PLANTS: Shrubs or trees, usually monoecious or dioecious. LEAVES: opposite, estipulate, simple, unlobed or palmately lobed, or palmately or pinnately compound. FLOWERS: aetinomorphic, often with disks; sepals 4 or 5, separate or fused; petals 4 or 5, distinct, or absent; stamens 4-10; pistil 1, the ovary superior, 2-locular. FRUIT: a schizocarp, the mericarps winged, the wings lateral (Acer) or peripheral (Dipteronia). NOTES: 2 genera, Dipteronia (2 Chinese spp.), and Acer with ca. 180 spp. in n temperate regions and the mountains of tropical Asia. REFERENCES: Landrum, Leslie R. 1995. Aceraceae. J. Ariz. - Nev. Acad. Sci. 29(1): 2, 2-3.