 Line drawing by M. Szent Ivany, J. Adelaide Bot. Gard. 4 (1981) 50, fig. 6. |
 Distribution map generated from Australia's Virtual Herbarium. |
Synonymy
*Solanum retroflexum Dunal, in DC., Prodr. 13(1): 50 (1852)
T: `In promont. Bonae Spei, in 1838, (Drège 7864); in Arabiâ circa Taifa (a Mus. Paris, mihi comm. n. 29)'; syn: G–DC n.v., fide R.J.F. Henderson, Contr. Queensland Herb. 16: 60 (1974), microfiche AD.
Description
Spreading, rounded annual herb, bright green, pubescent with simple hairs; prickles absent.
Leaves ovate to ovate-lanceolate, the lamina 4–8 cm long, 2–5 cm wide, slightly discolorous, lobed; petiole to 4 cm long.
Inflorescence short, 3–6–flowered; peduncle to 13 mm long; pedicels 4–6 mm long. Calyx 2–5.5 mm long; lobes triangular, 1–1.5 mm long. Corolla stellate, 12–14 mm diam., white. Anthers 1.5 mm long.
Berry globular, 6–9 mm diam., occasionally smaller, dull black. Seeds 1.8–2 mm long, light brownish-yellow or purple. n=24.
Distribution and ecology
Originally from South Africa. Sparingly naturalised on Eyre Peninsula and north end of Yorke Peninsula, S.A. The AVH map attached here suggests there is also a record from NE Victoria.
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. americanum, S. chenopodioides, S. furcatum, S. douglasii, S. opacum, S. physalifolium, S. nigrum, S. sarrachoides, S. scabrum and S. villosum.
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).
Notes
Part of ongoing studies in
See E. Van der Walt, A. Van Schalkwyk & D.K. Berger (2008). Genetic relationships between South African Solanum retroflexum and other related species using partial 18S sequencing. South African Journal of Botany 74: 391 (abstract).
Selected specimens
S.A.: Pillie Waterhole, Eyre Peninsula, C.R. Alcock 1268 (AD), and 2099 (AD).
From the web
A fact sheet for this species can be downloaded from the SA eFlora site.
Information about S. retroflexum and its possible identity in Africa, can be found on the PROTA (Plant Resources of Tropical Africa) site under Solanum grossedentatum which may be synonymous.
Further references to the use of S. retroflexum in