Glabrous, monoecious perennial with long woody rhizome; stems aerial, erect, to c. 1 m tall. Petiole usually < lamina. Lamina of lower lvs 8-20 × 3-7 cm, usually obovate or elliptic-obovate, ± coriaceous; margins entire or undulate and finely crisped; base rounded to broad-cuneate, sometimes oblique; apex rounded. Upper lvs similar but smaller. Infl. dense, ± pyramidal at flowering, to c. 15 cm long, often with axillary branches developing later, leafless except near base; fls in densely arranged whorls, with small lvs subtending basal whorls. Pedicels short, moderately stout, glabrous. Perianth segments of ♂ fls 2-3 mm long; margins ± hyaline. ♀ fls similar; outer segments ± ovate-elliptic, not reflexed at fruiting; inner segments greatly enlarging at fruiting. Fruiting valves 4.5-6 × 3-4.5 mm, ovate, entire with rounded apex, strongly reticulate; tubercles large, 2-3 mm long, ± oblong, constricted at intervals, 1 to each valve segment. Nuts c. 3 mm long, dark brown, strongly angled.