C. Longitudinal section of antheridium; st, stalk; w, wall.
"Encyclopaedia Britannica, 11th Edition, Volume 4, Part 3" by Various
It is called an "antheridium," and within are produced, by internal division, numerous excessively small spermatozoids.
"Elements of Structural and Systematic Botany" by Douglas Houghton Campbell
These particles become globose cells, grouped in the centre of the antheridium.
"Fungi: Their Nature and Uses" by Mordecai Cubitt Cooke
A bursting antheridium, and some of the accompanying jointed threads, highly magnified.
"The Elements of Botany" by Asa Gray