| Abstract: | Black fungi, belonging to the Dematiaceae, with yeast-like growth patterns, were isolated from rock surfaces in the Mediterranean. They tolerate high temperatures and sodium chloride stress although they are neither thermophilic nor halophilic organisms. Environmental stress factors not only affect growth velocity of the fungi but also the colony shape. A shift of the smooth and flat colonies developed under optimal culture conditions to more clump-like growth similar to the colony shape on the natural rock substratum is caused by both high temperature and osmotic stress. The “principle of uniformity” is proposed as a new term to interpret specific morphotypes of pleomorphic fungi of different taxonomic assignment. |
