Herbs, perennial, 3-8 dm. Stems prostrate, villous. Leaves sessile; blade oval to obovate, usually as broad as long, 1.3-3 × 1.1-1.7 cm, apex rounded, pilose, glabrate. Inflorescences axillary, sessile; heads stramineous, globose to ovoid, 0.6-1 × 0.6-0.7 cm; bracts equaling tepals, apex attenuate. Flowers: tepals dimorphic, stramineous, lanceolate, 5-7 mm, apex acuminate, spinose tipped, sparsely villous, hairs barbed; stamens 5; anthers 3-5, globose; pseudostaminodes triangular, shorter than filaments, margins dentate. Utricles included within tepals, brown, compressed, 1.8 mm, apex truncate. Seeds lenticular, 1.3-1.5 mm. Flowering summer-fall. Waste grounds, cleared limestone areas; 0-1500 m; introduced; Ala., Fla., La., N.Y., Tex.; West Indies; South America. Alternanthera pungens was long known as A. repens (Linnaeus) Link, a later homonym of A. repens J. F. Gmelin.

Plant: Perennial prostrate mat-forming forb from a thick vertical root Leaves: leaves opposite, oval, the pairs unequal Flowers: flowers in short axillary spikes with conspicuous white bracts.