zygospore

A zygospore is a thick-walled spore found in some algae and fungi. It is formed by the union of two similar sexual cells and typically functions as a resting spore, eventually producing the sporophytic phase.1

In the life cycle of sexually reproducing fungi, a haploid phase alternates with a diploid phase. The diploid phase begins with the formation of a zygote, which results from the fusion of two haploid sex cells (gametes). This fusion of nuclei is called karyogamy, and the resulting cell is the zygote. In most fungi, the zygote is the only diploid cell in the entire life cycle. After karyogamy, meiosis typically occurs, restoring the haploid state and initiating the haploid phase, which produces gametes.23