What is the difference between Primary protonema and secondary protonema? Plz let me know whether it is primary protonema or secondary protonema that gives rise to Leafy stage in the life cycle of mosses?

Hi, Kenny Toijam
Protonema is a filaentous thread-like (chain) of cells.
these first formed protonema is called primary and its branches are called as secondary.
go through the imge attached for furhter information.
These are formed during the early stages of (the haploid phase or sexual part like seed) plant growht of largely seen in plant sub kingdoms such as Bryophytes and Pteridophytes plant life cycle.
When a mossor a fern first froms protonema from the spore,
it grows as a protonema which develops into a leafy gametophore (vegetative structure)

Primary protonema is only responsible for germination of spore whereas secondary protonema helps in the whole development of gametophytic part of plant