Definition of "gametangium"

Gymnoascus and its allies; the gametangia are not much differentiated; both, like the mycelial cells, are multinucleate (it is difficult to gauge the significance of this character in Fungi) and the oogonium, or an outgrowth from it becomes septate after fertilization and gives rise to ascogenous hyphae.

2010, Helen Gwynne-Vaughan, Fungi: Ascomycetes, Ustilaginales, Uredinales, page 54