Solanum

Solanum is a large and diverse genus of flowering plants, which include three food crops of high economic importance: the potato, the tomato and the eggplant (aubergine, brinjal). It is the largest genus in the nightshade family Solanaceae, comprising around 1,500 species. It also contains the so-called horse nettles (unrelated to the genus of true nettles, Urtica), as well as numerous plants cultivated for their ornamental flowers and fruit. Solanum species show a wide range of growth habits, such as annuals and perennials, vines, subshrubs, shrubs, and small trees. Many formerly independent genera like Lycopersicon (the tomatoes) and Cyphomandra are now included in Solanum as subgenera or sections. Thus, the genus today contains roughly 1,500–2,000 species. The generic name was first used by Pliny the Elder (AD 23–79) for a plant also known as strychnos, most likely S. nigrum. Its derivation is uncertain, possibly stemming from the Latin word sol, meaning "sun", referring to its status as a plant of the sun. The species most commonly called nightshade in North America and Britain is Solanum dulcamara, also called bittersweet or woody nightshade (so-called because it is a (scandent) shrub). Its foliage and egg-shaped red berries are poisonous, the active principle being solanine, which can cause convulsions and death if taken in large doses. Black nightshade (Solanum nigrum) is also generally considered poisonous, but its fully-ripened fruit and its foliage are both cooked and eaten in some areas. Deadly nightshade (Atropa belladonna) belongs, like Solanum, to subfamily Solanoideae of the nightshade family, but, unlike that genus, is a member of tribe Hyoscyameae (Solanum belongs to tribe Solaneae). The chemistry of Atropa species is very different from that of Solanum species and features the very toxic tropane alkaloids, the best-known of which is atropine. Most parts of the plants, especially the green parts and unripe fruit, are poisonous to humans (although not necessarily to other animals), but many species in the genus bear some edible parts, such as fruits, leaves, or tubers.