Shrubs or sometimes small trees, deciduous. Branchlets 4-angled. Leaves opposite, simple, sessile or short petiolate, entire or minutely serrate. Inflorescences terminal or axillary panicles or racemes. Flowers small, pedicellate. Calyx 4-parted. Corolla deeply 4-lobed, united only at base. Stamens 2, inserted at base of corolla. Ovules 2 in each locule, pendulous. Style and forked stigma persistent. Fruit samara, flat, surrounded by wing. Seeds 1 in each locule; endosperm fleshy; radicle upward.