Melaleuca leucadendra
| Melaleuca leucadendra | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
Melaleuca leucadendra |
||||||||||||
| Systematics | ||||||||||||
|
||||||||||||
| Scientific name | ||||||||||||
| Melaleuca leucadendra | ||||||||||||
| ( L. ) L. |
Melaleuca leucadendra , also known as silver tree myrtle heather, cajeput tree, cajeput tree, is a species of the genus Melaleuca . It isnative tonorthern Australia , New Guinea and eastern Indonesia , but is rarely cultivated outside of this area.
description
Melaleuca leucadendra is an evergreen tree that reaches heights of maximum 43 meters. The corky, whitish bark that is also characteristic of other Melaleuca species is particularly striking (can also be brownish-white, gray, yellow-gray or pale brown-pink). It consists of numerous paper-thin layers, from which the outer layers peel off irregularly. The twigs are hairy and silky when young and later balding.
The alternately arranged, semi-hanging leaves reach 7.5 to 27 centimeters in length with a width of 6.5 to 40 millimeters, within the genus the species thus belongs to the broad-leaved species. The leaves have long stalks and silky hairs when they shoot, but soon become bald, their leaf blades are narrow, ovate to elliptical, often somewhat sickle-shaped. Their tip (apex) is pointed, sometimes with a small, stepped tip. The leaves have numerous oil glands, so they smell strongly aromatic when rubbed.
The flowers are usually in groups of three close together on 6 to 15 cm long inflorescences , which are at the end of the branches (subterminal) or basal, in the leafy sections, they reach a diameter of up to 35 millimeters. The sessile, hermaphrodite flowers have a double perianth . The sepals are fused to form a bare calyx tube, the edge of which can be narrow, dry-skinned, with 0.8 to 2 mm long calyx tips, the glands and a ciliate edge. The ephemeral petals that soon fall off are white to cream-colored. Five to twelve stamens are in a bundle, they are also white to greenish white in color.
Pedunculate, lignified, cup-shaped to cylindrical capsule fruits are formed, which have a diameter of 4 to 5 mm. They contain tiny seeds.
Distribution and location
Melaleuca leucadendra is widespread and common throughout northern Australia, west of the Bonaparte Archipelago ( Kimberley ) to Shoalwater Bay (Queensland), in the states of Western Australia , the Northern Territory and Queensland . It prefers the coastal region, but occurs in river valleys up to 350 kilometers inland. It is also found in New Guinea (both in the western and eastern parts of the island) and some eastern Indonesian islands.
It grows in riparian and swamp forests and in monsoon forest , in plains or small valleys in sandstone mountains, on loamy soils.
use
Cajeput oil is obtained from a number of broad-leaved Melaleuca species, including this one. The main source of the oil, however, is another species, Melaleuca cajuputi Powell , which was previously often indistinguishable from M. leucadendra . According to the content and chemical composition of the oil, three ecotypes , called chemotypes, are distinguished.
Taxonomy
Melaleuca leucadendra is the type species of the species-rich genus Melaleuca . The species became known in Europe as early as 1741 when Georg Eberhard Rumpf , an administrative officer in the service of the Dutch East India Company, described it in his monumental work Herbarium Amboinense as "Arbor alba" (Latin for "white tree"). Because Rumpf's work was published before 1753, the starting point of the botanical nomenclature by Carl von Linné , the name is not available according to the botanical nomenclature rules. Linnaeus took over the description from Rumpf's work, but renamed the species to Myrtus leucadendra . The type locality is therefore Rumpf's working area, the Moluccan island of Ambon , which today belongs to Indonesia. In 1767 Linnaeus himself noticed that the species could not belong to the genus Myrtus and established a new genus Melaleuca for it (in his work Mantissa plantarum ) . After the exploration and later colonization of Australia after 1770, the species was discovered here along with other members of the genus. George Bentham considered it in his Flora Australis published in 1867 as the only one of the broad-leaved species, because he did not succeed in finding useful distinguishing features between the very similar species described up to then. He used the emendation leucadendron in the name , which was not formally replaced by the original name variant until 1966, by resolution of the ICBN . In 1968 the broad-leaved Melaleuca species were revised by Stanley Thatcher Blake and nine species were removed, for example Melaleuca quinquenervia . In the case of older information, it may therefore be uncertain to which of the current species the name refers.
The broad-leaved Melaleuca species are traditionally grouped into the Melaleuca leucadendra species group according to morphological characteristics . The association of the species was confirmed by a phylogenomic study.
photos
Individual evidence
- ↑ a b c Joseph J. Brophy, Lyndley A. Craven, John C. Doran: Melaleucas: their botany, essential oils and uses. ACIAR Monograph No. 156, Australian Center for International Agricultural Research. Canberra. 415 pages, ISBN 978-1-922137-52-4 . online (Part Species lo, PDF; 19.5 MB) .
- ^ Lyn A. Craven: Behind the Names: Botany of Tea Trea, Cajaput and Niaouli . In: Ian Southwell, Robert Lowe (Eds.): Tea Tree - The Genus Melaleuca . Harwood Academic Publishers, Amsterdam 1999, ISBN 90-5702-417-9 , pp. 13 ( PDF ). PDF ( Memento of the original from August 9, 2017 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.
- ↑ Robert D. Edwards, Lyn A. Craven, Michael D. Crisp, Lyn G. Cook: Melaleuca revisited: cpDNA and morphological data confirm that Melaleuca L. (Myrtaceae) is not monophyletic. Taxon 59 (3), 2010, pp. 744-754, JSTOR 25677666 .
literature
- Robert Hegnauer : Chemotaxonomy of plants. Volume XIb-2, Springer, 2001, p. 190, ISBN 3-7643-5862-9 .
Web links
- Melaleuca leucadendra on Useful Tropical Plants, accessed October 18, 2018.