Plants perennial, cespitose or single, 30-70(-80) cm; rhizomes absent. Culms erect or excurved, lax, leafy, slender to wiry. Leaves overtopped by culm; basal leaves spreading, twisted, distal longer, erect or ascending; blades proximally flat, 1-3 mm wide, apex trigonous, subulate, tapering. Inflorescences: spikelet clusters 1-4, proximalmost widely spaced, spikelets elongate, open, turbinate or compact lobed hemispheric; branches erect to ascending; leafy bracts setaceous, exceeding proximal clusters, exceeded by distal clusters. Spikelets mostly dark brown to brown, globose to broadly ovoid, (2-)2.5-3(-4) mm, apex acute; fertile scales broadly ovate to orbiculate, 1.7-2.3 mm, apex obtuse to rounded or emarginate, midrib mostly included, sometimes excurrent as apiculus. Flowers: perianth bristles 6 or less, antrorsely barbellate, of various lengths. Fruits 1-3 per spikelet, 1.5-1-8 mm (-2 mm in var. pinetorum); body tumidly biconvex; surfaces transversely wavy rugose, intervals of vertically rectangular alveolae or transverse rugosity indistinct, surface isodiametrically alveolate or cancellate; tubercle short conic to patelliform apiculate.
Cespitose, 3-9 dm; lvs coarse, flat, 2-4 mm wide; cymes 1-4, compact, the lateral ones peduncled, the branchlets ending in a small glomerule of a few ovoid spikelets 2-4 mm with 1-3 frs; bristles 5-6, antrorsely barbellate, half to three-fourths as long as the achene; achenes brown, broadly obovoid or subrotund, much thickened distally, 1.1-1.5 mm, nearly as wide or slightly wider, transversely ridged; tubercle conic-deltoid, 0.3-0.6 mm. Swamps, bogs, and wet soil. Var. globularis, with few spikelets, seldom over 6 per glomerule, occurs on the coastal plain from Del. to Fla. and Tex., and in Calif. Var. recognita Gale (R. cymosa, misapplied), with dense glomerules, the spikelets numerous and crowded, occurs from N.J. to S.C. and w. through the s. states, also inland from O. to n. Ill. and Mo.; trop. Amer.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.
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