''Leptospermum'' is a

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

of shrubs and small trees in the myrtle

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

Myrtaceae Myrtaceae (), the myrtle family, is a family of dicotyledonous plants placed within the order Myrtales. Myrtle, pōhutukawa, bay rum tree, clove, guava, acca (feijoa), allspice, and eucalyptus are some notable members of this group. All ...

commonly known as tea trees, although this name is sometimes also used for some species of ''

Melaleuca ''Melaleuca'' () is a genus of nearly 300 species of plants in the myrtle family, Myrtaceae, commonly known as paperbarks, honey-myrtles, bottlebrushes or tea-trees (although the last name is also applied to species of '' Leptospermum''). They ...

''. Most species are

endemic Endemism is the state of a species being found only in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also foun ...

Australia Australia, officially the Commonwealth of Australia, is a country comprising mainland Australia, the mainland of the Australia (continent), Australian continent, the island of Tasmania and list of islands of Australia, numerous smaller isl ...

, with the greatest diversity in the south of the continent, but some are

native Native may refer to: People * '' Jus sanguinis'', nationality by blood * '' Jus soli'', nationality by location of birth * Indigenous peoples, peoples with a set of specific rights based on their historical ties to a particular territory ** Nat ...

to other parts of the world, including

New Zealand New Zealand () is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and List of islands of New Zealand, over 600 smaller islands. It is the List of isla ...

and

Southeast Asia Southeast Asia is the geographical United Nations geoscheme for Asia#South-eastern Asia, southeastern region of Asia, consisting of the regions that are situated south of China, east of the Indian subcontinent, and northwest of the Mainland Au ...

. Leptospermums all have five conspicuous

petal Petals are modified leaves that form an inner whorl surrounding the reproductive parts of flowers. They are often brightly coloured or unusually shaped to attract pollinators. All of the petals of a flower are collectively known as the ''corol ...

s and five groups of

stamen The stamen (: stamina or stamens) is a part consisting of the male reproductive organs of a flower. Collectively, the stamens form the androecium., p. 10 Morphology and terminology A stamen typically consists of a stalk called the filament ...

s which alternate with the petals. There is a single

style Style, or styles may refer to: Film and television * ''Style'' (2001 film), a Hindi film starring Sharman Joshi, Riya Sen, Sahil Khan and Shilpi Mudgal * ''Style'' (2002 film), a Tamil drama film * ''Style'' (2004 film), a Burmese film * '' ...

in the centre of the flower and the fruit is a woody capsule. The first formal description of a leptospermum was published in 1776 by the

German German(s) may refer to: * Germany, the country of the Germans and German things **Germania (Roman era) * Germans, citizens of Germany, people of German ancestry, or native speakers of the German language ** For citizenship in Germany, see also Ge ...

botanists

Johann Reinhold Forster Johann Reinhold Forster (; 22 October 1729 – 9 December 1798) was a German Reformed pastor and naturalist. Born in Tczew, Dirschau, Pomeranian Voivodeship (1466–1772), Pomeranian Voivodeship, Polish–Lithuanian Commonwealth (now Tczew, Po ...

and his son

Johann Georg Adam Forster Johann George Adam Forster, also known as Georg Forster (; 27 November 1754 – 10 January 1794), was a German geographer, naturalist, ethnologist, travel writer, journalist and revolutionary. At an early age, he accompanied his father, Joha ...

, but an unambiguous definition of individual species in the genus was not achieved until 1979. Leptospermums grow in a wide range of habitats but are most commonly found in moist, low-nutrient soils. They have important uses in

horticulture Horticulture (from ) is the art and science of growing fruits, vegetables, flowers, trees, shrubs and ornamental plants. Horticulture is commonly associated with the more professional and technical aspects of plant cultivation on a smaller and mo ...

, in the production of honey and in

floristry Floristry is the production, commerce, and trade in flowers. It encompasses flower care and handling, floral design, floral design and arrangement, merchandising, production, display and flower delivery. Wholesale florists sell bulk flowers ...

