Gametangia surrounded by jacket layer of sterile cells. These are the simplest of the true land plants. Water-conducting cells never contain lignin. Sporophyte usually inconspicuous, seta short, sporangium containing elaters mixed with spores. Division Anthocerotophyta - hornworts Chloroplasts occur singly in cells and contain pyrenoids.
Sporangium is long and hornlike.
This is a very small group of only about five genera. Gametophyte begins as a algae-like, filamentous protonema. Leafy buds growing from the protonema become the familiar moss plants. Sporophytes are more obvious than in liverworts, due to their usually elongate setae. The sporophyte is covered by an operculum, which detaches at maturity.