Plants annual, 30-60 cm tall. Stem erect, many branched or simple, glabrous. Leaves alternate; petiole 1-3.5 cm; leaf blade elliptic-ovate or elliptic-lanceolate, 7-15 × 3-5 cm, with 2 stipitate basal glands, both surfaces glabrous, setose between teeth, lateral veins 7-9 pairs, base cuneate, attenuate into petiole, margin coarsely crenate, apex acute or caudate-acuminate. Inflorescences axillary or terminal, 3-5-flowered; peduncles usually shorter than leaves, slender. Pedicels slender, bracteate at base; bracts often caducous, ovate-lanceolate. Flowers yellow or spotted; buds subovoid, apex rostellate. Lateral sepals 2, oblong-lanceolate, small, ca. 4 mm, narrow (to broad), apex acuminate. Lower sepal funnelform, narrowed into a slightly curved, slender spur; mouth oblique, tip cornute-rostellate. Upper petal orbicular, abaxial midvein not thickened; lateral united petals not clawed; basal lobes ovate-oblong; distal lobes long, narrow, apex acute or obtuse; auricle inflexed. Anthers obtuse. Ovary fusiform. Capsule unknown. Fl. May-Jul. 2n = 18.