Herbs perennial. Rhizomes white. Stems erect or inclined, 30-120 cm. Petiole 1-3 cm; leaf blade ovate to elliptic-ovate, 3-12 × 1.5-6 cm, base broadly cuneate to shallowly cordate, margin crenate-serrate, apex acute to acuminate. Spikes 5-15 cm; verticillasters 6-flowered, widely spaced; floral leaves bractlike, reflexed (especially in cultivated form), adaxial ones sessile, lanceolate, margin subentire, shorter than calyx; bracteoles linear, ca. 1 mm. Pedicel ca. 1 mm. Calyx narrowly campanulate, ca. 9 mm, glandular pubescent, ± conspicuously 10-veined; teeth narrowly triangular, ca. 4 mm, apex spinescent, slightly reflexed. Corolla red to purple; lower lip purple spotted, ca. 1.3 cm, tube ca. 9 mm, somewhat saccate, puberulent; upper lip oblong, ca. 4 × 2 mm, straight or slightly reflexed; lower lip ca. 7 × 7 mm, middle lobe subcircular, ca. 3.5 mm in diam., lateral lobes ovate. Filaments slightly dilated apically, puberulent. Nutlets black-brown, ovoid, ca. 1.5 cm in diam., tuberculate. Fl. Jul-Aug, fr. Sep.
While the plant is easy to grow, the tubers are small, convoluted, and indented, so they are considered very tedious, if not difficult to clean properly. The thin skin ranges from a pale beige to ivory-white colour. The flesh underneath, under proper cultivation, is white and tender. Chinese poets compare it to jade beads. It is in season[clarification needed] generally commencing with October. [clarification needed]
The flavor of the stem tubers is delicate, and they can be prepared similarly to Jerusalem artichokes in cooking. It is used as a vegetable, in salad compositions, but more so as a garnish. It has a nutty, artichoke-like flavor.