Adequate knowledge of a flora is fundamental for furthering research in several disciplines. In this context, our work arises from the necessity to update and improve available information on the native woody flora of Uruguay. The goals of this study were to objectively determine the Uruguayan native woody flora (shrub and trees), to evaluate its inventory completeness, and to explore its similarity with neighboring regions. By analyzing the Uruguayan flora we produced working definitions of shrubs and trees, and obtained a list of 313 species (57 families, 125 genera). Using 7418 distribution records, we generated cumulative species richness curves to estimate maximum species richness at national and local scales. We conclude that the completeness at the national level is high (89-95%), but at the local scale is lower and quite heterogeneous. There are still large areas without data or with little information. We found that comparatively, the similarity between Uruguayan tree species and the Province of Entre Ríos (Argentina) was high, while similarity with the Province of Buenos Aires (Argentina) was medium, and with Rio Grande do Sul (Brazil) was low. In conclusion, richness of tree and shrub species of the Uruguayan flora is greater than expected for a grassland region, and the differences found in the similarity index with the neighboring woody floras will stimulate future studies to reevaluate phytogeographic schemes of the region.
Geographic distribution; Inventory completeness; Shrub and tree flora; Uruguayan phytogeography
