Plants usually forming mats or low mounds or cushions (not tussock-forming), 2-5 cm; branches procumbent or decumbent, adventitiously rooted, proximal portions of stems with or without persistent leaf remnants. Leaves 3-8(-12) mm; blade obovate to spatulate-elliptic, 1.5-2.2(-3) mm wide, margins narrowly revolute, usually herbaceous, sometimes with narrow hyaline flange. Pedicels 5-20 mm, elongating to 30-50 mm. Flowers: sepals 4-7 mm; corolla 7-9 mm, lobes usually white, sometimes light pink or rose. Capsules 3-4(-6) mm diam. 2n = 12. Flowering Jun-Jul. Tundra, alpine heath, subalpine meadows, slopes and ridges, dry or moist areas, gravel, silt (run-off banks); 500-1500 m; B.C., N.W.T., Yukon; Alaska; Asia (Japan, Korea, Russia [Kamchatka], e arctic and subarctic Siberia).