Michaux, Fl. Bor.-Amer. 2: 225. 1803.
Heart-leaf or sand dune willow
0.4-3 m, (often forming clones by layering or stem fragmentation).
branches (sometimes ± brittle at base), red-brown, not glaucous (slightly glossy), tomentose to glabrescent; branchlets red-brown, moderately to very densely villous.
stipules foliaceous, apex acute or rounded; petiole shallowly grooved adaxially, 1-13 mm, tomentose adaxially; largest medial blade narrowly oblong, or narrowly to broadly elliptic, 33-88 × 13-45 mm, 1.6-3.2 times as long as wide, base cordate, rounded, or convex, margins flat or slightly revolute, serrulate or spinulose-serrulate, apex acuminate, abaxial surface not glaucous, moderately densely villous to glabrescent, midrib remaining hairy, hairs straight or wavy, adaxial dull or slightly glossy, very densely villous to glabrescent, midrib remaining hairy; proximal blade margins entire or serrulate; juvenile blade yellowish green, abaxially villous or midrib long-silky, hairs white.
flowering as leaves emerge; staminate stout, 17-40 × 8-15 mm, flowering branchlet 1-8 mm; pistillate moderately densely flowered, stout or slender, 27-65 × 8-19 mm, flowering branchlet 3-16 mm; floral bract brown, 1-2.6 mm, apex acute or rounded, abaxially hairy, hairs straight or wavy.
adaxial nectary oblong or narrowly oblong, 0.3-1.3 mm; filaments distinct, glabrous; anthers yellow, (ellipsoid or shortly cylindrical), 0.6-0.8 mm.
adaxial nectary oblong or narrowly oblong, 0.4-1.3 mm, about same length as stipe; stipe 0.5-1.4 mm; ovary pyriform or obclavate, glabrous, beak slightly bulged below styles; ovules 11-24 per ovary; styles 0.7-1.6 mm; stigmas flat, abaxially non-papillate with rounded tip, or 2 plump lobes, 0.2-0.3-0.36 mm.
Flowering mid Apr-early Jul. Sand dunes and beaches; 0-200 m; Nfld. and Labr., Ont., Que.; Ill., Ind., Mich., N.Y., Pa., Wis.
seems to be rare in Labrador, Newfoundland, and Quebec; the species needs further study in those areas.