''Eucalyptus radiata'', commonly known as the narrow-leaved peppermint or Forth River peppermint, is a species of tree that is

endemic Endemism is the state of a species being found 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 found else ...

to south-eastern Australia. It has rough, fibrous to flaky bark on the trunk and larger branches, smooth grey bark on the thinner branches, lance-shaped to curved or almost linear leaves, flower buds in groups of eleven to twenty or more, white flowers and cup-shaped, hemispherical or shortened spherical fruit.

Description

''Eucalyptus radiata'' is a tree that typically grows to a height of and forms a lignotuber. It has rough, finely fibrous or flaky grey bark on the trunk and branches, usually smooth grey bark on branches thinner than . Young plants and

coppice Coppicing is a traditional method of woodland management which exploits the capacity of many species of trees to put out new shoots from their stump or roots if cut down. In a coppiced wood, which is called a copse, young tree stems are repeate ...

regrowth have sessile, narrow lance-shaped to linear leaves that are long, wide, paler on the lower surface and arranged in opposite pairs. Adult leaves are the same shade of green on both sides, lance-shaped to curved or almost linear, long and wide, tapering to a petiole long. The flower buds are arranged in leaf

axil A leaf ( : leaves) is any of the principal appendages of a vascular plant stem, usually borne laterally aboveground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage", while the leaves, ste ...

s on an unbranched peduncle long, the individual buds on

pedicels In botany, a pedicel is a stem that attaches a single flower to the inflorescence. Such inflorescences are described as ''pedicellate''. Description Pedicel refers to a structure connecting a single flower to its inflorescence. In the absenc ...

long. Mature buds are club-shaped, long and wide with a rounded or conical operculum that is shorter and narrower than the floral cup at the join. Flowering occurs from October to January and the flowers are white. The fruit is a woody, cup-shaped, hemispherical or shortened spherical capsule long and wide with the valves near rim level.

Taxonomy

''Eucalyptus radiata'' was first formally described in 1828 by

Augustin Pyramus de Candolle Augustin Pyramus (or Pyrame) de Candolle (, , ; 4 February 17789 September 1841) was a Swiss botanist. René Louiche Desfontaines launched de Candolle's botanical career by recommending him at a herbarium. Within a couple of years de Candoll ...

in his book '' Prodromus Systematis Naturalis Regni Vegetabilis'', from an unpublished description by

Franz Sieber Franz Wilhelm Sieber (30 March 1789 – 17 December 1844), was a botanist and collector who travelled to Europe, the Middle East, Southern Africa and Australia. Early life Franz Sieber was born in Prague, Bohemia on 30 March 1789. After 5&nb ...

. In 1927,

William Blakely William Faris Blakely (November 1875 – 1 September 1941) was an Australian botanist and collector. From 1913 to 1940 he worked in the National Herbarium of New South Wales, working with Joseph Maiden on '' Eucalyptus'', Maiden named a ''red ...

described ''Eucalyptus robertsonii'' in '' Journal and Proceedings of the Royal Society of New South Wales''. In 1973, Lawrie Johnson and

Donald Frederick Blaxell Donald Frederick Blaxell (born 1 February 1934, Sydney, New South Wales), is an Australian botanist, botanical collector and taxonomist. Blaxell worked at the University of New South Wales for 11 years and joined the New south Wales Herbarium ...

reduced it to a subspecies of ''Eucalyptus radiata'', describing both the new subspecies and the

autonym Autonym may refer to: * Autonym, the name used by a person to refer to themselves or their language; see Exonym and endonym * Autonym (botany), an automatically created infrageneric or infraspecific name See also * Nominotypical subspecies, in zo ...

, subspecies ''radiata'' in ''Contributions from the New South Wales Herbarium''. The names of the two subspecies are accepted by the

Australian Plant Census The Australian Plant Census (APC) provides an online interface to currently accepted, published, scientific names of the vascular flora of Australia, as one of the output interfaces of the national government Integrated Biodiversity Information Syst ...

: * ''Eucalyptus radiata'' Sieber ex DC. subsp. ''radiata'' has greyish green leaves,

glaucous ''Glaucous'' (, ) is used to describe the pale grey or bluish-green appearance of the surfaces of some plants, as well as in the names of birds, such as the glaucous gull (''Larus hyperboreus''), glaucous-winged gull (''Larus glaucescens''), ...

buds and a pointed operculum; * ''Eucalyptus radiata'' subsp. ''robertsonii'' (Blakely) L.A.S.Johnson & Blaxell has green leaves, flower buds that are not glaucous and an operculum that is usually not pointed.

