Sexual reproduction is a fundamental process in plants that involves the production of egg and sperm followed by their fusion to form a zygote, which then divides and eventually develops into a new plant. Sexual reproduction in flowering plants involves four sequential processes: sporogenesis, game-togenesis, pollination, and fertilization, all of which occur within the reproductive organs (the anthers and ovules) of the flower. Anthers are the site of (male) pollen formation, and ovules are the site of (female) egg formation.

Seed spores along the ribs of a fern leaf.

Sporogenesis and Gametogenesis

Sporogenesis, or spore formation, begins with the differentiation of specialized spore mother cells within the anthers and ovules. The spore mother cells are unique because they undergo meiosis, a division that reduces the chromosome number by one-half, or from diploid to haploid. The haploid spores produced by meiosis in the anthers are called microspores...