Alternanthera peploides (Humboldt & Bonpland ex Schultes) Urban

Herbs, perennial, 1-5 dm. Stems prostrate to procumbent, villous, glabrate. Leaves sessile; blade rhombic-ovate, oval, or obovate, usually longer than broad, 0.5-2.5 × 0.3-1.5 cm, apex rounded, apiculate, sparsely villous, glabrate. Inflorescences axillary, sessile; heads white to stramineous, ovoid, 0.5-0.8 × 0.4-0.6 cm; bracts shorter than tepals, apex long-attenuate, aristate. Flowers: tepals dimorphic, whitish to stramineous, lanceolate, 3-5 mm, apex acuminate, spinose tipped, densely villous, hairs barbed; stamens 5; pseudostaminodes triangular or subulate, shorter than filaments, margins usually entire, rarely dentate. Utricles included within tepals, brown, ovoid-orbicular, 1.5 mm, apex slightly truncate. Seeds ovate-orbiculate, 1-1.5 mm.

Flowering summer-fall. Gravel, sand bars, sidewalks; 0-2000 m; introduced; Ala., Ariz., Ark., Calif., Fla., Ga., La., Md., Miss., N.Mex., N.C., Okla., S.C., Tex.; Mexico; Central America; South America.