The cultivated potato of world commerce, Solanum tuberosum, is one of the most important food crops on earth and forms the staple crop of many societies. It is a cultivated member of Solanum section Petota, a group of tuber-bearing species containing 199 tuber-bearing wild species, and seven cultivated species, with additional subspecies. Recent morphological and molecular studies have confirmed earlier ideas that: 1) potato likely had its origin from a group of about 30 South American wild species collectively known as the Solanum brevicaule complex, 2) members of this complex are likely over-described, belong to two clades, and may consist of only two species, 3) cultivated potatoes are likely of complex and multiple origins and hybridize in nature with other wild and cultivated species, 4) the morphological characters separating the cultivated species are imprecise and often fail to identify cultivated accessions clearly, 5) it is often impossible to distinguish some "wild" species from cultivated species and they may represent escaped cultivated populations, and 6) the two subspecies of S. tuberosum, while very similar, are distinguishable morphologically and molecularly. A recent morphological study by Huamán and Spooner reclassified all the cultivated landrace species as eight cultivar-groups under the International Code of Nomenclatural of Cultivated Plants (ICNCP), not as seven species under the International Code of Botanical Nomenclature (ICBN) by Hawkes. A similar study is in progress to reclassify the modern cultivars as cultivar groups under the ICNCP. These recent findings greatly aid investigations on the origins, genetic diversity, and search for progenitors of cultivated potatoes, and the new taxonomy allows for a more practical and phylogenetically valid classification of this major food crop.

Key words: cultivated, ICNCP, potato, section Petota, Solanum tuberosum