Molecular systematics of Lecanora subgenus Placodium

A first hypothesis for the phylogeny of Lecanora subgen. Placodium is presented by using molecular data. Previous evolutionary ideas and classification concepts for this group with non-molecular data are re-investigated using DNA sequence data from the nuclear ITS and 5.8S regions. Using Protoparmelia as an outgroup, the Lecanora subfusca group together with the L. rupicola group appear as a sister group to assemblages with lobate species. Subgen. Placodium, as currently accepted, is not monophyletic. Molecular data suggest that the Lecanora dispersa group and the L. polytropa group are widened by lobate species and there is evidence from the ITS data that the monotypic genus Arctopeltis Poelt is closely related to the L. dispersa group. A congruence between molecular data and secondary chemistry supports the broader concept of the L. dispersa group suggested by the molecular data. (C) 1998 The British Lichen Society.