A series of comparative physiological and morphological analyses are described for eighteen Dendryphiella isolates. Conidial characteristics of ten isolates showed relatively little variation as a result of different incubation conditions. Isolates were markedly tolerant to NaCl and KCl, although some variation between isolates was noted. A variety of nitrogen compounds could be utilized by most isolates although some grew poorly with certain nitrogen sources. Most isolates showed a wide pH growth range, particularly at alkaline values, and broad temperature growth profiles. The relevance of these physiological characteristics to the survival and fitness of Dendryphiella species in the marine environment is discussed.