Flexi Says: The diploid sporophyte has a structure called a sporangium (plural, sporangia) that undergoes meiosis to form haploid spores. These spores contain one cell that can become another new plant without mating. The gametophyte has male or female reproductive organs that undergo mitosis to form haploid gametes (sperm or eggs). Fertilization of gametes produces a diploid zygote. The zygote grows and develops into a mature sporophyte, and the cycle repeats.