20. Allophylus Linnaeus, Sp. Pl. 1: 348. 1753.
异木患属 yi mu huan shu
Shrubs, rarely trees [rarely woody climbers], monoecious or dioecious. Leaves digitate, stipules absent; leaflets 1-5, petiolate or subsessile, usually serrate, sometimes entire. Thyrses axillary, racemose or compound racemose; bracts and bracteoles subulate or lanceolate, small. Flowers unisexual, zygomorphic, closed, small. Sepals 4, concurved, outer 2 elliptic, slightly smaller, inner 2 suborbicular. Petals 4, each 2 in a pair, adaxially with scales at base. Disk 4-sect, lobes glandlike, apex truncate or obtuse. Stamens (male flowers) 8, sometimes fewer, exserted; filaments free or connate below middle. Ovary (female flowers) 2(or 3)-partitioned, 2-loculed, lobes subglobose or obovate; ovules 1 per locule, inserted near base of middle axis; style basilar, entire or 2- or 3-lobed nearly to base; stigma recurved. Fruit parted into 2 or 3 schizocarps, often only 1 developed, berrylike, subglobose or obovoid, base with rudimentary style and small, globose, sterile schizocarp, exocarp fleshy, juicy, endocarp crustaceous. Seeds nearly same as schizocarp in shape; embryo arched, reflexed. 2n = 28.
About 200 species: widely distributed in tropical and subtropical regions; 11 species (two endemic) in China.
This is a genus in need of taxonomic revision. Leenhouts (Blumea 15: 301-358. 1967), noting the clinal variation and regional intergraduation, considered that the genus is monotypic comprising a single polymorphic species. Verdcourt (Fl. Trop. E. Africa, Sapindaceae, 75. 1998) noted that some species are easier to delimit than others, particularly between forest and bushland species. Within China, the 11 species are very distinct.