False-colour scanning electron micrograph of aerial sporangia formed on the somatic mycelium of the mould IRhizopus sexualis i as part of its asexual life cycle. The sexual phase of the life cycle is initiated by directional growth of two hyphae towards one another. On contact their tips become distended to form progametangia which fuse together. Eventually they form a zygosporangium which can then develop a germ sporangium. The latter releases spores (sporangiospores) which germinate to produce more mycelium and sporangia (as here). IR. sexualis i develops a fluffy mycelium of white hyphae on bread, fruit and other foods. Magnification: x24 at 35mm size.