The female sex organ in bryophytes (mosses, liverworts, hornworts) is the archegonium (plural: archegonia) — a flask-shaped multicellular structure with a swollen base (venter) containing the egg cell and a long neck through which the sperm travels for fertilisation. The antheridium is the male sex organ producing sperm. Carpogonium is the female sex organ of red algae; ascogonium is found in ascomycete fungi.