Red mangrove
| Red mangrove | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
Red Mangrove ( Rhizophora mangle ) |
||||||||||||
| Systematics | ||||||||||||
|
||||||||||||
| Scientific name | ||||||||||||
| Rhizophora mangle | ||||||||||||
| L. |
The red mangrove ( Rhizophora mangle ) is a species of plant within the family of the Rhizophora plants (Rhizophoraceae).
The red mangrove is a common mangrove tree . Their natural range includes the tropical coasts of West Africa and North and South America . The northernmost occurrences are found in the Bahamas and Florida ( USA ), the southern limit of distribution is in the Brazilian state of Santa Catarina . An introduced population exists in Hawaii . The morphologically very similar, Pacific species Rhizophora samoensis is possibly identical to Rhizophora mangle . As a mangrove, Rhizophora mangle is adapted to survival in the tidal area . Their occurrence is limited to the coastal area. In areas strongly influenced by freshwater all year round, Rhizophora mangle does not occur or only occurs sporadically.
description
Red mangroves are evergreen and can reach a height of over 30 meters, but usually stay smaller. However, under unfavorable conditions, for example when there is a lack of nutrients , with a very high salt content of the pore water in the substrate or in the cooler northern and southern peripheral areas of their range, they develop bush-like dwarf forms. The trunk diameter reaches over 50 centimeters.
Like all species of the genus Rhizophora , Rhizophora mangle is characterized by arched, high stilt roots . The stilt roots and the brownish to light gray bark , which is cracked in older trees, have many lenticels . The thick bast visible after cutting the bark is reddish; the name "red mangrove" may be due to its coloring.
The ovoid to elliptical or obovate, -eilanzettlichen, undivided and entire, simple and short-stalked leaves are thick, leathery. Leaf size and shape vary with environmental conditions. The upper side of older leaves is shiny dark green, the lower side is lighter and covered with black, lenticelle-like points. Very young leaves are light green. The tips of the leaves are rounded and slightly bent downwards; the short petiole is strong. The leaves are arranged opposite one another. Only the uppermost, youngest area of the shoots has leaves and branches out, which culminate over the older shoots. The budding sides of older branch sections quickly lose the ability to sprout . The summit bud of each shoot is covered by the two large stipules like a hood. The stipules are shed when a new pair of leaves unfolds.
The little flowered inflorescence of R. mangle arises axially. It usually branches once or twice; from one branch two to four axes or flower stalks can arise. The flower buds are elongated and thickened in the lower quarter, their tips are slightly rounded. The hermaphroditic flowers with a double perimeter are wind pollinated . The four coarse, green or yellowish-green, leathery sepals that are overgrown at the base are lanceolate; they remain until the fruit is ripe. The four smaller and whitish petals , which are densely haired on the inside, are quickly shed. There are eight short and sedentary stamens present and a semi-permanent upper ovary with short pencil .
The gray-brown, conical and about 3–5 cm large fruit is leathery and hard. Like all taxa of the Rhizophoreae , R. mangle is " viviparous "; the seedlings with their pin-shaped, 15 to more than 30 cm long green hypocotyl develop on the mother tree and, after shedding, are able to take root quickly under favorable conditions ; But they also survive months of drifting in the tidal current.
The number of chromosomes is 2n = 36.
Possible confusion with other mangrove species
The inflorescences of the two other Rhizophora species ( Rhizophora racemosa , Rhizophora harrisonii ) occurring in parts of the distribution area are often dichotomously branched. The inflorescence of Rhizophora mangle is only branched once or twice, but often produces more than two axes or flower stalks at the branching point. The hypocotyl of the seedlings of Rhizophora racemosa is i. d. Usually considerably longer than that of Rhizophora mangle seedlings. Rhizophora mangle differs significantly from mangrove species of other genera by the spreading, arched stilt roots that branch out near the ground.
Use, hazard
The hard, heavy and durable, somewhat brittle wood of Rhizophora mangle is used in various applications and in carpentry as well as locally as fuel and for the production of charcoal . Poles made from young trunks are used by fishermen to build large traps and similar structures.
A brew from the tannin-rich bark is used to impregnate fishing nets and sails; however, peeling living trunks can lead to the death of individual areas of the tree crown or the entire plant. The species Rhizophora mangle is currently not endangered due to its wide distribution; However, the mangrove ecosystem is threatened in many places, for example by the establishment of shrimp farms .
literature
- FJ Breteler: The Atlantic Species of Rhizophora. Acta Botanica Neerlandica. 18 (3), 1969, 434-441 (English).
- C. v. Linnaeus: Species plantarum. 1, 443, 1753. (Latin).
- PB Tomlinson: The Botany of Mangroves. Cambridge University Press, Cambridge, 1986, 419 pages, ISBN 0-521-46675-X (English).
Web links
- First description by Carl von Linné: Species plantarum 1, p. 443, on botanicus.org.
- Rhizophora mangle in the Red List of Threatened Species of the IUCN 2013.2. Listed by: Ellison, A., Farnsworth, E. & Moore, G., 2007. Retrieved January 28, 2014.
- Rhizophora mangle on mangrove.at.
Individual evidence
- ↑ Rhizophora mangle at Tropicos.org. In: IPCN Chromosome Reports . Missouri Botanical Garden, St. Louis