Discovery of British and Irish bryophytes 2. Publication of finds in floras, checklists and papers, 1690–2021.

Introduction: The knowledge of British and Irish bryophytes has been summarised at intervals since 1690 in national floras and checklists. The number of species and varieties recognised in these works can be used to track the discovery of British and Irish bryophytes. Methods: The main floras and checklists were identified, and the taxa recognised in twenty of them counted and their identity assessed in relation to the current (2021) checklist. Key results: The number of known bryophytes increased rapidly after the publication of Ray's Synopsis (1690). Dillenius's (1741) Historia muscorum brought together all previous reports. His polynomials were the main source for Linnaeus's binomial names in Species plantarum (1753). Linnaeus cut the number of British and Irish species from 179 to 119, omitting those that seemed to him obscure. It was clumsily done, and William Hudson (1762), in Flora Anglica, increased the number to 139, with 51 varieties, of which 37 are now treated as species. His contemporary Richard Pulteney made an early attempt to trace first records in a manuscript compiled ca. 1789. We agree with 134 of Pulteney's first records, but disagree with 88. All the historic lists contain redundancies – species that were then thought distinct but are now lumped together, the maximum being Smith's (1804) Flora Britannica, with 62. From 1855 to 1930 numerous varieties were recognised. These peaked at 309 moss varieties in Duncan's (1926) checklist and 117 liverworts in Wilson's (1930) checklist. In 2021 they have shrunk to 33 moss varieties and 9 liverworts. [ABSTRACT FROM AUTHOR]