Prothallus
Pronunciation : Pro*thal"lus
Part of Speech : n.;
Etymology : [NL., fr. Gr. (Bot.)
Definition : Defn: The minute primary growth from the spore of ferns and other Pteridophyta, which bears the true sexual organs; the o?phoric generation of ferns, etc.
pl. Prothalli.
Source : Webster's Unabridged Dictionary, 1913