Distribution and habitat

Narrow-leaved peppermint grows in forest and woodland, usually in cooler or wetter habitats. It occurs in New South Wales south from near the Queensland border, in the

Australian Capital Territory The Australian Capital Territory (commonly abbreviated as ACT), known as the Federal Capital Territory (FCT) until 1938, is a landlocked federal territory of Australia containing the national capital Canberra and some surrounding township#Aust ...

, to the

Wombat State Forest The Wombat State Forest (locally: Bullarook) is located west of Melbourne, Victoria, Australia, between Woodend and Daylesford, at the Great Dividing Range. The forest is approximately in size and sits upon Ordovician or Cenozoic sediments. ...

, Great Otway National Park and ranges of

South Gippsland South Gippsland, a region of Gippsland in Victoria, Australia, is a well-watered region consisting of low, rolling hills descending to the coast in the south and the Latrobe Valley in the north. Low granite hills continue into Wilsons Prom ...

in Victoria. It also occurs in Tasmania where it is restricted to the catchment of the Forth River. Subspecies ''robertsonii'' is restricted to

montane Montane ecosystems are found on the slopes of mountains. The alpine climate in these regions strongly affects the ecosystem because temperatures fall as elevation increases, causing the ecosystem to stratify. This stratification is a crucial ...

and

subalpine Montane ecosystems are found on the slopes of mountains. The alpine climate in these regions strongly affects the ecosystem because temperatures fall as elevation increases, causing the ecosystem to stratify. This stratification is a crucial f ...

forests of north-eastern Victoria.

Uses

''Eucalyptus radiata'' has six known

chemotype A chemotype (sometimes chemovar) is a chemically distinct entity in a plant or microorganism, with differences in the composition of the secondary metabolites. Minor genetic and epigenetic changes with little or no effect on morphology or anatomy m ...

s of

essential oil An essential oil is a concentrated hydrophobic liquid containing volatile (easily evaporated at normal temperatures) chemical compounds from plants. Essential oils are also known as volatile oils, ethereal oils, aetheroleum, or simply as the o ...

. The leaves are distilled for

cineole Eucalyptol is a monoterpenoid. A colorless liquid, it is a bicyclic ether. Eucalyptol has a fresh mint-like smell and a spicy, cooling taste. It is insoluble in water, but miscible with organic solvents. Eucalyptol makes up ~70% - 90% of eucal ...

and

phellandrene Phellandrenes are a pair of organic compounds that have a similar molecular structure and similar chemical properties. α-Phellandrene and β-phellandrene are cyclic monoterpenes and are double-bond isomers. In α-phellandrene, both double bon ...

based

eucalyptus oil Eucalyptus oil is the generic name for distilled oil from the leaf of ''Eucalyptus'', a genus of the plant family Myrtaceae native to Australia and cultivated worldwide. Eucalyptus oil has a history of wide application, as a pharmaceutical, anti ...

s. ''E.radiata'' was the first eucalyptus species to be commercially utilized for oil by

Melbourne Melbourne ( ; Boonwurrung/ Woiwurrung: ''Narrm'' or ''Naarm'') is the capital and most populous city of the Australian state of Victoria, and the second-most populous city in both Australia and Oceania. Its name generally refers to a metro ...

pharmacist A pharmacist, also known as a chemist (Commonwealth English) or a druggist (North American and, archaically, Commonwealth English), is a healthcare professional who prepares, controls and distributes medicines and provides advice and instructi ...

Joseph Bosisto Joseph Bosisto CMG, MLA JP (21 March 1827 – 8 November 1898), was a chemist and politician in colonial Victoria, Australia. Background Bosisto was the son of William Bosisto and Maria née Lazenby, of Cookham, Berkshire, and was born on 21 M ...

, in 1854 as ''"

Eucalyptus amygdalina ''Eucalyptus amygdalina'', commonly known as black peppermint, is a species of flowering plant that is endemic to Tasmania. It is a small to medium-sized tree with rough bark on park of the trunk, smooth grey to brown bark above, lance-shaped to ...

"''.Boland, D.J., Brophy, J.J., and A.P.N. House, ''Eucalyptus Leaf Oils'', 1991, Eucalyptus radiata - street tree

Gallery

References

{{Taxonbar, from=Q2664982 radiata Myrtales of Australia Trees of Australia Flora of the Australian Capital Territory Flora of New South Wales Flora of Queensland Flora of Tasmania Flora of Victoria (Australia) Crops originating from Australia