Antheridium

Antheridium, the male reproductive organs of many cryptogams (Ferns, Horsetails, Mosses, &c., q.v.). They may consist of a single cell, but are usually multicellular sacs, within which the thread-like male reproductive elements or antherozoids are produced. These are liberated by the rupture of the antheridium wall, and the antherozoid is enabled, by means of the lashing movement of its cilia, to reach and descend the tubular passage of the archegonium to the female cell, which it is its function to fertilise. See ALGÆ, FERN.