The diplontic life cycle is found in the Sargassum in which there is no alternation of generation. The diploid sporophytic phase represents the dominant vegetative plant body. It develops antheridia and oogonia on specific conceptacles. Meiosis occurs during the gametes formation the ovum and sperms represent the gametophytic phase which then fuses to form diploid zygote. The diploid zygote germinates forming diploid thallus so the life cycle is known as the diplontic life cycle.