XVI International Botanical Congess

Photobiont ITS rDNAs were specifically amplified from genera of the Physciaceae without culturing the algae. The photobionts were dispersed over three of the four main clusters formed by the algal (Trebouxia) ITS rDNAs. Different degrees of specificity of mycobionts towards their photobionts were seen. Photobionts from foliose genera (Physcia, Phaeophyscia) were found in a single Trebouxia cluster, while those from the fruticose Anaptychia were in another independent cluster, and those from crustose genera (Buellia, Pyxine) were in all three clusters. More than one ITS genotype was present within a photobiont species from the foliose taxa. The degree of photobiont specificity may be an useful phylogenetic character. For the studied lichen taxa, similar degrees of relatedness as in the photobiont phylogeny are suggested by non-molecular characters. However, this needs to be tested by rDNA phylogenies for the corresponding mycobionts.