Over 700 types of eucalyptus trees and shrubs exist in various forms and sizes, mainly in Australia. Most species are native to Australia. However, eucalyptus can also be found in New Guinea, Indonesia, the Philippines and Northern California. The eucalyptus tree is among the tallest trees in the world, and the Eucalyptus regnans (or Australian mountain ash) is the tallest of all the flowering plants.
The name "eucalyptus" comes from the Greek word meaning "well covered." This describes the cap-like covering (operculum) over the eucalyptus flower bud. The flower discards the operculum as it grows. Eucalyptus fruits, which are called gumnuts, have valves that release seeds.
Eucalyptus trees can be identified and classified according to their bark. Stringybark trees have fibers which come off the tree in long pieces. Ironback trees have very rough and hard bark, which is furrowed and dark red in color. Tessellated bark has a flaky character. Box bark has short fibers, while ribbon bark peels off in long, thin strips, some of which may remain attached to the tree.
Eucalyptus leaves contain fragrant oil, which botanists first discovered in the late 1700s. The first commercial production of eucalyptus oil dates back to 1851, when a Yorkshire pharmacist named Joseph Bosito established a still in Victoria. By 1865, his oil exports reached England, and by the 1900s they were worldwide. Harvesting of the eucalyptus leaves encourages regrowth of the trees.
Eucalyptus Oil Uses
Eucalyptus oil is world-famous for its antiseptic, disinfectant and medicinal properties. However, only about 10 species of the tree produce the famous oil. Manufacturers say that eucalyptus oil relieves the symptoms of colds and flu, sore throats, hacking coughs, stuffy noses, insect bites and muscle and joint pain and stiffness. Eucalyptus oil is also a deodorizer, sanitizer and insect repellent. It is also a popular product in aromatherapy.
In the classic Australian bush song "Waltzing Matilda," the coolibah tree is a reference to the Eucalyptus microtheca, commonly called Blue Ghost. The coolibah tree is featured in all three versions of the song, written by Banjo Patterson in 1895, by Harry Nathan at the turn of the 20th century, and by Marie Cowan in 1903.
The Koala's Diet
Koala bears live in eucalyptus forests in eastern and southeastern Australia. They enjoy a diet of eucalyptus leaves. Since about half of the content of the leaves is water, koalas also derive most of the water they need from eucalyptus leaves. Koalas favor about 12 different species of eucalyptus tree leaves.