Plants annual, 20-60 cm. Stem erect, slender, branched. Leaves alternate; petiole 1.5-2 cm; leaf blade ovate or oblong-ovate, 3-10 × 2.5-4 cm, with 2 globose basal glands, lateral veins 5-7 pairs, base cuneate, margin crenate, apex acuminate. Inflorescences axillary, 1-flowered; peduncles ca. 4 cm, with 1 lanceolate bract above middle. Flower pale purple or purple-red. Lateral sepals 2, ovate, margin sometimes denticulate at one side, apex acuminate, abaxial midvein narrowly carinate. Lower sepal narrowly funnelform, base narrowed into an incurved, slender spur. Upper petal orbicular, base cordate, apex slightly emarginate, shortly rostellate, abaxial midvein thickened, entire or undulate; lateral united petals ± clawed, 2-lobed; basal lobes oblong; distal lobes broadly dolabriform, larger; auricle conspicuous, lunate. Anthers acute. Capsule linear. Fl. Jul-Sep, fr. Oct-Nov.

● Forest understories, thickets on slopes, along canals, shaded moist places; 1500-1700 m. Anhui, Guangxi, Henan, Hubei, Hunan, Shaanxi, Sichuan.