Plants perennial, cespitose or mat-forming.
Taproots filiform to somewhat thickened; rhizomes absent.
Stems ascending to erect, green, 2-8(-18) cm, moderately to densely stipitate-glandular (very rarely glabrous), internodes of stems 1-10 times as long as leaves; trailing stems absent.
Leaves overlapping, ± tightly, distally (cauline), concentrated proximally (cauline), connate proximally, with often loose, usually scarious sheath 0.2-0.7 mm; blade ± straight or outwardly curved, green, flat to 3-angled, prominently 3-veined abaxially, subulate, 1.5-10 × 0.3-1.3 mm, flexuous, margins not thickened, scarious, smooth, apex green or purple, acute to apiculate, often navicular, shiny, sparsely to densely ciliate, often stipitate-glandular; axillary leaves present among vegetative leaves.
Inflorescences 3-7+-flowered, open cymes or rarely flower solitary, terminal; bracts broadly subulate to narrowly lanceolate, herbaceous, margins scarious.
Pedicels 0.2-1.5 cm, densely stipitate-glandular.
Flowers: hypanthium disc-shaped; sepals prominently 3-veined, ovate to lanceolate (herbaceous portion oblong to narrowly ovate), 2.5-3.2 mm, not enlarging in fruit, apex green to purple, acute to acuminate, not hooded, stipitate-glandular; petals elliptic, 0.8-1.3 times as long as sepals, apex rounded, entire.
Capsules on stipe ca. 0.2 mm, ovoid, 4.5-5 mm, longer than sepals.
Seeds reddish brown, suborbiculate with radicle prolonged into beak, somewhat compressed, 0.4-0.5 mm, tuberculate; tubercles low, elongate, rounded (to angled on edge) (50×).
2n = 24.
Distinct among the arctic/alpine Minuartia species with its stiff, three-veined leaves, M. rubella is a circumpolar calciphile. We follow Ö. Nilsson (2001) in not recognizing infraspecific taxa that have been described based at least partly on pubescence. Variety propinqua has been applied to glabrous plants, which occur infrequently and sporadically throughout the range of the species. Where they do occur they are often intermixed with sparsely stipitate-glandular plants. This glabrous variety is rarely encountered in western North America.
