Description from Flora of China
Trees unarmed, glabrous. Leaves simple, estipulate. Flowers in single, terminal, paniculate (spikelike) inflorescences, upper ones solitary, lower ones umbellate, sessile or pedunculate; bracts caducous; flowers articulate below calyx tube. Calyx margin 5-dentate. Petals 5, hooked, valvate. Stamens 10, 5 often sterile. Style solitary. Fruit drupaceous, 1-seeded, oblong-ovoid, very hard when dry, mesocarp thick and woody. Seed laterally compressed and curved, horseshoe-shaped in cross section; endosperm uniform.
Two species: one in S China and N Vietnam, one in S Vietnam.
(Authors: Xiang Qibai (向其柏 Shang Chih-bei), Xiang Qiuyun (向秋云 Jenny Xiang); David E. Boufford, Porter P. Lowry II)