Tectobasidium (incertae sedis, Basidiomycota), a new genus for T. chlamydosporum, comb. nov., and T. cornutum, sp. nov

Abstract A new genus, Tectobasidium , is described to accommodate T. chlamydosporum , comb. nov. (= Achroomyces chlamydosporus ), and T. cornutum , sp. nov. Both species possess two-celled basidia and cylindrical basidiospores, as well as characteristic, thick-walled and cyanophilous chlamydospores. Tectobasidium spp. develop in the living basidiocarps of other basidiomycetes ( Helicogloea and Myxarium ) as intrahymenial fungi. No signs of the parasitic habit have been detected for them, although a mycoparasitic strategy cannot be completely ruled out. nc LSU rDNA-based phylogenetic inference places Tectobasidium at the very base of the subphylum Ustilaginomycotina , with moderate (BI) or strong (ML) support. Due to the lack of additional DNA, ultrastructural, and cultural data, we leave the suprageneric classification of Tectobasidium unresolved.