Annual herb, 30 ~ 80 cm tall. Roots are 2, relatively short and ovoid. The stem is erect. Leaves alternate, blade narrowly ovate, 6 ~12 cm long and 2 ~ 3 cm wide, apex tapering and base cuneate; Stems sessile, sheathlike; Both sides are hairless.

3 ~ 5 flowers with sparse apex axils, white corolla, about 1.5 cm in diameter; 3 perianth, 2 maids, linear and cunning, 8 mm long; The lip is 3-lobed, about 12 mm long and about 15 mm wide. The middle lobe is narrow and sharp, and the lobes on both sides are nearly semicircular, with irregular fine teeth on the edge, slightly thicker at the end and about 4 cm long. The lower end of the ovary is slightly larger. Capsule is short-angled. The seeds are numerous and small. Flowering in autumn.