T he simple, alternate leaves of the oaks have smooth edges and are usually lobed, as shown by the leaves of the white oak , which is the state tree of Maryland and Connecticut. White oak leaves may be yellow, bronze, red or brown and the lobes are rounded or smooth at their tips. The colorful leaves of the swamp chestnut oak , which is closely related to the white oak, have more numerous, shallow lobes, which are also rounded at the tips. The rock chestnut oak of dryer habitats has the same leaf form, but may be less colorful. And the three prominent lobes of the distinctive cross-shaped leaves of the post oak , another member of the white oak group, are also rounded.
Red oak leaves.
In contrast, the limbs of the leaves of the widespread black oak are pointed and have a bristle at the tip, as do other members of the black oak group, such as the Spanish oak of the southern Appalachians, the often colorful red oak , which is found in most of the eastern United States and is the state tree of New Jersey, and the brilliant scarlet oak of the forests of the northern and central states. The slender, unlobed, yellow to bronze leaves of the willow oak of the southeastern coastal plains have a bristle at the tip of the linear leaf. It, too, is a member of the black oak group.