Eucalyptus Smith, also known as Eucalyptus, is the general name of eucalyptus plants in Myrtaceae. 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. Its origin is mainly in the Australian mainland, and it was introduced to all parts of the world in the19th century. By 20 12, it has been cultivated in 96 countries or regions. It has medicinal and economic value.