Moss

The mosses are the largest of the three classes in the plant phylum Bryophyta. They have been divided into three subclasses: the true mosses (Bryideae), the peat mosses (Sphagnideae), and the granite mosses (Andreaeideae). The familiar small, green, and "leafy" moss plant is known as the gametophyte. This haploid multicellular phase is dominant in the moss life cycle. The mosses are the most broadly distributed of the three classes of bryophytes (which also includes liverworts and hornworts). There are more than 15,000 species of mosses worldwide.