Description

Plants in the genus ''Leptospermum'' range in size from

prostrate shrub A prostrate shrub is a woody plant, most of the branches of which lie upon or just above the ground, rather than being held erect as are the branches of most trees and shrubs. Background Prostration may occur because the supporting tissues in ste ...

s to small trees, and have fibrous, flaky or papery bark. The leaves are arranged alternately and are relatively small, rigid and often aromatic when crushed. The flowers may be solitary or in groups, and have bracteoles and

sepal A sepal () is a part of the flower of angiosperms (flowering plants). Usually green, sepals typically function as protection for the flower in bud, and often as support for the petals when in bloom., p. 106 Etymology The term ''sepalum'' ...

s which in most species fall off as the flower opens. There are five spreading, conspicuous petals which are white, pink or red. There are many stamens which are usually shorter than the petals and in five groups opposite the stamens, although they often appear not to be grouped. A simple style usually arises from a small depression in the ovary which has from three to five sections in most species, each section containing a few to many

ovule In seed plants, the ovule is the structure that gives rise to and contains the female reproductive cells. It consists of three parts: the ''integument'', forming its outer layer, the ''nucellus'' (or remnant of the sporangium, megasporangium), ...

s. The fruit is a woody capsule which opens at the top to release the seeds, although in some species this does not occur until the plant, or the part of it, dies.

Taxonomy and naming

The first formal description of a leptospermum was published by Johann Reinhold Forster and Johann Georg Adam Forster in their 1776 book, ''

Characteres Generum Plantarum ''Characteres generum plantarum'' (complete title , "Characteristics of the types of plants collected, described, and delineated during a voyage to islands of the South Seas, in the years 1772–1775 by Johann Reinhold Forster and Georg Forster ...

''. In 1876,

George Bentham George Bentham (22 September 1800 – 10 September 1884) was an English botanist, described by the weed botanist Duane Isely as "the premier systematic botanist of the nineteenth century". Born into a distinguished family, he initially studie ...

described twenty species, but noted the difficulty of discriminating between species. ("The species are very difficult to discriminate.") Of the species he named, only ten remain as valid. In 1979,

Barbara Briggs Barbara Gillian Briggs (born 1934) is one of the foremost Australian botanists. The '' IK'' lists 205 names of plants which have been published or co-published by her. She was one of the botanists in the Angiosperm Phylogeny Group, of th1998 APG ...

and

Laurie Johnson Laurence Reginald Ward Johnson (7 February 1927 – 16 January 2024) was an English composer and bandleader who wrote scores for dozens of film and television series, described as "one of the most highly regarded arrangers of big-band swing a ...

published a classification of the family Myrtaceae in the ''

Proceedings of the Linnean Society of New South Wales The Linnean Society of New South Wales promotes ''the Cultivation and Study of the Science of Natural History in all its Branches'' and was founded in Sydney, New South Wales (Australia) in 1874 and incorporated in 1884. History The Society succ ...

''. Although there have been revisions to their groupings, their paper allowed a systematic examination of species in the genus ''Leptospermum''. In 1989,

Joy Thompson Joy Thompson (born Joy Gardiner-Garden, 1923, died 2018) was an Australian botanist. Her main research areas were taxonomy and Myrtaceae. Life and career Thompson's university studies occurred during the second world war and in university vacat ...

published a complete revision of the genus. In 2000, O'Brien ''et al.'' published yet another revision, using matK-based evidence to suggest that ''Leptospermum'' is

polyphyletic A polyphyletic group is an assemblage that includes organisms with mixed evolutionary origin but does not include their most recent common ancestor. The term is often applied to groups that share similar features known as Homoplasy, homoplasies ...

, and should be split into persistent, Western non-persistent, and Eastern non-persistent fruiting plants, with ''Leptospermum spinescens'' as an outlier. However, neither phylogeny has been universally accepted. Current estimates recognize about ninety species of ''Leptospermum''. The common name ''tea tree'' derives from the practice of early Australian settlers who soaked the leaves of several species in boiling water to make a

herbal tea Herbal teas, technically known as herbal infusions, and less commonly called tisanes (UK and US , US also ), are beverages made from the infusion or decoction of herbs, spices, or other plant material in hot water. Often herb tea, or the plai ...

. The genus name (''Leptospermum'') means "slender-seeded".

