This study was focused on two species of lichen-forming fungi from Madagascan Region whose taxonomy has been controversial over the years, Cladonia mascarena Nyl. and Heterodea madagascarea Nyl. While some authors considered C. mascarena to belong to Cladonia, others place it in Pycnothelia Dufour. In this study three loci (ITS rDNA, rpb2 and ef1α) were used to determine the phylogenetic placement of C. mascarena. Our results show that it belongs to Pycnothelia and the combination Pycnothelia mascarena (Nyl.) Nyl. is substantiated. In addition, a key to the genus Pycnothelia is provided. The morphological study of new specimens of Gymnoderma coccocarpum Nyl. and H. madagascarea concluded that these taxa belong to a same species, confirming the extension of Gymnoderma Nyl. to Africa. The overlooked genus Baeoderma Vain. is regarded as a synonym of Gymnoderma, and its type species Baeoderma madagascareum (Nyl.) Vain. is referred to G. coccocarpum.
Cladoniaceae, lichen-forming fungi, genus concepts, phylogeny, Réunion