[Bolboschoenus maritimus var. polyphyllus, moreSchoenoplectus pungens var. polyphyllus (Boeck.) Dorn, Scirpus americanus var. polyphyllus (Boeck.) Beetle, Scirpus pungens Willd. ex Kunth, Scirpus pungens var. polyphyllus Boeck., Scirpus rothii Hoppe]
Rhizomatous, colonial perennial 1.5-15 dm; stems trigonous, with flat to slightly concave or slightly convex sides; lvs usually several, all borne near the base, the blade elongate (but scarcely surpassing the middle of the stem) or reduced, firm, flat and 2-4 mm wide, or more often channeled above or folded; spikelets 1-6, essentially sessile in a compact cluster, mostly 7-20 mm, subtended by a prominent, sharply pointed green bract (1-)2-15 cm that resembles a continuation of the stem; 1 or 2 smaller bracts nearly always present, resembling enlarged scales but not subtending fls; scales thin, largely hyaline-scarious, the brown midrib firmer, exserted beyond the broad apical notch as a prominent mucro or short awn; bristles 4-6, often unequal, retrorsely barbellate, not much if at all surpassing the achene, this 2.2-3.3 mm (including the 0.5 mm stylar apiculus); 2n=78. Marshes and wet, low ground, tolerant of alkali; interruptedly cosmopolitan, and throughout our range. Fr May-Aug. (S. americanus, misapplied; Schoenoplectus p.) Two vars. in our range. Var. pungens, with strictly bicarpellate fls, occurs mainly in and e. of the Appalachian region. Var. longispicatus (Britton) Cronquist, with many or all the fls tricarpellate, extends e. from w. U.S. into the Great Lakes region and the Ohio Valley. (S. longispicatus)
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.