Perennial, glabrous, 40-120 cm. Stems erect, simple or branched from base, brownish. Leaves usually crisp-undulate, sometimes minutely and obsoletely papillose on veins of lower surface; the lower leaves up to 20 x 8 cm., long-petioled, oblong-lanceolate, rounded or cuneate or truncat base, tapering towards the somewhat acute apex; upper leaves short-petioled, linear-lanceolate, tapering-cuneate at base. Panicles short-branched, somewhat interrupted at base, compact towards apex; branches almost erect, subtended by linear, crisp leaves; whorls many-flowered, approximate. Pedicels reflexed, filiform, jointed below middle, elongating and exceeding fruiting perianth. Flowers hermaphrodite, sometimes unisexual and plants then dioecious. Valves leathery, (3-)4-6 x 3-5 mm., more or less ovate, subcordate, entire or obsoletely denticulate, netted-veined; warts on 1 or all valves, about 2.5 mm., ovate, brown. Achene 2-3 mm., trigonous, ovoid, acuminate, brown.