oleander
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Oleander ( Nerium oleander ) |
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| Nerium oleander | ||||||||||||
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The oleander ( Nerium oleander ), also rose laurel mentioned, is the only kind of plant genus Nerium within the family of Hundsgiftgewächse (Apocynaceae). All parts of the plant are poisonous.
description
Vegetative characteristics
The oleander is an evergreen woody plant up to 6 meters high , usually a bush. The simple foliage leaves , usually in threes, whorled, less often opposite, on the branch are short-stalked, leathery, stiff, dark green on the top and lanceolate to oblanceolate with a length of 6 to 24 centimeters. The width of the entire, mostly pointed to rarely rounded and mostly bald leaf blades can be up to 5 centimeters. The veins are finely pinnate with many side veins.
Generative characteristics
The flowering period extends from mid-June to September. Several fragrant, short-stalked flowers stand together in a stalked trugdoldigen and terminal inflorescence . The hermaphrodite flowers are radially symmetrical and five-fold in the normal form with a double flower envelope . The calyx is only small, with narrow triangular tips. The corolla petals are fused funnel-shaped with sweeping corolla lobes, depending on the variety, they are white, yellowish or in different shades of pink to purple. Wild oleanders usually bloom pink-red. The petals have fringed appendages ( corona ) on the inside at the base, on the throat . The stamens with relatively short stamens, at the top of the corolla tube, with long hairy, feathery appendages often twisted into one another on the arrow-shaped anthers, are attached to the stylus head (clavuncula). The two-fan pistil with hairy ovary is on top. It is not entirely clear whether nectar is produced or a secondary pollen presentation takes place.
Up to 23 centimeters long and dry, grooved, ribbed and narrow follicles with a permanent calyx are formed and the many cone-shaped seeds are densely hairy with a one-sided head of hair.
The basic chromosome number is x = 11; in the wild type there is diploidy with a chromosome number of 2n = 22.
origin
The oleander has a large distribution area in a strip from Morocco (here up to altitudes of 2000 meters) and southern Spain over the entire Mediterranean area , the Near to Middle East, India to China and Myanmar . The earlier held view that the Asian wild forms are a separate species ( Nerium indicum ) is no longer confirmed because of the insufficient differences in phenotype . Nerium oleander is a neophyte in many frost-free areas of the world .
The oleander grows naturally in southern Mediterranean floodplain communities (Nerio-Tamaricetea) in the Mediterranean region.
Systematics
The genus Nerium was established in 1753 with the species Nerium oleander by Carl von Linné in Species Plantarum , 1, page 209.
The genus Nerium is usually regarded as monotypical, the only species being Nerium oleander . More rarely than one species is included in the genus.
Oleander as a garden plant
When keeping pots, care should be taken to water and fertilize well in the warm season. In winter, the oleander should be kept cool (5–10 ° C is ideal); wintering in a heated living space should be avoided because of the risk of severe spider mite infestation and gelling .
In Central Europe, oleander is mostly kept as a container plant; There are also some of the more than 200 varieties that can be planted in most areas of Germany with winter protection (e.g. fleece).
The following varieties survived practically no damage in field tests at −10 ° C: 'Nerium villa romaine', 'Nerium atlas', 'Nerium italia', 'Nerium cavalaire'. At temperatures below this, individual leaves begin to die off. Most of the leaves die below about −15 ° C, and from about −18 ° C the trunk wood also increases. Even after temperatures below −20 ° C and complete withering above ground, the plants can sprout again in spring.
toxicology
Oleander contains various cardenolides , including the toxic and pharmacologically relevant glycoside oleandrin . All parts of the plant are poisonous. Oleandrin is a poisonous cardiac glycoside and has a stimulating effect on the intercardiac muscle activity. In addition, the nausea center and the vagus nerve are activated. It causes hypoxemia ; this means a reduced oxygen content (C a O 2 ) in the arterial blood. Gloves should be worn when repotting and pruning. Even the smoke from the oleander is poisonous. Green cuttings should not be burned, but disposed of with household waste.
etymology
Lorandum , the Middle Latin name of the plant, is a word derived from the Latin laurus " laurel ". This naming was probably based on the similarity of the leaves. Under the influence of the Latin olea " olive tree ", the Italian word form oleandro and oleander emerged from lorandum .
The generic name Nerium , a Latinized form of ancient Greek νήριον nḗrion , also means "oleander".
literature
- Christoph Köchel: Oleander . Ulmer, Stuttgart 2000, ISBN 3-8001-6653-4 .
- Herbert Müller: Hardy exotic species. Formosa-Verlag, Witten 2011, ISBN 978-3-934733-07-7 .
- JF Brandt , JTC Ratzeburg : Germany's phanerogamic poisonous plants. Second edition, Hirschwald, 1838, pp. 85–88, Fig. 20, limited preview in the Google book search.
- Marilena Idžojtić: Dendrology. Acedemic Press, 2018, ISBN 978-0-444-64175-5 , p. 426.
Web links
- Nerium oleander at Useful Tropical Plants.
- Thomas Meyer: Data sheet with identification key and photos at Flora-de: Flora von Deutschland (old name of the website: Flowers in Swabia ) .
- The oleander as a poisonous plant .
- Nerium oleander onthe IUCN 2013 Red List of Threatened Species . Posted by: RV Lansdown ,, 2012. Retrieved May 11, 2014.
Individual evidence
- ^ A b P. F. Yeo: Secondary Pollen Presentation: Form, Function and Evolution. Springer, 1993, ISBN 978-3-7091-7375-6 (reprint), pp. 101-104, 107, 109 (illustrations).
- ↑ a b Erich Oberdorfer : Plant-sociological excursion flora for Germany and neighboring areas . With the collaboration of Angelika Schwabe and Theo Müller. 8th, heavily revised and expanded edition. Eugen Ulmer, Stuttgart (Hohenheim) 2001, ISBN 3-8001-3131-5 , pp. 760 .
- ^ Nerium at Tropicos.org. In: IPCN Chromosome Reports . Missouri Botanical Garden, St. Louis.
- ↑ a b Rafaël Govaerts (ed.): Nerium. In: World Checklist of Selected Plant Families (WCSP) - The Board of Trustees of the Royal Botanic Gardens, Kew . Retrieved January 10, 2019.
- ↑ Invasive Plant Atlas of the United States .
- ^ Nerium at Tropicos.org. Missouri Botanical Garden, St. Louis, accessed January 10, 2019.
- ^ Nerium in the Germplasm Resources Information Network (GRIN), USDA , ARS , National Genetic Resources Program. National Germplasm Resources Laboratory, Beltsville, Maryland. Retrieved January 10, 2019.
- ^ Bingtao Li, Antony JM Leeuwenberg, David J. Middleton: Apocynaceae. : Nerium , p. 173 - online with the same text as the printed work , In: Wu Zheng-yi, Peter H. Raven (Ed.): Flora of China. Volume 16: Gentianaceae through Boraginaceae. Science Press and Missouri Botanical Garden Press, Beijing and St. Louis 1995, ISBN 0-915279-33-9 .
- ^ Nerium at Tropicos.org. In: Flora of Pakistan . Missouri Botanical Garden, St. Louis.
- ↑ Oleander in the medicinal plant dictionary.
- ↑ Wesselin Denkow: Poisons of nature. Ennsthaler Verlag, Seyr 2004, ISBN 3-8289-1617-1 , p. 108 f.
- ↑ Duden online: Origin of oleander .
- ↑ Latin nerium and ancient Greek νήριον in the English Wiktionary.