Shrubs, 1-4 m. Stems: branches yellow-brown or red-brown, not or weakly glaucous, sparsely to densely tomentose; branchlets yellowish to yellow-brown, densely velvety, long-silky, or tomentose, (buds caprea-type or intermediate). Leaves: stipules rudimentary on early ones, foliaceous on late ones, apex acuminate, acute, or rounded; petiole shallowly grooved adaxially, 3-7 mm, tomentose adaxially; largest medial blade lorate, very narrowly elliptic, or oblanceolate, 58-144 × 11-30 mm, 2.8-7 times as long as wide, base convex or cuneate, margins slightly revolute, entire, irregularly serrate, serrulate, or sinuate, apex convex, acute, or acuminate, abaxial surface glaucous (sometimes obscured by hairs), sparsely to densely tomentose or woolly, hairs wavy, adaxial slightly glossy or dull, sparsely tomentose or villous; proximal blade margins entire; juvenile blade reddish or yellowish green, densely long-silky abaxially, hairs white or gray. Catkins flowering before leaves emerge; staminate slender, stout, or subglobose, 12-47 × 7-12 mm, flowering branchlet 0-1 mm; pistillate moderately densely flowered, slender, 19-59(-80 in fruit) × 5-10 mm, flowering branchlet 0-1 mm; floral bract tawny or light rose, 0.8-1.5 mm, apex rounded, abaxially hairy, hairs straight. Staminate flowers: adaxial nectary very narrowly oblong, 0.8-1.4 mm; filaments distinct or connate basally, glabrous; anthers yellow, ellipsoid or globose, 0.4-0.6 mm. Pistillate flowers: (abaxial nectary rarely present), adaxial nectary narrowly oblong to oblong, 0.6-1.5 mm, longer than stipe, (nectaries distinct); stipe 0-0.4 mm; ovary squat, flask-shaped, very densely tomentose, beak abruptly tapering to styles; ovules 4-12 per ovary; styles (sometimes distinct), 0.4-0.8 mm; stigmas flat, abaxially non-papillate with rounded tip, 0.16-0.24 mm. Capsules 4-6 mm. Flowering early Mar-mid Apr. Streamshores, rocky or gravelly substrates, serpentine soils; 300-1300 m; Calif. Hybrids:
Salix breweri apparently hybridizes with S. lasiolepis. The plants in Yolo County have less hairy leaves, long petioles, and capsules that are relatively long and slender, glabrescent, and distinctly stipitate.
See 111. Salix delnortensis for a discussion of origin.