Aa is a genus of plants of the family Orchidaceae.
Species in this genus can be found growing terrestrially in cold habitats near the snowline in the Andes and also in Costa Rica; they are usually found close to small streams. The elongated inflorescence grows from a basal rosette of leaves, terminating in a small white non-resupinate flower. This lip is fringed and hood-shaped. The flower gives off a pungent smell that attracts flies. This genus has often been included in the orchid genus Altensteinia.
The first scientific description of a species of this genus was made in 1815 by Karl Sigismund Kunth, naming it first Ophrys paleacea <small>Kunth (1806).</small>, and later Altensteinia paleacea. In 1854 Heinrich Gustav Reichenbach separated Aa from Altensteinia, to include two species Aa argyrolepis and Aa paleacea. The genus name apparently was rendered by the author to always appear first in alphabetical listings. Another – disputed – explanation, is that Reichenbach named this genus after Pieter van der Aa; the printer of the Dutch botanist Paul Herman's "Paradisus Batavus". A few years later, Reichenbach reviewed the name of the genus and named it again Altensteinia. Finally in 1912 Rudolf Schlechter switched the name again to Aa, as more species were being discovered making the new name more significant.
Species
The following species of Aa are accepted
- Aa achalensis <small>Schltr. 1920</small> (Argentina)
- Aa argyrolepis <small>Rchb.f. 1854</small> (Colombia to Ecuador)
- Aa aurantiaca <small>D.Trujillo</small> (Peru)
- Aa calceata <small>(Rchb.f.) Schltr. 1912</small> (Peru to Bolivia)
- Aa colombiana <small>Schltr. 1920</small> (Colombia to Ecuador)
- Aa denticulata <small>Schltr. 1920</small> (Colombia to Ecuador)
- Aa erosa <small>(Rchb.f.) Schltr. 1912</small> (Peru)
- Aa fiebrigii <small>(Schltr.) Schltr. 1912</small> (Bolivia)
- Aa figueroae <small>Szlach. & S. Nowak, 2014</small> (Colombia)
- Aa hieronymi <small>(Cogn.) Schltr. 1912</small> (Argentina)
- Aa lehmannii <small>Rchb. f. ex Szlach. & Kolan., 2014</small> (Ecuador)
- Aa leucantha <small>(Rchb.f.) Schltr. 1920</small> (Colombia to Ecuador)
- Aa lorentzii <small>Schltr. 1920</small> (Argentina)
- Aa lozanoi <small>Szlach. & S. Nowak, 2014</small> (Colombia)
- Aa macra <small>Schltr. 1921</small> (Ecuador)
- Aa maderoi <small>Schltr. 1920</small> (Venezuela; Colombia; Ecuador)
- Aa mandonii <small>(Rchb.f.) Schltr. 1912</small> (Peru to Bolivia)
- Aa matthewsii <small>(Rchb.f.) Schltr. 1912</small> (Peru)
- Aa microtidis <small>Schltr. 1922</small> (Bolivia)
- Aa paleacea <small>(Kunth) Rchb.f. 1854</small> (Costa Rica to Bolivia)
- Aa riobambae <small>Schltr. 1921</small> (Ecuador)
- Aa rosei <small>Ames 1922</small> (Peru)
- Aa schickendanzii <small>Schltr. 1920</small> (Argentina)
- Aa sphaeroglossa <small>Schltr. 1922</small> (Bolivia)
- Aa trilobulata <small>Schltr. 1922</small> (Bolivia)
- Aa weddelliana <small>(Rchb.f.) Schltr. 1912</small> (Peru to NW Argentina)
:Synonyms:
- Aa hartwegii <small>Garay 1978</small> (Ecuador; Colombia; Venezuela); syn., → Aa maderoi <small>Schltr.,</small>
- Aa gymnandra <small>(Rchb.f.) Schltr. 1912</small> a synonym of Myrosmodes gymnandra <small>(Rchb.f.) C.A.Vargas</small>
- Aa inaequalis <small>(Rchb.f.) Schltr. 1912</small> (Peru to Bolivia); a synonym of Myrosmodes inaequalis <small>(Rchb.f.) C.A.Vargas</small>
- Aa nervosa <small>(Kraenzl.) Schltr. 1912</small> (Chile); accepted name Myrosmodes nervosa <small>(Kraenzl.) Novoa, C.A.Vargas & Cisternas</small>
References
- W.E. Higgins (2006): Selby Vignette: The Aa's of Orchids. [http://www.selby.org/index.php?src=gendocs&link=vig_aa&category=Research]
- H.G. Reichenbach. 1854. Xenia Orchidaceae. 1:18.
- R. Schlechter (1912): Repertorium specierum novarum regni vegetabilis. Bd. XI S. 147ff. [http://www.botanicus.org/page/237313]
External links
- Pictures of Chilean Aa nervosa orchid