A multicellular plant gametangium (PO:0025124) that develops from an archegonium initial cell (PO:0025510) and has as parts a venter (PO:0030038) and an archegonium neck (PO:0030039). [source: ISBN:0521794331, POC:curators]
Comment
At maturity, the archegonium produces an archegonium egg cell (PO:0025122). In mosses, the archegonium also has part an archegonium stalk (PO:0030036). The archegonium (PO:0025126) occurs in bryophytes and pteridophytes, but never in angiosperms, where the female gamete (plant egg cell; PO:0020094) is produced by the embryo sac (PO:0025074), a specialized (reduced) gametangium.