Genetic variability in the Physconia muscigena group (Physciaceae, Ascomycota) in the Northern Hemisphere

The principal goal of our study was to test whether ecologically and chemically different populations of lichens in the Physconia muscigena (Ach.) Poelt group belong to multiple species or one. We used sequence data from three markers (ITS rDNA, mtSSU rDNA and TEF1-α) for the reconstruction of phylogenetic trees based on a sampling of mostly European and Canadian populations of P. muscigena (Ach.) Poelt, P. muscigena var. bayeri (Nádv.) Poelt, and P. isidiomuscigena Essl. Further, we sought any possible geographical or ecological trends among chemotypes and haplotypes. Results show that: 1) Sequence data of ITS rDNA and TEF1-α shows large genetic variation in the Physconia muscigena group. This genetic variability does not correlate with geographical distribution or thallus chemistry; 2) Physconia muscigena var. bayeri and P. isidiomuscigena appear undifferentiated in our phylogenetic trees with P. muscigena. These three species cannot be distinguished on the basis of ITS rDNA, mtSSU rDNA and TEF1-α sequences. 3) We synonymized Physconia muscigena var. bayeri with P. muscigena and we recombine P. isidiomuscigena as a variety of P. muscigena