This booklet collected vernacular English names for British bryophytes. Though scientific species names are used and recognised worldwide, common names have been and will always be used, though not usually by bryologists. Examples include use in popular natural history publications, television or radio, nature trail pamphlets, museum galleries, and Acts of legislation. This fourth edition has nomenclatural, reference and text updates etc., and the following nett changes: British mosses: +22 taxa, +72 names; British liverworts: +9 taxa, +19 names; foreign mosses 0 taxa, +1 name; foreign liverworts: +1 taxon, +1 name; altogether 447 more record-units. Also note substantial dehyphenation of moss names, and new sections: Limit to this compilation [p. 7], Cryptic taxa [p. 6], and a new figure 1.