Phytosociological data were collected to describe the terrestrial lichen and bryophyte vegetation of rock or saxicolous habitats within 14 Special Areas of Conservation (SAC) within upland Britain, with special reference to four saxicolous habitats listed in Annex I of the EU Habitats Directive. Additional data were available from other surveys within upland Britain, giving a total of 1539 releves available for analysis.
Data were analysed using TWINSPAN, combined with manual sorting. A total of 83 communities were distinguished, including 56 on siliceous rock and 27 on limestone. A description and floristic table is provided for each community, along with a key for the placement of individual releves is provided. As is commonly experienced in phytosociological work, delimitation of communities was not straightforward; this was attributed to the existence of variation in composition of vegetation in response to many independent environmental variables, precluding a simple system of classification. Despite these problems, the classification proposed is a major advance on earlier phytosociological knowledge of the lower plant communities of the British uplands.