Conceptacles are specialised cavities that contain the reproductive organs of certain algae. They are contained in the receptacles and open by a small ostiole. Specifically, conceptacles are known to be present in Corallinaceae, and some other red algae, as well as the brown fucales. In the Fucales there is no haploid phase in the reproductive cycle and therefore no alternation of generations. The thallus is a sporophyte. The diploid plants produce male (antheridia) and female (oogonia) gametangia by meiosis. The gametes are released into the sea, after fusion the zygote settles and begins growth.