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.

Name

The generic name was first used by Pliny the Elder (23–79 CE) for a plant also known as, most likely S. nigrum. Its derivation is uncertain, possibly stemming from the Latin word, meaning "sun", referring to its status as a plant of the sun.

Species having the common name "nightshade"

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 nightshades (many species in the Solanum nigrum complex, Solanum sect. Solanum) have varying levels of toxins and are considered too toxic to eat by many people in North America and Europe, but young stems and leaves or fully ripened fruit of various species are cooked and eaten by native people in North America, Africa, and Asia. 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.

Taxonomy

The genus was established by Carl Linnaeus in 1753. Its subdivision has always been problematic, but slowly some sort of consensus is being achieved. The following list is a provisional lineup of the genus' traditional subdivisions, together with some notable species. Many of the subgenera and sections might not be valid; they are used here provisionally as the phylogeny of this genus is not fully resolved yet and many species have not been reevaluated. Cladistic analyses of DNA sequence data suggest that the present subdivisions and rankings are largely invalid. Far more subgenera would seem to warrant recognition, with Leptostemonum being the only one that can at present be clearly subdivided into sections. Notably, it includes as a major lineage several members of the traditional sections Cyphomandropsis and the old genus Cyphomandra.

Subgenus Bassovia

Section Allophylla Section Cyphomandropsis Section Pachyphylla

Subgenus Leptostemonum

Section Acanthophora Section Androceras: 12 spp. Section Anisantherum Section Campanulata Section Crinitum Section Croatianum Section Erythrotrichum Section Graciliflorum Section Herposolanum Section Irenosolanum Section Ischyracanthum Section Lasiocarpa Section Melongena Section Micracantha Section Monodolichopus Section Nycterium Section Oliganthes Section Persicariae Section Polytrichum Section Pugiunculifera Section Somalanum Section Torva

Subgenus Lyciosolanum

Subgenus Solanum sensu stricto

Section Afrosolanum Section Anarrhichomenum Section Archaesolanum Section Basarthrum Section Benderianum Section Brevantherum Section Dulcamara Section Herpystichum Section Holophylla Section Juglandifolia Section Lemurisolanum Section Lycopersicoides Section Lycopersicon Section Macronesiotes Section Normania Section Petota Section Pteroidea Section Quadrangulare Section Regmandra Section Solanum

Other notable species

Formerly placed here

Some plants of other genera were formerly placed in Solanum:

Ecology

Solanum species are used as food plants by the larvae of some Lepidoptera species (butterflies and moths).

Toxicity

Most parts of the plants, especially the green parts and unripe fruit, are poisonous to humans (although not necessarily to other animals), with some species even being deadly.

Uses

Many species in the genus bear some edible parts, such as fruits, leaves, or tubers. Three crops in particular have been bred and harvested for consumption by humans for centuries, and are now cultivated on a global scale: Other species are significant food crops regionally, such as Ethiopian eggplant or scarlet eggplant (S. aethiopicum), naranjilla or lulo (S. quitoense), cocona (S. sessiliflorum), turkey berry (S. torvum), pepino or pepino melon (S. muricatum), tamarillo (S. betaceum), wolf apple (S. lycocarpum), garden huckleberry (S. scabrum) and "bush tomatoes" (several Australian species).

Ornamentals

The species most widely seen in cultivation as ornamental plants are:

Medicine

Several species are locally used in folk medicine, particularly by native people who have long employed them.