Aa macra

Aa macra is a species of terrestrial orchid in the family Orchidaceae, order Asparagales, belonging to the Andean genus Aa. The species epithet macra derives from the Greek makros, meaning 'long' or 'slender', and likely refers to an elongated feature of the plant — possibly the flowering stem, the leaves, or specific floral parts — that distinguishes this species from morphologically similar congeners within the genus. As a member of genus Aa, this orchid is a compact to moderately sized herbaceous perennial native to the high-altitude grasslands and shrublands of the Andes in South America. Like its congeners, Aa macra forms a basal rosette of leaves from which an erect stem rises to carry a dense raceme of small flowers. The leaves are typically lance-shaped, firm, and adapted to the cold, dry, and UV-exposed conditions of high Andean habitats. The name 'macra' suggests that the flowering stem or associated structures may be notably longer or more elongate than in closely related species — a character that would be observable in the field or from herbarium specimens and is useful in taxonomic identification. The flowers of Aa macra, like all orchids, feature three sepals, two petals, a modified third petal forming the lip, and a column. The flowers are small and arranged compactly along the flowering stem, typical of the genus. Aa macra inhabits the puna or páramo zones of the central or southern Andes, where it grows in rocky, well-drained soils and depends on mycorrhizal associations for nutrient uptake. Threats include overgrazing, burning, and climate change impacts on high-altitude Andean grasslands.