Apple-of-Sodom

Solanum linnaeanum Hepper & Jaeger

Synonyms - Solanum sodomaeum, Solanum sodomeum, Solanum hermannii

Family: Solanaceae.

Names:

Solanum comes from the Latin solamen meaning to quieten or comfort and refers to the narcotic properties of some species.
Linnaeanum recognises Linnaeus (1707-1778) a brilliant Swedish botanist responsible for naming many plants.
Apple-of-Sodom refers the biblical city of Sodom where plants with very bitter apples once grew.

Other names:

Bitter Apple (South Africa)
Poison Apple (South Africa)

Summary:

Apple of Sodom is a roundish, perennial shrub to 2 m high, with very spiny and hairy stems and leaves. The yellowish spines are coarse, up to 15 mm long and the hairs are of two types, some star-shaped and some gland-tipped. The leaves are 4-15 cm long and deeply lobed, the lobes rounded and often with wavy or further indented margins. The flowers are pale purple with bright yellow anthers and in a short spray. Each star shaped flower is 1.5-3 cm across with 5 petals and a hairy and prickly calyx. The berries are yellow or mottled eventually turning brown to black and are succulent, globular and 2-3.5 cm across.
Native to northern and southern Africa and the Mediterranean, it is now a serious weed of roadsides, creeklines, wasteland and disturbed woodlands. Apple of Sodom is a declared weed in several states including WA. It flowers from January to May or August to October and the berries are toxic.

Description:

See the Weedy Solanum Key.

Cotyledons:

Two.

Leaves:

Alternate.
Petiole - Short with spines.
Blade - Oblong to oval, 40-150 mm long x 30-60 mm wide, dark green, 5-7 deep rounded lobes with the larger lobes often scalloped, wavy edges, pale veins. Base tapered to squarish. Sometimes paler on the under side. Strong spines, 3-15 mm long and tiny star type and glandular hairs on the upper and lower surface. Usually hairier on the under side. Spines are associated with the veins and are longer than those on the stems and petioles.

Stems:

Irregularly branched, stiff, purple or brown in colour, 500-2000 mm tall and wide and carry straight or slightly curved spines, 3-12 mm long and tiny star type hairs.

Flower head:

1-6 flowers in a short raceme or cyme (group) consisting of one bisexual flower and the rest are male. The flower group is on a short stalk (peduncle) and individual flowers are on 10 mm long, densely prickly stalks (pedicels). The raceme is close to the ends of branches.

Flowers:

Purple with a yellow centre (anthers), about 25 mm in diameter.
Ovary -
Calyx - 7-9 mm long, 5 obtuse or acute tipped, triangular lobes, 2-5 mm long, about the same length as the tube. Lobes slightly enlarged and bent back when in fruit, persistent, densely spiny and with tiny star type hairs.
Petals - Purple to almost white, 15-35 mm diameter, star shaped to pentagonal, short tube with 5 folded, fused, acute tipped lobes that are concave (like a boat). Hairy on the outside.
Stamens - Very short, slender, smooth and hairless filaments.
Anthers - Yellow, longer than the filaments, parallel sided, oblong, 5-6 mm long, converging at the tips, protruding from the flower, opening at the top by 2 pores.

Fruit:

Soft, slightly flattened globular, juicy berry, like a little yellow tomato 20-35 mm in diameter with a small calyx. Initially white with green stripes and yellow when ripe then turning brown to black with age. Pulp bitter and poisonous. Persistent calyx on top with many fine prickles. Many seeds in each fruit.

Seeds:

Flattened, light brown to orange, circular, 2-3.5 mm diameter with tiny pits or warts.

Roots:

Strong, woody taproot, with a solid crown.

Key Characters:

Leaves obtuse, pinnatifid to pinnatipartite with scattered stellate hairs on both faces.
Calyx lobes obtuse.
Prickles long and yellow, on calyx, branches and usually on leaves.
Calyx scarcely enlarged in fruit, shorter than berry and not surrounding berry.
Corolla lobe and anthers equal.
Fruit 20-30 mm or more in diameter.
Perennial herb or shrub.
Adapted from J.M. Black and J.R. Wheeler.

Biology:

Life cycle:

Perennial. Seed germinates in spring and top growth is slow while the root system develops. After 2 seasons it may flower. Top growth dies back each winter and new shoots emerge in spring and summer Flowering starts in late spring and continues through summer.

Physiology:

Reproduction:

By seed.

Flowering times:

January to May or August to October in WA.
October to April in SA.

Seed Biology and Germination:

Vegetative Propagules:

None.

Hybrids:

Solanum sodomeum var. Hermannii has glabrous branches, the upper surface of the leaves is glabrous and occurs in southern Italy.

Allelopathy:

Population Dynamics and Dispersal:

Spread by seed. As the fruit is not attractive to animals or birds it is assumed that spread is by water or soil movement. The seed remains within the fruit, which ripens on the bush and eventually falls.

Origin and History:

Mediterranean and North and South Africa.
In Sydney in 1802. Proclaimed a noxious weed in Victoria in 1895 and South Australia in 1897.

Distribution:

NSW, QLD, SA, VIC, WA.

Courtesy Australia's Virtual Herbarium.

Habitats:

Climate:

Temperate. Mediterranean. Sub humid. Humid warm temperate areas.

Soil:

Sandy alkaline soils especially near the coast. Basalt soils.

Plant Associations:

Significance:

Beneficial:

Herbal medicine in South Africa for skin disorders, toothache and colds and roots carried as protection against poisoning.
Used as a poultice by pastoralists for skin disorders on stock and under investigation for its effects on skin cancer.

Detrimental:

Weed of grazed woodlands, streams, roadsides and disturbed areas.
Competes strongly with native species.
Crowds pasture species because it is not grazed.
Restrict stock and human movement.
Harbours rabbits and snails.

