Description from Flora of China
Agallochum Lamarck; Ophispermum Loureiro.
Trees or treelets. Leaves alternate, leaf blade pinnately veined; veins slender, ascending toward margins and joining several intramarginal veins. Inflorescences axillary or terminal, umbelliform or paniculiform, usually without involucre; peduncle short or absent. Flowers bisexual, pedicellate, usually 5-merous. Calyx tube persistent, yellow or yellowish green, campanulate; lobes 5, reflexed or erect. Petaloid appendages twice as many as the lobes, inserted at throat of tube, scalelike, united in a ring at base, usually densely pubescent or puberulous. Stamens twice as many as calyx lobes, alternating with petaloid appendages; filaments short or absent; anthers oblong, dorsifixed, pubescent, connectives broad. Disk absent. Ovary subsessile, pubescent, 2-loculed or incompletely 2-loculed; style very short; stigma capitate. Fruit a 2-valved loculicidal capsule, compressed laterally, obovoid, base enclosed by persistent calyx; pericarp leathery or woody. Seeds 2 or 1 by abortion, ovoid or ellipsoid, on carunclelike strongly tapered funicle; testa crustaceous, endosperm absent; cotyledons thick, plano-convex.
Members of this genus are important as the source of agarwood, a very highly prized aromatic gum produced in the wood in response to injury. It is used as incense, in perfumery, and in traditional medicine. Trees have been over-harvested throughout the range of the genus, and most species are of conservation concern. The genus as a whole is included in Category 2 of CITES.
About 15 species: Bhutan, Cambodia, China, NE India, Laos, Malaysia, Myanmar, Thailand, Vietnam; two species (both endemic) in China.
(Authors: Wang Yinzheng (王印政); Lorin I. Nevling, Michael G. Gilbert)