Abstract: A taxonomic revision is presented of all filamentous Hemiascomycetes that reproduce with predominantly arthric
conidiogenesis. On the basis of SSU rDNA data, two widely divergent groups (1 and 2) are known to exist. Both are distantly
related to the Hemiascomycetes, and show remarkable diversity in ITS rDNA, leading to the supposition that phylogenetically
ancient fungi are concerned. The teleomorph / anamorph genera occurring in Groups 1 vs. 2 are classified in (1) Galactomyces
and Dipodascus with Geotrichum anamorphs, vs. (2) Magnusiomyces with Saprochaete anamorphs. Taxonomy at the
species level is based on ITS rDNA sequences and nDNA/DNA reassociation data. In total, 32 taxa are recognized. The
phenetic data set applied is nutritional physiology. A key to the species is provided.