mould

A fungus that produces a distinct mycelium or spore mass, which often resembles a velvet-like pad, on the surface of its host. Moulds frequently occur on dead or decaying vegetable matter, such as food or stored fruits. Common examples are white bread mould (Mucor) and blue and green moulds of citrus fruit (Penicillium italicum and P. digitatum). See also Mucorales , Hyphomycetales , Eurotiales.