Plants perennial, mat-forming. Taproots filiform to slightly thickened. Stems ascending to erect, green, 3-10 cm, glabrous, internodes of all stems 2-4 times as long as leaves. Leaves overlapping prox-imally (basal rosette), perfoliate, connate proximally, with ± tight, herbaceous to scarious sheath 0.5-1 mm; blade erect to spreading, green, weakly 1-veined abaxially, flat, ± linear, 4-12(-15) × 0.5 mm, flexuous, margins not thickened, slightly scarious to herbaceous, smooth, apex green, rounded, dull, glabrous; axillary leaves absent. Inflorescences 3-5-flowered, open, leafy cymes or sometimes solitary, terminal; bracts linear to subulate, mostly herbaceous. Pedicels 0.2-1(-2) cm, glabrous. Flowers: hypanthium disc-shaped; sepals obscurely veined, elliptical-oblong to obovate (herbaceous portion elliptical-oblong to obovate), 2-4.5 mm, not enlarging in fruit, apex green, obtuse to rounded, not hooded, glabrous; petals clawed, broadly obovate, 2-2.2 times as long as sepals, apex rounded, shallowly notched. Capsules on stipe shorter than 0.1 mm, broadly ellipsoid, 5.5 mm, longer than sepals. Seeds brown, obliquely triangular with adaxial groove, radicle prolonged into short beak, compressed, 0.5-0.8 mm, obscurely tuberculate. 2n = 20.

Flowering late spring-summer. Rocky and gravelly slopes, ledges in alpine areas, cracks in exposed bedrock; 0-1800 m; Greenland; St. Pierre and Miquelon; Nfld. and Labr., N.S., Nunavut, Ont., Que.; Maine, N.H., N.Y., N.C., S.C., Tenn., Vt., Va., W.Va.; South America (Brazil).

Minuartia groenlandica is morphologically very similar to M. glabra (Michaux) Mattfeld; the two are clearly separable by habit, phenology, and elevation at the southern end of the range of M. groenlandica (R. E. Weaver 1970).

E. Hultén (1964) confirmed the report of Minuartia groenlandica from a mountain in southern Brazil (Morro de Igreja, Santa Catarina). This remains the only report of Minuartia in South America.