<i>Aspicilia fluviatilis</i> and <i>Circinaria leprosescens</i>, two lichen species of the family Megasporaceae new to Poland

The paper presents two saxicolous species of the family Megasporaceae, <i>Aspicilia fluviatilis</i> and <i>Circinaria leprosescens</i>, discovered as new to Poland. <i>Aspicilia fluviatilis</i> is a rare, arctic-alpine species with elongated marginal areoles, and <i>Circinaria leprosescens</i>, occurs only in marine and strongly nitrophilous habitats and is often found sterile with granular to isidiate upper cortex. The identity of <i>C. leprosescens</i> was confirmed by molecular data, BLAST searches and haplotype network analysis based on nucITS rDNA sequences. <i>Aspicilia fluviatilis</i> is also reported as new to Italy based on historical material from the Alps. Detailed information on morphology, chemistry, distribution and ecology are given for both species.