Phylogenetic relationships and reclassification of Spirosphaera lignicola, an enigmatic aeroaquatic fungus

The enigmatic Spirosphaera lignicola is revised based on recent collections from Austria. The taxon does not fit the generic circumscription of the genus Spirosphaera in its morphological features but clearly belongs to Dendroclathra. Nuclear ITS rDNA sequence data from recent collections and the type specimens indicate conspecificity of S. lignicola with Dendroclathra caeruleofusca. Spirosphaera lignicola is transferred to the genus Dendroclathra, and a recent collection with an ITS sequence identical to the type specimen is designated as epitype. Morphology is illustrated with SEM and LM pictures. Phylogenetic analyses of LSU, ITS and tef1 sequence data reveal a phylogenetic affinity of Dendroclathra to the Microascales (Hypocreomycetidae), being therefore phylogenetically distant from Spirosphaera floriformis, the generic type, which belongs to the Leotiomycetes. The recent collections are the first records of this species for Austria. The distribution and aeroaquatic ecology of D. lignicola are briefly discussed.