Toxicity:

Green fruit is especially toxic to children and sheep.
Poisoning is generally not a problem because the plant is rarely eaten.

Symptoms:

Alkaloid poisoning.
Glycoside poisoning.

Treatment:

Remove stock from the infestation or provide alternate feed.
Alkaloid poisoning.
Glycoside poisoning.

Legislation:

Noxious weed of TAS, VIC and WA.
Secondary and prohibited weed in Tasmania.

Management and Control:

It rarely survives in areas that are regularly cultivated. It only spreads slowly so effective control generally has benefits that lasts for several years.

Thresholds:

Eradication strategies:

Manually remove and burn isolated plants.
Apply a mixture of 120 mL amitrole(250g/L) in 10 L water and spray the bush until thoroughly wet. Seedlings and young plants can also be hand pulled with gloves. Cultivation, followed by treatment of regrowth and seedlings with Tordon® 75-D, is effective.Control infestations within 5 km of the target area to reduce the spread of seed by birds. Plant perennial species which provide a good mulch on the soil surface.

Herbicide resistance:

Biological Control:

Related plants:

See the Weedy Solanum Key.
Afghan Thistle (Solanum hoplopetalum)
Bittersweet (Solanum dulcamara)
Blackberry Nightshade (Solanum nigrum)
Brazilian Nightshade (Solanum seaforthianum)
Buffalo Burr (Solanum rostratum)
Desert Nightshade (Solanum oligacanthum)
Devils Apple (Solanum capsicoides)
Devils Fig (Solanum torvum)
Devils Needles (Solanum stelligerum)
Eggplant (Solanum melongena)
Flannel bush (Solanum lasiophyllum)
Giant Devils Fig (Solanum hispidum)
Glossy Nightshade (Solanum americanum)
Goosefoot Potato bush (Solanum chenopodinum)
Green-berry Nightshade (Solanum opacum)
Kangaroo Apple (Solanum aviculare)
Kangaroo Apple (Solanum laciniatum)
Kangaroo Apple (Solanum vescum)
Madeira Winter Cherry (Solanum pseudocapsicum)
Menindee Nightshade (Solanum karense)
Narrawa Burr (Solanum cinereum)
Oondooroo (Solanum simile)
Porcupine Solanum (Solanum hystrix)
Potato bush (Solanum ellipticum)
Potato climber (Solanum jasminoides)
Potato tree (Solanum erianthum)
Potato (Solanum tuberosum)
Quena (Solanum esuriale)
Rock Nightshade (Solanum petrophilum)
Silver-leaved Nightshade (Solanum elaeagnifolium)
Thargomindah Nightshade (Solanum sturtianum)
Three flowered Nightshade (Solanum triflorum)
Tomato bush (Solanum quadriloculatum)
Western Nightshade (Solanum coactiliferum)
White-edged Nightshade (Solanum marginatum) is very similar and often incorrectly identified, the leaves are less deeply lobed and have a white margin, the stems are silvery grey in colour, and the fruit has a larger calyx.
Wild Tobacco tree (Solanum mauritianum)
Woolly Nightshade (Solanum villosum)
Solanum arbutiloides
Solanum centrale
Solanum chippendalei
Solanum dimidiatum
Solanum dioicum
Solanum oldfieldii
Solanum orbiculatum
Solanum papaverifolium
Solanum sisymbriifolium

Plants of similar appearance:

Afghan Thistle (Solanum hoplopetalum) and (Solanum hystrix) are both extremely spiny sprawling herbs with pale blue to white flowers and their berries are enclosed in the prickly calyx.
Buffalo Burr (Solanum rostratum) is an annual with yellow flowers, and its berries which are almost hidden in the prickly calyx.
Silver-leaved Nightshade (Solanum elaeagnifolium) is a sparsely prickly perennial herb with entire to very shallowly lobed leaves and orange to brown berries up to 1.5 cm across.
Viscid Nightshade (Solanum sisymbriifolium) has twice lobed leaves with many gland-tipped hairs, rusty coloured spines and red berries partly enclosed in the prickly calyx.
White-edged Nightshade (Solanum marginatum) is an ornamental shrub with silvery leaves which are less deeply lobed and have white margins, and also larger berries at 3-4 cm across.
There are many prickly native Solanum species in the Kimberley and Pilbara, but they have not become weedy in the south of the state.

References:

Black, J.M. (1965). Flora of South Australia. (Government Printer, Adelaide, South Australia). P750. Diagram.

Hussey, B.M.J., Keighery, G.J., Cousens, R.D., Dodd, J. and Lloyd, S.G. (1997). Western Weeds. A guide to the weeds of Western Australia. (Plant Protection Society of Western Australia, Perth, Western Australia). P223. Photo.

Hyde-Wyatt, B.H. and Morris, D.I. (1980) The Noxious and Secondary Weeds of Tasmania. (Tasmanian Department of Agriculture, Hobart, Tasmania). P88-89. Diagram.

Lamp, C. and Collet, F. (1990). A Field Guide to Weeds in Australia. (Inkata Press, Melbourne).

Lazarides, M. and Hince, B. (1993). CSIRO handbook of economic plants of Australia. (CSIRO, Melbourne). #1140.18.

Marchant, N.G., Wheeler, J.R., Rye, B.L., Bennett, E.M., Lander, N.S. and Macfarlane, T.D. (1987). Flora of the Perth Region. (Western Australian Herbarium, Department of Agriculture, Western Australia). P537.

Parsons, W.T. and Cuthbertson, E.G. (1992). Noxious weeds of Australia. (Inkata Press, Melbourne). P614-616. Photos.

Acknowledgments:

Collated by HerbiGuide. Phone 08 98444064 or www.herbiguide.com.au for more information.