Description from Flora of China
Trees. Leaves opposite, 1-pinnately compound. Inflorescences terminal. Flowers yellow or yellow-red. Calyx closed in bud, laterally divided to base, spathelike at anthesis, floccose to lanate-woolly. Corolla lobes 5, subequal, rounded, tube short. Stamens 4, didynamous. Capsule dehiscing loculicidally, long, terete, compressed, yellow-brown floccose to lanate-woolly; septum woody, compressed, with 1 concave midrib. Seeds long ellipsoid, 2-rowed in each locule, transparent and membranous winged at both ends.
About ten species: mostly tropical Africa; one species in China.