THE LICHEN GENUS XANTHORIA IN ANTARCTICA

Three Xanthoria species occur in Antarctica: X. candelaria s.str., X. mawsonii and X. elegans. The genus was treated by previous authors und er different generic names: Blastenia, Caloplaca, Candelariella, Kuttl ingeria, Polycauliona and Xanthoria. Two new synonyms of X. elegans ar e provided, while five previously proposed synonyms are confirmed by t he examination of type specimens. Altogether, eleven taxa described fr om Antarctica are synonyms of two widespread Xanthoria species, X. can delaria s. str. and X. elegans. X. mawsonii, an endemic species, previ ously considered by most authors as conspecific with X. candelaria, pr oved to be a distinct species, differing from X. candelaria s. str. in morphology and in the longer spermatia. The three Xanthoria species a re keyed and discussed; a comprehensive list of synonyms is provided. X. elegans seems to be widespread in all Antarctic regions, X. candela ria is reported from subantarctic and maritime regions while X. mawson i seems to be restricted to continental Antarctica.