A diagnosis of the taxonomic and floristic knowledge on vascular plants from northern Mexico

Background: The taxonomic and floristic knowledge of vascular plants in northern Mexico presents relevant, though disaggregated advances. Therefore, it is crucial to make a diagnostic in order to define strategies to unify and complement the knowledge generated.& para;& para;Questions: how many species of vascular plants are there in northern Mexico? How many of these are restricted to this region? Which are the areas where main exploration efforts should be concentrated?& para;& para;Study site: northern Mexico (states of Chihuahua, Coahuila, Durango and Nuevo Leon).& para;& para;Methods: A database of vascular plants from northern Mexico was developed from the database of the CIIDIR Herbarium adding records gartered at the Universities of Chihuahua, Antonio Narro, and Nuevo Leon, as well as with data from taxonomic reviews and from herbaria (ANSM, CFNL, CIIDIR, FZ-UACH). From the report generated, richness and endemism per state and ecoregion were calculated. The best known groups and geographic areas were identified, as well as knowledge gaps; a list of the herbaria, programmes in botany and botanists in the region was compiled.& para;& para;Results: 8,503 species, 1,599 genera and 210 families of vascular plants were retrieved by the revision. 15 genera are strict endemics to the region. Durango is the richest state (4,954 species, 58 % of the total). Sierra Madre Occidental is the ecoregion with the higher richness (3,565 species, considering only its portion in the studied states), followed by Sierra Madre Oriental (2,862) and Chihuahuan Desert (2,602). The better known state and ecoregion are Chihuahua and Sierra Madre Occidental. Chihuahuan Desert is the region better explored.& para;& para;Conclusions: the magnitude of the richness and endemism presented here reflects the current knowledge, nonetheless, it is necessary' to increase floristic inventaries, taxonomic revision and ecological studies to acquire more precise and exact information of the real scene.