Quercus is a large genus containing hundreds of species of trees and shrubs commonly known as oaks. Found worldwide, oaks are one of the most versatile and widely used landscape plants. Oaks can be divided into two main groups, red and white. Since some diseases are restricted to or are more common in one group than the other, it’s helpful to know the difference. Leaf shape is typically a reliable way to tell them apart. Species in the red oak group have leaves with pointed lobes and species in the white oak group have leaves with rounded lobes.