A protonema (plural: protonemata) is a thread-like chain of cells that forms the earliest stage (the haploid phase) of a bryophyte or pteridophyte life cycle. When a moss first grows from the spore, it grows as a protonema which develops into a leafy gametophore. Hornworts do not have a protonemal stage, the spores germinate directly into a new Gametophyte generation.
Species taxanomy provided by GBIF Secretariat (2022). GBIF Backbone Taxonomy. Checklist dataset https://doi.org/10.15468/39omei accessed via GBIF.org on 2023-06-13; License: CC BY 4.0