Impatiens sigmoidea Hook. fil.

Plants annual, 50-60 cm tall, glabrous. Stem erect, long naked basally, branched. Leaves alternate; petiole 5-10 mm; leaf blade ovate or ovate-lanceolate, 3-6 × 2-3 cm, base without bristles or 2-setose, attenuate into petiole, midvein abaxially prominent, lateral veins 6 or 7 pairs, margin serrulate, teeth mucronulate, apex acuminate. Inflorescences in upper leaf axils, over subtending leaves, 2-flowered. Pedicels 1-2 cm, bracteate above middle; bracts persistent, ovate-lanceolate, 8-10 mm, apex acuminate. Flowers white or white-green, 1-1.5 cm wide. Lateral sepals 2, ovate, 6-7 mm, S-curved, quite inequilateral, margin entire or inconspicuously denticulate on one side, apex acuminate. Lower sepal funnelform, abruptly narrowed into an incurved spur 2-2.8 cm; mouth vertical, ca. 1 cm, tip cuspidate. Upper petal cucullate, orbicular, abaxial midvein broadly cristate; lateral united petals not clawed, 1-1.3 cm, 2-lobed; basal lobes cuneate or obovate, small; distal lobes clawed, dolabriform, ca. 2 × as long as basal lobes, apex abruptly narrowed and obtuse; auricle conspicuous, obtuse. Filaments short, broad; anthers obtuse. Ovary erect, fusiform. Capsule clavate, ca. 5 cm. Seeds few, 3-5 mm, smooth. Fl. Aug.

● Guizhou (Gaopo Shan, Pingba).