Plants colonial from long-creeping rhizomes. Culms solitary or few together, somewhat trigonous, (20-)30-70(-80) cm, stout, to 1.5(-4) mm diam. basally; basal sheaths persistent, brown to purplish brown, septate-nodulose. Leaves: blades filiform, trigonous-channeled, (2-)3-10 cm × 1-2 mm; distal 1-2 leaf sheaths bladeless, inflated. Inflorescences: involucral bracts absent. Spikelets solitary, erect, globose in fruit, 1.5-2(-4) cm; scales blackish to purplish brown; proximal empty scales not more than 7, obovate or trigonous-obovate, 4-20 mm, margins white or paler, as wide as dark portion, apex blunt; distal scales obovate to ovate-lanceolate, margins hyaline, 1 mm wide or wider. Flowers: perianth bristles 10 or more, red-brown to white, 20-40 mm, smooth; anthers (0.6-)1.5-3 mm. Achenes oblong-obovoid, 2-2.7 mm, as wide as long, apex apiculate (0.3-0.5 mm). 2n = 58. Fruiting summer. Peat, bogs, marshes, muskegs; 0-3000 m; Greenland; St. Pierre and Miquelon; Alta., B.C., Man., N.B., Nfld. and Labr., N.W.T., N.S., Nunavut, Ont., P.E.I., Que., Sask., Yukon; Alaska, Colo., Idaho, Minn., Mont., Nebr., N.Dak., Oreg., Utah, Wash., Wis., Wyo.; Eurasia. The Eriophorum chamissonis complex contains taxa based mainly on stem size and bristle color (M. Raymond 1954). Much of the variation appears to be continuous with abundant intermediates; experimental studies are needed to determine the biological basis of the variation.
Extensively colonial from creeping rhizomes, stems rather stout, 3-7 dm; lvs few, mostly near the base, ±with narrow, channeled or triangular blade 1-2 mm wide; bladeless sheaths 1 or 2, the upper near or below the middle of the stem; sterile scales few, obovate to triangular-ovate, blackish, pale-margined, ascending; anthers 1-2.5 mm; bristles reddish-brown to nearly white; achene dark, oblong-obovate, 2-2.7 mm, a third as wide, distinctly (0.3-0.5 mm) apiculate; 2n=58. Bogs; circumboreal, s. to N.B., Minn., and Oreg. Fr July, Aug. (E. russeolum
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.