<em>Thelomma ocellatum</em>, a range extension to the Yukon Territory and case study in the use of molecular data to recognize asexually reproducing crustose lichens

Abstract

An unusual sterile, asexually reproducing crustose lichen was encountered during fieldwork in the Yukon Territory of Canada. Genus and family level placement of the taxon were precluded by a lack of both sexual characters and any non-sexual characters that would have suggested an unambiguous generic affiliation. Examination of mtSSU and nrITS sequence data of the taxon revealed it to be a member of the Caliciaceae, with a sister relationship to the genus Tholurna . Subsequent molecular phylogenetic analyses of mtSSU sequence data suggested conspecificity with Thelomma ocellatum , one of the few calicioid lichens that reproduce asexually via lichenized diaspores. Comparison of the material from the Yukon with reference specimens and descriptions of T. ocellatum confirmed the identification of these populations, which extend the known distribution of T. ocellatum considerably northward in North America.