Abstract
The genus Adiantum L. can be easily recognized by the pseudoindusium formed by the revolute margin of the lamina and with veins. The species of this genus are terrestrial or lithophytics. It is a Pantropical group with approximately 200 species, 70 of which occur in South America, and 62 in Brazil. Its species are usually found in primary and secondary forests, from sea level to 2,000 meters. Aimed the regional knowledge of this group in Brazil, this study reports a floristic survey of the genus Adiantum to the state of Rio de Janeiro, providing an identification key, descriptions, comments, and illustrations of the species. There are 20 species of Adiantum in the state, corresponding to 30% of the species recorded to Brazil. They can be found in rainforests and sandy coastal plain vegetation, from sea level to 850 meters. Some species have a wide range of distribution in Central and South America (70%), whereas others are endemic to Brazil (30%).
Key words:
Adiantoideae; Atlantic Forest; ferns; taxonomy