Trees, to 16 m tall; bark black, striate. Branchlets densely yellow-brown stellate tomentose when young, becoming gray-white or yellowish gray stellate tomentose or nearly glabrous. Stipules palmately 3-5-fimbriate, densely hairy, caducous; petiole robust, 4-12 mm; leaf blade oblong-obovate in outline, usually irregularly lobed, 8-16 × 3.5-11 cm, leathery, abaxially densely gray-white or yellow-brown stellate tomentose, adaxially glabrous or minutely hairy along midrib, base cordate or obliquely cordate, apex truncate and 3-5-lobed, central lobe acute or acuminate, 1-2 cm. Flowers solitary, nearly sessile; epicalyx lobes fimbriate. Sepals linear, relatively thick, 4.5-6.5 × ca. 0.4 cm, abaxially densely brown tomentose, adaxially silvery white villous. Petals linear-falcate, 3-6 × 0.4-0.5 cm, base tapering. Stamens ca. 3.5 cm; staminodes filiform, ca. 5 cm, glabrous. Ovary ovoid, hairy. Fruiting pedicel to 8 mm; capsule woody, ovoid or ovoid-cylindrical, prominently 5-angular and 5-grooved, ca. 12 × 7 cm, densely brown stellate tomentose, verrucose or not, base narrowed into 2-3 × ca. 1 cm stipe. Seeds 6-10 per locule, in 2 rows, 4-5.5 cm including wing, wing linear, up to 4.4 cm, apex obtuse or truncate. Fl. Jul.

Dense forests on limestone; 300-500 m. SE Guangxi (Ningming, Longzhou), SE Yunnan (Jinping) [N Vietnam].