Trees deciduous. Terminal bud absent; buds with single scale. Leaves alternate; stipules absent; petiole short; leaf blade with both surfaces uniformly colored. Flowering precocious; male catkin pendulous; female catkin upright or ascending; bracts entire. Flowers anemophilous, without perianth or gland at base. Male flower: stamens 5, glabrous, shorter than bracts; filaments adnate to base of bracts. Female flower: ovary glabrous, 1-loculed, 4-ovulate, shortly stipitate; styles 2, distinct, each divided to ca. 1/2 into 2 stigmas. Capsule 2-valved. Seeds exalbuminous.