THE IMPACT OF MOLECULAR CHARACTERS ON SYSTEMATICS OF FILAMENTOUS ASCOMYCETES

Information derived from nucleic acid analyses either has complemented phylogenetic arguments based on phenetic characters or facilitated ch oice among competing hypotheses. Despite limited taxon sampling, a pic ture of the interrelationships of filamentous Ascomycetes at higher ta xonomic levels is developing. Intergeneric relationships within groups that include economically important fungi (e.g. Eurotiales, Hypocreal es) are being clarified, and generic circumscriptions redefined, Molec ular analyses have supported predictions of links between individual a sexual species of groups or asexual species of the Fungi Imperfecti, a nd groups of Ascomycete genera and species. However, individual asexua l species have not been linked unequivocally to individual Ascomycete species. Anamorph names are necessary and should be retained because t eleomorphs may not be recognized in vivo nor formed in vitro. In the f ew cases where phenetic and molecular phylogenies seem irreconcilable, the ribosomal genes may not give the most parsimonious explanation. T he taxon name ''Plectomycetes'' is confused and should be dropped.