Perennials, usually 8–18 cm tall, caespitose, subglabrous; rhizome ascending; plant base straw-brownish or pale castaneous brown. Basal leaves numerous, crowded, ±flat, usually up to 5 cm long, (2–) 3–4 mm wide; cauline leaves (1–) 2, 1–2 (–3) cm long, 1–2 mm wide; all leaves with obtuse slightly swollen tip with spinuliform mucro (caducous). Inflorescence congested in a single dark many-flowered head 0.8–1.0 × 0.6–0.9 cm, composed of 1–3 clusters; basal cluster sometimes on erecto-patent peduncle up to 3 cm long. Lower bract usually scarious to straw-brown, subglabrous, linear-lanceolate, 4–9 mm long, much shorter than inflorescence. Bracteoles ±ovate, ±obtuse, sparsely ciliate above, up to 1.2 mm long, dark brown. Tepals subequal, 1.6–1.9 (–2.0) mm long, acute, dark castaneous to blackish brown. Stamens 6; anthers 0.3–0.6 mm long; filaments 0.4–0.5 mm long; style 0.1–0.2 mm long; stigmas 0.8–1.0 mm long. Capsule ovoid-trigonous, exceeding tepals; capsule segments 2.1–2.3 × c. 1.2 mm, blackish brown. Seeds ellipsoidal, 1.0–1.2 × 0.6–0.7 mm, brown, distally with a greyish tip; basal appendage up to 0.2 mm long, fibrillate. 2n=24, fide G.Knaben & T.Engelskjøn, Acta Borealia, A. Sci., 21: 4 (1967).
Basal leaves with obtuse, often slightly swollen tip with a spinuliform mucro; seed base with appendage c. 0.2 mm long and fibrillate.
Moist places in arctic and mountain tundra.
Arctic regions of Eurasia and North America, mountains of S Siberia. 10: FIN, NOR, SVA, SWE. 14: RUN. 30: BRY, CTA, IRK, KRA, TVA, WSB, YAK. 31: MAG. 70: ASK, GNL, NWT, YUK. 71: BRC. 72: NFL, QUE.
10: NORWAY: Folldal, between Råtåsjø and Råtåsjøhø, T.Karlén 211 (LD). SVALBARD: Isfjorden, Green Harbour, 5 Jul 1925, Lagerkrantz s.n. (S). SWEDEN: Torne Lappmark, Jukkasjärvi, Mt Nissontjärro, 1300–1400 m, C.G.Alm & H.Smith 139 (LD); Torne Lappmark, Jukkasjärvi, Torneträsk Lake, K.H.Rechinger S–230 (W). 30: WEST SIBERIA: Novaya Zemlya, Krestovaya Guba, 10 Aug 1926, H.Steffen s.n. (LD). KRASNOYARSK: E Sayan Mtns, Udinskiy Range, L.I.Malyshev 376 (PRA). 70: GREENLAND: Heilprin Land, Brønlundhus, 31 Jul 1963, Fredskild [Pl. Vasc. Groenl. Exs. 268] (UPS); Melville Bugt, Tugtuligssuaq, 350 m, 16 Aug 1979, Fredskild [Pl. Vasc. Groenl. Exs.] 671 (S). NORTHWEST TERRITORIES [Nunavut]: Franklin, Southampton Is., Coral Harbour, O.Hedberg 3315 (UPS); Franklin, Corwallis Is., Resolute, O.Hedberg 3248 (UPS).