Plants perennial, mostly loosely cespitose, to 100 cm, bases swollen; rhizomes short, knotty, or scaly, slender, contorted. Culms sometimes solitary, narrowly linear, distally angular, glabrous. Leaves ascending, from 1/3 as long to equally as long as culms, glabrous to pubescent; sheaths apically ciliate; ligule essentially absent or (in rhizomatous individuals) present, complete or incomplete; blades narrowly linear, 1-2 mm wide, mostly strongly involute, scabrid-ciliate. Inflorescences: anthelae simple or compound, compact or diffuse, mostly broad, ascending-branching; scapes slender, wandlike, 1 mm thick; lower leafy involucral bracts exceeded by or exceeding panicle. Spikelets variously red-brown, broadly ovoid to lance-cylindric, 5-10 mm; fertile scales broadly ovate, obtuse or obtuse-angled, 2.5-3.5 mm, abaxially glabrous or variously puberulent, midrib excurrent as mucro. Flowers: stamens 3; styles 2-fid, flat, fimbriate. Achenes yellowish to dark brown, lenticular-obovoid, 1 mm, with 11-20 vertical lines of horizontally rectangular or isodiametric, distinct or indistinct pits. 2n = 20.
Perennial from short, stout, knotty rhizomes; stems solitary or in small tufts, to 1 m, smooth, slender, terete or broadly oval in section; lvs smooth or often hairy, usually involute, ca 1 mm wide; ligule inconspicuous or wanting; longest invol bract usually much shorter than the infl; spikelets 5-10 mm, ellipsoid to lance-ovoid or ovoid, not very numerous, in a usually compound system of subumbellate cymes; scales ovate to obovate or reniform, usually smooth, minutely excurrent- mucronate; stamens 3; anthers 2-2.5 mm; style bifid, fimbriate from near the middle to the branch-point; achene lenticular, obovate, 1 mm, finely cellular-reticulate in vertical rows; 2n=20, 40. Meadows, prairie swales, savannas, and upper edges of marshes and bogs, not or scarcely maritime; s. U.S., n. mainly on the coastal plain irregularly to L.I., Pa., Mich., and Ill., more commonly to Mo. and Neb., and irregularly to Utah. Ours is var. puberula. West of our range this gives way to var. interior (Britton) Kral, with numerous more slender rhizomes and with the longest bract usually surpassing the infl. (F. interior)
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.