Description from Flora of China
Unona subsect. Cananga Candolle, Syst. Nat. 1: 485. 1817.
Trees or shrubs. Petiole short; leaf blade large. Inflorescences axillary or extra-axillary, forming cymes, racemes, or with several flowers clustered on a peduncle. Flowers large. Sepals 3, valvate. Petals 6, in 2 whorls, subequal or inner petals slightly smaller, spreading, flat, valvate in bud. Stamens many; anther locules linear-lanceolate, lateral or subintrorse; connectives ca. 1/3 size of stamens, apex apiculate. Carpels many, oblong; ovules many per carpel, in 2 series; styles slender; stigmas sticking together at anthesis, clavate. Fruit apocarpous; monocarps several to many, long stipitate, ovoid to subglobose. Seeds several per monocarp, in 2 series, pitted, sending spinose processes into albumen.
Two species: tropical Asia and Australia; one species (introduced) in China.
(Authors: Li Bingtao (李秉滔 Li Ping-tao); Michael G. Gilbert)