ABSTRACT
The genus Penicillium consists of about 250 species. Most species are anamorphic because their sexual cycle is unknown. It can however be expected that many of these anamorphic species do carry mating type genes and are able to mate, as was recently shown for Penicillium roqueforti [1]. The sexual reproductive species corresponding to Penicillium are Eupenicillium and Talaromyces. Species of both genera are nutritionally undemanding and can be found especially in low-water activity foods. Penicillium belongs to the order Eurotiales and the family Trichocomaceae and to this family belong also Aspergillus and Paecilomyces. Whereas the morphology of the conidiophore of Aspergillus is quite different to Penicillium, Paecilomyces has a similar conidiophore structure; however, it is less densely organized and the conidia are more ellipsoidal than Penicillium. Because of these morphological similarities, Paecilomyces was formerly grouped with Penicillium.
