Plants cespitose; taproot stout. Stems simple (very rarely 1-branched), 5-30 cm, pubescent, often densely so distally, with long purple-septate glandular and eglandular hairs, rarely subglabrous. Leaves: basal numerous, blade 1-5 cm × 2-5 mm (including petiole), glabrous or softly pubescent, eglandular; cauline in 1-3 pairs, blade linear to narrowly lanceolate, 0.5-2.5 cm × 2-4 mm. Inflorescences simple, slender, with single terminal flower, occasionally branched with 2 (rarely 3) flowers, densely glandular-pubescent, slightly viscid. Pedicels slender. Flowers: nodding, becoming erect in fruit; calyx veined, ovate-elliptic, 11-17 × 6-10 mm, veins purple with long purple-septate hairs, lobes ovate to triangular, ca. 2.5 mm, margins purple tinged, broad, membranous; corolla dingy pink to purple, 1-11/ 4 times length of calyx, claw shorter than calyx, limb ovate, emarginate to 2-lobed, ca. 1-3 mm, appendages 2, lacerate, ca. 0.3 mm. Capsules equaling to slightly longer than calyx; carpophore 1-2 mm. Seeds brown, ± round to angular, 1.5-2(-2.5) mm diam.; wing flat, ca. as broad as body. 2n = 24.

Flowering summer. Arctic and alpine tundra, gravelly and grassy places; 0-4000 m; Greenland; Alta., B.C., Man., Nfld. and Labr. (Labr.), N.W.T., Nunavut, Ont., Que., Yukon; Alaska, Colo., Mont., Utah, Wyo.; arctic Asia.

Subspecies uralensis is an arctic-alpine taxon. The populations that extend through the Rocky Mountains from Alaska to Utah are often referred to subsp. attenuata. They tend to have a less-inflated calyx, slightly longer purple petals, flowers that are angled at less than 45° rather than nodding, and less well-developed cauline leaves. These differences are minor, however, and populations of subsp. attenuata often contain plants referable to subsp. uralensis, while plants resembling subsp. attenuata are scattered across the range of subsp. uralensis. Some collections from the southern Rocky Mountains (Colorado and Utah) appear to intergrade with S. kingii in having a narrow wing to the seeds. Hybrids with S. involucrata occasionally occur in nature, and A. Nygren (1951) reported a synthesized hybrid that was triploid (2n = 36) and sterile (see discussion under 57. S. sorensenis).