“…In our laboratory we have attempted to evaluate critically the taxonomic characters that have been used by various authors to classify this group of fungi. The stability and range of variation of the characters have been tested under a number of different cultural conditions and nutrient regimes, including effects of carbon sources (Satour, Vlebster, and Hewitt, 1969a), nitrogen sources (Satour, Webster, and Hewitt, 1969b), pH, temperature, light, and vitamins (Hewitt, Webster, and Satour, 1971), carbon: nitrogen ratio (Webster, Hewitt, and Satour, 1971), natural substrates ; and the natural variation in Diplodia naialensis isolates from grape in California (Webster, Hewitt, and Polach, 1969) .…”