Plants perennial, glabrous or very indistinctly papillose normally only on veins of leaf blades abaxially, with fusiform, vertical rootstock. Stems erect, branched from above middle, 80–150(–200) cm. Leaves: ocrea deciduous or partially persistent at maturity; blade ovate-lanceolate or oblong-lanceolate, normally 30–45(–50) × 10–15 cm, base truncate, broadly cuneate, or weakly cordate, margins entire, flat or weakly undulate, apex acute or subacute. Inflorescences terminal, occupying distal 1/2 of stem, normally dense, narrowly to broadly paniculate, branches usually straight or arcuate, rarely indistinctly flexuous. Pedicels articulated in proximal 1/3, sometimes almost near base, filiform, 5–13(–17) mm, articulation usually distinctly swollen. Flowers 10–20(–25) in whorls; inner tepals broadly ovate, suborbiculate, or orbiculate, (5–)5.5–8(–10) × 5–9(–10) mm, base usually distinctly cordate, margins entire or subentire to very weakly erose, apex obtuse or occasionally subacute; tubercles normally 1, more than 1 mm wide, normally less than 2 times as wide as inner tepals, occasionally 3, then 2 much smaller. Achenes brown, 3–3.5 × 1.5–2.5 mm. 2n = 60.
