Phylogeny of Ophioceras spp. based on morphological and molecular data

Collections from freshwater habitats of un- described Ophioceras-like pyrenomycetes with scole- cosporous ascospores were characterized using mor- phological characters, restriction analysis of PCR am- plified rDNA, and 18S rDNA sequences. Five species of Ophioceras were resolved and one species was ex- cluded from the genus. Parsimony analysis of mor- phological characters did not resolve relationships among species of Ophioceras and Pseudohalonectria, two closely related freshwater genera. Based on phy- logenetic analysis of partial 18S rDNA sequences, spe- cies of Pseudohalonectria form a sister clade to Ophi- oceras thereby supporting the integrity but close re- lationship of these two freshwater genera. Gaeuman- nomyces graminis falls within the Ophioceras/ Pseudohalonectria clade and is a sister taxon to a spe-