Plants perennial, mat-forming, rhizomatous. Stems creeping, much-branched, rooting, glabrous except for line of small hairs down each internode; flowering shoots decumbent or ascending, 5-10 cm; nonflowering shoots prostrate, 5-15 cm; small axillary tufts of leaves usually absent. Leaves sessile, tending to be marcescent, somewhat succulent; blade elliptic-oblong or linear-lanceolate, 2-12 × 1-3 mm, apex obtuse, rarely acute, glabrous, sometimes ciliate at base. Inflorescences lax, 1-3-flowered terminal cymes; bracts lanceolate, 2-5 mm, glabrous or ciliate. Pedicels becoming curved, slender, 5-35 mm, equaling or exceeding sepals, glandular-puberulent. Flowers: sepals narrowly lanceolate, 4-5 mm, margins narrow, midrib present, apex obtuse, glandular-pubescent towards base; petals 5-8 mm, 1-1.5 times as long as sepals, apex deeply 2-fid; stamens 10; styles 3(-6). Capsules ovoid-conic, oblong after dehiscence, straight, 7-10 mm, 1.5-2 times as long as sepals; teeth 6(-12), erect to spreading, margins convolute. Seeds brown, 0.5 mm diam., shallowly rugose; testa not inflated. 2n = 38.

Flowering summer. Wet, arctic areas, alpine rills, alpine and arctic snowbeds; 0-800 m; Greenland; Nfld. and Labr., Nunavut, Que.; Europe; amphi-Atlantic.