General: Perennial, mat- or cushion-forming, 4-14 cm tall; herbage appressed-pilose, often quite sparse on the leaves; caudex branched, clothed in old petiole bases and stipules; rhizomatous. Leaves: Mostly basal, some cauline, alternate, trifoliate, leaflets obovate, 1-2.5 cm long, the terminal one slightly larger than the adjacent lateral pair, apex truncate and mostly 3-toothed, the teeth rounded and mucronate, cauline blades similar but smaller; stipules fused to the petioles, lanceolate, the cauline ones slightly larger than the basal ones; petiole 1-5.5 cm long. Flowers: Inflorescence a spike, globose to ovoid, 1-2.5 cm long, the lower flowers often staminate, the upper ones pistillate, or all flowers bisexual; hypanthium urn- shaped; sepals 4, ovate, 4-5 mm long, greenish brown, often reddish, with a tuft of villous hairs on the inside, the apex mucronate; petals absent; stamens about 12; pistils 2; flowers May-June. Fruits: Achene, ovoid, 1.2-1.6 mm long, glabrous, smooth. Ecology: Rocky slopes, subalpine to alpine habitats; 2600-3700 m (8500-12000 ft); Coconino County; eastern and western Canada, western to southwestern U.S., circumpolar. Notes: In our range, S. procumbens is known primarily from the San Francisco Peaks. Editor: Springer et al. 2008
Flowering stems 5-10 cm, from a multicipital caudex, lfless or few- lvd below the congested cymes; basal lvs overtopping the stem; lfls cuneate to obovate, 1-3 cm, sparsely pilose, 3-5-toothed at the tip; sep longer than the bractlets, twice as long as the pet; 2n=14. Circumboreal, s. to alpine regions of e. Que. and n. N.H., and to Colo. and Calif. June, July.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.