This dataset results from the data gathered in the platform Flora-On ( http://www.flora-on.pt/ ), which contains observation records of vascular plants within mainland Portugal, made by an array of collaborators. Observations are uploaded directly by collaborators, who are either experienced botanists/naturalists, or occasional collaborators. In this latter case, the observations are first validated by the Editorial Board before publication. The Editorial Board is committed to ensure that only the most rigorous data is published, and it does not release observations whose uncertainty is judged to be high. Flora-On was created by and is kept up exclusively through the voluntary work of associate members of Sociedade Portuguesa de Botânica (Botanical Society of Portugal), its maintenance costs being supported only by the membership fees of the associates.