Leaves simple or digitate compound, alternate or spiral, petioles thickened at
both ends, stipules caducous. Flowers small, unisexual, axillary or at upper
leaf scars. Sepals 5, united at the base, calyx campanulate or urceolate,
stellate-pubescent. Petals absent.Male flowers with 8-10 stamens. Female
flowers with 4-6 locular ovary, each locule with one ovule, styles short, stigmas
4-5, free. Fruit a samara, indehiscent, winged or keeled.