Botanical efforts reveals unrecorded thalloid liverworts for both State of Maranhão and Brazilian Cerrado, northeastern Brazil

Abstract Despite its rich biodiversity, the State of Maranhão, northeastern Brazil, is one of the less explored and known Brazilian states from a bryological perspective. Until recently, the recorded thalloid liverwort flora of Maranhão comprised 13 species, distributed in seven families. This study reports first records of some species of thalloid liverworts for both Maranhão and the Brazilian Cerrado, based on botanical expeditions carried out in different areas of Maranhão between 2017 and 2025. We report 10 species newly recorded for the state, including Riccardia leptophylla, R. multifida, Riccia breutelii and R. subdepilata, which also represent new records for the Brazilian Cerrado, and Pteropsiella frondiformis, new record for Northeastern Brazil. These new records increased the number of thalloid liverwort species documented for Maranhão to nearly double, reaching a total of 23 species. The most rich family is Ricciaceae (9 species), followed by Aneuraceae (6), while Corsiniaceae, Lepidoziaceae, and Pallaviciniaceae are each represented by two species, and Cyathodiaceae and Monocleaceae by one species. This study underscores the importance of floristic and taxonomic research in underexplored regions and emphasizes the need for increased attention to overlooked plant groups such as bryophytes.