Melaleuca quinquenervia
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Melaleuca quinquenervia (also referred to as "niaouli") is a plant from the genus of Myrtenheiden ( Melaleuca ). It is native to Australia, New Zealand , New Guinea and New Caledonia , but is also cultivated outside of these areas. It belongs to the species group of Melaleuca leucadendra .
description
Vegetative characteristics
Melaleuca quinquenervia is an evergreen tree that reaches heights of growth of up to 25 (maximum 32) meters and whose slender trunk reaches chest height diameters of 60 to 100 centimeters or more. In the open, the tree remains small, reaches a height of 6 to 16 meters with a short, often twisted trunk and a narrow crown. What is particularly noticeable is the corky, grayish-whitish to light brownish bark that is characteristic of other types of tea trees and is up to 7.5 centimeters thick. It consists of numerous paper-thin layers, from which the outer layers peel off irregularly. The branches are brownish to reddish.
The rounded to cylindrical buds are 3 to 6 millimeters long and greenish-brown in color. The alternately arranged, stiff and leathery leaves are lanceolate to inverted eilanzettlicher or elliptical in shape. The point is pointed to pointed. On the upper side they are bald and of a stronger gray-green color than on the often slightly hairy underside. The leaves show five, rarely seven, parallel leaf veins extending from the base . The entire-edged leaves are 4 to 9 inches long and about 2 to 3 inches wide. The short, light green to reddish leaf stalk is about 3 millimeters long. The young leaves are long-haired, and with age they become bald. When rubbed, the leaves smell strongly aromatic of camphor . The substances released from the leaves and fruits can cause irritation of the respiratory tract in humans.
Generative characteristics
The flowers are in groups of three close together in 3 to 8 centimeters long and 2.5 to 4 centimeters diameter, multi-flowered spikes . The inflorescences are arranged terminally or over-axillary. The sessile, hermaphrodite, five-fold flowers have a diameter of about 1.6 centimeters. The little hairy flower base is cup-shaped and up to about 5 millimeters wide. There are small sepals. The approximately 4 millimeter long petals are usually white, rarely reddish, the many long, overgrown and protruding stamens at the base are mostly white, but can rarely be white-greenish or reddish. The half under continuous, insulated draft tube ovary has a very long, protruding stylus with capitate stigma , it is longer than the stamens. The nectar glands on the base of the flower are clearly visible. Pollination is carried out by insects .
Numerous sessile, gray-brown to blackish, woody, 3 to 4 millimeters long and 4 to 5 millimeters wide, cylindrical, columnar capsule fruits ( false fruits ) are formed. They contain 200 to 350 tiny, brownish to whitish seeds with a thousand grain weight of 0.03 grams. The very small, club-shaped seeds up to about 1.2 millimeters long can remain in the capsules for up to ten years, which open through three or four slits when ripe. The seeds ( diaspores ) are only released when the water supply is interrupted (xeriscenia), in the event of fire, frost or injuries (seed retention) and are spread by wind and water . The germination takes place epigeal.
Even under natural conditions, vegetative reproduction takes place through cane rash , on wet locations even the crowns of fallen trees can take root.
The number of chromosomes is 2n = 22.
Occurrence
Melaleuca quinquenervia is native to eastern Australia, New Caledonia and Papua New Guinea . They are also found in Burma , Malaysia and the Moluccas . Outside of the natural occurrences, the species is strongly represented in the south of Florida and on Hawaii , further occurrences there are in southern California , Texas , on the Caribbean islands , in India and on the Philippines . In all of these areas the species has become feral from culture.
Due to its undemanding nature and a certain ornamental value, it is also planted as an ornamental wood outside the area of origin or is used to drain water in wet locations. It often went wild, for example in several states in the USA . In Florida , in particular , it is now considered an unwanted intruder and now covers an area of 170,000 hectares.
Melaleuca quinquenervia is a frugal species that relies on damp to wet locations. It can also cope with intermittent floods or fire in the ground, and tolerates saltwater spray and brackish water. It has no special soil requirements and grows in Hawaii on acidic basal and lava soils, but is also used to reforest alkaline or saline sites.
use
This species is used to create windbreak hedges near the coast or to reforest alkaline problematic locations. The wood is used for building boats and houses, but also for railway sleepers, floors or as fuel. The bark is used to pack fruit such as grapes in particular. An essential oil can be obtained from leaves and twigs ( Niauli oil , which is also obtained from Melaleuca viridiflora ), which is used in the manufacture of perfumes or aromatherapy and has an insecticidal effect. Folk medical applications are also known. Today it is mainly extracted in New Caledonia .
Taxonomy
Melaleuca quinquenervia was grouped with nine other taxa under the name Melaleuca leucodendron until 1968 .
Individual evidence
- ↑ Melaleuca quinquenervia in Federal Noxious Weed Disseminules of the United States, accessed February 11, 2018.
- ^ LPA Oyen, Xuan Dung Nguyen: PROSEA: Plant Resources of South-East Asia. No. 19, PROSEA, 1999, 2006, ISBN 979-8316-00-2 , p. 131.
- ↑ Ernst Steinegger, Rudolf Hansel: Pharmakognosie. 5th edition, Springer, 1992, ISBN 978-3-662-09268-2 , pp. 330 f.
- ↑ Description in The RNGR Team (English)
literature
- Schütt, Weisgerber, Schuck, Lang, Stimm, Roloff: Trees of the tropics. Nikol, 2004, ISBN 3-933203-79-1 .
- Melaleuca quinquenervia (PDF), from worldagroforestry.org, accessed February 11, 2018.
- The Land Manager's Handbookon Integrated Pest Management of Melaleuca quinquenervia (PDF; 3.8 MB), at TAME Melaleuca, Univ. of Florida, accessed February 11, 2018.
- Klaus Kubitzki: The Families and Generas of Flowering Plants. Vol. X, Flowering Plants Eudicots , Springer, 2011, ISBN 978-3-642-14396-0 , p. 236.
Web links
- Melaleuca quinquenervia from Useful Tropical Plants, accessed February 11, 2018.