Penicillium fungus growing on orange rind, Light micrograph of a section through an orange rind (blue) infected with a Penicillium sp. fungus, showing the conidiophores (stalk-like), from which the fungal spores (conidia) are produced. Penicillium is important as some members of the genus produce the antibiotic penicillin. Magnification: x37 when printed 10 centimetres wide.