This dataset includes information on native eyebright plants (Euphrasia, Orobanchaceae) studied and measured at a range of sites across Britain and Ireland, with a special sampling focus on Fair Isle (Shetland, Scotland). Attributes measured are location information (Euphrasia species, coordinates and population description), individual plant trait data (including measures of floral and vegetative traits) and genome sizes. Full details about this dataset can be found at https://doi.org/10.5285/0a77d3b5-03ce-4a14-ab2d-acc4aa7bd0ef
