Plants densely cespitose; rhizomes arching, short. Culms trigonous, 10-40 cm, scabrous proximal to inflorescence. Leaves: basal sheaths gray-brown; distal leaf sheaths concave at mouth; blades 6-9 × 0.4-0.5 mm, much shorter than culms at flowering and fruiting. Inflorescences: spikelets 15-20-flowered, 5.4-8 × 2.2-3.5 mm; bracts equaling or shorter than spikelets, 4.5-7.8 mm, apex mucronate or awned, awn to 3 mm. Spikelets: scales yellow-brown, apex obtuse. Flowers: perianth bristles 6, white, flattened, exceeding achenes by as much as 20 times, smooth; anthers 1.1-1.6 mm. Achenes plano-convex, 1.2-1.6 × 0.5-0.8 mm. 2n = 58.

Fruiting summer (Jun-Aug). Open or shaded, wet, peaty or gravelly fens, bogs, sheltered banks of lakes, ponds, and streams, tending to occur on lime-rich substrates; 0-1400 m; Alta., B.C., Man., N.B., Nfld. and Labr., N.W.T., N.S., Nunavut; Ont., Que., Sask., Yukon; Alaska, Conn., Maine, Mass., Mich., Minn., Mont., N.H., N.J., N.Y., Vt., Wis.; Europe; c Asia (Kamchatka).

Stems clustered on a rather short, freely rooting rhizome, 1-4 dm, sharply triquetrous, antrorsely scaberulous on the angles, bearing several ±reduced scale-lvs at the base and 1 or 2 more normal lvs a little higher, these with narrow blade 5-12 mm; spikelet 1, terminal, brown, 5-7 mm, mostly 10-20-fld, the invol represented only by 2 or 3 empty scales at the base (these often deciduous as the spikelet approaches full maturity), the lowest scale with a strong midrib prolonged into a blunt mucro 0.5-2 mm; scales lance-ovate, blunt; bristles 6, white, flattened, crisped, elongate and much surpassing the scales, at maturity forming a silky-white tuft extending 1-2 cm beyond the end of the spikelet; anthers 0.6-1.1 mm; achene trigonous, brown, narrowly obovoid, 1-5 mm, apiculate; 2n=58. Bogs; circumboreal, extending s. to Conn., N.Y., Mich., Minn., and B.C. Fr June-Aug. (Eriophorum alpinum; Trichophorum alpinum) Transitional to Eriophorum.

Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.

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