Orchidaceae of the municipality of Igarapé-Miri, Pará, Brazilian Amazon

Abstract

The municipality of Igarapé-Miri is located in the Endemism Center of Belém, which corresponds to the most deforested portion of the Brazilian Amazon with only 38% of its native forest remaining. The family Orchidaceae has several endemic taxa and expressive diversity in the Amazon phytogeographic domain, including in the state of Pará where 97 genera and 395 species have been reported. Considering the advanced state of fragmentation and the loss of diversity in the region, together with the lack of information about the flora of the municipality of Igarapé-Miri (Pará, Brazil), a floristic-taxonomic study was undertaken of the species of Orchidaceae in the municipality, including an identification key, morphological descriptions, taxonomic comments, illustrations and information on habitat, phenology and the geographic distribution of species. Fifty-eight species distributed in 38 genera were recorded for the municipality of Igarapé-Miri. The most diverse genera were Epidendrum (7 spp.) and Catasetum (4 spp.), followed by Maxillaria, Scaphyglottis and Stelis (3 spp. each). Most species occur as epiphytes and in Terra Firme Forest, with 31 species being exclusive to this type of vegetation. The occurrence of Anathallis fastigiata, Catasetum albovirens, Dichaea brachyphylla and Palmorchis triquilhada, species restricted to the Brazilian Amazon, stands out. The distribution of Stelis palmeiraensis is expanded to the Amazon phytogeographic domain and Stelis ciliaris and Uleiorchis ulei are documented in the state of Pará for the first time.