The (usually
pinnately compound) leaves are evergreen and lack
stipules. They are alternate, rarely opposite. The plants are monoecious, the male flowers being in lateral panicles (several pairs of catkins on an inflorescence) and the female flowers born terminally either in a single spike or in a hermaphroditic panicle including several paired male catkins. Each flower has a wide bract, two bracteoles, and four sepals. The flowers are sessile. The male flowers have a round or oblong receptacle and six to ten stamens. The pollen grains are approximately 24 micrometers in diameter and are slightly triangular in polar view. The small fruits are nuts, one-chambered at the apex and eight-chambered (sometimes four-chambered) at the base. Germination is
hypogeal. ==Species==