Erect annual to c. 1.2 m high. Stems angled or grooved, glandular pubescent, sometimes reddish. Roots reddish. Leaves long-petiolate, ovate to rhombic, lamina 2–14 cm long, 1–8 cm wide; margin often crenulate and/or undulate; apex sometimes shortly mucronate. Spikes dense, crowded toward the ends of branches and in upper axils, to c. 10 cm long, 1–2 cm diam., greenish or reddish. Flowers unisexual; longest bracts and bracteoles lanceolate, 3–5 mm long, spinescent; tepals 5, oblong, 1.5–3 mm long, obtuse, truncate or emarginate, often shortly mucronate; stamens 5. Utricle circumsciss, subequal to perianth; seed discoid, brown, shiny, 1–1.5 mm diam. Flowers Feb.–May.