Trees. Leaves opposite, 1-pinnate (in ours). Domatia 0. Inflorescences composed of dense, terminal or lateral, clusters or panicles. Flowers bisexual or unisexual. Calyx 4-lobed or 0. Petals 4, free or ± connate, or 0. Stamens usually 2. Stigmas 2. Fruit a flattened, 1-2-seeded samara, with an elongate, apical wing.