Distribution and habitat

Most ''Leptospermum'' species are endemic to Australia where most are found in southern areas of the country. They are most common in moist, nutrient-poor soils although they sometimes occupy other situations. '' Leptospermum laevigatum'' is usually found growing on beach sand and '' L. riparium'' growing in

Tasmania Tasmania (; palawa kani: ''Lutruwita'') is an island States and territories of Australia, state of Australia. It is located to the south of the Mainland Australia, Australian mainland, and is separated from it by the Bass Strait. The sta ...

n rainforest on the edges of rivers. '' Leptospermum amboinense'' extends from

Queensland Queensland ( , commonly abbreviated as Qld) is a States and territories of Australia, state in northeastern Australia, and is the second-largest and third-most populous state in Australia. It is bordered by the Northern Territory, South Austr ...

to Southeast Asia and three species, '' L. javanicum'', '' L. parviflorum'' and '' L. recurvum'' are endemic to southeast Asia. ''L. recurvum'' is only found on

Mount Kinabalu Mount Kinabalu ( Dusun: ''Gayo Ngaran'' or ''Nulu Nabalu'', ) is the highest mountain in Malaysia and Borneo. With a height of , it is the third-highest peak of an island on Earth, the 28th highest peak in Southeast Asia, and 20th most prom ...

Sabah Sabah () is a States and federal territories of Malaysia, state of Malaysia located in northern Borneo, in the region of East Malaysia. Sabah has land borders with the Malaysian state of Sarawak to the southwest and Indonesia's North Kalima ...

. ''

Leptospermum scoparium ''Leptospermum'' is a genus of shrubs and small trees in the myrtle family Myrtaceae commonly known as tea trees, although this name is sometimes also used for some species of '' Melaleuca''. Most species are endemic to Australia, with the gre ...

'' is one of the most widespread in the genus and occurs in

New South Wales New South Wales (commonly abbreviated as NSW) is a States and territories of Australia, state on the Eastern states of Australia, east coast of :Australia. It borders Queensland to the north, Victoria (state), Victoria to the south, and South ...

Victoria Victoria most commonly refers to: * Queen Victoria (1819–1901), Queen of the United Kingdom and Empress of India * Victoria (state), a state of Australia * Victoria, British Columbia, Canada, a provincial capital * Victoria, Seychelles, the capi ...

, Tasmania and

, where it is one of the most widespread and important native shrub species.

Ecology

In Australia, ''Leptospermum'' species are sometimes used as food plants by the

larva A larva (; : larvae ) is a distinct juvenile form many animals undergo before metamorphosis into their next life stage. Animals with indirect development such as insects, some arachnids, amphibians, or cnidarians typically have a larval phase ...

e of hepialid

moth Moths are a group of insects that includes all members of the order Lepidoptera that are not Butterfly, butterflies. They were previously classified as suborder Heterocera, but the group is Paraphyly, paraphyletic with respect to butterflies (s ...

s of the genus ''

Aenetus ''Aenetus'' is a genus of moths of the family Hepialidae. There are 24 described species found in Indonesia, New Guinea, New Caledonia, Australia and New Zealand. Most species have green or blue forewings and reddish hindwings, but some are predomi ...

'', including ''A. lewinii'' and ''A. ligniveren''. These burrow horizontally into the trunk then vertically down.

Uses

Use in horticulture

Most ''Leptospermum'' species make desirable garden plants. The hardiest species (''L. lanigerum, L. liversidgei, L. polygalifolium, L. rupestre, L. scoparium'') are hardy to about to ; others are sensitive to frost. They tolerate most soils, but many suppliers specify ericaceous (i.e. lime-free) compost with good drainage and full sun. Established plants are

drought A drought is a period of drier-than-normal conditions.Douville, H., K. Raghavan, J. Renwick, R.P. Allan, P.A. Arias, M. Barlow, R. Cerezo-Mota, A. Cherchi, T.Y. Gan, J. Gergis, D. Jiang, A. Khan, W. Pokam Mba, D. Rosenfeld, J. Tierney, ...

tolerant. They are often found as hedge plants on the west coast of the

United States The United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 U.S. state, states and a federal capital district, Washington, D.C. The 48 ...

, and some species are popular for cultivation as

bonsai Bonsai (; , ) is the Japanese art of Horticulture, growing and shaping miniature trees in containers, with a long documented history of influences and native Japanese development over a thousand years, and with unique aesthetics, cultural hist ...

. Many

cultivar A cultivar is a kind of Horticulture, cultivated plant that people have selected for desired phenotypic trait, traits and which retains those traits when Plant propagation, propagated. Methods used to propagate cultivars include division, root a ...

s exist.

