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. It is the largest genus in the nightshade family Solanaceae, comprising around 1,500 species. It also contains the so-called horse nettles, 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 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 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. 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 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 belongs, like Solanum, to subfamily Solanoideae of the nightshade family, but, unlike that genus, is a member of tribe Hyoscyameae. 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 ''Acanthophora''

12 spp.
  • Series Androceras
  • Series Violaceiflorum
  • Series ''Pacificum''

    Section ''Anisantherum''

Section ''Campanulata''

Section ''Crinitum''

Section ''Croatianum''

Section ''Erythrotrichum''

Section ''Herposolanum''

Section ''Lasiocarpa''

Section ''Nycterium''

Section ''Oliganthes''

Section ''Pugiunculifera''

Section ''Somalanum''

Section ''Torva''

Also known as: Solanum sensu stricto.

Section ''Afrosolanum''

Section ''Anarrhichomenum''

Section ''Brevantherum''

Section ''Holophylla''

Section ''Lycopersicoides''

Also known as: tomato lineage.

Section ''Normania''

Also known as the "potato lineage". Including: subsections Estolonifera and Potatoe.

Section ''Quadrangulare''

Section ''Regmandra''

Section ''Solanum''

Some plants of other genera were formerly placed in Solanum:
The following phylogeny of Solanaceae is from Zhang et al. figure 1B. It is based on a consensus of 500 trees randomly sampled from 1-Mb genomic windows with 200-kb step size.
The non-italicized names inside of Solanum refer to the major clade names within Solanum. These names usually include the similarly-named section but do not have taxonomic standing.

Ecology

Solanum species are used as food plants by the larvae of some Lepidoptera species.

Toxicity

Most parts of the plants, especially the green parts and unripe fruit, are poisonous to humans, 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:
  • Tomato, S. lycopersicum
  • * Tomato varieties are sometimes bred from both S. lycopersicum and wild tomato species such as S. pimpinellifolium, S. peruvianum, S. cheesmanii, S. galapagense, S. chilense, etc.
  • Potato, S. tuberosum, fourth largest food crop.
  • * Less important but cultured relatives used in small amounts include S. stenotomum, S. phureja, S. goniocalyx, S. ajanhuiri, S. chaucha, S. juzepczukii, S. curtilobum.
  • Eggplant, S. melongena
Other species are significant food crops regionally, such as Ethiopian eggplant or scarlet eggplant, naranjilla or lulo, cocona, turkey berry, pepino or pepino melon, tamarillo, wolf apple, garden huckleberry and "bush tomatoes".

Ornamentals

The species most widely seen in cultivation as ornamental plants are:
Several species are locally used in folk medicine, particularly by native people who have long employed them.