''Aa'' is a

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

of plants of the family

Orchidaceae Orchids are plants that belong to the family Orchidaceae (), a diverse and widespread group of flowering plants with blooms that are often colourful and fragrant. Along with the Asteraceae, they are one of the two largest families of flowering ...

. Species in this genus can be found growing terrestrially in cold habitats near the snowline in the

Andes The Andes, Andes Mountains or Andean Mountains (; ) are the longest continental mountain range in the world, forming a continuous highland along the western edge of South America. The range is long, wide (widest between 18°S – 20°S ...

and also in

Costa Rica Costa Rica (, ; ; literally "Rich Coast"), officially the Republic of Costa Rica ( es, República de Costa Rica), is a country in the Central American region of North America, bordered by Nicaragua to the north, the Caribbean Sea to the no ...

; they are usually found close to small streams. The elongated

inflorescence An inflorescence is a group or cluster of flowers arranged on a stem that is composed of a main branch or a complicated arrangement of branches. Morphologically, it is the modified part of the shoot of seed plants where flowers are formed o ...

grows from a basal rosette of

leaves A leaf (plural, : leaves) is any of the principal appendages of a vascular plant plant stem, stem, usually borne laterally aboveground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage", wh ...

, terminating in a small white non-resupinate

flower A flower, sometimes known as a bloom or blossom, is the reproductive structure found in flowering plants (plants of the division Angiospermae). The biological function of a flower is to facilitate reproduction, usually by providing a mechani ...

. This lip is fringed and hood-shaped. The flower gives off a pungent smell that attracts

flies Flies are insects of the order Diptera, the name being derived from the Greek δι- ''di-'' "two", and πτερόν ''pteron'' "wing". Insects of this order use only a single pair of wings to fly, the hindwings having evolved into advanced ...

. 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 Carl Sigismund Kunth (18 June 1788 – 22 March 1850), also Karl Sigismund Kunth or anglicized as Charles Sigismund Kunth, was a German botanist. He is known for being one of the first to study and categorise plants from the American continents, ...

, 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 German orchidologist of the 19th century. His father Heinrich Gottlieb Ludwig Reichenbach (author of ''Icones Florae Germanicae et Helve ...

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

named this genus after

Pieter van der Aa Pieter van der Aa (Leiden, 1659 – Leiden, August 1733) was a Dutch publishing, publisher best known for preparing maps and atlases, though he also printed Copyright infringement, pirated editions of foreign bestsellers and illustrated volumes. ...

; 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 Friedrich Richard Rudolf Schlechter (16 October 1872 – 16 November 1925) was a German taxonomist, botanist, and author of several works on orchids. He went on botanical expeditions in Africa, Indonesia, New Guinea, South and Central America and ...

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 ''Aa calceata'' is a species of orchid in the genus ''Aa''. It can be publicly located at the countries Bolivia and Peru , image_flag = Flag of Peru.svg , image_coat = Escudo nacional del Perú.svg , other_symb ...

'' (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 ''Aa fiebrigii'' is a species of orchid in the genus '' Aa''. It is found in Bolivia and northwest Argentina Argentina (), officially the Argentine Republic ( es, link=no, República Argentina), is a country in the southern half of Sou ...

'' (Schltr.) Schltr. 1912 (Bolivia) *''

Aa figueroi ''Aa figueroi'' is a species of orchid in the genus '' Aa''. It is native to Colombia. It is listed as an Appendix II species by CITES CITES (shorter name for the Convention on International Trade in Endangered Species of Wild Fauna and F ...

'' Szlach. & S. Nowak, 2014 *''

Aa hieronymi ''Aa hieronymi'' is a species of orchid in the genus ''Aa''. It is found in northwestern Argentina Argentina (), officially the Argentine Republic ( es, link=no, República Argentina), is a country in the southern half of South Americ ...

'' (

Cogn. Célestin Alfred Cogniaux (7 April 1841 – 15 April 1916) was a Belgian botanist. Amongst other plants, the genus ''Neocogniauxia'' of orchids is named after him. In 1916 his enormous private herbarium was acquired by the National Botanic ...

) Schltr. 1912 (Argentina) *''

Aa lehmannii ''Aa lehmannii'' is a species of orchid in the genus '' Aa''. It is native to Ecuador Ecuador ( ; ; Quechua: ''Ikwayur''; Shuar: ''Ecuador'' or ''Ekuatur''), officially the Republic of Ecuador ( es, República del Ecuador, which liter ...

'' Rchb. f. ex Szlach. & Kolan., 2014 *''

Aa leucantha ''Aa leucantha'' is a species of orchid in the genus '' Aa''. It is native to Colombia and Ecuador, where it grows at altitudes of 2800 to 4300 meters. It is listed as an Appendix II species by CITES CITES (shorter name for the Convention ...

'' (Rchb.f.) Schltr. 1920 (Colombia to Ecuador) *''

Aa lorentzii ''Aa lorentzii'' is a species of orchid in the genus ''Aa''. It is endemic to Argentina Argentina (), officially the Argentine Republic ( es, link=no, República Argentina), is a country in the southern half of South America. Argentina ...

'' Schltr. 1920 (Argentina) *''

Aa lozanoi ''Aa lozanoi'' is a species of orchid Orchids are plants that belong to the family Orchidaceae (), a diverse and widespread group of flowering plants with blooms that are often colourful and fragrant. Along with the Asteraceae, they are on ...

'' Szlach. & S. Nowak, 2014 *''

Aa macra ''Aa macra'' is a species of orchid in the genus ''Aa''. It is found in Ecuador Ecuador ( ; ; Quechua: ''Ikwayur''; Shuar: ''Ecuador'' or ''Ekuatur''), officially the Republic of Ecuador ( es, República del Ecuador, which literally ...

'' Schltr. 1921 (Ecuador) *''

Aa maderoi ''Aa maderoi'' is a species of orchid in the genus ''Aa''. It is native to Ecuador, Colombia, and Venezuela Venezuela (; ), officially the Bolivarian Republic of Venezuela ( es, link=no, República Bolivariana de Venezuela), is a countr ...

'' 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., → ''

'' 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 Neotropical realm flora