Synopsis of Orchidaceae from Fazenda Sete Irmãos: a fragment of Amazon Forest in northwestern Maranhão, Brazil

Abstract

This study provides an inventory of the Orchidaceae in one of the most threatened areas of the Brazilian Amazon, situated in the eastern portion of the Belém Endemism Center. A total of 51 species, distributed in 24 genera, are recorded. Epiphytes represent 86% of the species, the remaining are terricolous (6%), hemiepiphytic (6%) or myco-heterotrophic (2%). The most representative genera were Epidendrum (6 spp.) and Maxillaria (5 spp.). This study cites for the first time five genera (Coryanthes, Sarcoglottis, Stelis, Trichosalpinx and Wullschlaegelia) and ten species for the flora of Maranhão, of which four are new records to the Brazilian Northeast. An identification key, photographs of the new records, taxonomic and ecological comments, as well as geographic distribution are provided. The data reinforce the importance of the forest fragments of the Amazon Forest in Maranhão for the conservation of Orchidaceae which is constantly threatened by deforestation in the Belém Endemism Center.