Angraecum
Angraecum is a genus of the orchid family ( Orchidaceae). It consists of about 210 species. The plants grow mostly epiphytic, they come in tropical Africa, Madagascar and other islands in the Indian Ocean off. Occasionally, they are cultivated as ornamentals, they bring forth predominantly white colored flowers.
Description
The Angraecum species have a monopodial growth, rarely branched stem axis. This may be compressed or make longer internodes, erect or pendulous grow. In the lower part there are long, enveloped by velamen aerial roots. The leaves sit in two rows on the shoot and are deducted from this by a separating tissue. The leaf base includes the shoot so that it is completely hidden by the leaf bases. They unfold conduplikat, the midrib is well marked. The shape of the leaves is often lanceolate with a leathery texture. In some species the leaves are succulent and round in cross section or v -shaped. The blade tip is retracted, so that two unequal lobes arise.
The flowers are individually or collectively in racemose or slightly branched inflorescences. A single plant can simultaneously produce multiple inflorescences. The predominant color is white, cream, yellow and green, often smell the flowers. There are species with resupinierten flowers ( by rotation of the ovary ), in others the lip at the top. The petals are not fused together, spread widely repulsed until, until the lip they are shaped similar to each other. The ungelappte (rarely indistinctly three-lobed ) lip forms a spur at its base. It is filled with nectar and can surpass the rest of the flower in length. At the base of the sides of the lip are turned up and include the column. This bears on the bottom of the slightly sunken scar and at the end of the stamen. The side of the blade, the dust column forms two lobes ( Klinandrium ), in the middle of the short separation between scar tissue and stamen sitting ( rostellum ). The two pollinia are connected by stalks to a common or two separate viscid ( Viscidium ).
The chromosome numbers for different types be 2n = 38, 40, 42, 46, 48 or 50
Dissemination
The species of the genus Angraecum are widespread in tropical Africa, Madagascar, the Comoros, Réunion, Mauritius, Seychelles and Sri Lanka.
On Reunion Island, it was observed that the flowers of the species endemic to Réunion and Mauritius type Angraecum cadetii be pollinated by a at the time of observation as yet unnamed species of Gryllacrididae; this was the first evidence of pollination by representatives of the Spring terror.
Systematics and botanical history
The genus Angraecum was erected in 1804 by Jean Baptiste Bory de Saint -Vincent. He made the name Angraecum from the Malay word " angrek ", which referred in Southeast Asia various orchids. The Bory first described species is Angraecum eburneum.
The genus Angraecum belongs to the tribe Vandeae, according to this genus the subtribe Angraecinae was named. Angraecum is not monophyletic and contains numerous not particularly closely related groups. Garay presented in 1973 before a subdivision of the genus into sections, which is often used.
Inter Generic hybrids
The following intergeneric hybrids with Angraecum be listed in the Royal Horticultural Society
- XAngrangis ( Angraecum x Aerangis )
- XAngranthes ( Angraecum x Aeranthes )
- XAngraecyrtanthes ( Angraecum x Aeranthes x Cyrtorchis )
- XAngranthellea ( Angraecum x Aeranthes x Jumellea )
- XAngraecentrum ( Angraecum x Ascocentrum )
- XCeratograecum ( Angraecum x Cerato Centron )
- XAngraeorchis ( Angraecum x Cyrtorchis )
- XEurygraecum ( Angraecum x Eurychone )
- XNeograecum ( Angraecum x Neofinetia )
- XAngreoniella ( Angraecum x Oeniella )
- XPlectrelgraecum ( Angraecum x Plectrelminthus )
- XAngraecostylis ( Angraecum x Rhynchostylis )
- XSobennigraecum ( Angraecum x Sobennikoffia )
- XTubaecum ( Angraecum x Tuberolabium )