The analysis of ITS and 28S rDNA, as well as sequences of tef1 and tub2 exons suggests that Arthrinium s. str. and Apiospora represent independent lineages within Apiosporaceae. Morphologically, Arthrinium and Apiospora do not seem to have clear diagnostic features, although species of Arthrinium often produce variously shaped conidia (navicular, fusoid, curved, polygonal, rounded), while most species of Apiospora have rounded (face view) / lenticular (side view) conidia. Ecologically, most sequenced collections of Arthrinium were found on Cyperaceae or Juncaceae in temperate, cold or alpine habitats, while those of Apiospora were collected mainly on Poaceae (but also many other plant host families) in a wide range of habitats, including tropical and subtropical regions.