The main plant body of Ulothrix (a green algae) is haploid (unicell). It produces male and female gametes, union between male and female gametes results a diploid structure, called the zygote. Zygote is only a diploid stage found in the life cycle of Ulothrix. First division in zygote is of meiotic type and it produces four haploid meiozoospores. Which under favourable condition increases their size and become young Ulothrix.