A critical assessment of criteria used in the taxonomy of the genus Rhizopus

Abstract

Scanning electron microscopy (SEM) and cultural physiology data have been used to assess their taxonomic applicability in delimiting species of the genus Rhizopus. SEM of the sporangiospores of a variety of isolates indicates that there is a continuum of patterns ranging from almost featureless surfaces to verruculose and deeply ridged or striated topologies. The degree of interspecific diversity was sufficient to reduce the diagnostic usefulness of this feature for interspecies delineation. Cultural characteristics, radial growth rate, sporulation pattern, and growth and viability at raised temperatures were also too variable for use in taxonomic studies.