1. Family: Myrtaceae Juss.
    1. Genus: Melaleuca L.
      1. Melaleuca alternifolia (Maiden & Betche) Cheel

        The genus Melaleuca belongs to the myrtle family (Myrtaceae) and includes about 250 species (including the paperbarks, some of which are cultivated as ornamentals). Most Melaleuca species are restricted to Australia. M. alternifolia bears fluffy, white masses of flowers from spring to early summer, and its narrow leaves help distinguish it from the similar species M. linariifolia, which has wider leaves and flattish-spherical fruits.

    [FTEA]

    Myrtaceae, B. Verdcourt, B.Sc., Ph.D. Flora of Tropical East Africa. 2001

    Habit
    Shrub or small tree 4–7 m tall with soft layered peeling papery bark; branchlets glabrescent.
    Leaves
    Leaves alternate, linear, 1–3.5 cm long, usually under 1 mm wide.
    Flowers
    Flowers white, solitary within each bract arranged in many-flowered spikes, terminal or from upper axils.
    Corolla
    Petals rounded ovate, 2 mm long and wide.
    Stamens
    Staminal bundles with claw 11 mm long and 30–35 filaments spread all over claw, those at base shortest.
    [KSP]

    Kew Species Profiles

    General Description
    The main source of commercially-produced tea tree oil, Melaleuca alternifolia is an efficacious natural antiseptic once heralded as 'a medicine chest in a bottle'.

    The genus Melaleuca belongs to the myrtle family (Myrtaceae) and includes about 250 species (including the paperbarks, some of which are cultivated as ornamentals). Most Melaleuca species are restricted to Australia. M. alternifolia bears fluffy, white masses of flowers from spring to early summer, and its narrow leaves help distinguish it from the similar species M. linariifolia, which has wider leaves and flattish-spherical fruits.

    Captain James Cook, the 18th century explorer, is reported to have used tea tree leaves to brew a spicy tea, although the common name ‘tea tree’ has been applied to several plants in the genera Melaleuca and Leptospermum (also in Myrtaceae), so the exact species he used is unknown.

    Species Profile
    Geography and distribution

    Melaleuca alternifolia is native to Australia, where it is found from Queensland to north-east New South Wales, at up to 300 m above sea level.

    Description

    A tall shrub or small tree up to 7 m high with a bushy crown and papery bark. The hairless leaves are scattered to whorled and are 10-35 mm long by about 1 mm wide. The leaves have prominent oil glands and are rich in aromatic oil. The leaves are borne on a petiole (leaf stalk) of about 1 mm long. The inflorescences are many-flowered spikes, 3-5 cm long, with axes bearing short hairs. The white flowers are solitary, each within a bract, and have petals 2-3 mm long. There are 30-60 stamens (male parts) per bundle and the style (female part) is 3-4 mm long. The fruit is cup-shaped and 2-3 mm in diameter, with a hole 1.5-2.5 mm in diameter, enabling the release and dispersal of the seeds by wind. Fruits are usually sparsely spaced along the branches.

    Uses

    Traditionally, the crushed leaves of Melaleuca alternifolia were used by Australian Aborigines to treat skin infections. Today, M. alternifolia is commercially cultivated (especially in north-east New South Wales) for tea tree oil, an essential oil which is used as an antiseptic in skin care products, in the perfume industry, and in soaps and mouthwashes. The oil is effective against bacterial, fungal and viral infections, and is used in products to treat such conditions as athlete’s foot, warts, acne and vaginal infections. Tea tree oil is also used for treating respiratory problems, such as asthma and bronchitis.

    Melaleuca alternifolia makes an excellent hedge and windbreak, and is also planted to stabilise embankments. Its wood is used in construction, and its branches are used for fencing.

    Related species include M. cajuputi , the source of cajuput oil, and M. quinquenervia (broad-leaved paperbark) which is used for Aboriginal bark paintings and is the source of niaouli oil.

    Millennium Seed Bank - Seed Storage

    Kew's Millennium Seed Bank Partnership aims to save plant life world wide, focusing on plants under threat and those of most use in the future. Seeds are dried, packaged and stored at a sub-zero temperature in our seed bank vault.

