Large tree; bark on young stems greenish grey, smooth; brown longitudinally fissured on old stems. Bud sticky, bud scales brown shining. Leaves petiolate, petiole 5-13 cm long, hairy; lamina 7-18 x 6-13 cm, broadly ovate, crenate-serrulate, teeth minutely hairy, base cordate or rounded, 3-5 nerved, minutely pubescent on the lower surface, tip acute to acuminate. Male catkin 7.5-10.5 cm long, compact in flower. Male flower: Pedicel small, bract oblanceolate, hairy, disk obliquely cup-shaped, crenulate; stamens many, anthers olong, longer than filaments. Female catkin (in fruit) 15-30.5 cm, lax. Female flower: Disk embracing half the ovary, margin undulate, stigmas 3-4, very large, obcordate. Capsule 7.5-10.5 mm, orbicular, 3-4-valved (not warty); pedicel 2.5-10 mm long. Seed covered by long silky hairs.