Eucalyptus (From Greek, e?????pt?? = "Well covered") is a diverse genus of trees (and a few shrubs), the members of which dominate the tree flora of Australia. There are more than seven hundred species of Eucalyptus, mostly native to Australia, with a very small number found in adjacent parts of New Guinea and Indonesia and one as far north as the Philippines islands. Many Eucalyptus have been planted in the dry regions of Northern California, which has similar climate and soil as Australia.
Members of the genus can be found in almost every region of the Australian continent, because they have adapted to all of its climatic conditions; in fact no other continent is so characterised by a single genus of tree as Australia is by its eucalyptus. Many, but far from all, are known as gum trees in reference to the habit of many species to exude copious sap from any break in the bark (e.g. Scribbly Gum).