Description from Flora of China
Bombycidendron grewiifolium (Hasskarl) Zollinger & Moritzi; Hibiscus bantamensis Miquel; H. cinnamomifolius Chun & Tsiang; H. praeclarus Gagnepain.
Trees evergreen, to 7 m tall. Branchlets terete, light gray-white, glabrous or very minutely hairy. Stipules filiform, minute, caducous; petiole 2-4.5 cm, pilose; leaf blade ovate-oblong to elliptic-oblong, not lobed, 8-15 × 6-7 cm, papery or nearly leathery, glabrous, basal veins 3(-5), prominently raised abaxially, base obtuse or broadly cuneate, margin entire, apex shortly acuminate. Flowers unknown. Epicalyx lobes 9, filiform, 1-1.5 cm, glabrous. Epicalyx cup-shaped, 8-12-dentate. Sepals 5, oblong-lanceolate, campanulate, connate for 1/5 of length, longer than capsule, glabrous, persistent. Capsule solitary, axillary, fruit stalk ca. 4.5 cm, glabrous, ovoid, ca. 2 cm in diam.; mericarps 5, glabrous. Seeds 4 or 5 per mericarp, reniform, ca. 5 × 3 mm, densely woolly abaxially. Fr. Jan-Feb.
Hill forests; ca. 2000 m. Hainan [Indonesia, Laos, Myanmar, Thailand, Vietnam].