Plants perennial, glabrous or indistinctly papillose-pubescent especially on leaf blade veins abaxially, with creeping or fusiform rhizomes. Stems erect, branched above middle (only in inflorescence), 60–100 cm. Leaves: ocrea deciduous or partially persistent at maturity; blade with lateral veins ± equal in size, oblong or oblong-lanceolate, 20–40(–50) × 8–15(–18) cm, more than 3 times as long as wide, base broadly cuneate, obtuse, or weakly cordate, margins entire, flat, apex acute, subacute, or acuminate. Inflorescences terminal, occupying distal 1/2 of stem, often dense, narrowly paniculate. Pedicels articulated in proximal 1/2, filiform, (5–)12–15(–17) mm, articulation indistinct, scarcely visible. Flowers 10–20 in whorls; inner tepals ovate-deltoid, 4.5–7 × 3.5–7 mm, widest in proximal 1/3, base truncate or weakly emarginate, margins erose to weakly serrate or indistinctly denticulate in basal part, apex acute to acuminate; tubercles absent. Achenes brown, 2.5–4 × 1.5–2.5 mm. 2n = 120.
