[Opportunistic fungi as producers of gray colonies and mycetomata].

Madurella grisea Mackinnon, Ferrada and Montemayor, 1949, is not the unique species that produces gray colonies and black-grained mycetomata. Perhaps, it is not one species, because its grains and colonies may be confounded with those of several species that can be distinguished through their fertile structures. I take this opportunity to compare some characters of Pyrenochaeta romeroi, Phoma-Phillosticta sp., Chaetosphaeronema larense, Pyrenochaeta mackinnonii, Plendomus avramii and of another aleurisopores Dematiacea with those assigned to Madurella grisea. The need is stressed for the search, the introduction and the divulgation of new methods fostering the formation of disseminating structures (pycnidospores in this case), in order to ensure the proper specification of the agent in every case of mycetoma.