Genetic diversity in Usnea flavocardia
Usnea flavocardia, a widespread species found in all continents excepting Antarctica, is characterized by a shrubby thallus growth form, the presence of soralia, a yellow central axis and/or the presence of red dots on the cortex. Using ITS rDNA and two protein-coding genes (MCM7 and RPB1) in a multispecies coalescent (MSC) approach, we showed that U. flavocardia is a highly supported monophyletic clade hereafter called the U. flavocardia aggregate, furthermore comprising five different lineages, four of which can be considered as putative new species. Each of the five lineages, but one, is characterized by specific chemical compounds. Within the outgroup that were used in this study, we furthermore showed that U. gaudichaudii and U. eulychniae, both endemic to Chile and Peru, constitute a new major clade in the subgenus Usnea sensus stricto.