Salix hookeriana

Barratt ex Hooker

Fl. Bor.-Amer. 2: 145, plate 180. 1838.

Common names: Coastal or Hooker’s willow
Endemic
Synonyms: Salix amplifolia Coville Salix hookeriana var. laurifolia J. K. Henry Salix hookeriana var. tomentosa J. K. Henry ex C. K. Schneider Salix piperi
Treatment appears in FNA Volume 7. Treatment on page 127. Mentioned on page 95, 96, 97, 98, 100, 103, 114, 115, 128, 129, 131, 156.

Shrubs or trees, (0.6–) 2–8 m, (sometimes forming clones by layering or stem fragmentation). Stems: branches (highly brittle at base), yellowbrown, gray-brown, redbrown, or violet, not or weakly glaucous, glabrous, tomentose, woolly, or sparsely villous to glabrescent (nodes hairy); branchlets gray-brown, redbrown, or yellowbrown (sometimes color obscured by hairs), glabrous, pilose, moderately densely villous, tomentose, or woolly, scale with inner membranaceous layer free, (not separating from outer layer). Leaves: 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. Catkins 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 flowers: 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. Pistillate flowers: 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. Capsules 5–10 mm. 2n = 114.


Phenology: Flowering mid Apr-mid Jun.
Habitat: Marine coastal beaches and sand dunes, interdunal depressions, coastal marshes, pine barrens, floodplains, ravines, wet sedge meadows, lakeshores, morainal flats, sandy or gravelly substrates
Elevation: 0-1800 m

Distribution

V7 135-distribution-map.gif

B.C., Alaska, Calif., Oreg., Wash.

Discussion

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.

Selected References

None.

Lower Taxa

None.

... more about "Salix hookeriana"
21 +, 4 +, 1 +, 16 +  and 29 +
woolly +, villous +, tomentose +, pilose +  and glaucous +
square +, oblong +  and ovate +
0.05 cm0.5 mm <br />5.0e-4 m <br /> (0.14 cm1.4 mm <br />0.0014 m <br />) +
tomentose;villous;tomentose;villous;pilose;glabrous +
0.05 cm0.5 mm <br />5.0e-4 m <br /> (0.07 cm0.7 mm <br />7.0e-4 m <br />) +
ellipsoid +  and cylindrical +
0.07 cm0.7 mm <br />7.0e-4 m <br /> (0.1 cm1 mm <br />0.001 m <br />) +
Acute (?) +, Rounded (?) +, Convex (?) +  and Acuminate (?) +
George W. Argus +
Barratt ex Hooker +
cuneate +, cordate +, subcordate +, rounded +  and convex +
Salix sect. Vetrix +
tapering +
reddish green +  and yellowish +
ferruginous +  and white +
serrulate +  and entire +
pilose or +  and sparsely densely long-silky tomentose woolly or villous +
toothed +  and 2-fid +
persistent +
flowered +  and pistillate +
subglobose to globose +  and stout +
woolly +, tomentose +, villous +, pilose +  and glabrous +
stout +  and slender +
0 cm0 mm <br />0 m <br /> (2 cm20 mm <br />0.02 m <br />) +
intermediate +
0.5 cm5 mm <br />0.005 m <br /> (1 cm10 mm <br />0.01 m <br />) +
pistillate +  and staminate +
pendulous +, spreading +  and erect +
staminate +
Coastal or Hooker’s willow +
B.C. +, Alaska +, Calif. +, Oreg. +  and Wash. +
0-1800 m +
connate +  and distinct +
hairy +  and glabrous +
bicolor +, black +  and brown +
0.11 cm1.1 mm <br />0.0011 m <br /> (0.36 cm3.6 mm <br />0.0036 m <br />) +
pistillate +  and staminate +
bisexual +  and unisexual +
Marine coastal beaches and sand dunes, interdunal depressions, coastal marshes, pine barrens, floodplains, ravines, wet sedge meadows, lakeshores, morainal flats, sandy or gravelly substrates +
yellowish +, ferruginous +  and white +
straight +
unbranched +  and spicate +
subterminal +  and axillary +
membranaceous +
hemiamphistomatous +, amphistomatous +  and hypostomatous +
oblong +  and narrowly broadly elliptic oblanceolate obovate or broadly obovate +
arranged +  and alternate +
marcescent +
deciduous +
36mm;123mm +
obovate +  and broadly obovate +
1.8 cm18 mm <br />0.018 m <br /> (6.3 cm63 mm <br />0.063 m <br />) +
entire +, sinuate +, serrulate +  and crenate +
2-7[-10]-carpellate +
woolly +, villous +, tomentose +  and glabrous +
pyriform +  and obclavate +
glandular-dotted +
tomentose +, pilose +, woolly +  and villous +
convex;flat +
0.4 cm4 mm <br />0.004 m <br /> (2.9 cm29 mm <br />0.029 m <br />) +
Flowering mid Apr-mid Jun. +
Fl. Bor.-Amer. +
overlapping +
distinct +
violet +, redbrown +, gray-brown +  and yellowbrown +
decumbent;erect +
non-papillate +
cylindrical +
0.03 cm0.3 mm <br />3.0e-4 m <br /> (0.08 cm0.8 mm <br />8.0e-4 m <br />) +
0.18 cm1.8 mm <br />0.0018 m <br /> (0.28 cm2.8 mm <br />0.0028 m <br />) +
0.05 cm0.5 mm <br />5.0e-4 m <br /> (0.18 cm1.8 mm <br />0.0018 m <br />) +
caducous +  and persistent +
distinct +  and connate +
0.06 cm0.6 mm <br />6.0e-4 m <br /> (0.23 cm2.3 mm <br />0.0023 m <br />) +
persistent +  and deciduous +
Salix amplifolia +, Salix hookeriana var. laurifolia +, Salix hookeriana var. tomentosa +  and Salix piperi +
Salix hookeriana +
Salix sect. Cinerella +
species +
pointed +  and rounded +
sympodial +, branching +  and heterophyllous +
tree +  and shrub +