Use in floristry

These flowers are also grown in double cultivars and are used in floral designs. However, they do not last when out of water and the single flowers do not last when wired. The 'Pacific Beauty' (''Leptospermum polygalifolium'') is a useful flower to use in large church-service bowls and function arrangements, however use of ''Leptospermum'' in corporate designs is less desirable as they dry and drop when subjected to heating and air conditioning.

Honey production

The

nectar Nectar is a viscous, sugar-rich liquid produced by Plant, plants in glands called nectaries, either within the flowers with which it attracts pollination, pollinating animals, or by extrafloral nectaries, which provide a nutrient source to an ...

from the flowers is harvested by bees, yielding Leptospermum honey, which is marketed as Manuka honey. Honey produced from Australian '' Leptospermum polygalifolium'' is also known as ''jelly bush'' or the ''lemon-scented tea tree''.Native honey a sweet antibacterial
''Australian Geographic'', March 3, 2011.

Species

The following is a list of species accepted by

Plants of the World Online Plants of the World Online (POWO) is an online taxonomic database published by the Royal Botanic Gardens, Kew. History Following the Convention on Biological Diversity, the Royal Botanic Gardens in Kew launched Plants of the World Online i ...

as at August 2024: *'' Leptospermum amboinense'' Blume - Qld, Malesia *'' Leptospermum arachnoides'' Gaertn. spidery tea-tree - Qld, NSW *'' Leptospermum argenteum''

Joy Thomps. Joy Thompson (born Joy Gardiner-Garden, 1923, died 2018) was an Australian botanist. Her main research areas were taxonomy (biology), taxonomy and Myrtaceae. Life and career Thompson's university studies occurred during the second world war and ...

Mt Royal tea-tree - NSW *'' Leptospermum barneyense'' A.R.Bean - Qld *'' Leptospermum continentale'' Joy Thomps. prickly tea-tree - NSW, Vic, SA *'' Leptospermum crassifolium'' Joy Thomps. - NSW *'' Leptospermum deuense'' Joy Thomps. - NSW *'' Leptospermum emarginatum'' H.L.Wendl. ex Link - NSW, Vic *'' Leptospermum epacridoideum'' Cheel - NSW *'' Leptospermum glabrescens'' N.A.Wakef. - Vic *'' Leptospermum grandiflorum'' Lodd. G.Lodd. & W.Lodd. - Tas *'' Leptospermum grandifolium''

Sm. Sir James Edward Smith (2 December 1759 – 17 March 1828) was an English botanist and founder of the Linnean Society. Early life and education Smith was born in Norwich in 1759, the son of a wealthy wool merchant. He started studying botan ...

- NSW, Vic *'' Leptospermum gregarium'' Joy Thomps. - Qld, NSW *'' Leptospermum hoipolloi'' L.M.H.Schmid & de Lange - New Zealand *'' Leptospermum javanicum'' Blume - Myanmar, Thailand, Malaysia, Indonesia, Philippines *''

Leptospermum juniperinum ''Leptospermum juniperinum'', commonly known as the prickly tea tree, is a species of broom-like shrub that is endemic to eastern Australia. It has narrow, sharply pointed leaves, white flowers usually arranged singly on short side shoots and sma ...

'' Sm. - Qld, NSW *''

Leptospermum lanigerum ''Leptospermum lanigerum'', commonly known as the woolly teatree, is a small tree or medium shrub from the plant Family (biology), family ''Myrtaceae''. Its common name derives from the conspicuously hairy capsules produced as fruit, along with t ...

'' ( Sol. ex Aiton) Sm. - Qld, NSW, Vic, SA, Tas *''

Leptospermum liversidgei ''Leptospermum liversidgei'', commonly known as the olive tea-tree, is a species of compact shrub that is endemic to eastern Australia. It has narrow egg-shaped, lemon-scented leaves, white or pink flowers and woody fruit that remain on the plan ...

'' R.T.Baker &

H.G.Sm. Henry George Smith (26 July 1852 – 19 September 1924) was an Australian chemist whose pioneering work on the chemistry of the essential oils of the Australian flora achieved worldwide recognition. Smith was born at Littlebourne, Kent, Engla ...

