The Classification of Taphrina and Other Fungi with Yeast-like Cultural States

ABSTRACTTEM studies show that species of Taphrina and Protomyces have cell walls with a thick, electron-transparent inner layer, similar to those of the Endomycetales, e.g., of species of Saccharomyces or Hanseniaspora. The budding is holoblastic at the attenuated end or ends of the cell and is rather similar to that of the apiculate yeasts. Members of the genera Microstroma and Exobasidium have an electron opaque, often multilayered cell wall and show enteroblastic budding, similar to that of the “red yeasts” (Sporobolomycetales) and Ustilaginales. The Taphrinales are consequently classified in the Endomycetes (Ascomycotina), while Microstroma and Exobasidium are placed in the Basidiomycetes. Species of the genera Kabatiella and Aureobasidium have ascomycete-like cell walls, and are therefore not related to Microstroma. The classes of the Ascomycotina and Basidiomycotina are discussed briefly.Key Words: TaphrinaProtomycesMicrostromaExobasidiumclassificationultrastructure