 These plants start as a haploid spore that grows into the dominant form, which is a multicellular haploid body with leaf-like structures that photosynthesize.Haploid gametes are produced in antheridia and archegonia by mitosis.The sperm released from the antheridia respond to chemicals released by ripe archegonia and swim to them in a film of water and fertilize the egg cells, thus producing zygotes that are diploid.