Culms decumbent and sprawling, rooting at the nodes, distally erect, to 15 dm; sheaths roughly retrorse-scabrous; ligule truncate, to 1 mm; blades very rough-margined with stiff colorless spinules, the main blades 15-30 cm נ6-15 mm; panicles pale green or whitish, the terminal one to 30 cm, exserted or partly included, its slender branches ±spreading when exserted; lower part of the panicle with 2 or 3(4) branches per node; spikelets ascending, 4-7.5 mm, a fourth to a third as wide, imbricate in spike-like clusters of 3-8 ending the branches; lemma pilose, stiffly ciliate on the keel; stamens 3; late-season axillary panicles reduced and ±included in the sheaths; 2n=48. Swamps, wet meadows, and muddy soil; Que. and N.S. to B.C., s. to Calif. and Fla.; Europe; e. Asia. Estuarine plants vary to a flaccid, virtually glabrous phase with included panicles.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.