Uncovering chemical variability: molecular data reveal the identity of a sterile crustose lichen from the Yukon and affirm an expanded circumscription for <em>Buellia griseovirens</em>

Here we present the results of a study using molecular data (nrITS and mtSSU sequences) to aid in the identification of a sterile, sorediate crustose lichen from the Yukon Territory of Canada. BLASTn and megaBLAST indicated an affinity to the family Caliciaceae, specifically the Buellioideae. Molecular phylogenetic analyses of mtSSU sequences from the Caliciaceae affirmed this placement, and recovered a strongly supported clade composed of the unidentified populations and members of Buellia s.l. Internal transcribed spacer sequences of the taxon were >99% similar to two sequences of B. griseovirens , a relationship supported by additional molecular phylogenetic analyses. This is the first report of the occurrence of norstictic acid deficient populations of B. griseovirens from North America. It is also the first study to use molecular data to examine, and confirm, some of the chemical variability in B. griseovirens proposed in previous revisions.