Noun
The male reproductive apparatus in the lower, consisting of a cell or other cavity in which spermatozoids are produced; -- called also spermary.
Source: Webster's dictionaryA very fine hypha, called trichogyne emerges from one gametangium, the ascogonium, and merges with a gametangium (the antheridium) of the other fungal isolate. Source: Internet
The nuclei in the antheridium then migrate into the ascogonium, and plasmogamy —the mixing of the cytoplasm —occurs. Source: Internet