Figure 3 from: Just A, Gourvil J, Millet J, Boullet V, Milon T, Mandon I, Dutrève B (2015) SIFlore, a dataset of geographical distribution of vascular plants covering five centuries of knowledge in France: Results of a collaborative project coordinated by the Federation of the National Botanical Conservatories. PhytoKeys 56: 47-60. https://doi.org/10.3897/phytokeys.56.5723

Figure 3 - Density of cells by richness of observed species: looking at the distribution within the dataset, it appears that cells with less than 250 distinct species recorded are over-represented.