Plants, with an estimated 300,000 species, provide crucial primary production and
ecosystem structure. To date, our quantitative understanding of diversity gradients of
megadiverse clades such as plants has been hampered by the paucity of distribution data.
Here, we investigate the global-scale species-richness pattern of vascular plants and
examine its environmental and potential historical determinants. Across 1,032 geographic
regions worldwide, potential evapotranspiration, the number of wet days per year, and …