The exponential growth of plant occurrence data can facilitate dynamic biodiversity analyses. However, raw plant diversity data alone should not be used indiscriminately due to inherent sampling biases, impediments that contribute to the Wallacean shortfall (i.e. the paucity of species’ geographic information). Here, we propose GreenMaps, a new tool that will permit a rapid initial assessment of the Wallacean shortfall for plants by building base maps of species’ predicted distributions upon which citizen science participation could contribute to spatial validation of the actual range occupied by species. The initial stages of GreenMaps have now been accomplished, providing a massive dataset of modeled range maps for over 230,000 vascular plant species. Ultimately, GreenMaps will interface with a mobile application to enable volunteers from any region of the world to validate predicted species distributions to be used for the generation of new and improved global maps of plant distributions at scales relevant to research and conservation.