Description from Flora of China
Paulownia rehderiana Handel-Mazzetti; P. thyrsoidea Rehder; P. viscosa Handel-Mazzetti.
Trees, 6-12 m tall; crown umbellate. Trunk short. Young shoot brown-gray, conspicuously lenticellate. Leaf blade cordate, to 8 cm, viscid-glandular hairy, margin entire or 3-5-lobed or angled, apex acute. Thyrses broadly conical, to 1 m; cymes often 3-flowered, yellow-brown tomentose; peduncle absent or less than 1.2 cm. Pedicel to 1.2 cm. Calyx conspicuously ridged, tomentose; lobes longer than 1/2 of calyx length, narrowly ovate, conspicuously green margined, apex acute. Corolla pale violet to blue-purple, subcampanulate, 3-5 X 3-4 cm, outside glandular hairy. Stamens 1-1.5 cm. Ovary glandular. Style ca. 1.4 cm. Capsule ovoid, 2.5-4 cm, apex short beaked; pericarp less than 1 mm; persistent calyx radiate, lobes often strongly reflexed. Seeds oblong, 3-4 mm including wing. Fl. Apr-May, fr. Aug-Sep.
* Scrub, forests, wastelands; 200-1500 m. Fujian, Guangdong, Guangxi, Guizhou, Hubei, Hunan, Jiangxi, Taiwan, Zhejiang.