The ascomycete Neurospora crassa, which is frequently used for genetic investigations, produces three reproductive structures on its haploid mycelium: Macroconidia, which serve vegetative dissemination; microconidia, which additionally take on a sexual function; and protoperithecia, which have only a sexual function. The film documents the most important phases of the life cycle, in part by means of time-lapse photography. Mycelial growth, macroconidia, and ascospore germination; development of the perithecia, different developmental phases of hooks and asci. The results of the crossing experiments between the black-pored wild type and the colourless mutant is included.