Background
Rhizoplaca subdiscrepans (Nyl.) R. Sant., a saxicolous, placodioid lichen, is considered to have a worldwide distribution in warm-temperate to boreal-arctic areas in Asia, Europe and North America. However, recent studies have revealed that this species includes five unrecognized species-level lineages-'subd A, B, C, D and E'. During research focused on the diversity of saxicolous lichens in mountainous areas of southern Poland, some interesting representatives of the genus Rhizoplaca were found. The main
Methods
Detailed morphological, anatomical and chemical examinations of reference material from Asia, Europe and North and South America focused primarily on a selected group of lecanoroid taxa with a placodioid thallus. In addition, 21 new generated sequences representing Lecanora pseudomellea, Protoparmeliopsis muralis, Rhizoplaca opiniconensis, R. subdiscrepans s. lat. and R. phaedrophthalma were selected for molecular study using the internal transcribed spacer region (ITS rDNA), together with 95 available GenBank sequences mainly from the genus Rhizoplaca.
Results
Polish specimens that clustered with members of a potential species-level lineage 'subd E' of Rhizoplaca subdiscrepans complex were recovered. Comprehensive analyses of the lichen group led us to the