Impatiens trigonosepala Hook. fil.

Plants ca. 30 cm, slender, subglabrous, with few supporting roots, simple or shortly branched at middle, basally long naked. Leaves alternate, sparse; petiole 2-4 cm; leaf blade pale green abaxially, green adaxially, 5-10 × 2-3 cm, membranous, with 1 pair of stipitate basal glands, lateral veins 5 or 6 pairs, fine, base cuneate, attenuate into petiole, margin coarsely crenate, apex shortly acuminate or acute. Inflorescences few, in upper leaf axils, 1-flowered; peduncles 3-5 cm, fibrous, glabrous or puberulent. Pedicels with lanceolate bracts at middle. Flowers pink, ca. 2.5 cm wide. Lateral sepals 2, triangular, ca. 6 × 3 mm, base truncate, apex mucronulate, abaxial midvein simple or carinate, green, glabrous or puberulent. Lower sepal navicular to funnelform, gradually narrowed into an incurved spur; spur 2-3 cm, longer than limb; mouth vertical, tip acute. Upper petal orbicular or oblate, large, ca. 1.5 cm in diam., base cordate, apex retuse, abaxial midvein narrowly carinate or not; lateral united petals ± clawed, 1.4-1.6 cm, 2-lobed; basal lobes erect or curved, small, apex entire or 2-fid; distal lobes obovate or obcordate, very large, ca. 1 cm wide; auricle inflexed. Filaments short; anthers acute. Capsule (immature) linear, ca. 2 cm. Fl. Aug.

E Sichuan.

● Shaded moist places by roadsides or canals; 1200-1300 m.