Fuirena simplex var. aristulata

Herbs usually annual, rarely taller than 30-40 cm; rhizomes mostly absent, when present very short. Culms tufted (more slender than in preceding variety). Leaves: principal blades 5-12 cm. Spikelets to 12, lance-ovoid or lanceoloid; fertile scales 2-3 mm. Flowers: anthers 1-3, 0.5-0.6 mm.

Fruiting summer-fall. Sand or clay, silt, of prairie swales, alluvial terraces, moist waste sites, pond and lakeshores; 0-500 m; Ark., Kans., La., Mo., Nebr., N.Mex., Okla., Tex.

Most North American material of var. simplex is cespitose, the rhizomes short. In such specimens the evident perennial habit and the longer anthers are more reliable characteristics.