''Aa'' is a
genus
Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...
of plants of the family
Orchidaceae
Orchids are plants that belong to the family (biology), family Orchidaceae (), a diverse and widespread group of flowering plants with blooms that are often colourful and fragrant. Orchids are cosmopolitan distribution, cosmopolitan plants that ...
.
Species in this genus can be found growing
terrestrially in cold habitats near the snowline in the
Andes
The Andes ( ), Andes Mountains or Andean Mountain Range (; ) are the List of longest mountain chains on Earth, longest continental mountain range in the world, forming a continuous highland along the western edge of South America. The range ...
and also in
Costa Rica
Costa Rica, officially the Republic of Costa Rica, is a country in Central America. It borders Nicaragua to the north, the Caribbean Sea to the northeast, Panama to the southeast, and the Pacific Ocean to the southwest, as well as Maritime bo ...
; they are usually found close to small streams. The elongated
inflorescence
In botany, an inflorescence is a group or cluster of flowers arranged on a plant's Plant stem, stem that is composed of a main branch or a system of branches. An inflorescence is categorized on the basis of the arrangement of flowers on a mai ...
grows from a basal rosette of
leaves
A leaf (: leaves) is a principal appendage of the stem of a vascular plant, usually borne laterally above ground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage", while the leaves, stem, ...
, terminating in a small white
non-resupinate flower
Flowers, also known as blooms and blossoms, are the reproductive structures of flowering plants ( angiosperms). Typically, they are structured in four circular levels, called whorls, around the end of a stalk. These whorls include: calyx, m ...
. This lip is fringed and hood-shaped. The flower gives off a pungent smell that attracts
flies
Flies are insects of the Order (biology), order Diptera, the name being derived from the Ancient Greek, Greek δι- ''di-'' "two", and πτερόν ''pteron'' "wing". Insects of this order use only a single pair of wings to fly, the hindwin ...
. 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''
Kunth (1806)., and later ''Altensteinia paleacea''. In 1854
Heinrich Gustav Reichenbach
Heinrich Gustav Reichenbach (Dresden, 3 January 1823 – Hamburg, 6 May 1889) was a botanist and the foremost Germany, German orchidologist of the 19th century. His father Ludwig Reichenbach, Heinrich Gottlieb Ludwig Reichenbach (author of ''Ico ...
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''
Schltr. 1920 (Argentina)
*''
Aa argyrolepis''
Rchb.f. 1854 (Colombia to Ecuador)
*''
Aa aurantiaca''
D.Trujillo (Peru)
*''
Aa calceata''
(Rchb.f.) Schltr. 1912 (Peru to Bolivia)
*''
Aa colombiana''
Schltr. 1920 (Colombia to Ecuador)
*''
Aa denticulata''
Schltr. 1920 (Colombia to Ecuador)
*''
Aa erosa''
(Rchb.f.) Schltr. 1912 (Peru)
*''
Aa fiebrigii''
(Schltr.) Schltr. 1912 (Bolivia)
*''
Aa figueroi''
Szlach. & S. Nowak, 2014
*''
Aa hieronymi''
( Cogn.) Schltr. 1912 (Argentina)
*''
Aa lehmannii''
Rchb. f. ex Szlach. & Kolan., 2014
*''
Aa leucantha''
(Rchb.f.) Schltr. 1920 (Colombia to Ecuador)
*''
Aa lorentzii''
Schltr. 1920 (Argentina)
*''
Aa lozanoi''
Szlach. & S. Nowak, 2014
*''
Aa macra''
Schltr. 1921 (Ecuador)
*''
Aa maderoi''
Schltr. 1920 (Venezuela; Colombia; Ecuador)
*''
Aa mandonii''
(Rchb.f.) Schltr. 1912 (Peru to Bolivia)
*''
Aa matthewsii''
(Rchb.f.) Schltr. 1912 (Peru)
*''
Aa microtidis''
Schltr. 1922 (Bolivia)
*''
Aa paleacea''
(Kunth) Rchb.f. 1854 (Costa Rica to Bolivia)
*''
Aa riobambae''
Schltr. 1921 (Ecuador)
*''
Aa rosei''
Ames 1922 (Peru)
*''
Aa schickendanzii''
Schltr. 1920 (Argentina)
*''
Aa sphaeroglossa''
Schltr. 1922 (Bolivia)
*''
Aa trilobulata''
Schltr. 1922 (Bolivia)
*''
Aa weddelliana''
(Rchb.f.) Schltr. 1912 (Peru to NW Argentina)
:Synonyms:
*''
Aa hartwegii''
Garay 1978 (Ecuador; Colombia; Venezuela);
syn., → ''
Aa maderoi''
Schltr.,
*''
Aa gymnandra''
(Rchb.f.) Schltr. 1912 a synonym of ''
Myrosmodes gymnandra''
(Rchb.f.) C.A.Vargas
*''
Aa inaequalis''
(Rchb.f.) Schltr. 1912 (Peru to Bolivia); a synonym of ''
Myrosmodes inaequalis''
(Rchb.f.) C.A.Vargas
*''
Aa nervosa''
(Kraenzl.) Schltr. 1912 (Chile); accepted name ''
Myrosmodes nervosa''
(Kraenzl.) Novoa, C.A.Vargas & CisternasWCSP Aa nervosa (Kraenzl.) Schltr.
/ref>
References
* W.E. Higgins (2006): ''Selby Vignette: The Aa's of Orchids''
* H.G. Reichenbach. 1854. Xenia Orchidaceae. 1:18.
* R. Schlechter (1912): ''Repertorium specierum novarum regni vegetabilis''. Bd. XI S. 147ff
External links
*
*
Pictures of Chilean ''Aa nervosa'' orchid
{{DEFAULTSORT:Aa (Plant)
Aa (plant),
Cranichideae genera
Flora of the Neotropical realm