Wild Potatoes (Solanum section Petota; Solanaceae) of North and Central America

Abstract

Solanum section Petota, the potato and its wild relatives, contains about 200 wild species distributed from the southwestern United States, to central Argentina and adjacent Chile. Although most species occur in South America, a secondary center of diversity peaks at 20 degrees north in the central Mexican highlands, including diploids (2n = 2x = 24), tetraploids (2n = 4x = 48), hexaploids (2n = 6x = 72), and triploid and pentaploid nothospecies. This treatment covers the wild potatoes of North and Central America (United States to Panama). It is a summary of recent morphological and molecular studies of species limits and their interrelationships. We collected herbarium and germplasm samples from all countries harboring wild potatoes in this region and now have access to germplasm of every species. A comprehensive treatment in 1990 recognized 33 species, 12 subspecies, and five nothospecies from the region, partitioned into eight formal taxonomic series. We recognize 25 species and four nothospecies from the region, partitioned into eleven informal species groups. It provides the first formal typification of many of these names, an extensive list of georeferenced localities, a geographic information systems based diversity analysis, and illustrations and maps of all the species.