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Foliage with flower and fruits. Photo: T. Low T. Low

Line drawing of branch with flowers and fruits by M. Szent Ivany, J. Adelaide Bot. Gard. 4 (1981).

Distribution map generated from Australia's Virtual Herbarium. For a more up to date map visit the AVH site through your local herbarium.

Synonymy

Solanum americanum Miller, Gard. Dict. 8th edn, no. 5 (1768) 

T: Cultivated Chelsea Physic Garden, origin Virginia, North America, Miller s.n.; lecto: BM, fide J.M. Edmonds, J. Arnold Arbor. 52: 634 (1971), photo AD. An image of the lectotype can be seen on the Solanaceae Source site.

S. nodiflorum Jacq., Collectanea 2: 288 (1789) & Icon. Pl. Rar. 2: 11; t. 326 (1789). 

T: Cultivated Vienna, origin Mauritius, Herb. Jacquin; lecto: BM, fide R.J.F. Henderson, Contr. Queensland Herb. 16: 28 (1974). The image from Jacquin's Icon. Pl. Rar. 2: t. 326 is reproduced on p. 24 in J. M. Edmonds & J. A. Chweya, The Black Nightshades. Solanum nigrum and its related species. Int. Plant. Genetic Res. Inst. Rome (1997) downloadable at www.ipgri.cgiar.org/publications/pdf/337.pdf or it can be accessed directly at http://www.botanicus.org/page/271014

S. nodiflorum subsp. nutans R. Henderson, Contr. Queensland Herb. 16: 30; t. 2 (1974).

T: Indooroopilly, Qld, Apr. 1969, R.J.F. Henderson 518; holo: BRI 86633; iso: K, MEL, NSW. 

[S. nigrum auct. non L.; G. Bentham, Fl. Austral. 4: 446 (1869) p.p.]

See Notes (below) for a discussion of the correct name for this species.

Description

Erect or spreading herb or short-lived perennial shrub to 1.3 m, glabrous or sparsely pubescent with simple hairs, green or the stems and leaves often purplish; prickles absent. Stems often angled or narrowly winged.  

Leaves ovate or ovate-lanceolate; lamina 2–12 cm long, 1–7 cm wide, concolorous, entire or shallowly lobed; petiole 1–4 (occasionally to 9) cm long.  

Inflorescence short, 4–12–flowered; peduncle to 25 mm long, lengthening to 45 mm in fruit; pedicels 5–8 mm long. Calyx 1–2 mm long; lobes rounded, 0.4–1.2 mm long. Corolla deeply incised, usually 8–9 mm diam., white or flushed purple with yellow-green centre. Anthers 1.5–2 mm long.  

Berry globular, 6–9 mm diam., purple-black. Seeds 1–1.5 mm long, light fawn or purplish; stone-cell granules, if present, c. 0.5 mm diam. n=12.

Distribution and ecology

A variable cosmopolitan weed in tropical and warm temperate regions. Usually grows in disturbed habitats associated with human activities.  

Occurs mainly in coastal areas of eastern Qld and N.S.W., where possibly indigenous or of pre-European introduction, and in scattered localities in Vic., W.A. and N.T. where naturalised from later introductions. Also on Lord Howe Is.

Common name

Glossy Nightshade.

Relationships

Part of the S. nigrum or "Black nightshade" group of species, usually referred to as cosmopolitan weeds and usually thought to have originated in the Americas. They are characterised by their lack of prickles and stellate hairs, their white flowers and their green or black fruits arranged in an umbelliform fashion.

The species can be difficult to distinguish. Other species to occur in Australia are S. chenopodioides, S. douglasii, S. furcatum, S. nigrum, S. opacum, S. physalifolium, S. retroflexum, S. sarrachoides, S. scabrum and S. villosum.

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Notes

There has been long disagreement as to the correct name for this species and also whether there are two different taxa involved; it was previously called S. nodiflorum Jacq. in much Australian literature. 

Recent work using AFLP markers to define African material of S. americanum (also designated as S. nodiflorum) has shown it to be distinct from the American S. americanum and  S. nodiflorum was considered to be deserving of species status. This global study included Australian material which would now also be assigned to the world-wide tropical/subtropical S. nodiflorum while S. americanum sensu stricto would be confined to the USA.

