Conceptacle

[4] The diploid plants produce male (antheridia) and female (oogonia) gametangia by meiosis.

The gametes are released into the surrounding water; after fusion, the zygote settles and begins growth.

[9] Some conceptacles form by the centripetal expansion of a hole near the thallus surface; in such cases, a roof forms by nearby filaments arching over and establishing themselves as short (often 1–9 cells long)[10][11] filaments that cover the chamber, leaving a central pore through which the spores can escape.

[8] There are a range of different conceptacles, classified according to the nature of the spores that they contain; some species may possess as many as four distinct types.

[8] L. incrustans has distinct male and female plants; the two conceptacle types never co-occur on the same thallus.

[12] These are not associated with tissue demineralization; rather, they start to form at the centre (as a female conceptacle) and develop radially.

[8] In most coralline algae, a cluster of reproductive cells forms in the middle layer of the alga, and is engulfed by the surrounding tissue, which grows up and over the reproductive cells to form a roof and a uniporate conceptacle.

[13] However the conceptacle may originate at any depth within the thallus, at the surface layer or at the basal perithallus.

Similar structures have been noted in Prototaxites, which would imply that this giant land organism was not a simple fungus (as most paleontologists assume today) but a lichen.