Cladonia trapezuntica (Cladoniaceae, lichenized Ascomycota): a robust morphotype of Pycnothelia papillaria, a taxonomic study with conservational survey

The long-neglected lichen described as Cladonia trapezuntica was rediscovered at its type locality in Turkey thanks to historical maps available at the Natural History Museum in Vienna. Molecular, morphological, and chemical analyses were applied to determine whether C. trapezuntica is a distinct species or rather falls within the phenotypic variation of Pycnothelia papillaria. Although most of the podetia appear to be unusual for P. papillaria, the molecular evidence indicates that C. trapezuntica should be considered as a synonym of P. papillaria, and the cushion-like growth form, taller podetia with irregular to dichotomously or trichotomously branching pattern, and scarce primary thallus should be recognized as morphological variability. Consequently, the southeastern distribution limit of P. papillaria is extended to Turkey. This species has not been found elsewhere in Turkey; therefore, it is considered as critically endangered in the country.