Floristic diversity of the northeastern region of Mexico, states of Coahuila, Nuevo Le & oacute;n and Tamaulipas

Background: The Northeastern Mexico, comprising the states of Coahuila, Nuevo Le & oacute;n and Tamaulipas, constitutes a heterogeneous region that includes mountains, continental and coastal plains with a variety of environments, geological substrates, and altitudinal gradients that favor the presence of a rich biodiversity. There is no a synthesis that documents the floristic diversity of this region.Questions: What is the magnitude of the diversity of vascular plants in northeastern Mexico? What are the families and genera with the largest number of species? How is the floristic richness distributed geographically throughout this region and what are its most characteristic elements?Studied species: 7,088 species of vascular plants.Study site and dates: states of Coahuila, Nuevo Le & oacute;n, and Tamaulipas.Methods: Floristic-taxonomic literature on the flora of the region and specimen databases were consulted to make a spatial analysis of biodiversity using cells of 1 degrees longitude and latitude. Richness and endemism in the region, states, and grid cells were calculated.Results: For northeastern Mexico, 7,088 species of vascular plants are reported, of which 1,767 are endemic to Mexico. Conclusions: The northeast of Mexico records a particularly interesting and complex floristic diversity, due to the fact that its territory is located primarily outside the Neotropics and because it constitutes the boreal limit for many elements of the flora of Mexico.