Taxonomy and developmental morphology of Rogersiomyces malaysianus comb. nov. (Cantharellales, Agaricomycetes).

A basidiomycete fungus from Vietnam, grown in a moist chamber on bark (as substrate) was identified as Hyphobasidiofera malaysiana. The isolation of this fungus into axenic culture allowed for investigations such as culture morphology, large and small subunit molecular phylogenies, life cycle karyology, and mating experiments. Comparative morphological data revealed that this species belongs to Rogersiomyces and the name Rogersiomyces malaysianus comb. nov. is proposed. Molecular studies revealed close relationships of Rogersiomyces, Sistotrema sensu lato, and Hydnum sensu stricto (Cantharellales, Agaricomycetes). The fungus produces binucleate basidiospores that germinate to form clamped and dikaryotic mycelium. The cultural characters and reproductive structures of this unusual sistotremoid fungus are described. It was concluded that the characteristic of dikaryotization into basidium, ephemeral basidiomata, and statismosporic basidia represent an adaptation of this fungus to irregular, but plentiful moistening during monsoon climate. [ABSTRACT FROM AUTHOR]