Trees or shrubs. Male flowers in catkins, bracteate; bracts 3-flowered; bracteoles 3-5, united. Tepals 4. Stamens 4. Female flowers in erect conoid spikes; bracts 2-flowered; bracteoles 2-4, small, united to form a 5-lobed persistent fruiting scale. Perianth absent. Fruit a nut, in the axil of the woody bracts.