Eucalyptus or Eucalyptus globulus (family Myrtaceae) is a genus of trees consisting of 700 species most of which grow in Australia. Many species are known as gum trees because they exude copious amounts of sap from breaks in the bark. Eucalyptus globulus, also known as Blue gum or Tasmanian blue gum, has aromatic leaves containing flavonoids and also large amounts of an essential oil that is rich in cineole and eucalyptol.
Native to Australia, the eucalyptus is a giant green evergreen tree, usually 30-100m tall with a smooth grey blue trunk. It grows in damp, marshy areas on moist land and clay. The leaves are leathery in texture, hang obliquely or vertically, and are studded with glands containing a fragrant volatile oil. The flowers in bud are covered with a cup-like membrane (hence the name of the genus, from the Greek eucalyptos, well-covered), which is thrown off as a lid when the flower expands. The fruit is surrounded by a woody, cup-shaped receptacle and contains numerous minute seeds.
The oil was traditionally used by Aboriginals for various health and wellbeing needs.