XVI International Botanical Congess

Morphological characters have for a long time been used to improve the classification of Physciaceae. These characters are certainly not sufficient to support the segregation of various genera. In parallel to further morphological and chemical investigations, analysis of nucleic acid sequences are now being used to test the current classification of genera. This will shed new light to the evolution of the numerous types of ascospores and diverse growth forms in Physciaceae. Preliminary results from phylogenetic studies of the ITS regions show that several of the generally accepted genera, e.g., Physcia and Phaeophyscia, seem to be monophylectic, whereas others, e.g., Anaptychia and Buellia, may be paraphyletic or polyphyletic.