thumb|Close up of mold on a strawberry thumb|Penicillium mold growing on a clementine A mold () or mould () is one of the structures that certain fungi can form. The dust-like, colored appearance of molds is due to the formation of spores containing fungal secondary metabolites. The spores are the dispersal units of the fungi. Not all fungi form molds. Some fungi form mushrooms; others grow as single cells and are called microfungi (for example yeasts).
thumb|close up of mold on a strawberry thumb|penicillium mold growing on a clementine a mold () or mould () is one of the structures that certain fungi can form the dust-like colored appearance of molds is due to the formation of spores containing fungal secondary metabolites the spores are the dispersal units of the fungi not all fungi form molds some fungi form mushrooms; others grow as single cells and are called microfungi (for example yeasts)