Melaleuca alternifolia
{{Short description|Species of tree in the flowering plant family Myrtaceae}}
{{Italic title}}
{{Speciesbox
|name = Tea tree
|image = Melaleuca alternifolia flowers.jpg
|image_caption =
|genus = Melaleuca
|species = alternifolia
|authority = (Maiden & Betche) Cheel{{cite web |title=Melaleuca alternifolia |url=https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:597833-1 |publisher=Plants of the World Online |access-date=24 August 2021}}
|synonyms= 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.File:Melaleuca alternifolia habit.jpg]]
Description
Melaleuca alternifolia is a small tree that can grow to about {{convert|7|m|ft|sigfig=1|abbr=on}} 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, {{convert|10-35|mm|in|sigfig=1|abbr=on}} long, and {{convert|1|mm|in|sigfig=1|abbr=on}} wide. They are also rich in oil with the glands prominent.{{cite web |title=Melaleuca alternifolia |url=http://plantnet.rbgsyd.nsw.gov.au/cgi-bin/NSWfl.pl?page=nswfl&lvl=sp&name=Melaleuca~alternifolia |publisher=Royal Botanic Garden Sydney |access-date=13 December 2018}}{{cite book |last=Holliday |first=Ivan |year=2004 |title=Melaleucas: a field and garden guide |edition=2nd |location=Frenchs Forest, N.S.W. |publisher=Reed New Holland Publishers |pages=16–17 |isbn=1876334983 }}
Flowers occur in white or cream-colored masses of spikes {{convert|3-5|cm|in|sigfig=1|abbr=on}} 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, {{convert|2–3|mm|in|sigfig=1|abbr=on}} 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 name Melaleuca linariifolia var. alternifolia in the Proceedings of the Linnean Society of New South Wales.{{cite web|title=Melaleuca linariifolia var. alternifolia|url=https://id.biodiversity.org.au/instance/apni/514223|publisher=APNI|access-date=4 March 2015}}{{cite journal |last1=Maiden |first1=Joseph |last2=Betche |first2=Ernst |title=Notes from the Botanic Gardens, Sydney No. 10 |journal=Proceedings of the Linnean Society of New South Wales |date=1905 |volume=29 |issue=4 |page=742 |doi=10.5962/bhl.part.20178 |url=https://www.biodiversitylibrary.org/item/30005#page/798/mode/1up |access-date=13 December 2018|doi-access=free }} In 1925, Edwin Cheel raised the variety to species status as Melaleuca alternifolia.{{cite web|title=Melaleuca alternifolia|url=https://id.biodiversity.org.au/instance/apni/508646|publisher=APNI|access-date=4 March 2015}}{{cite journal|last1=Cheel|first1=Edwin|title=Notes on Melaleuca with descriptions of two new species and a new variety|journal=Journal and Proceedings of the Royal Society of New South Wales|date=1924|volume=58|page=195}} The specific epithet (alternifolia) is derived from the Latin alternus meaning "alternate" and folium meaning "leaf", referring to the leaf arrangement.{{cite book|last1=Brophy|first1=Joseph J.|last2=Craven|first2=Lyndley A.|last3=Doran|first3=John C.|title=Melaleucas : their botany, essential oils and uses|date=2013|publisher=Australian Centre for International Agricultural Research|location=Canberra|isbn=9781922137517|page=73}}
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.{{Cite journal|last1=Carson|first1=C. F.|last2=Hammer|first2=K. A.|last3=Riley|first3=T. V.|date=2006-01-01|title=Melaleuca alternifolia (Tea Tree) Oil: a Review of Antimicrobial and Other Medicinal Properties|journal=Clinical Microbiology Reviews|language=en|volume=19|issue=1|pages=50–62|doi=10.1128/CMR.19.1.50-62.2006|issn=0893-8512|pmc=1360273|pmid=16418522}} It grows along streams and in swampy places.{{cite web|title=Melaleuca alternifolia|url=http://plantnet.rbgsyd.nsw.gov.au/cgi-bin/NSWfl.pl?page=nswfl&lvl=sp&name=Melaleuca~alternifolia|publisher=Royal Botanic Gardens, Sydney|access-date=4 March 2015}}
Uses
=Horticulture=
=Traditional medicine and potential toxicity=
{{See also|Tea tree oil}}
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.{{cite web|title=Tea tree oil|url=https://www.nccih.nih.gov/health/tea-tree-oil|publisher=MedlinePlus, U.S. National Library of Medicine|access-date=26 May 2021|date=1 October 2020}} 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.{{Cite journal | last1 = Shemesh | first1 = A. | last2 = Mayo | first2 = W. L. | year = 1991 | title = Australian tea tree oil: a natural antiseptic and fungicidal agent | journal = Aust. J. Pharm | volume = 72 | pages = 802–803 }}Low, T. 1990. Bush Medicine. Harper Collins Publishers, North Ryde, NSW, Australia
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.{{cite journal |doi=10.1128/CMR.19.1.50-62.2006 |title=Melaleuca alternifolia (Tea Tree) Oil: a Review of Antimicrobial and Other Medicinal Properties |year=2006 |last1=Carson |first1=C. F. |last2=Hammer |first2=K. A. |last3=Riley |first3=T. V. |journal=Clinical Microbiology Reviews |volume=19 |pages=50–62 |pmid=16418522 |issue=1 |pmc=1360273}} Tea tree oil is commonly used as a treatment for acne, although evidence is limited that it is effective for this purpose.{{Cite journal|title=A comparative study of tea-tree oil versus benzoylperoxide in the treatment of acne|journal = The Medical Journal of Australia|volume = 153|issue = 8|pages = 455–8|pmid = 2145499|year = 1990|last1 = Bassett|first1 = I. B.|last2 = Pannowitz|first2 = D. L.|last3 = Barnetson|first3 = R. S.|doi = 10.5694/j.1326-5377.1990.tb126150.x|s2cid = 45058057}}
If ingested, tea tree oil is toxic with serious side effects, including coma, and may cause skin irritation if used topically in high concentrations.{{cite journal |pages=616–25 |doi=10.1016/j.fct.2005.09.001 |title=A review of the toxicity of Melaleuca alternifolia (tea tree) oil |year=2006 |last1=Hammer |first1=K |last2=Carson |first2=C |last3=Riley |first3=T |last4=Nielsen |first4=J |journal=Food and Chemical Toxicology |volume=44 |issue=5 |pmid=16243420}} As of 2006, no deaths were reported in the medical literature.
=Gallery=
Image:Melaleuca alternifolia (Maria Serena).jpg|M. alternifolia (cultivated) growing in Menton, France
Image:Melaleuca alternifolia fruits.jpg|M. alternifolia fruits
Image:Melaleuca alternifolia bark.jpg|M. alternifolia bark
Image:Melaleuca alternifolia (Maria Serena) tree.jpg|M. alternifolia tree
Image:Melaleuca alternifolia (Maria Serena) flowers.jpg|M. alternifolia flowers
References
{{Reflist}}
{{Taxonbar|from=Q782073}}
{{Authority control}}
Category:Medicinal plants of Oceania
Category:Flora of New South Wales
Category:Myrtales of Australia