Plural antheridia (ān'thə-rĭd'ē-ə)
An organ in certain organisms that produces male gametes. Antheridia are found in many groups of organisms, including the bryophytes, ferns, ascomycete fungi, and some algae. Most gymnosperms and all angiosperms, however, have lost the antheridium, and its role is filled by the pollen grain. Compare archegonium.