Description from Flora of China
Catalpa syringifolia Bunge.
Trees 8-12 m tall. Petiole 2-8 cm; leaf blade triangular-ovate or ovate-oblong, 6-15 X ca. 8 cm, glabrous abaxially, dark green adaxially, base broadly cuneate or cordate, apex long acuminate. Inflorescences corymbose-racemose, terminal, 2-12-flowered. Calyx bilabiate, apex acutely 2-dentate. Corolla pale red, yellow 2-striate and dark purple spotted at throat, 3-3.5 cm. Capsule linear, 25-45 cm X ca. 6 mm. Seeds narrowly ellipsoid, ca. 10 X 2 mm, villous at both ends. Fl. May-Jun, fr. Jun-Oct. 2n = 40*.
* Roadsides. Gansu, Hebei, Henan, Hunan, Jiangsu, Shaanxi, Shandong, Shanxi, Zhejiang; cultivated in Guangxi, Guizhou, and Yunnan.