Herbs, perennial, cespitose, 5--30 cm. Stems compact. Leaves in narrow fans, 4--15 cm; sheaths reddish, soft, papillate; blade deep green, narrowly linear, 0.8--2(--3) mm wide, smooth, margins smooth to papillate. Inflorescences: scape sheaths exceeded by leaves; scapes linear, wiry, terete, (0.25--)0.5-- 0.8(--1) mm wide, distally with 2--4 ribs, ribs papillate; spikes broadly to narrowly ellipsoid or ovoid, 4--8 mm; fertile bracts 3--4(--4.5) mm, margins erose or minutely fimbriolate, sometimes with narrow reddish border, apex very slightly to slightly keeled. Flowers: lateral sepals slightly exserted, straight, 4.2--4.7 mm, keel scarious, entire or apically lacerate, apex red, narrow, firm; petals unfolding in morning, blade obovate, 3--4 mm; staminodes bearded. Seeds translucent, narrowly ellipsoid, (0.6--)0.7--0.9(--1) mm, finely lined. Flowering summer--fall. Sphagnous bogs, poor fens, acid seeps, shores of glacial lakes, streams, muskegs, or floating bog mats; 0--500 m; N.B., Nfld. and Labr. (Nfld.), N.S., Ont., Que.; Conn., Maine, Mass., Mich., Minn., N.H., N.J., N.Y., Pa., R.I., VtT., Wis. Most or all known populations of this species fall within the boundaries of Wisconsin glaciation. The long stems (a trait not known for other North American species) are a response to the burial of the clump bases in deep sphagnum.
Densely tufted, lvs narrowly linear, mostly 4-15 cm נ1-2.5 mm, ascending, straight or slightly twisted, with pistillate or scabrous-tuberculate surface, dark green except at the dilated, soft, thin, keeled, anthocyanic base; scapes 0.5-3 dm, terete and slightly twisted below, usually 2-4-keeled just below the spike, the ridges papillate; spikes few-fld, less than 1 cm long; lateral sep shortly included, slightly curved, narrow, the thickened, narrow keel entire or slightly ragged or ciliate apically; seeds 0.8-1 mm, somewhat caudate, finely papillate-ridged, often some (or most) of them abortive. Sphagnum-bogs, tamarack-swamps, etc.; N.S. and s. Me. to Pa., w. to Mich., Wis., Minn., and s. Ont. Midsummer-fall.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.