Evolutionary relationships between the major populations of Xanthoparmelia tasmanica are investigated using parsimony, likelihood, and Bayesian analyses of ITS sequence data. Results indicate that this taxon is comprised of at least two geographically distinct lineages. Moreover, these lineages belong to two larger clades of Xanthoparmelia s. str. (also defined by geography) that were recognized in previous phylogenetic studies of the genus. The geographically distinct, but morphologically and chemically identical populations of X. tasmanica are treated here as separate taxa with independent evolutionary histories. While the name X. tasmanica is properly applied to Australasian populations, populations from North America that were previously called X. tasmanica are here referred to X. hypofusca.