protonema

noun

pro·​to·​ne·​ma ˌprō-tə-ˈnē-mə 

plural protonemata ˌprō-tə-ˈnē-mə-tə 

-ˈne-

: the primary usually filamentous thalloid stage of the gametophyte in mosses and in some liverworts comparable to the prothallus in ferns

protonemal

ˌprō-tə-ˈnē-məl 

adjective

protonematal

ˌprō-tə-ˈnē-mə-tᵊl  -ˈne- 

adjective

Word History

Etymology

New Latin protonemat-, protonema, from prot- + Greek nēma thread — more at nemat-

First Known Use

1857, in the meaning defined above