Life cycle of Rhizopus stolonifer, a black bread mold

1 A haploid mycelium grows in size and reproduces asexually by mitotic production of spores in sporangia atop specialized hyphae.
2 When hyphae of different mating strains (+ and —) come into close proximity, they produce branches (gametangia) that grow toward one another.
3 Cytoplasmic fusion of the gametangia produces a dikaryotic zygospore, a structure that contains haploid nuclei from both parents.
4 Fusion of nuclei produces a mature zygospore containing diploid cells.
5 The zygospore undergoes meiosis, germinates, and produces an aerial hypha with haploid spores at its tip.