The phylogenetic relationships among fungi that cause spring dead spot disease of Bermuda grass in Australia and the United States were studied from nucleotide sequence data of the ITS region of the rDNA. High levels of sequence similarity were observed among Ophiosphaerella herpotricha, O. korrae and Leptosphaeria narmari. These species clustered into a distinct clade that was distant from other Leptosphaeria and Phaeosphaeria species. Based on sequence data and previous descriptions of the ascoma and ascospore characteristics of these species, we propose a taxonomic transfer of L. narmari to O. narmari. Oligonucleotide primers specific for O. narmari were developed from ITS1 and ITS2 regions to help identify non-sporulating isolates. These primers amplified all isolates of O. narmari, including those from the United States, but not those of O. herpotricha, O. korrae or other ectotrophic root-inhabiting fungi. This is the first report of O. narmari in North America. Two Group I introns were found in the small subunit rDNA of some isolates of O. korrae and O. narmari, but not O. herpotricha. A 425-nucleotide intron in O. narmari and O. korrae was inserted two nucleotides downstream from the ITS5 conserved primer sequence. These introns exhibited an 80% sequence identity. In addition, a second 431-nucleotide intron in O. narmari was similar in size and location to one in O. korrae.