Penicillium. Coloured scanning electron micrograph (SEM) of the mycelium and fruiting bodies of the fungus Penicillium sp. Penicillin mould grows as a mycelium of hyphal threads, as seen here in the background. In the foreground (centre) is a hyphal branch which bears fruiting bodies at its tip, known as conidia. These tuft-like clusters of conidia contain rounded spores strung together in chains. Once ripe, each spore can germinate into a new fungus. Species of Penicillium are the source of antibiotic penicillin for use as drugs to combat bacterial infection. They are also used in the fermentation of roquefort and camembert cheeses. Magnification: x620 at 6x7cm size.