Impatiens mengtszeana

Plants annual, 20-40 cm tall, glabrous. Stem erect, robust, simple, naked basally, with many fibrous roots. Leaves alternate; petiole 2.5-3 cm; leaf blade pale green abaxially, dark green adaxially, ovate, obovate, elliptic, or oblanceolate, 5-10 × 2.5-3.5 cm, papery, abaxially glabrous, adaxially sparsely adpressed strigose, rarely ciliate, lateral veins 6-8 pairs, base acuminate, margin crenate-serrate, teeth mucronulate, apex acuminate or shortly acute. Inflorescences in upper leaf axils, 1- or 2-flowered; peduncles longer or shorter than leaves, 3-5 cm. Pedicels 0.5-2.5 cm, bracteate at or near base; bracts caducous, narrowly lanceolate, 3-7 mm. Flowers yellow, large, 3-5 cm deep. Lateral sepals 2, ovate or ovate-lanceolate, 8-10 × 7-8 mm, membranous, 3-5-veined, apex acute, abaxial midvein fine, not thickened. Lower sepal red spotted, funnelform or subsaccate, limb ca. 1.4 cm deep, narrowed into an involute spur; spur longer than limb, ca. 2.5 cm; mouth vertical, 1.5-2.2 cm, tip acute or acuminate. Upper petal orbicular to broadly ovate, 1.5-1.8 × ca. 2 cm, abaxial midvein fine, with a crista 2-3 mm high at middle; lateral united petals ± clawed, 3-4 cm, 2-lobed; basal lobes orbicular to broadly triangular-obovate, ca. 1.2 × 1.2 cm, large; distal lobes broadly dolabriform to suborbicular, ca. 1.8 × 1.4 cm, longer, apically slightly retuse; auricle inflexed, reniform. Filaments linear, 6-7 mm; anthers ovoid, apex obtuse. Ovary curved, fusiform. Capsule oblong, 1.5-2.5 cm. Seeds many. Fl. Aug-Oct. 2n = 16*.

S Yunnan.

● Mixed forests, riversides, along canals in valleys, moist places; 600-2100 m.