Melaleuca linariifolia var. alternifolia Maiden & Betche
Melaleuca alternifolia, commonly known as tea tree, is a species of tree or tall shrub in the myrtle family, Myrtaceae. Endemic to Australia, it occurs in southeast Queensland and the north coast and adjacent ranges of New South Wales where it grows along streams and on swampy flats, and is often the dominant species where it occurs.
Melaleuca alternifolia is a small tree that can grow to about 7 m (20 ft) with a bushy crown and whitish, papery bark. The leaves are arranged alternately, sometimes scattered or whorled. The leaves are smooth, soft, linear in shape, 10–35 mm (0.4–1 in) long and 1 mm (0.04 in) wide. They are also rich in oil with the glands prominent. Flowers occur in white or cream-colored masses of spikes 3–5 cm (1–2 in) long over a short period, mostly spring to early summer, and give the tree an appearance of looking fluffy. The small woody, cup-shaped fruit, 2–3 mm (0.08–0.1 in) in diameter are scattered along the branches.
Taxonomy and naming
This species was first formally described in 1905 by Joseph Maiden and Ernst Betche and given the Melaleuca linariifolia var. alternifolia in the Proceedings of the Linnean Society of New South Wales. In 1925, Edwin Cheel raised the variety to species status as Melaleuca alternifolia. The specific epithet (alternifolia) is derived from the Latin alternus meaning "alternate" and folium meaning "leaf", referring to the leaf arrangement.
Distribution and habitat
Melaleuca alternifolia is endemic to Australia and is found from the Grafton district in New South Wales as far inland as Stroud and in coastal districts north to Maryborough in Queensland. It grows along streams and in swampy places.
This species grows well in a wide range of soils and climates. It prefers moist, but well-drained soils and to be grown in full sun.
Traditional medicine and potential toxicity
Tea tree has been used as a folk medicine treatment among Indigenous Australians of eastern inland areas who use tea trees by inhaling the oils from the crushed leaves to treat coughs and colds. They also sprinkle leaves on wounds, after which a poultice is applied. In addition, tea tree leaves are soaked to make an infusion to treat sore throats or skin ailments.
Characteristic of the myrtle family Myrtaceae, it is used to distill essential oil. It is the primary species for commercial production of tea tree oil (melaleuca oil), a topical treatment. Tea tree oil is commonly used as a treatment for acne, although there is limited evidence that it is effective for this purpose.
If ingested, tea tree oil is toxic with serious side effects, including coma, and may cause skin irritation if used topically in high concentrations. As of 2006, no deaths were reported in the medical literature.
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- ^ Carson, C. F.; Hammer, K. A.; Riley, T. V. (2006-01-01). "Melaleuca alternifolia (Tea Tree) Oil: a Review of Antimicrobial and Other Medicinal Properties". Clinical Microbiology Reviews. 19 (1): 50–62. doi:10.1128/CMR.19.1.50-62.2006. ISSN 0893-8512. PMC 1360273. PMID 16418522.
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- ^ Carson, C. F.; Hammer, K. A.; Riley, T. V. (2006). "Melaleuca alternifolia (Tea Tree) Oil: a Review of Antimicrobial and Other Medicinal Properties". Clinical Microbiology Reviews. 19 (1): 50–62. doi:10.1128/CMR.19.1.50-62.2006. PMC 1360273. PMID 16418522.
- ^ Bassett, I. B.; Pannowitz, D. L.; Barnetson, R. S. (1990). "A comparative study of tea-tree oil versus benzoylperoxide in the treatment of acne". The Medical Journal of Australia. 153 (8): 455–8. doi:10.5694/j.1326-5377.1990.tb126150.x. PMID 2145499. S2CID 45058057.
- ^ a b Hammer, K; Carson, C; Riley, T; Nielsen, J (2006). "A review of the toxicity of Melaleuca alternifolia (tea tree) oil". Food and Chemical Toxicology. 44 (5): 616–25. doi:10.1016/j.fct.2005.09.001. PMID 16243420.