- Qld, NSW *'' Leptospermum macrocarpum'' (

Maiden Virginity is a social construct that denotes the state of a person who has never engaged in sexual intercourse. As it is not an objective term with an operational definition, social definitions of what constitutes virginity, or the lack thereof ...

Betche Daniel Ludwig Ernst Betche (31 December 1851, in Potsdam – 28 June 1913, in Sydney) was a German-Australian horticulturist and botanist. His mother died at his birth and he was of delicate constitution all his life. His father was sufficiently ...

) Joy Thomps. - NSW *'' Leptospermum micromyrtus'' Miq. - NSW, Vic *'' Leptospermum minutifolium'' C.T.White - Qld, NSW *'' Leptospermum morrisonii'' Joy Thomps. - NSW *'' Leptospermum myrtifolium'' Sieber ex DC. - NSW, ACT, Vic *'' Leptospermum nitidum'' Hook.f. - Tas *'' Leptospermum novae-angliae'' Joy Thomps. - Qld, NSW *'' Leptospermum obovatum''

Sweet Sweetness is a basic taste most commonly perceived when eating foods rich in sugars. Sweet tastes are generally regarded as pleasurable. In addition to sugars like sucrose, many other chemical compounds are sweet, including aldehydes, ketones, ...

- NSW, Vic *'' Leptospermum oreophilum'' Joy Thomps. - Qld *'' Leptospermum parvifolium'' Sm. - Qld, NSW *'' Leptospermum petersonii'' F.M.Bailey - Qld, NSW *'' Leptospermum petraeum'' Joy Thomps. - NSW *'' Leptospermum polygalifolium'' Salisb. - Qld, NSW, Lord Howe Island ** ''Leptospermum polygalifolium'' subsp. ''cismontanum'' Joy Thomps. - Qld, NSW ** ''Leptospermum polygalifolium'' subsp. ''howense'' Joy Thomps. - Lord Howe Island ** ''Leptospermum polygalifolium'' subsp. ''montanum'' Joy Thomps. ** ''Leptospermum polygalifolium'' Salisb. subsp. ''polygalifolium'' - NSW **''Leptospermum polygalifolium'' subsp. ''transmontanum'' Joy Thomps. - Qld, NSW **''Leptospermum polygalifolium'' subsp. ''tropicum'' Joy Thomps. - Qld *''

Leptospermum recurvum ''Leptospermum recurvum'' is a species of shrub or tree that is native to Mount Kinabalu in Malaysian Borneo and to Sulawesi. It has pale, flaky bark, broadly elliptical to almost round leaves, white flowers about wide and fruit that tend to re ...

'' Hook.f. - Sabah, Sulawesi *'' Leptospermum repo'' de Lange & L.M.H.Schmid - New Zealand *'' Leptospermum riparium'' D.I.Morris - Tas *'' Leptospermum rotundifolium'' (Maiden & Betche) F.A.Rodway - NSW *'' Leptospermum rupestre'' Hook.f. - Tas *'' Leptospermum rupicola'' Joy Thomps. - NSW *''

'' J.R.Forst. &

G.Forst. Johann George Adam Forster, also known as Georg Forster (; 27 November 1754 – 10 January 1794), was a German geographer, naturalist, ethnologist, travel writer, journalist and revolutionary. At an early age, he accompanied his father, Joha ...

- Vic, NSW, Tas, NZ *'' Leptospermum sejunctum'' Joy Thomps. - NSW *'' Leptospermum spectabile'' Joy Thomps. - NSW *'' Leptospermum sphaerocarpum'' Cheel - NSW *'' Leptospermum squarrosum'' Gaertn. - NSW *'' Leptospermum tairawhitiense'' G.J.Atkins, de Lange & M.A.M.Renner - New Zealand *''

Leptospermum thompsonii ''Leptospermum thompsonii'', commonly known as the monga tea-tree, is a species of tall shrub that is endemic to south eastern New South Wales. It has rough, flaky bark, broadly elliptical to egg-shaped leaves with the narrower end towards the ba ...

'' Joy Thomps. - NSW *'' Leptospermum turbinatum'' Joy Thomps. - Vic *'' Leptospermum variabile'' Joy Thomps. - Qld, NSW *'' Leptospermum wooroonooran'' F.M.Bailey - Qld

References

{{Authority control Myrtaceae genera Taxa named by Georg Forster Taxa named by Johann Reinhold Forster