Ah (plant)

The Aa are a genus of plants in the Orchidaceae family that has approximately 25 species.

Etymology

Apparently, the name was given to always appear first in alphabetical listings. Another (controversial) explanation is that Heinrich Gustav Reichenbach named this genus after Pieter van der Aa, the printer of Paradisus Batavus by the Dutch botanist Paul Hermann.

Habitat

These species are found in mountainous regions, right at the altitude limit where snow remains year-round, growing in the Andes and in Costa Rica, as well as along streams.

Description

The elongated inflorescences arise from the basal rosette of leaves, terminating in a small, inverted white flower with a fringed, cap-shaped lip at the end. The flower gives off a strong odor that attracts flies.

Aa species

There are more than 25 known species endemic to the Andes. They have often been confused with the orchid genus Altensteinia.

• Aa achalensis: (Argentina).
• Aa argyrolepis: (Colombia to Ecuador).
• Aa calceata: (Peru to Bolivia).
• Aa Colombian: (Colombia to Ecuador).
• Aa denticulata: (Colombia to Ecuador).
• Aa erosa: (Peru).
• Aa fiebrigii: (Bolivia).
• Aa filamentosa Mansf.
• Aa gymnandra: (Bolivia).
• Aa hartwegii: (Ecuador, Colombia and Venezuela).
• Aa hieronymi: (Argentina).
• Aa inaequalis: (Peru to Bolivia).
• Aa leucantha: (Colombia to Ecuador).
• Aa lorentzii: (Argentina).
• Aa macra: (Ecuador).
• Aa maderoi: (Venezuela, Colombia and Ecuador).
• Aa mandonii: (Peru to Bolivia).
• Aa matthewsii: (Peru).
• Aa microtidis: (Bolivia).
• Aa nervosa: (Chile).
• Aa paleacea: (Costa Rica to Bolivia).
• Aa riobambae: (Ecuador).
• Aa rosei: (Peru).
• Aa rostrata: (Ecuador).
• Aa schickendantzii: (Argentina).
• Aa sphaeroglossa: (Bolivia).
• Aa trilobulata: (Bolivia).
• Aa weddeliana: (Peru and N.O. of Argentina).