Vascular flora of Lençóis Maranhenses National Park, Maranhão State, Brazil: checklist, floristic affinities and phytophysiognomies of restingas in the municipality of Barreirinhas

ABSTRACT This study presents a floristic survey of the vascular plants of restingas of Lençóis Maranheses National Park, in the municipality of Barreirinhas, Maranhão, Brazil, including descriptions of the principal phytophysiognomies and similarity analyses including other restinga areas in North and Northeastern Brazil. Samples from the study area deposited in the herbaria MG, IAN and MAR were inventoried and fieldwork for the collection of additional botanical samples was undertaken between September 2015 and August 2017. Unweighted pair group method with arithmetic mean (UPGMA) using Jaccard index was used to calculate the similarity among floras of the restingas of the states of Pará, Piauí, Ceará and Maranhão. A total of 289 species in 189 genera and 73 families was recorded, including 56 new occurence records for the state of Maranhão. The richest families were Poaceae, Cyperaceae, Fabaceae, Rubiaceae, Eriocaulaceae and Myrtaceae. Similarity indexes revealed low similarity among the selected areas, suggesting high floristic identity for each area, as well as possible collection bias among the areas.