<P> Antheridia are present in the gametophyte phase of cryptogams like bryophytes and ferns . Many algae and some fungi, for example ascomycetes and water moulds, also have antheridia during their reproductive stages . In gymnosperms and angiosperms, the male gametophytes have been reduced to pollen grains and in most of these the antheridia have been reduced to a single generative cell within the pollen grain . During pollination, this generative cell divides and gives rise to sperm cells . </P> <P> The female counterpart to the antheridium in cryptogams is the archegonium, and in flowering plants is the gynoecium . </P> <P> An antheridium typically consists of sterile cells and spermatogenous tissue . The sterile cells may form a central support structure or surround the spermatogenous tissue as a protective jacket . The spermatogenous cells give rise to spermatids via mitotic cell division . In some bryophytes, the antheridium is borne on an antheridiophore, a stalk - like structure that carries the antheridium at its apex . </P> <Ul> <Li> <P> Oogonium (larger) and antheridium (with red centre) of the alga Chara, produced on the stem of a plant </P> </Li> <Li> Magnified view of developing antheridia in Hypnum cupressiforme </Li> <Li> <P> "Moss flowers": each shoot has a cluster of antheridia, i.e., an androecium . </P> </Li> <Li> <P> Sperm of the liverwort Marchantia polymorpha are produced on the upper surface of antheridiophores . </P> </Li> </Ul>

The antheridium and archegonium are part of what generation