A table of morphological differences between the species is given in this paper and the Australian material certainly has the shorter styles, not or hardly exceeding the anthers, and shiny black fruit of S. nodiflorum, but other characters such as petal length and inflorescence shape need to be checked further. Nor did there seem to be any but shiny fruits evident in a survey of web photographs. Adding further to the confusion both of the species appear to occur in the USA.  

Reference: M.L.K. Manoko, R.G. van den Berg, R.M.C. Feron, G.M. van der Weerden & C. Mariani (2007). AFLP markers support separation of Solanum nodiflorum from Solanum americanum sensu stricto (Solanaceae). Pl. Syst. Evol. 267: 1–11. Downloadable at www.springerlink.com/content/gmm700927409465h/fulltext.pdf

S. americanum/S. nodiflorum  is extremely widespread throughout warm temperate and tropical areas. In Africa, New Guinea and Oceania the young green shoots are cooked and eaten as greens.

Some members of the complex (these would all be assigned to S. nodiflorum using the Manoko et al. (2007) concept) have long been important food and medical sources in parts of Africa, India, Indonesia and China. Leaves are used as herbs or as vegetables, fruits are edible and provide dye and the plants have been used for various medicinal treatments. However other parts of the complex are poisonous. Because of this it is important to develop techniques for distinguishing between the species and the work to develop genetic markers is ongoing, particularly in Africa where these plants can provide a more easily obtained food resource than imported foods. Of the species which occur in Australia S. americanum, S. scabrum and S. villosum are all considered to be edible.

References: Keller, G.B. (2004). African nightshade, eggplant, spiderflower et al. - production and consumption of traditional vegetables in Tanzania from the farmer's point of view. MSc dissertation, George-August University, Gottingen.; Mwai GJ, Onyango, JC & Abukusta-Onyango, M (2007) Taxonomic identification and characterisation of African nightshades (Solanum L. Section Solanum). AJFAND Online 7(4); Olet EA, Heun M, & Lye KA (2005). African crop or poisonous nightshade; the enigma of poisonous or edible black nightshade solved. African Journal of Ecology 2005; 43: 158-161. 

A useful reference to the Black Nightshades is J. M. Edmonds & J. A. Chweya, The Black Nightshades. Solanum nigrum and its related species. Int. Plant. Genetic Res. Inst. Rome (1997). This can be downloaded from www.ipgri.cgiar.org/publications/pdf/337.pdf 

Selected specimens

W.A.: South Perth, R.D. Royce 8408 (PERTH). N.T.: Adelaide River, 22 Nov. 1972, J. Holmes (DNA, NT). Qld: Belmont, S.L. Everist 5606 (BRI). N.S.W.: Kogarah, E.F. Constable 5633 (NSW). Vic.: E of Marlo, 7 Feb. 1972, J.H. Willis (MEL).

From the web

Images of S. americanum can be accessed through the description of this species in Bean's interactive key at http://delta-intkey.com/solanum/www/american.htm

Further information and images of this species in NSW can be seen on the PlantNET site and for WA on the FloraBase site.

Images and information on this species in California can be accessed through the Encycloweedia pages at www.cdfa.ca.gov/phpps/ipc/weedinfo/solanum-americanum2.htm or www.cdfa.ca.gov/phpps/ipc/weedinfo/solanum-americanum.htm and in Missouri at www.missouriplants.com/Whitealt/Solanum_americanum_page.html

Further information on this species in America is available through the Plants Profile site of the US Department of Agriculture and the Plants of Hawaii site. Both sites have numerous images. It is treated for the Pacific on the PIER site at www.hear.org/pier/species/solanum_americanum.htm

A comprehensive fact sheet on S. americanum in Africa, with images, can be found on the PROTA (Plant Resources of Tropical Africa) site

Work on African material using AFLP markers has supported the recognition of the name S. nodiflorum for almost all previously recognised  S. americanum apart from that which occurs in the USA (see Note above).

 

Reference: M.L.K. Manoko, R.G. van den Berg, R.M.C. Feron, G.M. van der Weerden & C. Mariani (2007). AFLP markers support separation of Solanum nodiflorum from Solanum americanum sensu stricto (Solanaceae). Pl. Syst. Evol. 267: 1–11. Downloadable at www.springerlink.com/content/gmm700927409465h/fulltext.pdf