Bark furrowed. Buds viscid. Leaf blade usually deltoid-ovate or rhombic-ovate, both surfaces green, with stomata, base truncate or broadly cuneate, margin crenate-serrate, distinctly translucent at edge, apex long acuminate. Male flower: stamens 15--30(--60); anther subglobose or elliptic. Female flower: disc entire, persistent; style absent; stigmas 2. Capsule 2(or 3)-valved.