Orchids of the central region of eastern Maranhão, Brazil

Abstract

Abstract The eastern portion of the state of Maranhão is a transitional area between Amazon Rainforest, Cerrado and Caatinga. Knowledge about the flora of this region is very poor, especially regarding Orchidaceae. The aim of this study was to provide a survey of the species of this family in the central area of this region. Fieldwork was performed monthly between December 2015 and April 2019 in the municipalities of Aldeias Altas, Caxias, Codó and São João do Sóter. An identification key, morphological descriptions and illustrations of the species are presented. Orchidaceae is represented in the area by seven genera and 17 species. The richest genera were Catasetum (five species), and Habenaria (four species). Habenaria schenckii is a new record for the state. The majority of the species are epiphytes (eight species, 47%) or terrestrial (seven species, 41%). The municipality of Caxias was the richest, with 13 species (76%), of which six were collected in the conservation units (CU’s) existing in the municipality (Área de Proteção Ambiental Municipal (APAM) Buriti do Meio Municipal and APAM Inhamum). Our data highlight the importance of the CU’s for the conservation of Orchidaceae, and the potential of ecotonal regions for discovering new records for the region.