New insights into the systematics of and its allies and introducing new genera, species and morphological patterns in the and ().

The newly discovered systematic placement of , the lectotype species of the genus, prompted a re-evaluation of the traditionally broadly conceived genus . Fresh material, axenic cultures and new DNA sequence data of five gene regions of six species, i.e. , , , and , were studied. is a strongly resolved lineage in the (), supported by Bayesian and Maximum Likelihood methods. The genus is emended and delimited to hyphomycetes characterised by sporodochial conidiomata, mononematous often fasciculate conidiophores, holoblastic conidiogenesis and acrogenous, solitary, dry, pigmented, transversely or rarely longitudinally septate conidia. The conidia are seceding rhexolytically, exhibiting multiple secession patterns. An identification key to 35 species accepted in is given, providing the most important diagnostic characters. Novel DNA sequence data of and confirmed their placement in the (). For other , molecular data are available for and , which position them in the and , respectively. All four species are excluded from and segregated into new genera, , and . Classification of 20 other species and varieties not recognised in the genus is discussed. Based on new collections of , the type species of , the genus is emended to accommodate monodictys-like freshwater lignicolous fungi of the characterised by effuse colonies, holoblastic conidiogenous cells and dictyosporous, pigmented conidia with a pore in each cell. Study of additional new collections, cultures and DNA sequence data revealed several unknown species, which are proposed as taxonomic novelties in the and closely related . , and are described from terrestrial, lentic and lotic habitats from New Zealand and France, respectively. New combinations are proposed for and . Relationships and systematics of the are discussed in the light of recent phylogenies and morphological patterns newly linked with the order through cultural studies.