Stem green or red, 80-150 cm tall, stout, often branched. Petiole green or red, 2-6 cm; leaf blade green, red, purple, or yellow, ovate, ovate-rhombic, or lanceolate, 4-10 × 2-7 cm, glabrous, base cuneate, margin entire or undulate, apex obtuse or notched, with a mucro. Flowers in dense clusters at leaf axils or in spike at apex; male and female flowers in same inflorescences. Bracts and bracteoles ovate-lanceolate, 2.5-3 mm, transparent, apex long pointed. Stamens 3. Stigmas 3. Utricles included in perianth, ovate-oblong, 2-2.5 mm, circumscissile. Seeds brownish black, subglobose or obovoid, ca. 1 mm in diam. Fl. May-Aug, fr. Jul-Sep. 2n = 34*, 68, 85*.