Scanning electron micrograph (SEM) the fruiting bodies or conidia of a penicillin fungus growing on a piece of English cheddar cheese which has gone mouldy in the refrigerator. The fungus (Penicillium sp. ) grows as a mycelium of hyphal threads on and within the cheese, sending out branches or conidiophores, which bear from their tips the conidia (tuft-like clusters). The conidia resemble beads strung together in a chain. Once ripe, each bead can germinate into a new organism. Fungal colouring is determined by the conidioph- ore, which in penicillin is green. The mycelium is colourless. Magnification: X 185 at 35mm size, X 1300 at 8x10 inch size.