The Wisdom of Fools: new molecular and morphological insights into the North American apodetiate species of Cladonia

The taxonomy of the North American apodetiate and superficially apodetiate species of Cladonia with persistent, primarily squamulose thalli (viz., C. apodocarpa, C. caespiticia, and C. petrophila) is revised using morphological, chemical, and ecological data in combination with molecular phylogenetic analyses of ITS1, 5.8S, and ITS2 sequence data. The results of this approach confirm some established taxonomic concepts in the group and raise doubts about others. The taxon known as C. apodocarpa is well supported by likelihood- and parsimony-based molecular phylogenetic inferences as well as morphology, chemistry, and ecology. However, molecular evidence gives an equivocal answer to the question of whether C. petrophila is a distinct monophyletic entity or if C. apodocarpa is nested within it. In addition, no phylogenetic structure is detected for the chemical races of C. petrophila with and without fumarprotocetraric acid, based on the markers used in these analyses. However, C. petroph...