pro·to·ne·ma 
(prō′tə-nēmə)
(prō′tə-nēmə)n. pl. pro·to·ne·ma·ta (-nēmə-tə, -nĕmə-)
The filamentous growth that arises following spore germination in liverworts and mosses and develops into a mature gametophyte.
[PROTO- + Greek nēma, thread; see (s)nē- in the Appendix of Indo-European roots.]
pro′to·nemal (-nēməl), pro′to·nema·tal (-nēmə-təl, -nĕmə-) adj.