Meiosis occurs within the "zygospore" (see article Phycomyces). The zygosporangium typically contains a single zygospore. The two gametangia fuse to form an immature zygospore. It is also the fungus from which the term "zygospore" was coined. This zygospore appear black or grey in colour. The data from this cross provided supporting evidence for meiosis during zygospore development. During the course of zygospore maturation and dormancy, lasting several months, most nuclei are degraded. Initially the developing zygospore contains thousands of nuclei contributed by the gametangia. High humidity increases zygospore formation and low humidity increases sporangiophore formation. Historically, all fungi producing a zygospore were considered to be related and placed into Zygomycota. A zygospore is formed by the fusion of two gametes. Lower temperatures favor zygospore formation and higher temperatures favor sporangiophore production. The gametangium develops into a zygospore, a thick-walled spore formed by the union of gametes. Upon germination, a zygospore produces colonies that are genetically different from either parent.