Taxonomy, nomenclature and phylogeny of three cladosporium-like hyphomycetes, Sorocybe resinae, Seifertia azaleae and the Hormoconis anamorph of Amorphotheca resinae.

Using morphological characters, cultural characters, large subunit and internal transcribed spacer rDNA (ITS) sequences, and provisions of the International Code of Botanical Nomenclature, this paper attempts to resolve the taxonomic and nomenclatural confusion surrounding three species of cladosporium-like hyphomycetes. The type specimen of Hormodendrum resinae, the basis for the use of the epithet resinae for the creosote fungus {either as Hormoconis resinae or Cladosporium resinae) represents the mononematous synanamorph of the synnematous, resinicolous fungus Sorocybe resinae. The phylogenetic relationships of the creosote fungus, which is the anamorph of Amorphotheca resinae, are with the family Myxotrichaceae, whereas S. resinae is related to Capronia (Chaetothyriales, Herpotrichiellaceae). Our data support the segregation of Pycnostysanus azaleae, the cause of bud blast of rhododendrons, in the recently described anamorph genus Seifertia, distinct from Sorocybe; this species is related to the Dothideomycetes but its exact phylogenetic placement is uncertain. To formally stabilize the name of the anamorph of the creosote fungus, conservation of Hormodendrum resinae with a new holotype should be considered. The paraphyly of the family Myxotrichaceae with the Amorphothecaceae suggested by ITS sequences should be confirmed with additional genes.