[en] Arctomia borbonica sp. nov. is described as new for science from montane natural and secondary habitats in Reunion in the Mascarene archipelago (Indian Ocean). It has a sterile, foliose, usually wrinkled, thallus whose margins produce goniocysts that disintegrate into a soredioid margin; it looks like a Leptogium species. Its phylogenetic position in the Arctomiaceae (Ostropomycetidae, Ascomycota) has been determined with 3 genes (nuLSU, mtSSU, RPB1) inferences.
