Description from Flora of China
Stereospermum sinicum Hance, J. Bot. 20: 16. 1881; Radermachera tonkinensis Dop.
Trees ca. 10 m tall. Petioles, leaf axis, and inflorescences glabrous. Leaves 2(or 3)-pinnately compound; leaf rachis ca. 30 cm; lateral petiolules less than 5 mm, terminal one 1-2 cm; leaflets ovate to ovate-lanceolate, 4-7 X 2-3.5 cm, glabrous, base broadly cuneate, margin entire, apex caudate-acuminate; lateral veins 5 or 6 on each side of midrib. Inflorescences paniculate, terminal, erect, 25-35 cm; bracts linear-lanceolate, ca. 10 cm, deciduous, bractlets linear, 4-6 cm. Calyx teeth 5, ovate-lanceolate, ca. 12 mm. Corolla white to pale yellow, campanulate-funnelform, 6-8 cm; lobes rounded, ca. 2.5 cm. Stamens 4, didynamous; staminode present, filiform. Ovules 2-rowed. Style exserted; stigma 2-lobed. Capsule terete, nodding, angular, ca. 85 X 1 cm; pericarp thin leathery, indistinctly lenticellate; septum terete, slightly compressed. Seeds ellipsoid, including wing ca. 2 cm X 5 mm. Fl. May-Sep, fr. Oct-Dec.
Slopes and forests; 300-800 m. Guangdong, Guangxi, Guizhou, Taiwan, Yunnan [Bhutan, India (Assam, Darjeeling), N Myanmar, Vietnam].