Orchids of the central region of eastern Maranhão, Brazil

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