C. P. Kurtzman's evolving concepts of species, genus and higher categories

Cletus P. Kurtzman transformed the way yeast systematists practice their trade and how they perceive the yeast species. He redefined many genera of ascomycetous yeasts and provided a sound basis upon which to base higher taxonomic categories. Within his extraordinary corpus lies a trail of elements that can be used to reconstruct his evolving vision of the concepts that underlie the species and the genus, rarely set in a theoretical framework. While occasionally tipping his hat to the biological and phylogenetic species, Kurtzman espoused a concept founded primarily on genetic distance, even when claiming otherwise. In contrast, his notion of genus incorporated components of both genetic distance and phylogenetic structure, and possibly a size consideration. A phylogenetic approach predominated with higher taxa.