Meriderma species (Myxomycetes) from the Polish Carpathians: a taxonomic revision using SEM-visualized spore ornamentation

Meriderma represents a recently described genus of nivicolous myxomycetes with high morphological variability. Due to many complications in its taxonomy and species recognition in the past, the group was considered a morphologically variable complex. Recent clarifications and recognition of morphological boundaries into species and morphotypes has fostered a classification revision of specimens found in the Carpathians. Material used in this study was systematically collected in the Polish part of the Carpathians from 2004 to 2009. As a result of micro- and macroscopic observations of 54 collections, we recorded nine taxa of Meriderma. Seven of these (all but M. carestiae and M. cribrarioides) are the first records for Poland and for the Carpathians overall. Our observations based on analysis of spore ornamentation by SEM are in accordance with recently proposed classification and confirm segregation of taxa based on spore ornamentation pattern.