Although extrafloral nectaries (EFNs) are reported as extremely important to understand ecological interactions, the diversity of EFN-bearing plants remains underappreciated. In Brazil, studies are concentrated in Cerrado and extremely poorly known in other phytogeographic domains, such as Atlantic forest. Thus, this study provides one of the first checklists of angiosperms with EFNs in a protected area of the Brazilian Atlantic forest, bringing information about the richness, location of EFNs on the plant's organs, as well as plant's habit and conservation status. A total of 93 EFN-bearing species belonging to 61 genera and 29 families is reported, which corresponds to 16.5 % of the local flora. The vast majority has not been evaluated for their conservation status, and twenty species are endemic to the Brazilian Atlantic forest. Vines and trees are the predominant plant habits and EFNs are mostly found on leaves. More than half of the species (53.7 %) comprises new additions to the world list of EFN-bearing plants, including the first record in Dilleniaceae. Our findings show a large number of EFN-bearing plant species from a single and small protected area in the Brazilian Atlantic forest. It reinforces the lack of studies of this nature, where further investigations are strongly recommended.

The Atlantic Forest is one of the most threatened biomes in the world. Despite that, this biome still includes many areas that are poorly known floristically, including several protected areas, such as the "Floresta Nacional do Rio Preto" ("Flona do Rio Preto"), located in the Brazilian State of Espírito Santo. This study used a published vascular plant species list for this protected area from the "Catálogo de Plantas das Unidades de Conservação do Brasil" as the basis to synthesise the species richness, endemism, conservation and new species occurrences found in the "Flona do Rio Preto". The published list of vascular plants was based on field expeditions conducted between 2018 and 2020 and data obtained from herbarium collections available in online databases. Overall, 722 species were documented for the "Flona do Rio Preto", 711 of which are native to Brazil and 349 are endemic to the Atlantic Forest. In addition, 60 species are geographically disjunct between the Atlantic and the Amazon Forests. Most of the documented species are woody and more than 50% of these are trees. Twenty-three species are threatened (CR, EN and VU), while five are Data Deficient (DD). Thirty-two species are new records for the State of Espírito Santo. Our results expand the knowledge of the flora of the Atlantic Forest and provide support for the development of new conservation policies for this protected area.