The Collaborative International Dictionary
Prothalli
Prothallus \Pro*thal"lus\, n.; pl. Prothalli. [NL., fr. Gr. ? before + ? a young shoot.] (Bot.) The minute primary growth from the spore of ferns and other Pteridophyta, which bears the true sexual organs; the o["o]phoric generation of ferns, etc.
Wiktionary
prothalli
n. (plural of prothallus English)
WordNet
prothalli
See prothallus