Dark septate endophytes (DSE) are distributed worldwide as root-colonising fungi, and frequent in environments
with strong abiotic stress. DSE is not a taxon, but constitutes numerous fungal taxa belonging to several
orders of Ascomycota. In this study we investigate three unidentified DSE lineages belonging to Pleosporales that
were found previously in semiarid sandy grasslands. For molecular phylogenetic studies seven loci (ITS, partial 18S
nrRNA, 28S nrRNA, actin, calmodulin, transcription-elongation factor 1-α and ß-tubulin genes) were amplified and
sequenced. Based on morphology and the resulting molecular phylogeny these isolates were found to represent
three novel genera within the Pleosporales, namely Aquilomyces, Flavomyces and Darksidea, with eight novel species.
Molecular data revealed that monotypic Aquilomyces belongs to Morosphaeriaceae, monotypic Flavomyces
represents an incertae sedis lineage related to Massarinaceae, and Darksidea, with six new species, is allied to
the Lentitheciaceae. During this study we tested numerous conditions to induce sporulation, and managed for the
first time to induce several DSE to form their sexual morphs.