7. Eriophorum chamissonis C. A. Meyer in C. F. Ledebour, Fl. Altaica. 1: 70. 1829.
Russett (Rusty) cotton-grass, linaigrette de Chamisso
Eriophorum altaicum Meinshausen var. neogeum Raymond; E. chamissonis var. aquatile (Norman) Fernald; E. rufescens Andersson; E. russeolum Fries subsp. rufescens (Andersson) Hylander; E. russeolum var. albidum F. Nylander; E. russeolum var. leucothrix (Blomgren) Hultén; E. russeolum var. majus Sommier
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.