Description from Flora of China
Trees, unarmed; buds strongly compressed with stipules erect and pressed together [rarely subconical]. Raphides absent. Leaves opposite, usually with domatia; stipules caducous or persistent, interpetiolar, generally elliptic or obovate. Inflorescences terminal and sometimes also axillary, capitate with heads 1-5, globose, and solitary to fasciculate, many flowered, pedunculate, bracteate; peduncles articulate and often bracteate near middle. Flowers sessile, fused by their ovaries, bisexual, monomorphic. Calyx limb 4- or 5-lobed. Corolla white to yellow, funnelform to salverform, inside glabrous; lobes 4 or 5, imbricate in bud. Stamens 4 or 5, inserted in upper part of corolla tube, exserted; filaments short; anthers basifixed. Ovary 2-celled, ovules numerous in each cell, pendulous to horizontal on Y-shaped axile placentas attached to upper third of septum; stigma fusiform, exserted. Infructescences with fruiting heads each comprising a globose multiple fruit (i.e., syncarp). Fruit (i.e., fruitlets, arising from one flower) baccate, fleshy or fibrous, with calyx limb deciduous; seeds numerous, small, ovoid or ellipsoid, sometimes slightly compressed, without aril.
The wood of several Nauclea species is strong and used for lumber.
The S Asian species Nauclea orientalis (Linnaeus) Linnaeus is occasionally cultivated; this can be recognized by its elliptic-oblong leaves 6-12 cm wide, its flowering heads 15-20 mm in diam. across the calyces, and its fruiting heads to 5 cm in diam. Both N. officinalis and N. orientalis species are encountered and occasionally confused in cultivation with the more commonly cultivated Neolamarckia cadamba, which has free (i.e., distinct or separate) flowers and free dehiscent fruit (see p. 255).
About ten species: tropical Africa, Asia, and Australia; one species in China.
(Authors: Chen Tao (陈涛); Charlotte M. Taylor)