"Fern prothallus; cross-sections showing antheridia (an), sperms (sp), and rhizoids (rh). Below at the right is a sperm (sp) greatly enlarged." -Gager, 1916

Fern Prothallus

"Fern prothallus; cross-sections showing antheridia (an), sperms (sp), and rhizoids (rh). Below at the…