A further new species in the lichen genus Arctomia: A. borbonica from Reunion (Mascarene archipelago)

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.