Plants annual, 25-30 cm tall, glabrous. Stem erect or obliquely ascending, simple or shortly branched from lower part. Leaves alternate or subverticillate, sessile, subsessile, or petiolate; petiole absent to 1-2 cm; leaf blade pale purple-tinged abaxially, dark green adaxially, ovate or ovate-lanceolate, 3-5(-7) × 2-2.5 cm, rigid, lateral veins 6 or 7 pairs, curved, midvein and lateral veins abaxially conspicuous, base cuneate, shortly attenuate into petiole, margin crenate, teeth mucronulate, apex acuminate or caudate-acuminate. Inflorescences in upper leaf axils, racemose, usually 3-5-flowered; peduncles erect, longer or ca. as long as leaves, 5-6(-7) cm. Pedicels fibrous, 1-1.5 cm, bracteate at base; bracts caducous, linear-subulate, 2-3 mm. Flowers yellow, ca. 2 cm deep. Lateral sepals 2, ovate, hooked-curved, 2-4 mm, apex elongated into awn 3-4 mm. Lower sepal navicular, limb ca. 1 cm deep, base abruptly narrowed into a slender spur 2-2.5 cm; mouth oblique, 5-6 mm wide, tip 5-6 mm, fibrous, sometimes involute aristate. Upper petal obovate, 7-8 mm, apex rounded; lateral united petals ca. 1.8 cm, 2-lobed; basal lobes long acuminate; distal lobes linear, slightly dilated at base, apex obtuse; auricle small, narrow. Filaments linear; anthers obtuse. Ovary erect, fusiform. Capsule (immature) clavate, ca. 1 cm. Fl. Jul-Aug.