Cyperus pseudothyrsiflorus

Herbs, perennial, cespitose, rhizomatous. Culms trigonous, base thickened, tuberous, 15-40 cm × 2-2.6 mm, glabrous. Leaves flat to V-shaped, 10-30 cm × (3-)4-5.8 mm. Inflorescences: spike 1, densely oblong to ellipsoid, 10-20 × 10-20 mm; rays 4-12, 10-20 cm bracts 3-6, horizontal to ascending at 30°, V-shaped, 3-15 cm × (3-)4-5.8) mm; rachilla deciduous, wings persistent, 0.5-0.7 mm wide. Spikelets (5-)10-20(-30), linear to oblong, quadrangular, (2.2-)4-12(-16) × 0.7-1.2 mm, densly packed on rachis with 11-21 spikelets per 5 mm rachis; distal spikelet spreading or ascending; floral scales persistent, 1-5, appressed, laterally whitish to reddish brown, medially green, narrowly oblong to ovate, laterally 3-6-ribbed, 2.4-3.4 × 1.6-2 mm, apex rounded to ± acute, entire, mucronate, mucro 0.1-0.3 mm; sterile terminal scale, involute, only 0.4-0.6 mm wide with mucro 0.2-0.5 mm. Flowers: anthers (0.3-)0.4-0.7 mm; styles 0.4-0.5 mm; stigmas 0.5-0.9 mm. Achenes light brown, sessile to slightly stipitate, ellipsoid to narrowly ellipsoid to narrowly obovoid, 1.4-1.9 × 0.5-0.75 mm, apex slightly apiculate, surfaces puncticulate.

Fruiting mid summer-early fall (Jul-Sep). Damp, disturbed soils, croplands; 0-1000 m; Tex.; Mexico.