54. PYGEUM Gaertner, Fruct. Sem. Pl. 1: 218. 1788.
臀果木属 tun guo mu shu
Lu Lingdi (Lu Ling-ti); Bruce Bartholomew
Trees or shrubs, evergreen. Branches unarmed. Stipules small, free, soon caducous, rarely persistent. Leaves simple, alternate, petiolate; leaf blade abaxially with a pair of flat to depressed nectaries near base and additional nectaries sometimes near margin, margin entire or very rarely minutely serrulate. Racemes axillary, solitary or sometimes several in a fascicle, unbranched or branched; bracts small, soon caducous, very rarely persistent after anthesis. Flowers bisexual or unisexual by want of ovary, sometimes polygamo-dioecious. Hypanthium obconic, campanulate, or cyathiform, caducous at fruiting time, only annular base remained. Perianth segments 5–10(–14), small. Sepals and petals often similar but sometimes distinct in shape and texture. Petals white, as many as sepals, very rarely absent, usually 1.5–2 × as long as sepals. Stamens 10–30(–85), in 1 to many series; filaments filiform. Ovary superior, 1-loculed, glabrous or hairy; ovules 2, collateral, pendulous. Style terminal; stigma capitate. Fruit a drupe, dry, usually transversely oblong to ellipsoid, obscurely didymous, sometimes subglobose to oblong and distinctly longer than wide; endocarp cartilaginous.
About 40 species; tropical Africa, S and SE Asia, NE Australia, New Guinea, Pacific Islands; six species (all endemic) in China.
Pygeum griseum Blume ex Müller Stuttgart (Prunus grisea (Blume ex Müller Stuttgart) Kalkman) was reported from Lan Yu off the coast of SE Taiwan by Ohashi (Fl. Taiwan, ed. 2, 3: 98–100. 1993, as Prunus grisea). The species is not included in this treatment because the present authors have seen no Chinese specimens.