Two new Tricladium species from streams in Alaska.

Two new species of aquatic hyphomycetes in the genus Tricladium are described from streams in Alaska, USA. Both species were isolated from submerged decaying sedges. Tricladium kelleri has blackish colonies and typical tricladioid conidia formed on sympodial conidiogenous cells. Tricladium alaskense has conidia with fine elements and 0-4 lateral branches; conidia are formed on sympodial conidiogenous cells. The two species are compared to other species in the genus and related genera using morphological characters and/or rDNA sequencing data (ITS and 28S). Molecular phylogenetic analysis placed both species in the Helotiales.