Description from Flora of China
Plants annual, 40-70 cm tall. Stem succulent, robust, many branched in upper part, glabrous, lower nodes often swollen with fibrous roots. Leaves alternate, upper leaves shortly petiolate or subsessile; petiole 2-5 cm, slender; leaf blade green abaxially, dark green adaxially, ovate or ovate-elliptic, 3-8 × 1.5-4 cm, both surfaces glabrous, base cuneate or rounded, margin crenate, teeth mucronulate, apex obtuse, rarely acute. Inflorescences 2-4-flowered; peduncles 1-1.5 cm. Pedicels 1.5-2 mm, bracteate above middle; bracts persistent, lanceolate, 3-5 mm, herbaceous. Flowers yellow. Lateral sepals 2, ovate or broadly ovate, 5-6 mm, apex acute. Lower sepal sparsely orange spotted, broadly funnelform, gradually narrowed into an incurved spur 1-1.5 cm. Upper petal orbicular or suborbicular, ca. 1 cm in diam., apex emarginate, rostellate, abaxial midvein green cristate; lateral united petals not clawed, 2-2.5 cm, 2-lobed; basal lobes oblong, small; distal lobes orange spotted at base, broadly dolabriform; auricle narrow. Filaments linear, slightly swollen above; anthers ovoid, apex acute. Ovary erect, fusiform. Capsule linear-cylindric, 1.5-2.5 cm. Seeds many, brown, oblong-globose, 3-4 mm, smooth. Fl. Jul-Sep. 2n = 20.
Forest understories, forest margins, grasslands, along canals; 900-2400 m. Anhui, Gansu, Guangdong, Hebei, Heilongjiang, Henan, Hubei, Hunan, Jilin, Liaoning, Nei Mongol, Ningxia, Qinghai, Shaanxi, Shandong, Shanxi, Zhejiang [Japan, Korea, Mongolia, Russia (Far East, Siberia); C and SW Asia, Europe, NW North America].