Phylogenetic relationships of Gymnodenna coccocarpum and Cetradonia linearis were investigated using nucleotide sequence data of the SSU rDNA. Our results show that Gymnodenna and Cetradonia form a clade, which is a sister group of Pycnothelia and Carassea. As a result, both Gynmoderma and Cetradonia are clearly members of the family Cladoniaceae and the family name Cetradoniaceae has to be abandoned. The SSU rDNA of Gymnoderma contains seven group I and one spliceosomal intron, the positions and lengths of which are discussed. introns, lichens, Cetradonia, Gymnodenna, SSU rDNA