Impatiens leptocaulon Hook. fil.

Plants annual, 30-50 cm tall. Stem erect, slender, simple or branched, nodes and upper part brown pubescent. Leaves alternate; leaf blade ovate or ovate-lanceolate, 5-10 × 2-3 cm, with few basal glands, base narrowly cuneate, margin serrulate, apex acute or acuminate. Inflorescences 1- or 2-flowered; peduncles slender. Pedicels short, bracteate above middle; bracts lanceolate. Flowers purple-red. Lateral sepals 2, subovate, long cuspidate, inequilateral, hyaline margined, denticulate on one side. Lower sepal navicular, narrowed into an incurved, long spur. Upper petal orbicular, apex rostellate, abaxial midvein carinate; lateral united petals not clawed, 2-lobed; basal lobes orbicular, small; distal lobes obovate-oblong; auricle obtuse. Anthers obtuse. Capsule linear. Fl. May-Aug, fr. Sep-Oct.

Guizhou, Henan, W Hubei, Hunan, Sichuan, Yunnan.

● Forest understories, grasslands on slopes, along canals, shaded moist places; 1200-2000 m.