Melaleuca
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{{Taxobox | color = lightgreen | name = Melaleuca | image = Melaleuca quinquenervia.jpg | image_width = 240px | image_caption = Melaleuca quinquenervia foliage and fruit capsules | regnum = Plantae | divisio = Magnoliophyta | classis = Magnoliopsida | ordo = Myrtales | familia = Myrtaceae | genus = Melaleuca | genus_authority = L. nom. cons.. | subdivision_ranks = Species | subdivision = 236; see List of Melaleuca species }}
Melaleuca is a genus of plants in the myrtle family Myrtaceae. It currently contains 236 species, all of which occur in Australia. About 230 species are endemic to Australia, the few remaining species occurring as far afield as Indonesia, New Guinea, New Caledonia and even Malaysia.
The species are shrubs and trees growing (depending on species) to 2–30 m tall, with flaky, exfoliating bark. The leaves are evergreen, alternately arranged, ovate to lanceolate, 1-25 cm long and 0.5-7 cm broad, with an entire margin, dark green to grey-green in colour. The flowers are produced in dense clusters along the stems, each flower with fine small petals and a tight bundle of stamens; flower colour varies from white to pink, red, pale yellow or greenish. The fruit is a small capsule containing numerous minute seeds.
Melaleuca is closely related to Callistemon, the main difference between the genera is that the stamens are generally free in Callistemon but grouped into bundles in Melaleuca.
In the wild, Melaleuca plants are generally found in open forest, woodland or shrubland, particularly along watercourses and the edges of swamps.
Common names of many Australasian genera are inaccurate and unhelpful. In consequence, the best-accepted common name for Melaleuca is simply melaleuca; however most of the larger species are also known as paperbarks, and the smaller types as honey myrtles. Some melaleucas are used in the manufacture of an essential oil called tea tree oil and called "tea trees", which is confusing, as "tea tree" has also been used for several other plants, including Leptospermum, a related and superficially similar-looking genus. In particular, the paperbark tree Melaleuca alternifolia was dubbed the "tea tree" as its foliage when steeped in water produces a brown tincture faintly resembling tea to the early Europeans, although it was generally recognised to be only a very poor (and potentially toxic) substitute. Similarly small bodies of water near Melaleuca scrub are sometimes coloured brown due to the seepage from the leaves.
In Australia, Melaleuca species are sometimes used as food plants by the larvae of hepialid moths of the genus Aenetus including A. ligniveren. These burrow horizontally into the trunk then vertically down.
Scientific studies have shown that tea tree oil made from Melaleuca alternifolia is a highly effective topical antibacterial and antifungal, although it may be toxic when ingested internally in large doses or by children. In rare cases, topical products can be absorbed by the skin and result in toxicity.
Melaleucas are popular garden plants, both in Australia and other tropical areas worldwide. In Hawaii and the Florida everglades, Melaleuca quinquenervia was introduced in order to help drain low-lying swampy areas. It has since gone on to become a serious invasive weed.
Uses
The oils of Melaleuca can be found in organic solutions of medication that claims to eliminate warts, including the Human papillomavirus. No scientific evidence proves this claim (reference: "Forces of Nature: Warts No More").
 A Melbourne paperbark |
 A paperbark in Melbourne |
 Melaleuca quinquenervia bark showing the papery exfoliation from which the common name 'paperbark' derives |
 Paperbark trees in Tasmania after sunset |
 19th century illustration of Melaleuca leucadendra |