Salix humboldtiana
Salix ovalifolia
Humboldt's willow
arctic seashore or oval-leaf willow, oval-leaf willow
trailing;
branches yellow-brown, gray-brown, or red-brown, glabrous or hairy;
branchlets yellow-green, yellow-brown, or red-brown, glabrous or pilose.
stipules usually absent or rudimentary, rarely foliaceous;
petiole (deeply to shallowly grooved adaxially), 1.1–16 mm, (glabrous);
largest medial blade hypostomatous, narrowly to broadly elliptic, circular, subcircular, or obovate, 13–46 × 7–20 mm, 1–3.4 times as long as wide, base subcordate, cordate, rounded, or convex, margins slightly revolute or flat, entire, sometimes ciliate, apex convex, rounded, acuminate, acute, or retuse, abaxial surface glabrous, villous, long-silky, pubescent, or pilose, hairs wavy or straight, adaxial highly glossy, usually glabrous;
proximal blade margins entire;
juvenile blade (reddish or yellowish green), pilose, villous, or long-silky abaxially.
abaxial nectary 0.6–1 mm, adaxial nectary oblong or ovate, 0.6–1.6 mm, nectaries distinct or connate and cup-shaped;
filaments distinct or connate less than 1/2 their lengths (glabrous);
anthers elliptic, short-cylindrical, or globose, 0.3–0.5(–0.6) mm.
abaxial nectary (0–)0.4–0.6 mm, adaxial nectary longer than stipe;
stipe 0.2–1.4 mm;
ovary obclavate or pyriform, glaucous or not, usually glabrous or tomentose, sometimes pubescent or villous, beak abruptly tapering to styles;
ovules 10–15 per ovary;
styles 0.2–0.8 mm;
stigmas flat, abaxially non-papillate with pointed tip, or slenderly cylindrical, 0.32–0.41–0.64 mm.
5.2–9.6 mm.
humboldtiana Willdenow: Humboldt willow is not known to occur in the flora area.
is characterized by: trees, 4–25 m;
branches highly brittle at base, bud-scale margins distinct and overlapping adaxially;
stipules on late leaves rudimentary or foliaceous;
largest medial leaf blade usually linear, abaxial surface not glaucous, adaxial dull;
pistillate bract deciduous after flowering;
stamens 3–7;
capsules with distinct, often raised, white veins.;
it occurs throughout much of Mexico to central Chile.
staminate 4.8–46 × 5–11 mm, flowering branchlet 1.5–24 mm;
pistillate moderately densely flowered, stout, subglobose, globose, or slender, 6.3–50 × 5–28 mm, flowering branchlet 2.5–22 mm;
floral bract brown, greenish, or bicolor, 1.2–2 mm, apex rounded, entire or, sometimes, 2-fid, abaxially hairy, hairs straight or wavy.
= 38.
Salix humboldtiana
Salix ovalifolia
Salix humboldtiana is closely related to S. nigra in its generally narrow leaf blades, which are not glaucous abaxially. The two differ in the following characters: S. humboldtiana has leaf blades linear to sometimes narrowly oblong (10–28.6 times as long as wide), ovaries usually ovoid to ellipsoid, ovary walls often stomatiferous and with raised, white veins, and capsule valves relatively thick, slightly recurved. S. nigra has leaf blades usually narrowly lanceolate (6–13 times as long as wide), ovaries pyriform to obclavate, ovary walls neither stomatiferous nor notably veined, and capsule valves relatively thin and strongly recurved. Both species occur in Chihuahua, Mexico.
The report by R. I. Lonard et al. (1991) that specimens identified as Salix nigra from the lower Rio Grande, Texas, resemble S. humboldtiana in having strongly veined capsules suggests that S. humboldtiana, or intergrades with that species, may occur in Texas. Attempts to locate a voucher specimen were unsuccessful; because strongly veined capsules are diagnostic, further field study is indicated.
An earlier name, Salix chilensis Molina, has been applied to this species; it does not seem to pertain to this taxon (C. K. Schneider 1918).
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Varieties 4 (4 in the flora).
The varieties of Salix ovalifolia are relatively minor variants; their ranges overlap and their differences in leaf shape and ovary indumentum intergrade (G. W. Argus 1969, 1973). The only one with a more or less distinctive geographical distribution is var. cyclophylla; where its range overlaps with var. ovalifolia there is intergradation. Variety arctolitoralis, which is characterized by larger leaves and catkins, may be an ecotype. Variety glacialis is known only from near Point Barrow, Alaska. E. Hultén (1968) suggested, probably based on its often tomentose ovaries, that it is S. arctica × S. ovalifolia. All varieties of the species have some plants with hairy ovaries, but the suggestion that this character is an indication of hybridization deserves study.
Hybrids:
Salix ovalifolia forms natural hybrids with S. arctica and S. fuscescens.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
1. Ovaries usually tomentose, sometimes glabrous; largest medial blades 8.5-14 mm; endemic to Point Barrow, Alaska. | var. glacialis |
1. Ovaries usually glabrous, sometimes pubescent or villous; largest medial blades 13-46 mm; not endemic to Point Barrow, Alaska | → 2 |
2. Largest medial blades subcircular to circular, 1-1.5 times as long as wide. | var. cyclophylla |
2. Largest medial blades narrowly to broadly elliptic, obovate, or subcircular, 1.1-3.4 times as long as wide | → 3 |
3. Largest medial blades elliptic, broadly elliptic, or subcircular, 13-28 mm. | var. ovalifolia |
3. Largest medial blades narrowly to broadly elliptic or obovate, 25-46 mm. | var. arctolitoralis |
WildflowerSearch
iNaturalist
USDA Plants Database
