Description from Flora of China
Chelidonium grandiflorum (Candolle) Candolle; C. majus subsp. grandiflorum (Candolle) Printz; C. majus var. grandiflorum Candolle.
Herbs, perennial, 30-60(-100) cm tall. Taproot conical, stout, lateral roots many. Stems cymose, branched; branches often pubescent, densely so on nodes, later glabrous. Basal leaves few, caducous; petiole 2-5 cm, pubescent or glabrous, base ampliate to sheath; blade glaucous abaxially, green adaxially, obovate-oblong or broadly obovate, 8-20 cm, abaxially sparsely shortly pubescent, adaxially glabrous, pinnatisect; lobes 2-4 pairs, obovate-oblong, irregularly parted or lobed; lobe margin crenate. Upper cauline leaves: petiole 5-15 mm; blade 2-8 × 1-5 cm. Inflorescence an umbel, multiflorous. Pedicel tenuous, 2-8 cm, villous when young, later glabrous. Bracts ovate, small, 1-2 mm. Flower buds ovoid, 5-8 mm in diam. Sepals caducous, ovoid, cymbiform, 5-8 mm, glabrous or sparsely pubescent. Petals yellow, obovate, ca. 1 cm, entire. Stamens ca. 8 mm; filaments yellow, filamentous; anthers oblong, ca. 1 mm. Ovary green, linear, ca. 8 mm, glabrous; styles ca. 1 mm; stigmas 2-lobed. Capsule narrowly terete, 2-5 cm × 2-3 mm; pedicel usually shorter than fruit. Seeds dark brown, shiny, ovoid, ca. 1 mm or shorter, alveolate. Fl. and fr. Apr-Sep. 2n = 10, 12.
One of us (Grey-Wilson) notes that the Asian plant is often distinguished as Chelidonium majus var. grandiflorum on account of its larger flowers (flowers to 3.5 cm wide; rarely over 2.5 cm in European and SW Asian specimens).
Slopes, forest margins, grasslands, roadsides, stone crevices, shaded banks, streamsides; 500-2200 m. Anhui, Gansu, Guizhou, Hebei, Heilongjiang, Henan, Hubei, Hunan, Jiangsu, Jilin, Liaoning, Qinghai, Shaanxi, Shandong, Shanxi, C and NE Sichuan, Yunnan, Zhejiang [Japan, Korea, Russia; Europe].