Perennial, with thick, blackish, tuberous roots. Shoots and lvs puberulent when young, later glabrous or nearly so. Stems swollen at nodes, branched. Petioles usually 1-4 cm long. Lamina 3.5-15 × 3-7 cm (largest in lower lvs), ovate or oblong-ovate, entire; undersurface with numerous rod-like cystoliths; base truncate to broadly cordate; apex acute to acuminate. Upper lvs smaller with shorter petioles. Fls in terminal cymes, fragrant. Involucre calyx-like, 9-15 mm long, hairy, strongly lobed, each containing 1 fl. Calyx 4-4.5 × 3.5-4.5 cm across limb, yellow, magenta or streaked or with sectors of either colour in the same fl., salverform, soon withering; tube c. 3 cm long. Stamens and style exserted. Anthocarp c. 8 mm long, ovoid to ellipsoid, hairy, black or almost so.