Monoecious trees. Leaves alternate, pinnate. Stipules 0. Male inflorescences pendulous, sometimes branched, catkins; female flowers solitary or several together in bracteate inflorescence. Male flowers: stamens 3-many; perianth zygomorphic. Female flowers: calyx 4-lobed, adnate to the inferior ovary; stigmas 2-4-branched. Fruit usually a drupe with a husk containing a large 2-4-lobed seed.