| Because the egg is retained and fertilized within the archegonium, the early stages of the developing sporophyte are protected and nourished by the gametophytic tissue. |
| The axis of the embryo is inclined to that of the archegonium and may be almost at right angles. |
| The young sporogonium is protected by a thick calyptra derived from the tissue of the thallus around the archegonium. |
| An archegonium consists of neck cells and a large egg cell. |
| In all the Archegoniate fertilization and the first critical phases of embryogeny occur within the shelter provided by the archegonium and the adjacent gametophytic tissue. |
| When the sporophyte has developed all three regions, the seta elongates, pushing its way out of the archegonium and rupturing it. |
