Plants perennial, glabrous or nearly so, with fusiform, oblique rootstock, occasionally with horizontal, short-creeping rhizome. Stems erect, simple or branched in distal 2/3 (then with few, comparatively short branches), 10–70(–100) cm. Leaves: ocrea deciduous or partially persistent at maturity; blade narrowly lanceolate, lanceolate, or oblong-lanceolate, normally 5–15(–20) × 1.5–5 cm, base cuneate to broadly cuneate, rarely truncate or very weakly cordate, margins entire or rarely indistinctly repand, flat, apex acute or subacute. Inflorescences terminal, occupying distal 1/2–2/3 of stem, interrupted, paniculate, simple or nearly so (branches, when present usually less than 7–8 cm). Pedicels articulated in proximal 1/3, filiform, 5–13(–17) mm, usually not more than 2–2.5 times as long as inner tepals, articulation weakly evident, not swollen. Flowers 7–15 in whorls; inner tepals ovate, 4.5–7.5(–8) × 4–6(–7) mm, base truncate to weakly cordate, margins entire, apex obtuse or subacute; tubercles absent. Achenes reddish brown, 3–4 × 1.5–2 mm. 2n = 40, 120, ca. 170, ca. 200.
