Perennials, c. 15–35 (–65) cm tall, loosely caespitose; rhizome creeping, c. 2 mm in diam., with internodes long. Stem compressed, two-edged, c. 1.5–3.0 mm wide. Cataphylls 1–3, c. 2.5–8 cm long, pale brownish to purplish, gradually changing to cauline leaves. Cauline leaves (2–) 3–5 (–6); blade c. 10–15 (–22) cm long, 2.5–4.5 (–6.0) mm wide, gradually narrowing in acute tip, pluritubular, imperfectly septate; sheaths loose, with distinct membranous margin; auricles absent. Lower bract sometimes submembranous, to 1 cm long, or often leaf-like, c. 2–6 cm long, longer than inflorescence. Inflorescence composite, of 1–2 (rarely 4–10) heads; heads globose or ±lobulate, dark, many-flowered, subsessile or shortly pedunculate, 0.8–1.1 cm wide. Capitulum bracts brownish-membranous with distinct midrib, 2–3 mm long, ovate-lanceolate. Tepals ±equal, or outer slightly longer, narrowly lanceolate, with outer acuminate and inner acute-acuminate, (2.4–) 2.7–3.2 (–3.6) mm long, dark castaneous-brown; margins not visible (very narrow in the inner tepals). Stamens 3; anthers 0.5–0.7 mm long; filaments 0.6–0.9 mm long; style c. 0.3–0.4 mm long; stigmas c. 1 mm long. Capsule unilocular, narrowly oblong-trigonous, subacute, with c. 0.2 mm mucro, c. 2.5–3.2 mm long, usually exceeding or ±equalling perianth, dark castaneous-brown to dark brown. Seeds pale brown, ±ellipsoid, distinctly apiculate on both ends, c. 0.45–0.60 × 0.20–0.25 mm, distinctly longitudinally reticulate. 2n = 40, fide S.Snogerup, Bot. Not. 116: 151 (1963); R.L.Taylor & G.A.Mulligan, Fl. Queen Charlotte Is. 2: 43 (1968); N.A.Harriman & D.Redmond, Rhodora 78: 733 (1976).
Auricles absent; Inflorescence of 1–2 (–10) heads; tepals dark castaneous.
Widely distributed in North America, particularly common in the NW and W, reaching Mexico in the S; also found in the Kuril Is. and Japan. Introduced in N and C Europe, in the eastern United States, Hawaii, New Zealand, and likely to be introduced elsewhere, probably with garden peat. 10: fin, grb, swe. 11: aut, bgm, ger, net. 31: KUR. 38: JAP. 51: nzn, nzs. 63: haw. 70: ALU, ASK. 71: ABT, BRC, SAS. 72: ont, que. 73: COL, IDA, MNT, ORE, WAS, WYO. 74: SDA, wis. 75: nwy. 76: CAL, NEV, UTA. 79: MXC, MXN.
31. KURIL IS.: Urup, Kohune, 3 Aug 1929, S.Bergman (S). 38. JAPAN: Honshu, Fukushima, Ozegahara, K.Ito 73 (TI). 63. HAWAII: Hawaii, Kalanilehua, Jul 1912, J.F.Rock s. n. (W). 70. ALEUTIAN IS.: Unalaska, 28 Jul 1931, Y.Kobayasi (TI). ALASKA: Juneau, Mendenhall, J.P.Anderson 6170 (W). 71. BRITISH COLUMBIA: Moresby Is., Copper Bay, J.A.Calder, D.B.O.Savile & R.L.Taylor 23195 (K; 2n = 40). 73. IDAHO: Nez Perce Co., Craig Mtns, Mill Pond, W.H.Baker 15049 (W). OREGON: Coast Mtns, Taft, Schoover Creek, H.R.Bennett 1591 (W). MONTANA: Spanish Basin, c. 1950 m, P.A.Rydberg 3112 (S). WASHINGTON: Okanogan Co., Mason Ck, 650 m, J.H.Sandberg & J.B.Leiberg 608 (S).
Wet meadows, marshes, shores and banks, to 3000 m.