Word Study
prothallus
CIDE DICTIONARY
prothallus, n. [NL., fr. Gr. before + a young shoot.].
The minute primary growth from the spore of ferns and other Pteridophyta, which bears the true sexual organs; the oöphoric generation of ferns, etc. [1913 Webster]
OXFORD DICTIONARY
prothallus, n. (pl. prothalli) Bot. the gametophyte of certain plants, esp. a fern.
Etymology
mod.L f. PRO-(2) + Gk thallos green shoot
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