Hypogymnia phylogeny, including Cavernularia, reveals biogeographic structure

We inferred phylogenetic relationships using Bayesian and maximum likelihood approaches for two genera of lichenized fungi, Hypogymnia and Cavernularia (Parmeliaceae). Based on the combined ITS and GPD1 dataset from 23 species (49 specimens) of Hypogymnia and two species (8 specimens) of Cavernularia, we conclude that Hypogymnia is paraphyletic, and that it should include Cavernularia to retain its monophyly. Hypogymnia hultenii (= Cavernularia hultenii) and H. lophyrea (= C. lophyrea) are accepted here. Five species of Hypogymnia represented by more than a single individual were found to be monophyletic and significantly supported. The phylogeny reflects a statistically significant biogeographic pattern where continental-scale endemic taxa tend to occur within the same phylogenetic group. Sorediate taxa, which have worldwide or broader geographical ranges than affiliated species lacking soredia, are spread across the phylogenetic tree. Hypogymnia contains three species pairs: H. krogiae and the sorediate counterpart H. incurvoides, H. minilobata and the sorediate H. mollis, and H. lophyrea and the sorediate H. hultenii. In the case of H. minilobata, both members of the pair are restricted to a small area in southern California. In the other two cases, the fertile counterpart occurs only in North America, while the sorediate species occurs in both North America and Fennoscandia. This suggests but not proves an origin of each species pair in North America, with migration of the sorediate member to Fennoscandia following the prevailing wind direction.