Oncidium
| Oncidium | ||||||||||||
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Oncidium sphacelatum |
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| Systematics | ||||||||||||
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| Scientific name | ||||||||||||
| Oncidium | ||||||||||||
| Sw. |
The genus Oncidium from the family of orchids (Orchidaceae) contains numerous, in the Neotropics -based species . Depending on the concept, between 336 and 800 species are distinguished. The plants usually grow epiphytically , i. H. as a sitter on other plants, mostly trees.
description
The Oncidium species grow sympodially : There are shoots on a rhizome , each with limited growth. The stem axis is thickened to pseudobulbs . These are green, oval and often squeezed together on the sides. Below the pseudobulbs are lower leaves , the uppermost of which are leaf-like. At the tip of the pseudobulbs there are one to two, rarely three leaves . They are lanceolate to linear in shape and folded in the bud along the midrib. Young plants have no pseudobulbs and unifacial leaves; the thickened stem axis and bifacial leaves only develop later. The flower stem is usually branched and many-flowered and can be very long. It arises laterally below the pseudobulb. The resupinated flowers are usually yellow or brown. The petals are not fused together. The lip is three-lobed and is roughly perpendicular to the column . There is a distinct callus at the base of the lip. The column itself is short, with two lateral appendages at the top. The stamen contains two furrowed pollinia .
distribution
Distribution area of the genus Oncidium are the tropics of America from Mexico over the West Indies to Bolivia and Paraguay. The greatest biodiversity can be found in higher-lying forests.
Systematics and botanical history
Oncidium was first described in 1800 by Olof Peter Swartz . The type species was Oncidium variegatum . The name Oncidium refers to a bulge- shaped elevation of the lip base (Greek onkos "bulge, callus").
In the years that followed, many species were described under the name Oncidium , some of which varied in appearance. In particular, the type species and a small group of close relatives turned out to be not at all typical of the rest of the genus. According to the rules of nomenclature , the name Oncidium should have stayed with the type species, which would have meant the renaming of hundreds of plant names . To avoid this, a new type species had to be established ( Oncidium altissimum (Jacq.) Sw. ), The original type species was renamed Tolumnia .
Other former Oncidium species can be found in the genera Caucaea , Rossioglossum , Cyrtochilum , Cyrtochiloides , Otoglossum , Psychopsis , Trichocentrum and Zelenkoa . Hundreds of species still remain in the genus Oncidium , which is by no means monophyletic due to these splitting offs . Further changes in the generic boundaries are to be expected. In the meantime, the genus Odontoglossum has been revised and integrated into the genus Oncidium .
A list of the 336 recognized species (as of 2020) can be found at R. Govaerts.
Culture
Some species are cultivated for their flowers. Numerous hybrids, also with closely related genera, have been achieved. Most species require a cool to temperate, light position. High humidity, a good supply of fresh air and a period of rest must be observed.
supporting documents
The information in this article comes mainly from:
- Mark W. Chase: Oncidium . In: Flora of North America Editorial Committee (Ed.): Flora of North America North of Mexico . tape 26 . Oxford University Press, New York and Oxford, S. 648 ( eFloras.org [accessed October 19, 2008] 1993+).
- Manfred Wolff, Olaf Greeting: Orchid Atlas . Ulmer, Stuttgart 2007, ISBN 978-3-8001-3870-8 , pp. 258-259 .
Individual evidence
- ↑ a b Rafaël Govaerts (Ed.): Oncidium. In: World Checklist of Selected Plant Families (WCSP) - The Board of Trustees of the Royal Botanic Gardens, Kew . Retrieved April 9, 2020.
- ↑ Mark W. Chase: Oncidium . In: Flora of North America
- ↑ a b Mark W. Chase, Lynda Hanson, Victor A. Albert, W. Mark Whitten, Norris H. Williams: Life History Evolution and Genome Size in Subtribe Oncidiinae (Orchidaceae) . In: Annals of Botany . tape 95 , no. 1 , 2005, p. 191-199 , doi : 10.1093 / aob / mci012 .
- ↑ Norris H. Williams: Phylogenetics of Maxillarieae: Oncidiinae (Orchidaceae). Retrieved October 19, 2008 .
- ↑ Kew Gardens: Entry of Odontoglossum at Kew Gardens. Retrieved August 18, 2013 .
Further information
- Willibald Koeniger: Oncidium. A monograph . 5 vols., 2004+
