New filobasidiaceous yeasts found in the phylloplane of a fern.

Nitrate-positive strains of anamorphic yeasts representing the genus Cryptococcus were isolated on fern infusion agar from Athyrium filix-femina. Phylogenetic analyses of the D1/D2 domain of the LSU rRNA and of the ITS region placed them in Cylindricus clade in the Filobasidiales. Morphological and physiological characteristics, as well as mycocinotyping and molecular analysis, show a close affinity between strains. Subsequent comparative studies of new isolates revealed that they were not conspecific with any other known Cryptococcus species, and the cultures represented an undescribed species with two varieties, for which the names Cryptococcus filicatus var. filicatus (type strain VKM Y-2954 = CBS 10874) and Cryptococcus filicatus var. pelliculosus (type strain VKM Y-2955 = CBS 10875) are proposed.