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.

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.

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.  

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