This section is from the book "An Illustrated Flora Of The Northern United States, Canada And The British Possessions Vol1", by Nathaniel Lord Britton, Addison Brown. Also available from Amazon: An Illustrated Flora of the Northern United States, Canada and the British Possessions. 3 Volume Set..
Plants not stoloniferous; culms tufted, stiff, obtusely triangular, forming tussocks, slender, 8'-2o' tall, leafless, except at the base, rough at the top, bearing 2 or 3 distant inflated sheaths, the upper one usually above the middle. Leaves stiff, filiform, triangular, channeled, slightly rough, shorter than or sometimes overtopping the culm; involucral leaf wanting; spikelet solitary, erect; scales ovate-lanceolate or the lowest lanceolate, acuminate, purple-brown to nearly black, thin; bristles white or red-brown, straight, glossy, 4-5 times as long as the scale; anthers linear; achene obovoid, obtuse, brown, minutely apiculate.
In bogs, Newfoundland to Alaska, south to Massachusetts, Pennsylvania, Wisconsin and Manitoba. Also in Asia. Hare's-tail. Cotton-grass or -rush. Canna-down. Catlocks. Moss-crops. June-Aug.
E. vaginatum opacum Bjornst. Grunddr. af. Pit. Lappm. Vaxt. 35. 1856.
E. opacum Fernald, Rhodora 7: 85. 1905.
Loosely tufted, not stoloniferous. Culms slender, terete or nearly so, 1°-2° high, smooth; basal leaves elongated, filiform-channeled; stem-leaves reduced to 2 or 3 close sheaths, the lower one sometimes with a short blade; spikelet solitary, erect; scales thin, ovate-lanceolate or the inner ones linear-lanceolate, acuminate; bristles white or brownish; achene obo-vate-oblong, apiculate.
Bogs, Maine and Massachusetts to Ontario, Alberta, the Yukon Territory and British Columbia. Also in Europe and Asia. Summer.
Culms slender, smooth, nearly terete, spreading or reclining, 20 long or less. Leaves triangular-channeled, the basal ones mostly wanting at flowering time, those of the culm 2 or 3, the upper one with a blade shorter than its sheath, 1 3/4 long or less; involucral leaf about 1/2' long; spikelets 2-4, rarely 6, the slender peduncles pubescent, mostly less than 1' long; scales ovate, grey to nearly black, acutish, the midvein prominent; achenes obovate-oblong, about 1" long; bristles bright white, 1/2'-3/4 long.
In bogs, Quebec to British Columbia, New York, Pennsylvania, Iowa, Nebraska, Colorado and California. Also in Europe and Asia. June-Aug.
Eriophorum tenellum Nutt. Gen. Add. 1818.
Culm slender, stiff, obtusely triangular, rough on the angles above, 1°-21/2° tall, the sheaths all blade-bearing. Leaves narrowly linear, 1" wide or less, triangular-channeled, rough-margined, the upper longer than its sheath; involucral leaf commonly only 1, stiff, erect; spikelets 3-8, capitate or subumbellate, the longer-peduncled ones drooping; scales ovate or oblong, obtuse or subacute, pale yellow to brown, the midvein rather strong, often with a weaker nerve on each side; bristles numerous, bright white, 8"-12" long, 4-6 times as long as the scale; achene linear-oblong, acute, pointed, 1 1/2" long.