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 rather stout, 40 high or less, tufted. Leaves flat, 1"-2 1/2" wide; spikelets several or numerous in several rather loose axillary clusters, 1 1/2"-2" long, fusiform, their scales brown; bristles upwardly barbed, as long as the achene and tubercle; achene narrowly obovate, brown, smooth, shining, about 3/4" long, the smooth tubercle about one-half as long.
Bogs and damp hillsides, New Jersey and Pennsylvania to North Carolina. July-Aug.
Light green, culms tufted, sharply 3-angled, smooth, 1°-2° tall. Leaves flat, narrowly linear, grass-like, l 1/2"-2" wide or the basal ones broader, the uppermost sometimes overtopping the culm; spikelets ovoid-oblong, acute, 1 1/2" long, sessile or nearly so, capitate in 2's-7's on the ultimate branches of the axillary and terminal clusters; bracts setaceous; scales dark brown, broadly ovate or suborbicular; bristles 6, upwardly barbed, shorter than the achene; achene broadly obovate to oblong, lenticular, transversely wrinkled; style 2-cleft; tubercle conic, one-fourth to one-third as long as the achene.
Moist soil, New Jersey to Illinois, Arkansas, Florida and Texas. Also in the West Indies and South America. June-Aug.
Rynchospora rariflora (Michx.) Ell., of the Southeastern States, Cuba and Jamaica, recently found at Cape May, New Jersey, has filiform culms and leaves and filiform-peduncled spikelets.
Rhynchospora Torreyana A. Gray, Ann. Lye. N. Y. 3: 197. 1835.
Culms terete or obscurely 3-angled, smooth, slender, 1 1/2°-3° tall. Leaves involute, the lower 1 1/2"-2" wide at the base and elongated, the upper bristle-like, distant; spikelets ovoid, 1 1/2" long, peduncled, numerous, in 1-4 loose distant clusters; scales brown, ovate, mucronate; bristles 6, upwardly barbed, shorter than the oblong-obovate transversely wrinkled lenticular achene; style 2-cleft; tubercle flat, conic, one-fourth to one-third as long as the achene.
In wet pine barrens, New Hampshire and Massachusetts to South Carolina and Georgia. July-Aug.
Schoenus inexpansus Michx. Fl. Bor. Am. 1: 35. 1803.
Rootstocks slender, culms tufted, smooth, slender, 3-angled, 2°-3° tall. Leaves smooth, 1 1/2" wide or less, flat, the lower elongated, the upper bristle-like, remote; spikelets spindle-shaped, acute at both ends, about 3" long, numerous, in 1-4 narrow finally drooping panicles; scales brown, lanceolate, acuminate; bristles 6, upwardly hispid, very slender, about twice as long as the achene; achene narrowly oblong, transversely wrinkled; style 2-cleft; tubercle flat, triangular-subulate, one-half as long as the achene
Moist soil, Virginia to Louisiana. June-Aug.