Herb, annual or perennial, glabrous, to 350 cm tall; rhizome present, to 3 x to 4 cm; stolon absent. Leaves emerged, green to green-brown, petiole triangular, 17.5-55 x 0.5-1.1 cm, basal sheath to 23 cm long, blade narrowly elliptic to elliptic-ovate, 12.5-27 x 1.4-15 cm, margin entire, apex acute, base truncate to attenuate, basal lobes absent, veins 5-7, pellucid markings absent. Inflorescence racemose or paniculate, erect or rarely decumbent, with 4-8 whorls, overtopping leaves, often vegetatively proliferating, to 40 x to 30 cm; whorls with 6-40 flowers; peduncle triangular, not winged, 40-100 x 0.03-0.1 cm; rachis between whorls triangular, not winged; bracts shorter than pedicel subtended, coarse, linear, 15-31 x 0.2-0.5 mm, apex acuminate to subulate, not dilated basally; pedicels in flower and fruit spreading, cylindrical, 0.5-6.5 x 0.05-0.1 cm. Flowers ca. 1.6 cm wide; sepals in flower and fruit spreading, 4.5-6.5 x 1.8-3.2 mm, with ca. 20 veins, mostly not papillose; petals not clawed, ca. 7 x ca. 6 mm; stamens 20 or more, filaments to 1.5 mm long, anthers versatile, to 2.5 mm long, apex obtuse; carpels 30 or more. Fruit terete, obelliptic, 1.5-3 x 0.4-0.8 mm, 4-ribbed, 1-keeled, eglandular, beak terminal, erect, to 0.7 mm long.
Argentina present, Guyana present, Northern America, Southern America: Nicaragua (Nicaragua present); Paraguay (Paraguay present), northern S America present
from Mexico, Nicaragua, and northern S America S to Paraguay and Argentina; more than 100 collections examined, 2 from Guyana (GU: 2).