Eucalyptus (EucalyptusrobustaSmith), also known as Eucalyptus, is a general term for Myrtaceae and Eucalyptus. Evergreen tall trees, about 600 species. Evergreen plants have periodic dead leaves falling off within one year, most of which are tall trees, a few are small trees and a few are shrubs. The crown shapes are steeple, multi-branch and vertical branch. Leaves simple, entire, leathery, sometimes covered with a thin layer of wax. Leaves can be divided into three categories: young leaves, middle leaves and mature leaves. The leaves of most varieties are opposite, small, heart-shaped or broadly lanceolate.