26. Salix nivalis Hooker, Fl. Bor.-Amer. 2: 152. 1838.
Dwarf snow willow Dwarf snow willow
Salix nivalis var. saximontana (Rydberg) C. K. Schneider; S. reticulata Linnaeus subsp. nivalis (Hooker) Á. Löve, D. Löve & B. M. Kapoor; S. reticulata var. saximontana (Rydberg) Kelso
Plants 0.01-0.04 m, (dwarf, forming clonal mats by rhi-zomes). Stems trailing or erect; branches yellow-brown or red-brown, glabrous or pubescent; branchlets yellow-brown or red-brown, glabrous or pilose. Leaves: stipules absent or rudimentary; petiole 1.5-7 mm (sometimes glandular distally or throughout); largest medial blade hypostomatous, (veins impressed-reticulate, 2 pairs of secondary veins arising at or close to base, arcing toward apex,), elliptic to broadly elliptic, 6-22 × 4-15 mm, 1.1-2.8 times as long as wide, base convex, rounded, subcordate, or cuneate, margins slightly revolute, entire (glandular-dotted), apex convex, rounded, or retuse, abaxial surface glabrous or with long-silky hairs, adaxial slightly glossy, glabrous; proximal blade margins entire; juvenile blade glabrous. Catkins: staminate 7-19 × 2.5-6 mm, flowering branchlet 0.5-17 mm; pistillate densely to loosely flowered (4-17 flowers), stout, subglobose or globose, 7-21 × 2-9 mm, flowering branchlet 1-10 mm; floral bract tawny or light rose, 0.8-1.8 mm, apex rounded, entire, abaxially glabrous. Staminate flowers: abaxial nectary 0.5-1.3 mm, adaxial nectary narrowly oblong, oblong, or square, 0.5-1.2 mm, nectaries connate and cup-shaped; filaments distinct, glabrous or hairy basally; anthers ellipsoid or shortly cylindrical, 0.4-0.6 mm. Pistillate flowers: abaxial nectary (0-)0.2-0.5 mm, adaxial nectary oblong, 0.2-1 mm, longer than stipe, nectaries distinct or connate and shallowly cup-shaped; stipe 0-0.8 mm; ovary obturbinate, short-silky, hairs flattened, beak abruptly tapering to styles; ovules 8-10 per ovary; styles distinct to connate 1/2 their lengths, 0.2-0.4 mm; stigmas flat, abaxially non-papillate with rounded tip, 0.2-0.26-0.36 mm. Capsules 3-4 mm. 2n = 38.
Flowering late Jun-late Aug. Alpine tundra, cirques, lake basins, rocky slopes and ridges, fellfields; 1900-4000 m; Alta., B.C.; Calif., Colo., Idaho, Mont., Nev., N.Mex., Oreg., Utah, Wash., Wyo.
Because geographic overlap is small and evidence of intergradation is tenuous, Salix nivalis is best treated as a species separate from S. reticulata; S. nivalis was previously treated as a subspecies of S. reticulata (G. W. Argus 1986b, 1991).