Knudsen, K. & Kocourková, J. 2020: Two poorly-known species of European Acarospora (Acarosporaceae). – Herzogia 33:1 – 8.
The European species Acarospora franconica and Acarospora helvetica are revised. Acarospora franconica is a lowland species of central Europe collected on sandstone and volcanic rock. It is reported as new for the Czech Republic. Acarospora helvetica is a montane species which occurs on basic and intermediate siliceous rock. Acarospora helvetica was described and reported from Switzerland and France by A. H. Magnusson and is reported new for Austria, Greece, Italy and Germany. Lectotypes are designated for A. austriaca, A. franconica and A. helvetica. Acarospora austriaca is a synonym of A. helvetica.