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..
Similar to the preceding species, perennial by long rootstocks, culms stout, sharply 3-angled with concave sides, 2°-7° tall. Leaves 1-3, 1-5' long, or sheaths sometimes leafless; spikelets capitate in dense clusters of 5-12, oblong or ovoid-oblong, obtuse, 2 1/2"-4" long, the solitary involucral leaf short, stout, erect, 1/2'-1 1/4' long; scales oval or orbicular, dark brown with a green midvein, emarginate or mucronulate, glabrous; bristles usually 6, slightly shorter than or equalling the achene, downwardly barbed; stamens 2-3; style 2-cleft; achene obovate, plano-convex, brown, mucronate.
Scirpus Torreyi Olney, Proc. Providence Frank. Soc. 1: 32. 1847.
Perennial by short or slender rootstocks, culms sharply 3-angled, rather slender, nodulose, 2°-4° tall. Leaves narrowly linear, elongated, nodulose, light green, sometimes overtopping the culm; spikelets 1-4, in an apparently lateral capitate cluster, oblong, narrowed at each end, 5"-8" long; involucral leaf 2'-6' long, erect; scales ovate or lanceolate, shining, chestnut-brown, glabrous, obtuse or the upper acute, mucronulate; bristles about 6, downwardly barbed, longer than the achene; stamens 3; style 3-cleft; achene obovoid, smooth, shining, light brown, 3-angled, one of its sides broader and flatter than the others.
In swamps, Maine to Rhode Island and Pennsylvania, west to Minnesota and Manitoba. July-Sept.
Scirpus mucronatus L. Sp. PI. 50. 1753-
Perennial, culms stout, somewhat tufted, sharply 3-angled, smooth, 1°-3° tall. Spikelets 5-12 in a capitate cluster, oblong, obtuse, many-flowered, 4"-9" long, rather more than 1" in diameter, subtended by the solitary linear abruptly spreading involucral leaf; scales broadly ovate, obtuse, light brown with a narrow green midvein, mucronate; bristles 6, stout, rigid, downwardly barbed, as long as the achene; stamens 3; style 3-cleft; achene obovoid, smooth, shining, dark brown, 3-angled, two of the sides narrower and more convex than the third.
In a swamp in Delaware county, Pennsylvania. Probably adventive or fugitive from Europe. Widely distributed in the Old World. July-Sept.
Scirpus maritimus var. cylindricus Torr. Ann. Lye. N. Y.
3: 325. 1836. Rhxnchospora etuberculata Steud. Syn. PI. Cyp. 143.
Perennial by stout rootstocks, culm stout, sharply 3-angled above, 3°-6° high, the linear nodulose keeled and channeled dark green leaves nearly or quite as long. Involucral leaf solitary, 4'-10' long, erect; spikelets in an apparently lateral simple or compound umbel, drooping, oblong-cylindric, acutish, 6"-10" long; primary rays of the umbel 1'-4' long, bracted by 1 or more subulate-linear leaves; scales ovate or ovate-lanceolate, pale brown with scarious margins, acute, mucronulate; bristles 6, stout, rigid, about as long as the achene, serrate; stamens 3; style 3-cleft; achene obovoid, 3-angled, light brown, smooth, abruptly subulate-pointed.
In ponds and swamps, Maryland to Florida and Louisiana, mostly near the coast. Pole or Pool-rush. July-Sept.