Importance of type specimen study for understanding genus boundaries-taxonomic clarifications in based on integrative taxonomy approach leading to resurrection of the old genus .

Type specimens of four species of (Myxomycetes, Amoebozoa)-, and have been studied using an integrative approach including application of traditional taxonomy methods, i.e., morphological study under stereoscopic and compound microscopes, detailed analysis of micromorphological characters using scanning electron microscopy, and molecular analysis by way of Sanger sequencing of molecular markers (nuc 18S rDNA and elongation factor 1-alpha gene, ). Results of the study revealed that is conspecific with is a malformed specimen of , whereas and represent two well-defined morphologically and genetically separate species. Phylogeny of Physarales shows the polyphyletic character of the genus . The type species of clusters together with , whereas other representatives of this genus form a monophyletic, well-supported clade. The species from this clade are proposed to belong to the genus described by A. Corda in 1842 that is resurrected and emended here. Nine species of are transferred to . A new key to Didymiaceae including is provided.