Perennial or biennial, glabrous, 60-120 cm., often with vertical rhizome. Stems erect, often paniculately branching, more or less flexuous, striate-angular. Branches divaricate to ascending. Lower leaves up to 18 x 15 cm., long-petioled, broadly oblong-lanceolate, rounded or truncate or subcordate at base, obtuse at apex, entire or somewhat repand; upper ones smaller, short-petioled, ovate-lanceolate, rounded or subcordate at base, more or less acute or short-acuminate at apex, sometimes minutely crisp. Panicles large, many-whorled; whorls many-flowered, more or less remote, subtended by leaves except for the uppermost ones. Pedicels jointed below middle or near base, reflexed, elongating, equalling or somewhat exceeding fruiting perianth in length. Flowers 1.5-2 mm., usually hermaphrodite. Valves 2-3 x 1.5-2.5 mm., oblong-ovate, entire, each with an ovate-oblong wart, 1-2 mm. long. Achene up to 2 mm., trigonous to ovoid, acute, brown, shining. Fl. April-September.