Cyperus compressus

Herbs, annual, cespitose with fibrous roots. Culms trigonous, (2-)6-15(-35) cm × (0.3-)1-1.8 mm, glabrous. Leaves 1-5, flat to V-shaped, (1-)5-15(-22) cm × (0.5-)1.5-3 mm. Inflorescences: spikes ± digitate, ± globose, 7-40 × 10-20 mm; rays (0-)1-6, 2-12 cm; if absent, inflorescence a sessile cluster of (1-)3-10 spikelets; rachis 2-5 mm; bracts (1-)4-5(-6), ascending, V-shaped, 1-15(-20) cm × 0.5-3.5 mm; rachilla persistent, wingless. Spikelets (1-)3-12(-16), greenish white, linear to linear-lanceoloid, compressed-quadrangular, 6-34(-40) × 2-3(-3.6) mm; floral scales deciduous, (8-)16-36(-42), spreading, laterally whitish, greenish, or pale brownish, medially green, weakly 7-9-ribbed, laterally weakly 1-2-ribbed, most ribs medial, ovate, (2.4-)2.6-3 × (1.9-)2-2.4(-2.5) mm, apex acute to ± acute, cuspidate tip (0.3-)0.5-0.7(-0.8) mm. Flowers: anthers 0.6-0.7 mm; styles 0.9-1.3 mm; stigmas 0.5-0.8 mm. Achenes brown, stipitate to sessile, obovoid, (1-)1.2-1.4(-1.5) × 0.9-1(-1.1) mm, apex obtuse to emarginate, surfaces very finely puncticulate.

Fruiting summer-early fall. Various disturbed soils; 0-900 m; Ala., Ark., Del., Fla., Ga., Ill., La., Md., Miss., Mo., N.Y., N.C., Ohio, Pa., S.C., Tex., Va.; Mexico; Central America; South America; Asia; Africa.

Tufted annual 1-3 dm; lvs ±basally disposed, flat or folded, 1-2 mm wide; bracts 3-5, surpassing the infl, 1-2 mm wide; spikes few and sessile, or 1-4 rays present and up to 10 cm; spikelets 3-10, digitately spreading, 1-2.5 cm נ2-4 mm, flattened, 10-40-fld; rachilla persistent; scales 2.5-3.5 mm, broadly ovate, keeled, acuminate and with shortly excurrent midrib, multinerved, greenish, with broad, thin, coppery or pale (often also red-lineolate) margins; achenes shining brownish, broadly obovoid- trigonous, 1-1.4 mm. Sandy woods and fields; pantrop., n. near the coast to Del. and inland to Mo.

Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.

©The New York Botanical Garden. All rights reserved. Used by permission.