Plants erect, 30-50 cm. Stem robust, nodes turgid. Leaves alternate, often crowded at upper part of stem, shortly petiolate or subsessile; petiole with sparse glands; leaf blade oblong-obovate or oblanceolate, 8-15 × 2.5-6 cm, setose between teeth, adaxially sparsely pilose on veins, lateral veins 6-8 pairs, base long cuneate, margin remotely crenate, apex acute or acuminate. Inflorescences in terminal leaf axils, racemose, 4-10-flowered; peduncles 4-6 cm. Flowers white, large. Lateral sepals 4, outer 2: ovate; inner 2: falcate. Lower sepal saccate, constricted into a curved, short spur. Upper petal elliptic, apex emarginate, mucronulate, abaxial midvein carinate; lateral united petals not clawed, 2-lobed; basal lobes oblong; distal lobes dolabriform, large; abaxial auricle short. Anthers obtuse. Ovary fusiform. Capsule unknown. Fl. Aug-Sep.

● Forest understories, along canals, shaded moist places; 800-1000 m. Sichuan (Emei Shan).