"Polystachya (Orchidaceae) in the Pan-Amazon"

Floristics; Morphology; Orchidaceae; Taxonomy

Polystachya is a pantropical genus of Orchidaceae, easily recognized by its imbricate andconduplicate leaves, erect to suberect stems, covered by papyraceous bracts, in addition to the generally panicledinflorescence, bearing non-resupinate flowers and with a mentum. Two general taxonomic reviews have been carried out for the genus up to now and a third was focused on American species. However, there is still a need for better interspecific delimitations, since the most recent reviews are conflicting, with the aggravating factor that many species have numerous synonymies, in addition to not including complete data on the Amazonian species of the genus. Therefore, there is no satisfactory taxonomic listing or study on Polystachya for the Amazon phytogeographic domain, although the genus is a common component of the Amazon epiphytic flora. Thus, the objective is to carry out a taxonomic review for the genus in the Pan-Amazon, in order to facilitate the recognition of taxa and, in this way, also contribute to the knowledge of Amazonian plant diversity. Morphological analyzes will be carried out on specimens deposited in national and international herbaria and descriptions and an identification key for the species will be prepared. The data collected so far allows us to highlight the occurence of five species of Polystachya in the Amazon, requiring the recognition of diagnostic characters and the resolution of taxonomic problems to obtain updated and reliable numbers of Amazonian Polystachya species.