Corymbia citriodora, also known as Eucalyptus citriodora, is an evergreen tree that grows up to 50m tall at a fast rate. It originates from temperate and tropical eastern Australia, but is now grown in other parts of the world such as Brazil and China. Its name comes from the Latin citriodorus, meaning lemon-scented. It has a smooth or slightly mottled bark that is a white to coppery colour in season.
The refined essential oil that is steam distilled from this tree is the raw material used in Citriodiol®, but the unrefined version is extensively used in the perfume industry. The refined oil used for insect repellents has a very high citronellal content that is turned into cis- and trans- isomers of p-menthane-3,8-diol or PMD, a process that occurs naturally as the eucalyptus leaves age.