''Eucalyptus kochii'', commonly known as oil mallee, is a species of mallee, sometimes a tree, and 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 Western Australia. It has rough, flaky or fibrous bark on the trunk, smooth grey bark above, linear to narrow lance-shaped adult leaves, flower buds in groups of nine to fifteen, white flowers and urn-shaped fruit. Eucalyptus kochii buds

Description

''Eucalyptus kochii'' is a mallee that typically grows to a height of , rarely a tree to , and forms a

lignotuber A lignotuber is a woody swelling of the root crown possessed by some plants as a protection against destruction of the plant stem, such as by fire. Other woody plants may develop basal burls as a similar survival strategy, often as a response t ...

. It has rough, flaky or fibrous, light grey to brown bark on the trunk and larger branches, smooth grey to pink bark on the thinner branches. The adult leaves are arranged alternately, linear to narrow lance-shaped, the same shade of green on both sides, long and wide tapering to a petiole long. The flower buds are arranged in leaf axils, usually in groups of seven, nine or eleven 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 cylindrical to spindle-shaped, the floral cup long and about wide with a conical to horn-shaped operculum of similar dimensions. Flowering occurs between October and February and the flowers are white. The fruit is a woody, oval to urn-shaped capsule long and wide with the valves protruding above rim level.

Taxonomy

The species was formally described in 1929 by the

botanist Botany, also called , plant biology or phytology, is the science of plant life and a branch of biology. A botanist, plant scientist or phytologist is a scientist who specialises in this field. The term "botany" comes from the Ancient Greek wo ...

Joseph Maiden Joseph Henry Maiden (25 April 1859 – 16 November 1925) was a botanist who made a major contribution to knowledge of the Australian flora, especially the genus '' Eucalyptus''. This botanist is denoted by the author abbreviation when citin ...

and

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 ...

in Maiden's book, '' A Critical Revision of the Genus Eucalyptus''. The

specific epithet In taxonomy, binomial nomenclature ("two-term naming system"), also called nomenclature ("two-name naming system") or binary nomenclature, is a formal system of naming species of living things by giving each a name composed of two parts, bo ...

(''kochii'') honours Max Koch for his "very keen interest in the flora of South and Western Australia". In 1950, Charles Gardner changed the name to ''E. oleosa'' var. ''kochii'' in the '' Journal of the Royal Society of Western Australia'', but the change has not been 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 ...

. In the same journal, Gardner described ''E. oleosa'' var. ''borealis'', the name of which has subsequently been changed to ''E. kochii'' subsp. ''borealis'' by

Dean Nicolle 270px, Dean Nicolle and '' Eucalyptus deanei'' Dean Nicolle (born 1974), is an Australian botanist, arborist and ecologist. He is widely recognised as the leading authority on the genus '' Eucalyptus''. Nicolle was born in Adelaide, South Austr ...

, and ''E. oleosa'' var. ''plenissima'', changed to ''E. kochii'' subsp. ''plenissima'' by

Ian Brooker Murray Ian Hill Brooker AM (2 June 1934 – 25 June 2016), better known as Ian Brooker, was an Australian botanist. He was widely recognised as the leading authority on the genus ''Eucalyptus''. Ian Brooker was born in Adelaide, South Australi ...

. In 2005, Dean Nicolle also described ''E. kochii'' subsp. ''amaryssia'' and subsp. ''yellowdinensis'', publishing the names in the journal, ''

Australian Systematic Botany ''Australian Systematic Botany'' is an international peer-reviewed scientific journal published by CSIRO Publishing. It is devoted to publishing original research, and sometimes review articles, on topics related to systematic botany, such as bio ...

''. The five subspecies names recognised by the Australian Plant Census are: * ''Eucalyptus kochii'' subsp. ''amaryssia'' D.Nicolle has fruit with a rounded operculum and very glossy adult leaves with a high oil content; * ''Eucalyptus kochii'' subsp. ''borealis'' (C.A.Gardner) D.Nicolle has fruit with a conical operculum and very glossy adult leaves; * ''Eucalyptus kochii'' Maiden & Blakely subsp. ''kochii'' has dull green adult leaves; * ''Eucalyptus kochii'' subsp. ''plenissima'' (C.A.Gardner) Brooker has fruit with a rounded operculum and very glossy adult leaves but with a very low oil content; * ''Eucalyptus kochii'' subsp. ''yellowdinensis'' D.Nicolle has unusually narrow, glossy green adult leaves but with a low oil content.

Distribution

Oil mallee is found on flats, depressions, rises and along roadsides from Kondut to near

Pindar Pindar (; grc-gre, Πίνδαρος , ; la, Pindarus; ) was an Ancient Greek lyric poet from Thebes. Of the canonical nine lyric poets of ancient Greece, his work is the best preserved. Quintilian wrote, "Of the nine lyric poets, Pindar ...

in the

Avon Wheatbelt The Avon Wheatbelt is a bioregion in Western Australia. It has an area of . It is considered part of the larger Southwest Australia savanna ecoregion. Geography The Avon Wheatbelt bioregion is mostly a gently undulating landscape with low reli ...

and Yalgoo biogeographic regions of Western Australia where it grows in sandy-loamy-clay soils over

laterite Laterite is both a soil and a rock type rich in iron and aluminium and is commonly considered to have formed in hot and wet tropical areas. Nearly all laterites are of rusty-red coloration, because of high iron oxide content. They develop by ...

granite Granite () is a coarse-grained ( phaneritic) intrusive igneous rock composed mostly of quartz, alkali feldspar, and plagioclase. It forms from magma with a high content of silica and alkali metal oxides that slowly cools and solidifies un ...

Cultivation

This eucalypt is cultivated in plantations for the production of

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 ...

. The distilled oil has a very high content of

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 ...

(83-94%).

References

External links

* Byrne, M., "High genetic identities between three oil mallee taxa, Eucalyptus kochii ssp. kochii, ssp. plenissima and E. horistes, based on nuclear RFLP analysis", ''Heredity'', 1999, 82, pp205–21

{{Taxonbar, from=Q5227129 Eucalyptus, kochii Eucalypts of Western Australia Myrtales of Australia Crops originating from Australia Plants described in 1929 Taxa named by Joseph Maiden