Forest, F.; Brown, R.; Buerki, S.; Colville, J. F.; Moat, J.; Lughadha, E. N.; Owen, N. R.; Raimondo, D. C.; Rivers, M.; Rosindell, J.; Walker, B. E.; Bachman, S. P.; Pipins, S.; Gumbs, R.; Brown, M. J. M.

Extinction results in not only loss of species, but also loss of the unique evolutionary history that they represent and the irreplaceable features they exhibit. There is broad consensus regarding the necessity to optimise the preservation of the tree of life by including evolutionary information in conservation prioritisation, a notion also endorsed by major policy frameworks. However, evolutionarily-informed prioritisations are lacking for most plants, resulting in a taxonomic imbalance in the evolutionary information incorporated in global biodiversity analyses, which has undermined conservation for decades. Here, we use comprehensive species-level phylogenetic trees, and extinction risk estimates, to generate the first global assessment of angiosperm evolutionary history at risk, and to identify phylogenetically-informed conservation priorities for the world's flowering plants. We estimate that more than one fifth of angiosperm evolutionary history is at risk of extinction in the short term. Using the Evolutionarily Distinct and Globally Endangered approach, we identify 9,945 threatened plant species that disproportionately account for total evolutionary history at risk. Species and area prioritisations incorporating evolutionary history are urgently needed to correct imbalances between plants and animals, monitor the effectiveness of conservation efforts, and optimise conservation resource allocation in the face of increasing human pressures on Earth's biodiversity.