Plants 3-6(-8) dm. Stems as-cending to erect, base often reddish, branched proximally. Leaves: ocrea loose, glabrous; petiole 2-29 cm, glabrous; blade ovate to ovate-oblong or triangu-lar, 3-13 × 1.1-12 cm, base mostly truncate to subcordate, apex obtuse to acute. Staminate flowers 1-8 per ocreate fascicle; tepals narrowly oblong to oblanceolate, 1.5-2 mm. Pistillate flowers 2-7 per ocreate fascicle; outer tepals ovate to oblong, 4-6 mm in fruit, inner tepals linear-lanceolate, 5-6 mm in fruit, apex acute. Fruiting perianths 5-6 × 5-6 mm, spines spreading to reflexed, 2-4 mm, base broad. Achenes 4-5 × 2-3 mm, shiny. 2n = 20.

Flowering year-round. Sandy shores, disturbed ground; 0-500 m; introduced; Calif., Fla., Mass., N.J., Tex.; South America (Argentina, Ecuador, Peru); Eurasia (Mediterranean region); n Africa (Mediterranean region); introduced in Eurasia (Cyprus, India, Iran, Iraq, Israel, Lebanon, Pakistan, Syria, Turkey), Africa (Algeria, Kenya, Kuwait, Mauritius, Morocco), Atlantic Islands (Canary Islands), Pacific Islands (Hawaii), Australia.