Perennials (somewhat cespitose, subscapose) ; glabrous through-out. Rhizomes absent (caudex usually with slender, rarely stout, rhizomelike branches). Stems erect to ascending, branched (several), 0.1-0.8 (-1.4) dm, glabrous. Basal leaves rosulate, simple, (0.6-)1.2-5(-7) cm; petiole (3-)1-3.5(-5.5) cm; blade usually ovate to oblong, rarely oblanceolate to obovate, (0.4-)0.8-1.7(-2.5) cm × (2-)5-10(-16) mm, base cuneate to obtuse, margins usually entire, rarely repand or obtusely small-toothed (apex obtuse). Cauline leaves 0 or 1 (or 2), simple, shortly petiolate; petiole base not auriculate; blade similar to basal leaves, much smaller. Racemes ebracteate. Fruiting pedicels ascending to erect, 3-6(-8) mm. Flowers: sepals oblong, 2-3(-4) × 0.8-1.5(-2) mm, lateral pair not saccate basally; petals white, oblanceolate, 4-5.5(-7) × 1.3-2(-2.5) mm (not clawed, apex rounded or emarginate); filaments: median pairs 2.5-4 mm, lateral pair 2-3 mm; anthers oblong, 0.5-0.9 mm. Fruits linear, (0.8-)1.3-2.8(-3.7) cm × 1.3-2 mm; ovules 8-18 per ovary; style 0.5-3 mm. Seeds brown, oblong, 1.5-2 × 0.9-1.2 mm. 2n = 16. Flowering Jun-Sep. Mossy areas, tundra, marshes at stream headwaters, cliffs, talus slopes, barren chert slopes, moist rock crevices, rocky slopes, alpine streams, sandy beaches, moist rocky streambeds; 0-2300 m; Greenland; Alta., B.C., Nfld. and Labr. (Labr.), N.W.T., Nunavut, Que., Yukon; Alaska, Calif., Maine, N.H., Oreg., Wash.; n Europe; Asia (Russian Far East, Siberia).