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Texas, USA.  Photo: M.Crisp M.Crisp

Texas, USA. Photo: M.Crisp M.Crisp

Line drawing by M. Szent Ivany, J. Adelaide Bot. Gards 4 (1981) 153, fig 56.

Distribution map generated from Australia's Virtual Herbarium .

Synonymy

*Solanum elaeagnifolium Cav., Icon. 3: 22; t. 243 (1795)

T: From tropical America; C, MA, P-Juss., fide W.G. D'Arcy, Ann. Missouri Bot. Gard. 61: 847 (1974). Two specimens from Cavanille's herbarium in MA can be seen on the Solanaceae Source site.

Description

Erect, clonal perennial herb to 1 m, often suckering, silvery-green, rarely rusty-green, densely pubescent with stellate hairs; prickles 2–5 mm long, usually on stems, less common elsewhere.  

Leaves oblong-lanceolate to oblong; lamina 2.5–10 cm long, 1–3 cm wide, sometimes larger, slightly discolorous, entire (upper leaves) to shallowly lobed (lower leaves); petiole 5–10 mm long.

Inflorescence 1–4–flowered; peduncle 5–10 mm long; rachis 20–30 mm long; pedicels c. 10 mm long, lengthened in fruit. Calyx 9–10 mm long, enlarged in fruit; tube 5–ribbed; lobes awl-shaped, 4–5 mm long. Corolla rotate-stellate, 20–30 mm diam., blue, rarely white, pink or deep purple. Anthers 5–8 mm long.  

Berry depressed globular, 8–14 mm diam., orange-brown; fruiting pedicels 20–30 mm long. Seeds 2.5–4 mm long, light brown. n=12.

Distribution and ecology

Native to south-western U.S.A., northern Mexico and temperate South America, now introduced to Europe, Asia, Africa and Australia. Naturalised in south-eastern Qld, western slopes and southern plains of N.S.W., Vic., southern S.A. and south-western W.A.; occasional in southern N.T.

Usually a weed of cereal land and pasture. S. elaeagnifolium is on the list of Declared Plants for N.S.W., Vic., Tas., S.A. and W.A. (See Navie, S. (2004). Declared Plants of Australia. (Centre for Biological Information Technology, Brisbane).  

Common name

Silver-leaf Nightshade, White Horse Nettle

Relationships

Australian material has previously often been confused with S. esuriale Lindley and S. ellipticum R.Br. It is distinct from both of these by its much longer anthers.

Bean (2004) treated S. elaeagnifolium as a member of the S. esuriale group of subgen. Leptostemonum, whereas Whalen (1984) had earlier treated it as part of the Ellipticum group.  S. elaeagnifolium was the only member in both cases of groups which were composed of entirely Australian species.

More recently Levin et al. (2006) have shown S. elaeagnifolium not to be part of the Old World clade and to have closer relationships with other Mexican and southern USA species.

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Notes

A declared noxious weed in Qld, Vic., Tas and S.A. Silver-leaved Nightshade remains a significant weed in cereal growing areas. Much effort has been concentrated on its control. An account of its weedy qualities is given in W.T. Parsons & E.G. Cuthbertson, Noxious Weeds of Australia, Inkata Press, Melbourne (1992) but for a full account of its biology see J.W.Heap & R.J.Carter, Plant Protection Quarterly 14 (1999) 2-12.

For extra images and background information of it as a Declared Plant see Navie, S. (2004). Declared Plants of Australia. An identification and information system. (Centre for Biological Information Technology, Brisbane). 

Selected specimens

W.A.: Muresk, 3 Mar. 1953, H.A. Lovegrove (PERTH). S.A.: Darlington, Hj. Eichler 12167 (AD). Qld: Gatton, 12 Dec. 1977, M. Olsen (BRI). N.S.W.: Cowra, D.E. Symon 9893a (ADW, NSW). Vic.: Corio Bay, T.B. Muir 3168 (MEL).

Plant status, if any

Usually a weed of cereal land and pasture. S. elaeagnifolium is on the list of Declared Plants for N.S.W., Vic., Tas., S.A. and W.A. (See Navie, S. (2004). Declared Plants of Australia. (Centre for Biological Information Technology, Brisbane) and http://www.weeds.org.au/docs/weednet6.pdf.  

From the web

This is an extremely widespread weed and there is copious information available on the web.

A very detailed fact sheet on S. elaeagnifolium can be downloaded from the European and Mediterranean Plant Protection Organization

Images and background information on this plant as a weed in Tasmania can be found at www.dpiwe.tas.gov.au/inter.nsf/WebPages/SLEN-5NL72M?openand from the Weeds in Australia site and the Weeds Australia site. Images of the plant in WA can be seen on the Florabase site.

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

Images of various aspects of S. elaeagnifolium can be seen at the Digital Flora of Texas site and on the Flora of Chile site. A set of close-up images is available from the Texas AgriLife Research and Extension at Uvalde site and at http://www.plantsystematics.org/

Images and information on this species in California can be accessed through the Encycloweedia pages at http://www.cdfa.ca.gov/phpps/ipc/weedinfo/solanum-elaeagnifolium.htm and through CalPhotos

Further information about this species can be accessed through the Plants Profile site of the US Department of Agriculture and there are images of plants and herbarium specimens on the Solanaceae Source site.

S. elaeagnifolium as a weed in the Pacific is treated on the Pacific Island Ecosystems at Risk (PIER) site.