Verrucaria tenebrosa (Verrucariaceae), a new lichen species from Finland and Norway, and notes on the taxonomy of epiphytic taxa belonging to the V. hydrophila complex

Abstract

Species related to Verrucaria hydrophila and V. placida in Finland were studied based on morphology and ITS sequences. V. tenebrosa is described as new. The species is characterized by a thin, variable-coloured thallus, small and rather sparsely occurring perithecia with a thin thalline cover, and relatively broad ascospores. V. tenebrosa occurs in shady habitats, usually on calcareous pebbles on N-facing cliffs. It has an eastern distribution in Finland, but it also occurs in Norway. The sequences of an epiphytic species V. lignicola were grouped together with V. hydrophila. However, based on morphological differences we consider them not to be conspecific, but suggest that V. hydrophila is a species complex in need of further studies. An epiphytic occurrence of V. hydrophila is confirmed by an ITS sequence. One putative sequence of V. trabicola is also grouped together with V. hydrophila, but further studies are needed on the identity of V. trabicola.