Culms 10-50 cm × 0.4-1.7 mm. Leaves 12-40 cm × 0.8-3.5 mm. Inflorescences: spikes loosely to densely ovoid, 8-16 mm; rays 0 or 1-4, 1-6 cm; bracts 2-4, 6-25 cm. Spikelets 15-40(-60), 6-22 × 3-4 mm; floral scales 5-22, 2.5-4 × 2-2.6 mm, margins not clasping achene. Achenes 1.7-2.2 × 0.8-1.2 mm.

Fruiting summer. Well-drained, open roadsides, fields, prairies; 0-1700 m; Ont.; Ark., Colo., Conn., Del., Idaho, Ill., Ind., Kans., Ky., Mass., Mich., Minn., Mo., N.J., N.Y., N.C., Ohio, Oreg., Pa., R.I., Tenn., Tex., Vt., Va., W.Va., Wis.

Perennial herb with knotted, tuberous rhizomes, tufted 10 cm - 0.5 m tall Leaves: alternate, light green, 12 - 40 cm long, 0.5 - 3.5 mm wide, flat, linear, parallel-veined, keeled beneath, with a sheathing base that encloses the stem. Inflorescence: consisting of one to a few terminal spikes, subtended by spirally arranged leafy bracts. Bracts two to four, more or less horizontal, unequal, 16 - 25 cm long, flat. Rays (branches of inflorescence) zero or one to four, 1 - 6 cm long. Spikes 8 - 16 mm long, loosely to densely egg-shaped, consisting of 15 to 40 spikelets. Flowers: minute, in the axil of a floral scale, lacking sepals and petals. Stamens exserted. Anthers about 0.5 mm long. Pistil one. Style about 1 mm long. Stigma 1 - 1.5 mm long. Fruit: a one-seeded achene, stalkless, dark brown to black, 1.5 - 2 mm long, 0.5 - 1 mm wide, ellipsoid with a small, slender point at the rounded apex, three-angled, tiny-dotted. Seed with a thin, non-adherent wall. Culm: 10 cm - 0.5 m long, 0.5 - 1.5 mm wide, triangular in cross-section, solid. Spikelets: 0.5 - 2 cm long, 3 - 4 mm wide, compressed, narrowly lance-shaped with a rounded or tiny-pointed apex, subtended by two small bracts, with five to twenty-two floral scales. Scales whitish to reddish brown, 2.5 - 4 mm long, 2 - 2.5 mm wide, narrowly elliptic, three- to five-ribbed, lowest one empty.

Similar species: No information at this time.

Flowering: June to late September

Habitat and ecology: Sandy soil.

Occurence in the Chicago region: native

Etymology: Cyperus is the ancient Greek word for sedge. Lupulinus means "resembling hops."

Author: The Morton Arboretum

From Flora of Indiana (1940) by Charles C. Deam

Fernald & Griscom discuss this species and its varieties in Rhodora 37: 153-154. 1935. If I interpret their discussion correctly the distribution of this species is principally on the Atlantic slope and in the Great Plains states. My only specimen is from a dry, sandy ridge in Gibson County. Geise (Amer. Midland Nat. 15: 254. 1934) cites specimens from Lake, La Porte, Marshall, Porter, and St. Joseph Counties, but I refer these specimens to the variety [macilentus].