Geographic distribution of wild potato species

The geographic distribution of wild potatoes (Solanaceae sect. Petota) was analyzed using a database of 6073 georeferenced observations. Wild potatoes occur in 16 countries, but 88% of the observations are from Argentina, Bol ivia, Mexico, and Peru. Most species are rare and narrowly endemic: for 77 species the largest distance between two observations of the same species i s < 100 km. Peru has the highest number of species (93), followed by Bolivi a (39). A grid of 50 X 50 km cells and a circular neighborhood with a radiu s of 50 km to assign points to grid cells was used to map species richness. High species richness occurs in northern Argentina, central Bolivia, centr al Ecuador, central Mexico, and south and north-central Peru. The highest n umber of species in a grid cell (22) occurs in southern Peru. To include al l species at least once, 59 grid cells need to be selected (out of 1317 cel ls with observations). Wild potatoes occur between 38 degrees N and 41 degr ees S, with more species in the southern hemisphere. Species richness is hi ghest between 8 degrees and 20 degrees S and around 20 degrees N. Wild pota toes typically occur between 2000 and 4000 m altitude.