protonema
/ˌproʊtəˈniːmə/
noun
- A thread-like structure that grows from a moss or liverwort spore and develops into the mature plant.
- The moss spore first grows into a green, branching protonema before forming leafy shoots.
- Under the microscope, the protonema looks like a network of thin green threads.
- The protonema stage is an important part of the life cycle of many bryophytes.