Plants annual, sparsely pubescent. Stems prostrate to ascending, branched mainly from base, 0.1-0.4(-0.5) m. Leaves: petiole shorter than blade; blade rhombic-ovate to oblong, 0.5-1.5(-2.5) × 0.3-0.8(-1.5) cm, base cuneate, margins crisped-erose, conspicuously undulate, apex acute to subobtuse, with short mucro. Inflorescences axillary glomerules, green, axes not thickened, not indurage at maturity. Bracts lanceolate to oblong-lanceolate, 1.2-1.7 mm, ± equaling or slightly shorter than tepals. Pistillate flowers: tepals 5, spatulate-oblong, equal to subequal, 1.2-1.7 mm, margins entire, apex rounded to subacute; style branches spreading; stigmas 3, sessile. Staminate flowers intermixed with pistillate; tepals 5; stamens 5. Utricles ellipsoid or obovoid, 1.5-2 mm, slightly longer than tepals, smooth to slightly wrinkled, indehiscent. Seeds black to dark reddish brown, lenticular to obovoid-lenticular, 0.7-1 mm diam., smooth. Flowering summer-fall. Waste places, other disturbed habitats, mostly at seaports and on ballast; 0-500 m; introduced; N.J., N.Y., N.C., Va.; native to South America (Argentina); introduced in s Eurasia and other regions.
Monoecious; stem prostrate, much-branched, 2-6 dm, minutely pubescent; lvs very many, ovate-oblong, 0.5-1.5 cm, acute to rounded, minutely cuspidate, crisped on the margin; infls axillary, 3-10 mm; sep of pistillate fls 4 or 5, spatulate-obovate, 1-1.5 mm, minutely aristate; fr flattened-obovoid, thin-walled, indehiscent, minutely roughened, 1.5-2 mm; seed obovate, reddish- brown, 1 mm. Native of Argentina, occasionally found in waste places in our range, especially about seaports.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.