31a. Salix rotundifolia Trautvetter var. rotundifolia
Round-leaf or least willow
Salix leiocarpa (Chamisso) Coville; S. polaris Wahlenberg var. leiocarpa Chamisso
Plants 0.01-0.05 m. Leaves: petiole 0.5-2-4.6(-5.5) mm; largest medial blade 4.5-8-16.3 × 3-5.9-10.5 mm, 0.92-1.23-2.27(-2.53) times as long as wide. Catkins: staminate subglobose or stout, 9.5-18.5 × 5-12 mm, flowering branchlet 1-9 mm; pistillate: (3-)4-7-15 flowers, stout, subglobose, or globose, 13-35 × 6-17 mm, flowering branchlet 2-22 mm; floral bract hairs usually wavy, some straight, curly, or crinkled, exceeding bract by 0.32-0.71-1.25(-2.4) mm. Staminate flowers: abaxial nectary 0.5-0.6 mm. Pistillate flowers: abaxial nectary present or absent, oblong or narrowly oblong, 0.9-2 mm; stigmas slenderly or broadly cylindrical, 0.36-0.47-0.6 mm. Capsules 4-8.3 mm. 2n = 114.
Flowering Jul-early Aug. Arctic-alpine, Dryas tundra and willow thickets along streams, sedge-grass tundra, sandy, saline coastal flats, beach cobbles, Empetrum-lichen heath on wet slopes, upland shrubby tundra, polygonal tundra and raised center polygons, snowbeds, scree and colluvial slopes, substrates from clay to coarse rubble, both calcareous limestone and acidic; 0-2200 m; N.W.T., Yukon; Alaska; e Asia (Chukotka, Russian Far East, Wrangel Island).