Taxonomy and phylogeny of Dermatocarpon (Verrucariales, lichenized Ascomycotina) with special emphasis on the Nordic species

Abstract: In this thesis Dermatocarpon (Verrucariales, lichenized Ascomycotina) of the Nordic countries is revised. Useful characters for species identification are epinecral layer type, spore length, medulla sensitivity to Melzer´s Reagent, and lower surface colour anappearance. The pruinosity of certain members of Dermatocarpon, which earlier was considered an important character, is caused by an epinecral layer consisting of air filled cells. In all eight species Dermatocarpon in the Nordic countries are accepted.The relationships of D. bachmannii and D. deminuens are studied in detail using statistical methods. Both PCA and t-test are utilized and the results indicate that although the two species are closely related they should be treated as distin species.Dermatocarpon miniatum is a common and widely distributed species which shows a considerable morphological plasticity. The D. miniatum-complex is studied by molecular methods. The ITS and 5.8S areas of the rDNA were sequenced for 25 representatives of the D. miniatum-complex and 21 representatives of other Dermatocarpon species. D. leptophyllum, D. linkolae, and D. miniatum var. cirsodes are monophyletic units, but considered synonyms of D. miniatum. D. miniatum var. miniatum and D. miniatum var. complicatum are polyphyletic and should not be treateds separate taxa. An undescribed species similar to D. miniatum from the southern part of North America is discussed.