Phylogeny of the European Collema species (Peltigerales, Lecanoromycetes)

The phylogenetic relationships and morphological diversity within European <i>Collema</i> s. str. species were investigated. A total of 104 new sequences (four molecular markers; mtSSU, b-tub, MCM7, and RPB2 genes) from 28 specimens were generated, and analysed and used for multi-locus phylogenetic analyses. Our results suggest that <i>Collema</i> is only monophyletic if <i>Collemaglebulentum</i> is considered part of <i>Leptogium</i> <i>s. str.</i> where it originally was described. This is supported by its paraplectenchymatous thallus. Degelius´ informal <i>Collema</i> "<i>Flaccidum</i>"- and "<i>Nigrescens</i>"-groups are not natural, as the "<i>Flaccidum</i>"-group is nested within the "<i>Nigrescens</i>"-group. Based on our findings, seven currently accepted <i>Collema</i> occur in Europe: <i>C.flaccidum</i>, <i>C.subflaccidum</i>, <i>C.curtisporum</i>, <i>C.furfuraceum</i>, <i>C.nigrescens</i>, <i>C.ryssoleum</i>, and <i>C.subnigrescens</i>. <i>Collemafurfuraceum</i> is further non-monophyletic, suggesting a need for taxonomic revision.