    Description of seeds : Average 1,000 seed weight = 0.11 g

    Number of seed collections stored in the Millennium Seed Bank : One

    Cultivation

    Melaleuca alternifolia can be grown in a wide range of soils in sub-tropical climates, but performs best in well-drained but moist soil in full sun. It responds well to heavy pruning. Tea trees are drought-tolerant and can survive flooding and fire, but are not frost-tolerant.

    Commercial cultivation involves planting seed at high densities and then cutting back the whole plant close to ground level (coppicing) every 6-18 months to harvest the essential oil. The oil is extracted by steam distillation of the leaves and terminal branchlets.

    This species at Kew

    Melaleuca alternifolia is not grown at Kew, but other Melaleuca species can be seen in the Temperate House. Pressed and dried specimens of M. alternifolia are held in the Herbarium, where they are available to researchers from around the world by appointment. A sample of tea tree oil from M. alternifolia is held in the Economic Botany Collection in the Sir Joseph Banks Building.

    Australia Landscape - Kew at the British Museum

    In 2011, Kew and the British Museum brought to the heart of London a landscape showcasing the rich biodiversity of Australia, and how these fragile systems are under threat from land usage and climate change.

    Melaleuca alternifolia (tea tree) was one of 12 star plants featured in the Landscape, which took you on a journey across a whole continent, from eastern Australia’s coastal habitat, through the arid red centre, to the western Australian granite outcrop featuring unique and highly endangered plants.

    Australia Landscape was part of the Australian season at the British Museum. Supported by Rio Tinto .

    Distribution
    Australia
    Ecology
    Along streams and on swampy flats, on the coast and adjacent ranges.
    Conservation
    Widespread and common in the wild. Not evaluated according to IUCN Red List criteria.
    Hazards

    Pure tea tree oil should not be ingested, and should be kept out of the reach of children; several cases of tea tree oil poisoning have been recorded. The oil can also cause contact dermatitis.

    [KSP]
    Use
    Medicinal (tea tree oil), ornamental.

    Images

    Distribution

    Found In:

    New South Wales, Queensland

    Common Names

    English
    Tea tree

    Melaleuca alternifolia (Maiden & Betche) Cheel appears in other Kew resources:

    Date Identified Reference Herbarium Specimen Type Status
    Boorman, J.L. [s.n.], New South Wales K000793546

    First published in J. Proc. Roy. Soc. New S. Wales 58: 195 (1924)

    Accepted in:

    • [3] Govaerts, R., Sobral, N., Ashton, P., Barrie, F., Holst, B.K., Landrum, L.L., Matsumoto, K., Fernanda Mazine, F., Nic Lughadha, E., Proença, C. & al. (2008) World Checklist of Myrtaceae . Kew Publishing, Royal Botanic Gardens, Kew
    • [5] Govaerts, R. (2003) World Checklist of Selected Plant Families Database in ACCESS . The Board of Trustees of the Royal Botanic Gardens, Kew

    Literature

    • [1] World Checklist of Selected Plant Families (2011). Melaleuca alternifolia. Published on the internet by the Board of Trustees of the Royal Botanic Gardens, Kew.
    • [2] Bown, D. (2008). The Royal Horticultural Society Encyclopedia of Herbs and Their Uses. Dorling Kindersley, London.
    • [4] Holliday, I. (2004). Melaleucas: a Field and Garden Guide, 2nd edition. Reed New Holland, Sydney.
    • [6] Southwell, I. & Lowe, R. (1999). Tea Tree: the Genus Melaleuca. Harwood Academic Publishers, the Netherlands.
    • [7] Harden, G.J. (ed.) (1991). Flora of New South Wales, Volume 2. New South Wales University Press, Australia.

    Sources

    Flora of Tropical East Africa
    Flora of Tropical East Africa
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    Kew Names and Taxonomic Backbone
    The International Plant Names Index and World Checklist of Selected Plant Families (2017). Published on the internet at http://www.ipni.org and http://apps.kew.org/wcsp
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    Kew Species Profiles
    Kew Species Profiles
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