Single-spore colonies of Diplodia natalensis P. Evans originating from individual pycnidia were compared with each other and with those from different pycnidia from the same grape cane, different canes from the same vineyard, and different vineyards, to evaluate the natural range in variation and stability of taxonomic characters currently used to delimit this species. Distinct colony types were recognized—in some cases as many as four originating from an individual pycnidium. Colony type per se is not considered to be useful for taxonomic purposes. Results suggest that several genera now recognized in this group are congeneric, and indicate a great need for determination of the inherent variation that these fungi are capable of exhibiting.
