Postia alni Niemelä & Vampola (Basidiomycota, Polyporales) – member of the problematic Postia caesia complex – has been found for the first time in Hungary

Due to their bluish basidiocarps the Postia caesia (syn. Oligoporus caesius) complex forms a distinctive morphological group within the polypore genus Postia Fr., 1874. Five species of this group occur in Europe: P. alni Niemelä & Vampola, P. caesia (Schrad.) P. Karst., P. luteocaesia (A. David) Jülich, P. mediterraneocaesia M. Pierre & B. Rivoire and P. subcaesia (A. David) Jülich. In this study P. alni is reported for the first time from Hungary. The dichotomous key of the species of the European Postia caesia complex was prepared as well.