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..
Culms 1 1/2°-4° tall and slender, erect, rough above. Leaves 1°-2° long, 1"-3" wide, shorter than the culm; sheaths red-dotted and rugulose; head narrowly oblong, 1 1/2'-2 1/2' long, 3"-5" thick, sometimes branched at the base; bracts bristle-like, longer than the spikes or shorter; spikes androgynous, ovoid or ovoid-oblong, 2 1/2"-4" long, usually close together; perigynia dull at maturity, 1 1/2" long, lanceolate or ovate-lanceolate, tapering from a more or less truncate base to a narrow rough 2-toothed beak, few-nerved on outer face; scales acuminate, short-awned.
Vermont to Ontario, south to Maryland and Kentucky. June-Aug.
Loosely caespitose from short rootstocks, rather light green, culms slender, erect, very rough above, 1°-3° tall. Leaves 1/2'-1 1/2" wide, shorter than or sometimes equalling the culm, the lower sheaths reddish-brown dotted; bracts very small or scalelike; spikes several or numerous, staminate above, in a narrowly oblong compact or somewhat interrupted terminal cluster 1'-2' long, 5" thick or less; perigynia broadly ovoid, smooth, dark brown, very plump, hard, shining, strongly rounded and nerved on the outer side, slightly rounded and faintly nerved at base on the inner, 1'-1 1/4" long, not margined, the body slightly more than i" long, suborbicular, truncate or rounded at the base, short-stalked, tapering into a flat conic beak nearly its own length; scales thin, ovate, brownish, acute or short-awned, about equalling the perigynia; stigmas 2.
Loosely caespitose from short rootstocks, the culms sharply triangular, slender, erect, rough above, 1 1/2°-4° tall. Leaves 1/2"-1 1/2" wide, shorter than culm, lower sheaths reddish-brown dotted; bracts small or scalelike; spikes many, androgynous, clusters widely separate, lower usually compound, forming a flexuous nodding head 1 1/2'-3' long, often more than 5" wide; perigynia ovoid, smooth, light brown, plump, hard, rounded and obscurely nerved on the outer side, flatfish on inner, 1 1/4"-1 1/2" long, not margined, round-truncate at base, slightly stipitate, tapering into a flat beak shorter than body; scales thin, ovate, light brown with broad hyaline margins, acuminate or short-awned, usually exceeding perigynia; stigmas 2.
In wet meadows, Quebec to British Columbia, south to Connecticut, New Jersey, Kentucky and Utah. May-July.