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Hosking 1095, between Somerton and Manilla, NSW. Photo: J.R. Hosking  J.R. Hosking

Hosking 1095, between Somerton and Manilla, NSW. Photo: J.R. Hosking  J.R. Hosking

Line drawing by M. Szent Ivany, J. Adelaide Bot. Gard. 4 (1981) 109, fig. 33.

Distribution map generated from Australia's Virtual Herbarium.

Synonymy

* Solanum rostratum Dunal, Hist. Nat. Solanum 234, t. 24 (1813); Nycterium rostratum (Dunal) Link, Enum. Hort. Berol. 1: 189 (1821); Androcera rostrata (Dunal) Rydb., Bull. Torrey Bot. Club 33: 150 (1906).

 

T: Described from material cultivated in Montpellier, France; G, G-DC, MPU, P; n.v., fide W.G. D'Arcy, Ann. Missouri Bot. Gard. 61:858 (1974).

 

Solanum cornutum auct.non Lam.: of many authors outside Australia.

Description

Annual herb to c. 1 m, green or grey-green, pubescent with stellate and minute glandular hairs; prickles to 1 cm long, abundant on most parts.  

Leaves ovate or ovate-oblong; lamina 2-10 cm long, 1-8 cm wide, concolorous, lobed; lobes obovate, the lower ones often forming leaflets; petiole to 5 cm long, decurrent.  

Inflorescence few-10-flowered; peduncle 15-30 mm long; rachis up to 6 cm long, pedicels 5-10 mm long. Calyx 6-10 mm long, enlarged in fruit; lobes narrowly triangular, 3-5 mm long. Corolla irregularly rotate, 30-40 mm diam., bright yellow. Four anthers 6-8 mm long, straight, the fifth 10 mm long, curved.  

Berry globular, 10 mm diam., drying blackish, skin papery. Seeds 2-2.5 mm long, dark brownish or black. n=12.

Distribution and ecology

Native to northern Mexico and the plains of southern U.S.A., now widespread in U.S.A. and naturalised in Europe, South Africa, West Indies and Australia. Occurs in cereal-growing areas in Qld, N.S.W., Vic., S.A. and W.A., usually in disturbed habitats.

Common name

Buffalo Burr, Pincushion Nightshade

Relationships

S. rostratum is the only member of Solanum and subgen. Leptostemonum in Australia to have yellow flowers.

It belongs to Solanum sect. Androceras (Symon 1981), once treated as a separate genus Androcera. There are about 12 American species in this group and S. rostratum is the only one to have spread further as a weed. The group is characterised by corollas which have two of the petals larger than the other three, the anthers unequal in size and the fruit enclosed within a particularly prickly calyx.

Whalen (1984) distinguished the Rostratum group within subg. Leptostemonum and molecular studies (Levin et al. 2006) support the retention of this SW American group of species in combination with the Crinitum group of species from South America in a clade referred to as the Androceras/Crinitum clade.

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Notes

Roots reported poisonous to pigs, foliage to stock.

Discussion of the status of S. rostratum as a weed may be found in W. T. Parsons & E. G. Cuthbertson, Noxious Weeds in Australia, Inkata Press, Melbourne, 1992 while excellent photographs and background information can also be found in Navie, S. (2004). Declared Plants of Australia. An identification and information system. (Centre for Biological Information Technology, Brisbane). See web information for further links.

Selected specimens

W.A.: West Wagin, Mar. 1965, A.J. McKenzie (PERTH). S.A.: near Virginia, B. Copley 1865 (AD). Qld: Jandowae, Nov. 1961, F. Sperling (BRI). N.S.W.: Yanco, 10 Jan. 1945, J.L. Green (NSW). Vic.: near Dooen, 1 Mar. 1960, J.H. Willis (MEL).

Plant status, if any

A declared noxious weed in Vic. and N.S.W. (see http://www.weeds.org.au/docs/weednet6.pdf)

From the web

Further information and links can be found on the Weeds in Australia site and through the Plants Profile site of the US Department of Agriculture.

Images of S. rostratum can be seen on the FloraBase site, the CalPhotos site, the Missouri Plants site and on the Digital Flora of Texas site.   

A fact sheet for this species can be downloaded from the SA eFlora site.

Further information, images and links for this species can be found on the Solanaceae Source site.