Trees , to 12 m; crowns low, broad. Bark gray or light brown, scaly and flaky. Wood weak, brittle. Branches unarmed, spreading; twigs hirtellous when young, glabrate. Leaves: stipules falling early; petiole present. Leaf blade rhombic-ovate to ovate-oblong, base oblique to rounded or cuneate, margins unequally serrate, apex acute; venation pinnate. Inflorescences: staminate fascicles; pistillate solitary flowers or 2-3 together. Flowers normally unisexual, pedicellate, staminate and pistillate on same plants, a few bisexual flowers usually present; calyx deeply 4-5-lobed; stamens when present 4-5. Fruits nutlike, ellipsoid, with irregular, thickened ribs.