# Phylogeny of the European Collema species (Peltigerales, Lecanoromycetes)

## TL;DR

This study explores the evolutionary relationships and diversity of European Collema lichen species using genetic data.

## Contribution

The study provides new genetic evidence for redefining the classification of European Collema species.

## Key findings

- Collema is monophyletic only if Collema glebulentum is included in Leptogium.
- Degelius' informal Collema groups are not natural, with the Flaccidum group nested within the Nigrescens group.
- Seven Collema species are recognized in Europe, with Collema furfuraceum requiring taxonomic revision.

## Abstract

The phylogenetic relationships and morphological diversity within European Collema 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 Collema is only monophyletic if Collemaglebulentum is considered part of Leptogiums. str. where it originally was described. This is supported by its paraplectenchymatous thallus. Degelius´ informal Collema “Flaccidum”- and “Nigrescens”-groups are not natural, as the “Flaccidum”-group is nested within the “Nigrescens”-group. Based on our findings, seven currently accepted Collema occur in Europe: C.flaccidum, C.subflaccidum, C.curtisporum, C.furfuraceum, C.nigrescens, C.ryssoleum, and C.subnigrescens. Collemafurfuraceum is further non-monophyletic, suggesting a need for taxonomic revision.