Perennial herb with knotty rhizomes, tufted 5 cm - 0.5 m tall Leaves: basal, alternate, 12 - 30 cm long, 1 - 6 mm wide, 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 eight, slightly ascending, unequal, 3 - 20 cm long, 1 - 3.5 mm wide, flat. Rays (branches of inflorescence), 1 - 8 cm long. Spikes 1 - 2 cm wide, more or less spherical to broadly egg-shaped, consisting of three to eighteen 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 0.5 mm long. Stigma 1 - 1.5 mm long. Fruit: a one-seeded achene, stalkless, dark brown, 1.5 - 2 mm long, 1 - 1.5 mm wide, widely ellipsoid with a small, slender point at the rounded apex, three-angled, smooth to bumpy, with concave faces. Seed with a thin, non-adherent wall. Culm: 5 cm - 0.5 m long, 0.5 - 1.5 mm wide, triangular in cross-section, solid. Spikelets: 4 - 15 mm long, 2.5 - 3.5 mm wide, compressed, egg-shaped to narrowly lance-shaped, subtended by two small bracts, with three to eighteen floral scales. Scales straw-colored to reddish brown, 1.5 - 2.5 mm long, 1 - 1.5 mm wide, widely egg-shaped with a tiny point at the apex, three- to four-ribbed, lowest one empty.
Similar species: No information at this time.
Flowering: June to September
Habitat and ecology: This rare species has been recorded growing in cinders at railroad yards. One was also found in a Black Oak savanna.
Occurence in the Chicago region: native
Etymology: Cyperus is the ancient Greek word for sedge. Houghtonii is named after the Michigan geologist Douglas Houghton (1809-1845), who discovered this species.
Author: The Morton Arboretum
From Flora of Indiana (1940) by Charles C. Deam
This is a species of the dune area and it has been found only in Lake and Porter Counties.
Much like no. 25 [Cyperus schweinitzii Torr.]; stems smooth, rather obtusely angled, mostly 0.5-1.5 mm thick below the infl; lvs smooth or scabrous on the margins; invol bracts divergently ascending or ±spreading, scales rotund, 2-2.5 mm, in side-view over half as wide as long, multinerved, obtuse or the uppermost minutely mucronulate; achenes 1.5-2 mm, two-thirds as thick (or a little thicker), trigonous with evidently concave faces; 2n=ca 168-172. Dry, often sandy soil, commonly with Pinus banksiana; Mass., N.H., Vt., and s. Que. to Minn. and nw. Ind.; isolated (as a waif?) in n. Va. and e. W.Va. Thought to be derived by stabilizing selection from hybrids between nos. 25 and 27 [Cyperus lupulinus (Spreng.) Marcks] but the achenes different from both.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.