[Salix cordata var. denveriana L. Kelso, moreSalix cordata var. desolata (E.H. Kelso) L. Kelso, Salix cordata var. lutea (Nutt.) Bebb, Salix cordata var. platyphylla (Ball) L. Kelso, Salix cordata var. watsonii Bebb, Salix eriocephala var. famelica (Ball) Dorn, Salix eriocephala var. watsonii (Bebb) Dorn, Salix flava Rydb., non Schoepf, Salix lutea var. desolata E.H. Kelso, Salix lutea var. famelica Ball, Salix lutea var. platyphylla Ball, Salix lutea var. watsonii (Bebb) Jepson, Salix ormsbyensis von Seem., Salix rigida var. watsonii (Bebb) Cronq., Salix watsonii (Bebb) Rydb.]
Shrubs, 3-7 m, (sometimes forming clones by stem fragmentation). Stems: branches (sometimes ± brittle at base) yellow-gray, yellow-brown, or gray-brown, (sometimes weakly glaucous, with sparkling wax crystals), glabrous; branchlets red-brown or brownish, glabrous or pilose, (inner membranaceous bud-scale layer free, separating from outer layer). Leaves: stipules rudimentary or foliaceous on early ones, foliaceous on late ones, apex acute or rounded; petiole convex to flat, or shallowly grooved adaxially, 4-19 mm, pilose, velvety, or pubescent to glabrescent adaxially; largest medial blade (sometimes amphistomatous), lorate, narrowly elliptic, elliptic, lanceolate, or narrowly oblanceolate, 42-90 × 8-32 mm, 2.8-3.9-5.6 times as long as wide, base rounded, convex, or subcordate, margins flat, entire, serrulate, crenulate, or sinuate, apex acuminate to acute, abaxial surface glaucous, glabrous, pilose, or sparsely long-silky, hairs straight, adaxial dull or slightly glossy, glabrous, pilose, sparsely long-silky, especially midrib; proximal blade margins entire, serrulate, or crenulate; juvenile blade reddish or yellowish green, glabrous or sparsely to moderately densely long-silky throughout, hairs white. Catkins flowering as leaves emerge; staminate stout, slender, or subglobose, 10-45 × 6-12 mm, flowering branchlet 0.5-2 mm; pistillate loosely to densely flowered, stout or subglobose, 13.5-38 × 7-15 mm, flowering branchlet 0.5-7 mm; floral bract brown, tawny, or bicolor, 0.6-1.2 mm, apex acute or rounded, abaxially glabrous or sparsely hairy, hairs curly. Staminate flowers: adaxial nectary narrowly oblong, oblong, square, or flask-shaped, 0.4-0.9 mm; filaments distinct or connate less than 1/2 their lengths, glabrous; anthers yellow or purple turning yellow, (ellipsoid or globose), 0.4-0.8 mm. Pistillate flowers: adaxial nectary oblong, square, or ovate, 0.3-0.9 mm, shorter than stipe; stipe 0.9-3.8 mm; ovary pyriform or ovoid, glabrous, beak gradually tapering to styles; ovules 12-24 per ovary; styles 0.1-0.6 mm; stigmas flat, abaxially non-papillate with rounded tip, or 2 plump lobes, 0.14-0.2-0.3 mm. Capsules 3-5 mm. 2n = 38. Flowering Mar-May. Banks of streams, meadows, hillsides, gullies, sandy-clay, sandy or rocky substrates; 600-3100 m; Ariz., Calif., Colo., Idaho, Mont., Nev., Oreg., Utah, Wyo. The possible occurrence of Salix lutea in Ginkgo Petrified Forest Park, Washington, needs to be investigated.
Salix lutea forms natural hybrids with S. arizonica.
Plant: tree or shrub; 1.5-7 m tall. STEMS: yellowish, yellow-brown, or gray-brown, glabrous, villous, or glabrescent, sparsely pilose at buds; branchlets yellow-brown or gray-brown, glabrous, villous, or velvety Leaves: stipules leaflike; petioles glabrous or pubescent, 3-27 mm long, without glands at base of blade; mature leaf ligulate, narrowly elliptic, elliptic, or oblanceolate, 42-116 mm long, 10-31 mm wide, 2.2-5.6 times as long as wide, the lower surface glaucous, glabrous, glabrescent, or pilose, the upper surface dull, glabrous, glabrescent, or pilose, especially on midrib; base acute to rounded, the margins slightly revolute or flat, entire, gland-dotted, or serrulate, with 5-12 teeth or glands per cm, the apex acuminate to acute INFLORESCENCE: cylindrical to subspherical catkins; subprecocious or coetaneous; floral bracts brown, 0.6-2 mm long, glabrous or with straight, wavy, or curly hairs, the apices acute to rounded Flowers: STAMINATE FLOWERS in moderately to densely flowered catkins, 15-50 mm long; flowering branchlets 0.2 mm long; filaments glabrous; nectary slender, 0.4-0.7 mm long. PISTILLATE FLOWERS in loosely flowered catkins 20-75 mm long; flowering branchlets 0.8 mm long; ovaries glabrous; stigmas 0.16-0.36 mm long; styles 0.2-0.6 mm long; stipes 1-3.4 mm long; nectary slender or broad, 0.2-0.6 mm long, shorter than stipe Fruit: lanceolate to ovate Misc: thickets along rivers and creeks; 1200-1300 m (3800-4100 ft); Mar-May REFERENCES: Argus, George W. 1995. SalicaceaePart 2. Salix. J. Ariz. - Nev. Acad. Sci. 29(1): 39