QUICK-GROWING trees with angled or round twigs, set with scaly buds, soft, light wood, and bitter bark. Leaves decidu ous, simple, alternate, usually broad, on long petioles. Flowers dicecious, both kinds in crowded, pendulous catkins; each flower subtended by a bract with deeply cut, hairy margin. Fruit pendulous racemes of to 4-valved pods; seeds minute with dense, silky float attached.