Description from Flora of China
Trees, evergreen. Branchlets with white lenticels; terminal buds sericeous. Leaves petiolate; leaf blade margin entire or serrate. Flowers bisexual, axillary, solitary or rarely 3-5 in a short raceme. Pedicel ± slender, apically thickened and recurved; bracteoles usually 2(or more), apically on pedicel, caducous. Sepals 5, imbricate, persistent, basally slightly connate. Petals 5, white, basally connate and adnate with distinct filaments. Stamens numerous; anther dorsifixed. Ovary densely tomentose, 5-loculed with 2 or 3 ovules per locule, placentation axile; style stout, glabrous; stigma capitate, 5-lobed. Capsule globose or depressed globose; pericarp woody, splitting for 1/2 length into 5 valves; columella persistent, stout, extending for 2/3 or more of locule length. Seeds small, reniform, flat, with a marginal membranous wing; endosperm thin; cotyledons leaflike.
About 20 species: Bhutan, Cambodia, China, NE India, Indonesia, Japan (Ryukyu Islands), Laos, Malaysia, Myanmar, Nepal, Thailand, Vietnam; 13 species (six endemic) in China.