Phylogenetic analysis of the lichen family Umbilicariaceae based on nuclear ITS1 and ITS2 rDNA sequences

The lichen family Umbilicariaceae is accepted by most lichenologists as con sisting of two genera, Lasallia and Umbilicaria. The monophyly of these two genera was examined by phylogenetic analyses of nucleotide sequences of IT S1 and ITS2 rDNA. Sequences of these regions from three Lasallia and 17 Umb ilicaria species were aligned to those of seven representatives of the outg roup taxa including Eurotiales, Onygenales and Caliciales (Mycocaliciaceae) and subjected to maximum parsimony, maximum likelihood and neighbour-joini ng analyses. The resulting phylogenetic hypotheses supported the monophyly of the representative species of Lasallia. However, the species of Umbilica ria did not form a monophyletic sister-group to Lasallia due to the basal p lacement of other Umbilicaria species in some analyses. Based on these anal yses, if Lasallia is recognized as a separate genus then Umbilicaria appear s to be paraphyletic. Although further taxon sampling is required to resolv e the monophyly of Umbilicaria, for the present we recommend retaining the current treatment of Lasallia as separate from Umbilicaria. (C) 1999 The Br itish Lichen Society.