Perennial herb with short rhizomes and runners, tufted 10 cm - 0.5 m tall Leaves: numerous, basal, alternate, 10 - 40 cm long (about equal to the culm), 2 - 5 mm wide, flat or V-shaped in cross-section, linear, parallel-veined, keeled beneath, with a sheathing base that encloses the stem. Inflorescence: consisting of terminal spikes, subtended by spirally arranged leafy bracts. Bracts three to five, more or less horizontal, unequal, 1 - 20 cm long, 1 - 4 mm wide, flat. Rays (branches of inflorescence) four to nine, usually branched above, 1 - 8 cm long (upper ones 0.5 - 2 mm long). Spikes short, 1 - 3 cm in diameter, palmate, consisting of two to six spikelets. Flowers: minute, in the axil of a floral scale, lacking sepals and petals. Stamens three, exserted. Anthers about 1.5 mm long. Pistil one. Style to 1 mm long. Stigma to 1.5 mm long. Fruit: a one-seeded achene, stalkless, reddish brown, about 1 mm long and 0.5 mm wide, reverse egg-shaped and three-angled with a blunt apex that bears a scarce, slender point. Seed with a thin, non-adherent wall. Culm: solitary, 10 cm - 0.5 m long, 1 - 3 mm wide, triangular in cross-section, solid. Spikelets: 3 - 24 mm long, 2 - 2.5 mm wide, flattened, linear to oblong, subtended by two small bracts, bearing bulblets, with three to twenty floral scales. Scales two-ranked, reddish brown with a prolonged-pointed midrib, 2 - 3 mm long, 1.5 - 2 mm wide, egg-shaped, one- to three-ribbed, lowest one empty.
Similar species: No information at this time.
Flowering: late July to late August
Habitat and ecology: Local in wet, sandy areas and in marshes.
Occurence in the Chicago region: native
Etymology: Cyperus is the ancient Greek word for sedge. Dentatus means toothed.
Perennial from short rhizomes ending in tubers; stems solitary, 1-5 dm; lvs numerous, 2-5 mm wide, about equaling the stem; bracts 3-5, the longer surpassing the infl; rays numerous, 1-5(-10) cm, often branched above; spikes short, loosely hemispheric, 1-3 cm wide; spikelets few to many, flattened, 3-15 mm, with 8-25 fls; some spikelets usually proliferated, bearing much elongate scales; scales normally ovate, 2-3 mm, the midvein prolonged as a short stout point; rachilla wingless; achenes obovoid trigonous, 1 mm or less, half as thick; 2n=34. Sandy shores; Que. and N.S. to n. N.Y., s. to W.Va. and N.C.; nw. Ind.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.