Acostaea (orchids)

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Acostaea
Acostaea trilobata

Acostaea trilobata

Systematics
Order : Asparagales (Asparagales)
Family : Orchids (orchidaceae)
Subfamily : Epidendroideae
Tribe : Epidendreae
Sub tribus : Pleurothallidinae
Genre : Acostaea
Scientific name
Acostaea
Schltr.

The genus specklinia the family of orchid (Orchidaceae) comprises six plant species , all of which occur in South and Central America. The only a few centimeters small plants grow epiphytically and form dense clumps. The genus was named after Guillermo Acosta, a collector of orchids from Costa Rica.

description

All species of this genus form tightly upright, slender shoots on a creeping rhizome that are covered by sheathed lower leaves. Each shoot has a leaf , this is elongated-oval to roundish in shape, tapering into a short stem at the base and longer than the shoot. Leaf and shoot together measure only two to three centimeters.

The racemose inflorescence appears laterally from the base of the shoots and protrudes slightly above the leaf. The three to ten resupinated flowers open one after the other. The bracts include the peduncle tubular. The sepals are yellow, red or purple in color, the two lateral sepals are fused to one another up to the middle, the middle one is bent over the column in the shape of a helmet and at the base fused somewhat with the two lateral ones. The lateral petals are small, about as long as the column and triangular in shape. They are fused to the base of the column at their base, as is the lip . This is not lobed, at its base a fleshy, highly arched and hairy callus arises . The column is upright and has broad wings. The stamen sits at the end of the column and is bent down relative to the column axis. The two yellow, pear-shaped pollinia are connected by short, broad stalks and viscidia.

The plants of the subtribe Pleurothallidinae are mostly pollinated by flies. In Acostaea , the lip is articulated to the base of the column. If the lip is touched, it folds up and presses an insect sitting on it against the column, where it gets the pollinia attached by means of the sticky viscidium, or any pollinia on the body of the insect are placed on the scar .

distribution

The species of the genus Acostaea occur from Costa Rica to Ecuador. There they grow as epiphytes in very moist forests at altitudes of 500 to 1500 meters.

Systematics

The genus Acostaea has been delimited mainly due to the movable lip. According to a DNA study, sister taxon is Pleurothallis costaricensis . The relationship to the genus Acostaea is composed of species that were previously assigned to different subgenera of Pleurothallis . It is to be expected that further research will lead to taxonomic changes.

Six species have been described in this genus, other authors only count four and classify other taxa as subspecies. R. Govaerts later placed all Acostaea species in the genus Specklinia Lindl. .

literature

  • CH Dodson, CA Luer (2005): Orchidaceae part 2 (Aa-Cyrtidiorchis) . In: G. Harling, L. Andersson (Eds.): Flora of Ecuador . Vol. 76, p. 22ff. Botanical Institute, Göteborg University, ISBN 91-88896-51-X
  • Robert L. Dressler (1993): Phylogeny and Classification of the Orchid Family . P. 195f. Cambridge University Press, ISBN 0-521-45058-6

Web links

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

Photos of some Acostaea species . Jay's Internet Orchid Species Photo Encyclopedia

Individual evidence

  1. ↑ Acostaea. Species - Genera Recognized. The Pleurothallid Alliance, accessed January 1, 2014 .
  2. ↑ Alec M. Pridgeon, Rodolfo Solano, Mark W. Chase (2001): Phylogenetic relationships in Pleurothallidinae (Orchidaceae): combined evidence from nuclear and plastid DNA sequences . American Journal of Botany. 88: 2286-2308
  3. ↑ Rafaël Govaerts (ed.): Acostaea. In: World Checklist of Selected Plant Families (WCSP) - The Board of Trustees of the Royal Botanic Gardens, Kew . Retrieved July 3, 2018.