Light micrograph of the fungus Epidermophyton floccosum showing septate hyphae (filaments) and macroconidia (dark blue). Hyphae are the branching, filamentous structures of a fungus, that in this species are separated by septa (walls) into cellular compartments. Macroconidia are large complex asexual spores (reproductive cells). This fungus causes superficial infections of the skin and nails and is one of several species responsible for ringworm, jock itch and athlete's foot.