A new species and new records of Leptogium (Ach.) Gray (Collemataceae, Peltigerales) from Rio Grande do Sul State with an identification key for the genus.

Specimens of Leptogium collected in ten localities from the State of Rio Grande do Sul were studied. Sixteen species were found of 28 records mentioned to the state, which represents around 57% of the Leptogium diversity known for Rio Grande do Sul. Leptogium exaratum is proposed as a new species.