gametangium

noun

1. A gamete-producing organ or cell found in many multicellular protists, algae and fungi, and in the gametophytes of plants.

   “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.”