Biatora ligni-mollis (Ramalinaceae) — a new species for the lichen flora of Russia

The species Biatora ligni-mollis is reported for the first time for Russia from the Kaluga Region (Central European Russia). Species identity of the specimen was confirmed by morphological examination and secondary metabolite analysis. The species was described from virgin mountain forests of North America and is widespread in Europe but has a rare occurrence there. A description of the species is provided, along with differences between morphologically similar species found in Central European Russia.