6 mm.
flowering before or as leaves emerge; staminate slender or stout, 26–73 × 10–27 mm, flowering branchlet 0–10 mm; pistillate densely flowered, slender or stout, 36–92(–140 in fruit) × 10–25 mm, flowering branchlet 0–20 mm;
floral bract brown, black, or bicolor, 1.1–3.6 mm, apex convex, rounded, or acute, abaxially hairy, hairs straight or wavy.
flowering as leaves emerge; staminate stout, 17–29.5 × 8–11 mm, flowering branchlet 3.5–12 mm; pistillate moderately densely flowered, slender, stout, or subglobose, 10–37.5(–45 in fruit) × 5–12 mm, flowering branchlet 2.5–16 mm;
floral bract brown or bicolor, 0.8–1.6 mm, apex rounded, convex or retuse, abaxially hairy throughout or proximally, hairs straight, curly, or wavy.
= 114.
Salix hookeriana
Salix ballii
Salix hookeriana is primarily a coastal species occurring from northern California northward to Oregon, Washington, and southern Vancouver Island, with disjunct populations on Queen Charlotte Islands, British Columbia, and northward to Yakatut Bay, Turnagain Arm, and Kodiak, Alaska. It was treated by G. W. Argus (1973) and R. D. Dorn (2000) in a broad sense because of an absence of strong distinguishing characters and intergradation in characters that could be used to divide it. It is highly variable and three very similar taxa have been named: S. amplifolia, S. hookeriana (including vars. tomentosa and laurifolia), and S. piperi. Although extremes of these taxa sometimes are recognizable, the intergradation displayed is so great that even attempts to recognize them as varieties are thwarted. The amplifolia variant in Alaska is characterized by having only white leaf hairs, hairy ovaries, no stipules, and catkins often borne on distinct flowering branchlets, but variation can occur within the same population, and typical S. hookeriana on Vancouver Island sometimes displays the same characteristics. The piperi variant, an inland population in western Oregon and Washington, is usually recognized by local botanists as different from coastal populations. It is characterized by leaves and branchlets soon becoming glabrate and stipules prominent. These characteristics, however, sometimes appear in northern California coastal populations, and some inland populations in Oregon include very hairy individuals that are indistinguishable from coastal variants of S. hookeriana. In general, very hairy populations of S. hookeriana are probably an adaptation to marine coastal environments, but some variation may be due to hybridization and introgression with S. scouleriana. Inland populations suggest the influence of S. lasiolepis. Two hexaploid chromosome numbers reported for S. hookeriana from Vancouver Island (R. L. Taylor and S. Taylor 1977) and Queen Charlotte Islands (R. L. Taylor and G. A. Mulligan 1968), British Columbia, indicate that hybridization has played a role in the evolution of this complex. It is possible that each variant of S. hookeriana has had a different, possibly even recurrent, polyploid origin. Further cytological and genetic study is indicated.
The following comparisons may help to distinguish Salix hookeriana, S. lasiolepis, and S. scouleriana.
Vegetative specimens of Salix hookeriana can be distinguished from S. lasiolepis by having floral buds ellipsoid, beaks distinctly long-tapered, densely long-hairy (villous), red-brown, blades usually pilose, villous, or woolly on abaxial surfaces, usually 18–63 mm wide, and 1.5–4.2 times as long as wide; S. lasiolepis has floral buds ovoid, beaks inconspicuous and blunt, sparsely to moderately densely short-hairy (velvety), yellowish to red-brown, blades usually tomentose on abaxial surfaces, usually 6–32 mm wide, and 3.2–9.6 times as long as wide.
Salix hookeriana is distinguished from S. scouleriana by having branchlets with spreading hairs (woolly or tomentose to glabrate), petioles usually pilose to tomentose, blades typically narrowly elliptic but variable, stigmas 0.3–0.74, short in relation to styles (0.6–2.3 mm), and pistillate nectaries 0.5–1.4 mm, shorter or longer than stipes; S. scouleriana has branchlets usually with short, erect hairs (velutinous), sometimes spreading (villous or tomentose), petioles velvety or villous adaxially, blades typically oblanceolate but variable, stigmas 0.4–1.04 mm, long in relation to styles (0.2–0.6 mm), and pistillate nectaries 0.2–0.8 mm, shorter than stipes.
Hybrids:
Salix hookeriana forms natural hybrids with S. barclayi and S. scouleriana. Variation in some S. hookeriana populations suggests hybridization with S. lasiolepis but no positive identifications have been made. R. D. Dorn (2000) doubted that hybridization in California between these species with different chromosome numbers was possible, but species with different chromosome numbers do hybridize [for example, S. athabascensis (4x) × S. pedicellaris (2x)]; synthetic hybridization studies are indicated.
Salix hookeriana × S. scouleriana: Plants from southern British Columbia with leaves similar to S. hookeriana but with prominent stipules, catkins both erect and recurving, and relatively long stigmas were thought by J. K. Henry (1915) to be this hybrid.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Occurrence of Salix ballii in Nunavut is on Charlton Island in James Bay.
Salix ballii differs from S. myrtillifolia in having leaves that are distinctly glaucous abaxially. It was described as S. myrtillifolia var. brachypoda by Fernald, who noted that among the characters that distinguish it from S. myrtillifolia only the presence of leaf glaucescence does not occur elsewhere in S. myrtillifolia. This character may be lost when dried over excessive heat. For example, the only specimen supporting the occurrence of S. myrtillifolia on the Gaspe Peninsula, Quebec, is a badly damaged, poorly dried collection that may have lost its glaucescence in drying. A single character difference such as this usually would not recommend a taxon for species rank, but in this case it may be justified inasmuch as S. ballii and S. myrtillifolia are allopatric. A specimen from Île Couture, Lac Mistassini Region, Quebec, may be an exception but confirmatory collections are needed.
Hybrids:
Salix ballii forms natural hybrids with S. glauca var. cordifolia (S. ×ungavensis Lepage). This sterile hybrid with aborted ovaries is known only from the type locality in northern Quebec. It generally resembles S. glauca var. cordifolia but its ovaries are glabrous except for hairy patches at the base and on the stipe. It is evidently a hybrid involving S. glauca var. cordifolia and a species with glabrous ovaries. E. Lepage (1962) was correct in suggesting that the latter was S. ballii (as S. myrtillifolia var. brachypoda). Both taxa grow together in the area; style and floral bract lengths fall within the range of S. ballii, except for a slight overlap with S. glauca var. cordifolia, and its serrulate to crenulate leaf margins are characteristic of S. ballii.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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