A new checklist of the bryophytes of Britain and Ireland, 2020

Introduction. Many taxa have been added to the bryophyte flora of Britain and Ireland since the publication of the previous checklist in 2008. This has coincided with numerous taxonomic and nomenclatural changes in the European flora, especially as a consequence of molecular sequencing. With the publication of a new European checklist in 2020 it is now appropriate to provide an updated and annotated list for Britain and Ireland.Methods. A working group was convened to consider and reach a consensus on taxonomic and nomenclatural matters arising from the European checklist. Special consideration was given to the citation of the authors of names. Taxa reported as new to Britain and Ireland since the previous checklist in 2008 were incorporated.Key results. A new checklist of bryophytes (hornworts, liverworts and mosses) is presented. Based on the taxonomy adopted in the checklist, the bryophyte flora of Britain and Ireland comprises four hornworts (Anthocerotophyta), 299 liverworts (Marchantiophyta), and 795 mosses (Bryophyta) at species rank, with 42 additional infraspecific taxa.