Biosystematics of the potato

The potato of commerce belongs to a single species, Solanum tuberosum L., apart from certain cultivated forms in South America which will be mentioned later and which are generally regarded as distinct. Other well-known cultivated plants in the genus Solanum are the egg-plant or aubergine (S. melongena), the pepino (S. muricatum) and the naranjillo (S. quitoense). The chilli peppers (Capsicum spp.) and tomato (Lycopersicon esculentum) are better known and more widely grown than the last two Solanum species mentioned above. Less well-known fruits such as Cyphomandra and Physalis as well as a number of ornamentals such as Petunia, Schizanthus, Salpiglossis and Lycium also belong to Solanaceae. On the other hand, several genera such as Nicotiana, Datura, Atropa and Mandragora, have acquired a more sinister reputation because of their poisonous alkaloids. Even so, probably all members of the family possess some alkaloids, even though in small amounts in many cases.