Numerical analysis and computerized identification of the yeast genera Candida and Torulopsis

Abstract

Numerical analysis of the published standard descriptions of 104 species of Candida and 48 species of Torulopsis suggested that the number of species should be reduced to 78 and 33 respectively. Four examples are noted of closely matched species differing in ability to assimilate nitrate; these species may be combined as nitrate-variable species. Although the ability to form pseudomycelium is the only important difference between the genera, only three examples were noted of Candida and Torulopsis species sufficiently closely matched to be regarded as synonymous. Close relationships with species of the perfect genera were more common. A system, derived from the results of the analysis, is described for computerized identification of species of both genera.