XVI International Botanical Congess

Letharia is currently described as two closely related species with similar natural histories. One is sexual and one mostly clonal. They were chosen as a model system to examine the effect of reproductive mode on population genetics. Thirteen variable DNA sequence-based loci present in all individuals were identified. The markers proved to be phylogenetically informative. Two new species were revealed: L. columbiana (sexual) and L. vulpina (mostly clonal) each consist of two lineages. A cryptic lineage of L. columbiana is the sister clade of L. vulpina. One lineage of L. vulpina has soredia, the other has isidia. A comparative population study is underway in a field site where the sorediate species and its sister sexual species co-occur.