Keys are provided to 54 genera, 142 species, 6 infraspecific taxa, and 3 undescribed species of California liverworts and hornworts within 33 families. In addition, 3 genera and 16 species previously reported have been excluded from the California bryoflora. The keys emphasize gametophytic characters. Annotated comments for each species focus on what to look for and how to separate it from species with similar morphology. The worldwide and California distribution of each species is provided.