Plants solitary or tufted, with bulbils on caudices. Leaves basal; petiole ± absent; blade oblanceolate, 6-15(-30) cm, ± fleshy, base cuneate, margins subentire, sometimes 1-3-toothed distally, eciliate or sparsely ciliate, surfaces glabrate. Inflorescences 2(-5+)-flowered, (proximal flowers replaced by bulbils), narrow, branched, sometimes ± open, cylindric thyrses, sometimes solitary flowers, 5-15 cm, glabrous or sparsely purple-tipped stipitate-glandular. ( Pedicels erect to ascending.) Flowers: sepals reflexed, lanceolate; petals white, each with 1-2 basal yellow spots, lanceolate, clawed, 3-8 mm, longer than sepals; filaments linear, flattened; pistils connate 1/2+ their lengths; ovary superior, (to 1/3 adnate to hypanthium). Capsules green to purplish, valvate. 2n = 56. Flowering late summer. Mossy tundra near streams and flushes, wet, rocky slopes, snowbeds; 0-1800 m; Greenland; Nfld. and Labr., N.W.T., Nunavut, Que., Yukon; Alaska, Colo., Maine; n Europe; n Asia.
Stems 5-20 cm from a slender caudex; basal lvs in a small rosette, oblanceolate to narrowly obovate, essentially sessile, 1-2 cm, ciliate below, few-toothed above; cauline lvs none; infl sparsely branched, most of the fls replaced by axillary bulbils, usually with a single terminal fl; pet white, clawed, 4-5 mm, subequal; 2n=56, 64. Circumboreal, s. to Mt. Katahdin, Me. (Hydatica f.; S. stellaris var. comosa)
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.