Perennial rhizomatous, herbs, (often cultivated as an annual), producing tubers mostly at the end of growing season, tubers knobby, white, red or purple skinned, 7.5–10 cm long, 3–5 cm wide; stem erect 1.5–3 m tall, hirsute. Leaves opposite or the upper ones alternate, 10–25 cm long, 6–15 cm wide, ovate to ovate–oblong, serrate–dentate, ± scabrid above, whitish beneath, petiole ± winged, 2–8 cm long. Capitula 3–15, terminal, on 1–15 cm long peduncles, 4–7.5 cm across. Involucre ± hemispherical. Phyllaries usually dark green, almost blackish on drying, subequal, lanceolate, hispidulous, with ciliate margins. Ray florets 12 – 20, light yellow, limb 25–40 mm long. Disc florets yellow, many, 6 – 7 mm long. Anthers dark brown – black. Cypselas 5–6 mm long, glabrous – finely, hairy at the apex. Pappus of 2 aristate 1.5 – 3 mm long scales, with usually 0-1 small, deltate, scale (squamellae).