Using more than 50 monosporic isolates ofN. vibrissa–like fungi mainly obtained from Japanese beach coasts, we investigated their molecularphylogeny, morphological characteristics, mating compatibility, nuclear behavior during sporeformation, and life cycles. Molecular phylogenetic analyses separated the examined strains intoseven clades. Each clade of fungi exhibited distinctive characteristics in fruitbodies and sporesproduced by culturing monokaryotic strains and mated dikaryotic strains; these characteristicsincluded the color of fruitbodies, apical structure of peridial hair hyphae, spore shape, and apicalstructure of spore appendages. Mating tests of monokaryotic strains demonstrated mating com-patibility between strains within a clade and incompatibility among clades. Therefore, each cladeof fungi was phylogenetically, morphologically, and biologically recognized as a different Niaspecies.