Salix exigua Nutt.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.
Species Description - Many-stemmed colonial shrub 1.5–3(–5) m, the slender, brown to reddish-brown, leafy twigs sericeous at least when young, often soon glabrous; stipules minute and caducous (rarely to 3 mm) or obsolete; lvs linear or broadly linear to linear-oblanceolate, 5–14 cm × 5–12(–18) mm, acute or acuminate at both ends, subsessile, remotely and irregularly spinulose-denticulate, green on both sides but paler beneath, often sericeous when young, later glabrous (or the new lvs produced after insect-attack more densely and permanentlSy sericeous); catkins with the lvs, 1–3 together on very short lateral branches from axillary buds of the previous year, and often again in midsummer, terminating leafy lateral branches 3–10 cm; scales pale, yellowish, soon deciduous; stamens 2; pistillate catkins lax, 2–6(–8) cm; frs narrowly lanceolate, 5–8 mm; pedicels 0.5–1.5 mm; style virtually obsolete; 2n=38. Common on sandbars, mudbars, and moist alluvial soil; widespread in the U.S., s. Can., and n. Mex. Plants from e. of the Rocky Mts., as here described, constitute the subsp. interior (Rowlee) Cronquist (S. interior; S. longifolia Muhl., not Lam.), which has 2 vars. All or nearly all our plants belong to the var. angustissima (Andersson) Reveal & C. R. Broome, which has the ovaries hairy at least when young, although the frs are often glabrate. The more n. or nw. var. pedicellata (Andersson) Cronquist, with the ovaries and frs glabrous from the first, may be sought along the w. margin of our range.