Plants annual, 10-16 cm tall, slender, glabrous, with few supporting roots and fibrous roots. Stem erect, often with opposite branches basally, rarely simple, naked at base. Leaves alternate, petiolate or upper leaves subsessile; petiole 0.5-1(-2) cm; leaf blade green on both sides, ovate or ovate-oblong, 1-2 × 0.8-1 cm, membranous, lateral veins 2 or 3(or 4) pairs, inconspicuous, base broadly cuneate or rounded, margin remotely crenate or shallowly undulate, teeth mucronulate, apex obtuse. Inflorescences in upper leaf axils, 1-or 2-flowered; peduncles often ca. 1/2 as long as leaves. Pedicels 5-10 mm, slender, bracteate above middle; bracts persistent, lanceolate, ca. 2 mm. Flowers golden-yellow, large, ca. 3.5 cm deep. Lateral sepals 4, outer 2: orbicular, 2-3 mm, submembranous, midvein fine, apex mucronulate; inner 2: ovate, very small, membranous, midvein inconspicuous, apex obtuse. Lower sepal purple spotted, funnelform, 2-2.5 cm deep, gradually narrowed into an incurved, slender spur 1.5-2 cm; mouth vertical, ca. 8 mm wide, tip acute. Upper petal suborbicular, 5-6 mm, apex emarginate, abaxial midvein thickened, carinate at middle; lateral united petals not clawed, 2.3-2.9 cm, 2-lobed; basal lobes orbicular, very small, 2-3 mm in diam.; distal lobes broadly dolabriform, 5-7 mm, apex rounded; auricle inflexed, very small. Filaments linear, 4-5 mm; anthers obtuse. Ovary erect, fusiform, ca. 5 mm. Capsule not seen. Fl. Aug.