Herbs , annual, with taproot, 3-20 dm. Stems simple or branched from base, erect. Leaf blades ovate to broadly ovate, distal blades becoming ovate-lanceolate to lanceolate, 7-15 × 5-10 cm, base truncate to cordate, margins coarsely dentate, apex acute to caudate; cystoliths rounded or occasionally elongate. Inflorescences racemose, elongate. Flowers unisexual, staminate and pistillate in separate inflorescences, or with a few pistillate flowers at apex of staminate inflorescences, subsessile to short-pedunculate. Pistillate flowers: outer tepals lanceolate to narrowly ovate, 0.8-1 mm, inner tepals broadly ovate, 1.4-2.2 × 1.3-1.4 mm. Achenes ovoid, 1.4-1.6 × 1-1.1 mm. 2 n = 26.

Flowering summer-fall, occasionally all year. Alluvial or calcareous soils, often in moist, shaded places; 1200-2800 m; Ariz., N.Mex., Tex.; n Mexico.