1. Phenotypic characterizations:
The classification of actinomycete was originally based largely upon the morphological observations. So,morphology is still an important characteristic for the description of taxa and it is not adequate in itself to differentiate between many genera. In fact, it was the only characteristic which was used in many early descriptions, particularly of Streptomyces species in the first few editions of Bergey's Manual. These observations are best made by the variety of standard cultivation media. Several of the media suggested for the International Streptomyces Project (Shirling and Gottlieb, 1966) and by Pridham et al. (1957) have proven to be useful in our hands for the characterization of strains accessioned into the ARS Actinomycetales Culture Collection (Labeda, 1985). It iincludes some basic tests. Aerial mass colour, Reverse side pigment, Melanoid pigments, Spore chain morphology and Spore morphology.