"Horsenettle" and variants redirect here. If used for a particular species, this name usually applies to the Carolina Horsenettle (S. carolinense).

Solanum, the nightshades, horsenettles and relatives, are a large and diverse genus of annual and perennial plants. They grow as forbs, vines, subshrubs, shrubs, and small trees, and often have attractive fruit and flowers. Many formerly independent genera like Lycopersicon (the tomatoes) or Cyphomandra are included in Solanum as subgenera or sections today. Thus, the genus nowadays contains roughly 1,500-2,000 species. The species usually most commonly called nightshade in North America and England is Solanum dulcamara, also called bittersweet and 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. The black nightshade (S. nigrum) is also generally considered poisonous, but its fully ripened fruit and foliage are cooked and eaten in some areas.

The generic name was first used by Pliny the Elder (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. Another possibility is that the root was solare, meaning "to soothe," or solamen, meaning "a comfort," which would refer to the soothing effects of the plant upon ingestion.^[2]

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. Several species are cultivated, including three globally important food crops:

• Tomato, S. lycopersicum
• Potato, S. tuberosum
• Eggplant, S. melongena

Other species are significant food crops regionally, such as Ethiopian Eggplant and gilo (S. aethiopicum), naranjilla or lulo (S. quitoense), Turkey Berry (S. torvum), pepino (S. muricatum), or the "bush tomatoes" (several Australian species).

While most medical relevance of Solanum is due to poisonings which are not uncommon and may be fatal, several species are locally used in folk medicine, particularly by native peoples who have long employed them. Giant Devil's-fig (S. chrysotrichum) has been shown to be an effective treatment for seborrhoeic dermatitis in a scientific study.^[3]

Solanum species are used as food plants by the larvae of some Lepidoptera species (butterflies and moths) - see list of Lepidoptera that feed on Solanum.

Systematics

The genus was established by Carl Linnaeus in 1753.^[4] 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.^[4] 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 suggests 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.^[5]

Subgenus Bassovia

Section Allophylla

• Solanum granuloso-leprosum

Section Cyphomandropsis

• Solanum glaucophyllum Desf. – Waxy-leaved Nightshade

Section Pachyphylla

• Solanum betaceum Cav. – Tamarillo
• Solanum exiguum
• Solanum roseum

Subgenus Leptostemonum

Solanum palinacanthum

Five-minute Plant (S. atropurpureum) fruit

Shrubby Nightshade (S. robustum) flowers

Giant Potatocreeper (S. wendlandii) flowers

Porcupine Tomato (S. pyracanthum) fruit

Subgenus Lyciosolanum

• Solanum guineense L.

Subgenus Solanum sensu stricto

Solanum erianthum

Jasmine Nightshade (S. laxum) flowers

Currant Tomato (S. pimpinellifolium) fruit

Andean black potatoes (S. tuberosum)

Turkey Berry (S. torvum) flowers

Yellow Nightshade (S. villosum) fruit

Other notable species

Forked Nightshade (S. furcatum)

Bluewitch Nightshade (S. umbelliferum) flowers

Formerly placed here

Lycianthes rantonnetii and its congeners were often placed in Solanum

Some plants of yet other genera also were placed in Solanum in former times:

• Chamaesaracha coronopus (as S. coronopus)
• Lycianthes biflora (as S. multifidum Buch.-Ham. ex D.Don)
• Lycianthes denticulata (as S. gouakai var. angustifolium and var. latifolium)
• Lycianthes lycioides (as S. lycioides var. angustifolium)
• Lycianthes mociniana (as S. uniflorum Dunal in Poir. and S. uniflorum Sessé & Moc.)
• Lycianthes rantonnetii (as S. rantonnetii, S. urbanum var. ovatifolium and var. typicum)
• Undetermined species of Lycianthes have been referred to under names such as S. chrysophyllum, S. ciliatum Blume ex Miq., S. corniculatum Hiern, S. lanuginosum, S. loxense, S. mucronatum, S. retrofractum var. acuminatum, S. violaceum Blume, S. violifolium f. typicum, S. virgatum notst β albiflorum, S. uniflorum Lag. or S. uniflorum var. berterianum.

References

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