An updated Checklist of the Bryophytes of Italy, including the Republic of San Marino and Vatican City State

The present contribution offers an updated inventory of recorded bryophyte species for Italy, providing the regional distribution for each one. The checklist is based on literature data, revision of bryological collections from several Italian and foreign institutional or private herbaria and recent observations and reports. Five categories based on Natural Breaks have been identified to highlight the floristic diversity between the administrative regions. The checklist includes 1273 taxa (1220 species, 17 subspecies and 36 varieties). Among these, hornworts and liverworts are represented by 301 species, 5 subspecies and 4 varieties, grouped into 99 genera and 55 families, while mosses total 919 species, 12 subspecies and 32 varieties, grouped into 259 genera and 77 families. Such data is presented by a table distinguishing their presence before and after 1968, as well as indicating dubious species based on information relating to bibliographic data. Critical notes on distribution and taxonomy are included and, for ease of reference, synonyms are given for each species. In the last three years, the bryoflora of Italy has increased by 29 taxa. The analysis of the data showed that the regions with the highest peaks of the Alpine chain are the ones with the greatest biodiversity. Among the Apennine regions, Tuscany is the most floristically rich. Sardinia and Sicily have medium levels of biodiversity, favoured by their geomorphological diversity and insularity. For some regions, the low bryophyte richness is linked to the lack of research. Furthermore, the trend of scientific publications on bryophytes over the last 200 years is highlighted.