Exceptional plant species: taxonomic standardization of 23,792 species to World Flora Online version 2023.12

While conservation in seed banks has been widely adopted, this technology cannot be applied to Exceptional Plant Species (species with desiccation intolerant seeds, short-lived seeds, unavailable seeds, or deeply dormant seeds). Pence et al. (2020a; 2020b) created a Global Working List of Exceptional Plants. The list was downloaded on 30th June 2025 from https://cincinnatizoo.org/exceptional-plant-conservation-network/global-working-list-of-exceptional-plants/. Here I provide a dataset where the listed species were standardized to World Flora Online (Borsch et al. 2020; taxonomic backbone version 2023.12) by matching names with those in the Agroforestry Species Switchboard (Kindt et al. 2025; version 4). Taxa for which no matches could be found were standardized with the WorldFlora package (Kindt 2020), using similar R scripts and the same taxonomic backbone data as those used to standardize species names for the Switchboard. For species listed in the Switchboard, the number of database sources and whether the species was identified as tree-like was added. References Pence, V.C., Meyer, A., Linsky, J., Gratzfeld, J., Pritchard, H.W., Westwood, M. and Bruns, E.B., 2022. Defining exceptional species—A conceptual framework to expand and advance ex situ conservation of plant diversity beyond conventional seed banking. Biological Conservation, 266, p.109440. https://doi.org/10.1016/j.biocon.2021.109440 Pence, V.C., Bruns, E.B., Meyer, A., Pritchard, H.W., Westwood, M., Linsky, J., Gratzfeld, J., Helm-Wallace, S., Liu, U., Rivers, M. and Beech, E., 2022. Gap analysis of exceptional species—Using a global list of exceptional plants to expand strategic ex situ conservation action beyond conventional seed banking. Biological Conservation, 266, p.109439. https://doi.org/10.1016/j.biocon.2021.109439 Borsch, T., Berendsohn, W., Dalcin, E., Delmas, M., Demissew, S., Elliott, A., Fritsch, P., Fuchs, A., Geltman, D., Güner, A., Haevermans, T., Knapp, S., le Roux, M.M., Loizeau, P.-A., Miller, C., Miller, J., Miller, J.T., Palese, R., Paton, A., Parnell, J., Pendry, C., Qin, H.-N., Sosa, V., Sosef, M., von Raab-Straube, E., Ranwashe, F., Raz, L., Salimov, R., Smets, E., Thiers, B., Thomas, W., Tulig, M., Ulate, W., Ung, V., Watson, M., Jackson, P.W. and Zamora, N. (2020), World Flora Online: Placing taxonomists at the heart of a definitive and comprehensive global resource on the world's plants. TAXON, 69: 1311-1341. https://doi.org/10.1002/tax.12373 Roeland Kindt, Ilyas Siddique, Ian Dawson, Innocent John, Fabio Pedercini, Jens-Peter B. Lillesø, Lars Graudal. 2025. The Agroforestry Species Switchboard, a global resource to explore information for 107,269 plant species. Sci Data 12, 1150 (2025). https://doi.org/10.1038/s41597-025-05492-w Kindt, R. 2020. WorldFlora: An R package for exact and fuzzy matching of plant names against the World Flora Online taxonomic backbone data. Applications in Plant Sciences 8(9): e11388. https://doi.org/10.1002/aps3.11388 Funding The development of this dataset was supported by the German International Climate Initiative (IKI) to the regional tree seed programme on The Right Tree for the Right Place for the Right Purpose in Africa, by Norway’s International Climate and Forest Initiative through the Royal Norwegian Embassy in Ethiopia to the Provision of Adequate Tree Seed Portfolio project in Ethiopia, and by the Bezos Earth Fund to the Quality Tree Seed for Africa in Kenya and Rwanda project.