J. Arnold Arbor. 2: 188. 1922.
Shrubs, 1–8 m. Stems: branches yellow-brown, gray-brown, or red-brown, not glaucous, glabrous or villous; branchlets yellow-green or yellow-brown, glabrous, sparsely to densely villous, or velvety, (inner membranaceous bud-scale layer free, not separating from outer layer). Leaves: stipules foliaceous, apex rounded, convex, acute or acuminate; petiole convex to flat, or shallowly grooved adaxially, 3–18 mm, glabrous, pilose, or velvety to glabrescent adaxially; largest medial blade lorate, narrowly oblong, or narrowly elliptic, 60–133 × 12–30 mm, 2.9–6.4 times as long as wide, base rounded, convex, or subcordate, margins flat, usually serrulate or serrate, rarely (apparently) entire, apex acuminate to acute, abaxial surface glaucous, glabrous, sparsely short-silky or pubescent, hairs straight or wavy, adaxial dull, glabrous, sparsely short-silky, or midrib pubescent; proximal blade margins entire, serrulate, or crenulate; juvenile blade reddish or yellowish green, glabrous or sparsely to moderately densely pilose or puberulent abaxially, hairs white. Catkins flowering as or just before leaves emerge; staminate stout, 20.5–34 × 8–11 mm, flowering branchlet 0–3 mm; pistillate moderately densely flowered, slender to subglobose, 15.5–49 × 8–18 mm, flowering branchlet 1–6 mm; floral bract brown or bicolor, 0.8–1.6 mm, apex acute or rounded, abaxially hairy throughout or proximally (hairs usually arising from rachis), hairs wavy or curly. Staminate flowers: adaxial nectary narrowly oblong, oblong, flask-shaped, or triangular, 0.3–0.8 mm; filaments distinct or connate less than 1/2 their lengths (or appearing as a single stamen), glabrous or hairy basally; anthers purple or red turning yellow, (ellipsoid or globose), 0.5–0.8 mm. Pistillate flowers: adaxial nectary oblong, narrowly oblong, or flask-shaped, 0.3–0.9 mm, shorter than stipe; stipe 0.9–2.5 mm; ovary pyriform, glabrous, beak sometimes slightly bulged below styles; ovules 12–21 per ovary; styles 0.2–0.6 mm; stigmas flat, abaxially non-papillate with rounded tip, or slenderly cylindrical, 0.16–0.25–0.4 mm. Capsules 4–6 mm. 2n = 38.
Phenology: Flowering late Mar-mid Jun(-late Jul).
Habitat: Banks and floodplains, cienegas, sandy-clay or gravelly substrates
Elevation: 0-3100 m
Ariz., Calif., Colo., N.Mex., Oreg., Utah, Wyo.
Salix ligulifolia sometimes has leaf teeth that are so short that it is referred to as “entire-leaved.” That condition is uncommon and, even when some leaves appear to be entire, others with fine serrulations can be found on the same plant.
Salix ligulifolia forms natural hybrids with S. geyeriana.