Plants annual, 30-50 cm tall, rarely taller. Stem erect, green or purple-tinged basally, many branched, pubescent or subglabrous basally. Leaves alternate, sessile or subsessile; petiole with 2 globose basal glands; leaf blade ovate or ovate-lanceolate, 5-15 × 1.5-2 cm, apices of teeth with marginal glands, abaxially pubescent, adaxially sparsely strigose, lateral veins 7-9 pairs, base subrounded, margin sharply serrate, apex acuminate. Inflorescences in leaf axils, 1-3-flowered, shortly pedunculate; pedicels bracteate at middle; peduncles, pedicels, and bracts brown pubescent; bracts persistent, setose or setose-lanceolate, apex long mucronulate. Flowers golden-yellow, purple spotted, ca. 2.5 cm deep. Lateral sepals 2, ovate, sparsely pubescent, apex mucronulate. Lower sepal broadly funnelform, abruptly narrowed into a curved spur ca. 1 cm. Upper petal broadly orbicular, abaxial midvein green, cornute-cristate, crista conspicuous in flowering buds; lateral united petals not clawed, 2-lobed; basal lobes orbicular, short; distal lobes oblong-dolabriform; auricle inflexed, narrow. Anthers obtuse. Capsule linear, 2.5-3 cm, glabrous or sparsely hairy. Fl. Jul-Sep. 2n = 14.
Annual 12-60 cm or more tall. Shoots puberulous to glabrous. Leaves elliptic-ovate to oblong-ovate, 30-150 x 20-50 mm, acuminate to subacuminate, crenate to crenate-dentate; petiole up to 35 mm long, with 2 lateral sessile glands at the base. Peduncles 50-70 mm long, (1-)3-flowered. Flowers lemon yellow, spotted brown within, 24-40 mm long. Pedicel slender, with 1-2 linear-lanceolate, 3-4 mm bracteoles. Lateral sepals pubescent, ovate-suborbiculate, 5-7 x 4-7 mm, sometimes mottled brown-black. Lower sepal saccate or conical, spur 8-20 mm long, curved. Anterior petal broad, orbicular, 10-14 x 17-19 mm, crested, apex bibbed. Capsule erect, 23-35 mm long, puberulous. Seed ovoid, 2.2-2.5 mm long, rugose.