Salix hookeriana
Salix maccalliana
coastal willow, dune willow, Hooker's willow
Maccalla's willow, mccalla'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).
branches dark red-brown, slightly or highly glossy, glabrous;
branchlets red-brown or yellow-brown, puberulent to glabrescent, hairs wavy, curved, straight, or geniculate.
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;
petiole convex to flat, or shallowly grooved adaxially, 4–15 mm, pilose or pubescent adaxially;
largest medial blade lorate or narrowly oblong, 40–85 × 8–25 mm, 2.9–4.8(–5.7) times as long as wide, base convex or cuneate, margins flat, entire, serrulate, or crenate, apex acute to sometimes acuminate, abaxial surface (pale), glabrous or sparsely pubescent, hairs white and ferruginous, straight, relatively short and stiff, adaxial highly glossy, glabrous, puberulent, or sparsely tomentose, hairs white and ferruginous;
proximal blade margins serrulate;
juvenile blade reddish.
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.
abaxial nectary (0–)0.6–0.9 mm, adaxial nectary oblong or narrowly oblong, 0.5–1 mm, nectaries distinct or connate and cup-shaped;
filaments distinct, hairy on proximal 1/2;
anthers (purple turning yellow), ellipsoid or shortly cylindrical.
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.
(abaxial nectary present), adaxial nectary oblong, 0.4–1 mm, (nectaries distinct);
ovary pyriform;
ovules 12–16 per ovary;
styles connate or distinct 1/2 their lengths, 0.8–1.2 mm;
stigmas flat, abaxially non-papillate with rounded tip, or slenderly cylindrical, 0.3–0.6 mm.
5–10 mm.
7–11 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.
staminate (stout or subglobose), 15.5–42 × 9–16 mm, flowering branchlet 1.5–11 mm; pistillate densely flowered, slender, stout, or subglobose, 25–50 × 10–20 mm, flowering branchlet 3–12 mm;
floral bract 1.6–3.6 mm, apex rounded to truncate, entire, abaxially hairy throughout or proximally, hairs white and ferruginous, wavy.
= 114.
= ca. 190, ca. 228.
Salix hookeriana
Salix maccalliana
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.)
The decaploid to dodecaploid chromosome number for Salix maccalliana, highest in the genus, suggests a complex origin. Relationships with subg. Chamaetia and subg. Salix were suggested by Rowlee and by H. M. Raup (1959). Staminate flowers with abaxial nectaries, tawny and persistent bracts, and villous ovaries suggest a link with S. glauca; leaves with coarse, ferruginous hairs and serrate margins suggest S. lucida (Rowlee). Although S. maccalliana is phenetically closer to sect. Salicaster than to (subg. Chamaetia) sect. Glaucae (G. W. Argus 1997), it is probable that because it incorporates genomes from more than one subgenus, its subgeneric placement is arbitrary.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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