Aerangis

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Aerangis
Aerangis luteoalba var. Rhodosticta

Aerangis luteoalba var. Rhodosticta

Systematics
Order : Asparagales (Asparagales)
Family : Orchids (orchidaceae)
Subfamily : Epidendroideae
Tribe : Vandeae
Sub tribus : Aerangidinae
Genre : Aerangis
Scientific name
Aerangis
Rchb.f.

The genus Aerangis from the family of the orchid (Orchidaceae) consists of about 58 types . The plants usually grow epiphytically , they occur in tropical Africa, on Madagascar and with one species as far as Sri Lanka. Occasionally they are cultivated as ornamental plants, they produce predominantly white colored flowers .

description

The Aerangis species have a monopodial , rarely branched stem axis . This can be compressed or form longer internodes , grow upright or drooping. In the lower area there are long aerial roots covered by velamen . The leaves sit in two rows on the shoot and are separated from this by a separating fabric. The leaf base encompasses the shoot in such a way that it is completely covered by the leaf bases. They unfold conduplicate , the midrib stands out clearly. The shape of the leaves ranges from narrowly lanceolate to oval, broadest above the center. The tip of the leaf is drawn in, creating two unequal lobes. The leaves are usually dark green, occasionally gray-green or with black spots.

Aerangis modesta

The resupinated flowers are rarely single, but mostly in multi-flowered, racemose inflorescences . A single plant can produce multiple inflorescences at the same time. The flowering season often coincides with the rainy season. The predominant flower color is white, cream-colored, occasionally tinged with green or pinkish-brown. Aerangis pallidiflora and Aerangis seegeri have completely light green colored flowers. The petals are not fused with each other, widely spread out or thrown back. The unlobed lip forms a spur at its base. It is filled with nectar and can be longer than the rest of the flower. The column bears the slightly sunken stigma on the underside and the stamen at the end . The separating tissue between stigma and stamen (rostellum) is undivided and greatly elongated. It extends back over the stigma, in Aerangis fastuosa into the spur, in other species the rostellum is curved forward. The two pollinia are connected by a common stalk with an adhesive disk (Viscidium).

The fruit is a cylindrical to oval capsule fruit .

The chromosome numbers for different species are 2n = 42, 46, 50 or 54.

distribution

The species of the genus Aerangis are distributed in tropical Africa with 31 species, in Madagascar 21 species occur, five of which also occur on the Comoros and one on Réunion . Aerangis hologlottis has a disjoint distribution area in East Africa and Sri Lanka.

Systematics and botanical history

Aerangis fastuosa
Aerangis gracillima
Aerangis hildebrandtii
Aerangis mooreana
Aerangis thomsonii
Aerangis verdickii

The genus Aerangis was established in 1865 by Heinrich Gustav Reichenbach . He formed the name Aerangis from the Greek words aer "air" and angos "vessel". It belongs to the Vandeae tribe . For a long time it was placed in a subtribe Aerangidinae with several other genera . However, more recent works favor the amalgamation under a broad subtribe Angraecinae . Aerangis is paraphyletic in relation to the genus Microterangis , both together form a monophyletic clade .

The following species are included in the genus Aerangis :

literature

The information in this article comes mainly from:

  • Joyce Stewart: Angraecoid orchids: Species from the African region . Timber Press, Portland, Oregon 2006, ISBN 0-88192-788-0 .
  • Isobyl la Croix, Phillip Cribb: Orchidaceae . In: Flora Zambesiaca . tape 11 , no. 2 , 1998 ( Flora Zambesiaca [accessed April 25, 2008]).

Individual evidence

  1. ↑ a b Barbara S. Carl Ward, W. Mark Whitten, Norris H. Williams, Benny Bytebier: Molecular phylogenetics of Vandeae (Orchidaceae) and the evolution of leaflessness . In: American Journal of Botany . tape 93 , no. 5 , 2006, p. 770-786 .
  2. ↑ a b c Rafaël Govaerts (Ed.): Aerangis. In: World Checklist of Selected Plant Families (WCSP) - The Board of Trustees of the Royal Botanic Gardens, Kew . Retrieved April 3, 2020.

Further information

Commons : Aerangis  - album with pictures, videos and audio files