Solanum carolinense L.—Horsenettle
Solanum nigrum L —Black nightshade; deadly nightshade; common nightshade; garden nightshade
FAMILY: Solanaceae—the Nightshade Family (see Datura)
PHENOLOGY: Solanum carolinense and S. nigrum flower May through October.
DISTRIBUTION: Both are found in disturbed soil, woods, meadows and pastures, and cultivated fields; S. carolinense is also found in barren fields and wasteland.
PLANT CHARACTERISTICS: Horsenettle can he recognized by its prickly, stellately pubescent appearance. Plants are rhizomatous, to 1 m with leaves: 7-12 cm, half as wide, with 2-5 large teeth or shallow lobes, prickly on veins beneath. elliptic to ovate; inuorescence: several flowered, elongating at maturity to a simple racemiform cluster; flowers: 2 cm wide; corolla: violet to white; anthers: equal; fruit: yellow, 1-1.5 cm, subtended but not enclosed by the unarmed calyx.
Black nightshade is a branching annual, 1.5-6 dm, glabrous or somewhat strigose above; leaves: irregularly blunt-toothed or subentire, ovoid to deltoid, 2-8 cm; flower: white corolla, 5-10 mm; fruit: black, globose, 8 mm, mature calyx 2-3 mm, lobes often unequal.
POISONOUS PARTS: The berries and vegetation are poisonous. The toxicity is not lost in drying and may be toxic in hay.
SYMPTOMS: In sheep, severe intestinal lesions develop as a result of horsenettle toxicosis. There may be inflammation of the mouth and esophagus in calves. Nervous symptoms may include apathy, drowsiness, salivation, dyspnea, trembling, progressive weakness or paralysis, prostration, and even unconsciousness. In humans, loss of senses sometimes occurs. Gastrointestinal effects may include anorexia, nausea, colic, vomiting, and constipation or diarrhea (possibly with blood). Poisoning is not always fatal (fatalities are due to paralysis).
Postmortem: gross lesions: kidneys surrounded by blood-tinged serum and edema; toxicosis of longer duration produces blood clots; histological lesions: pale kidneys with toxic tubular necrosis with casts and proteinaceous precipitate in the lumen; focal hemorrhages and edema associated with the toxic nephrosis; digestive tract lesions include acute catarrhal or hemmorrhagic gastritis and enteritis with ulcers that may extend to or throughout the muscularis propria.
Ingestion of black nightshade may cause nervous symptoms including apathy, drowsiness, salivation, dyspnea, trembling, progressive weakness or paralysis, prostration, and loss of consciousness. In humans, stupefaction and loss of senses develop, Gastrointestinal irritation may include anorexia, nausea and vomiting, cholic, and constipation or diarrhea (diarrhea may contain blood). Poisoning does not always end in death. Toxicosis climaxes in a number of hours, or in 1 to 2 days. Death is the result of paralysis. Chronic poisoning may occur and may include ascites as a symptom.
POISONOUS PRINCIPLES: Solanine, a saponic glycoalkaloid that breaks down into a sugar (solanose) and an alkamine (solanidine), is responsible for poisoning. The alkamines are steroidal. Concentration of solanine may increase 10 times with maturity.
CONFUSED TAXA: There are approximately 10 species of Solanum encountered in Pennsylvania. The taxa are separated by technical characters such as pubescence, leaf and corolla shape, and calyx structure. The genus Physalis (ground cherry) is sometimes confused with Solanum. Physalis has longitudinally dehiscent anthers and a spineless mature calyx. Solanum has anthers dehiscing by terminal pores and often a spiny calyx. The unripe fruits of Physalis are poisonous.
SPECIES OF ANIMALS AFFECTED: All species of livestock, deer, and humans are susceptible.
TREATMENT: (11a) (b); (26); (17)
OF INTEREST: The dried berries of horsenettle, which cling to the plant over the winter, killed cattle in March. The berries may be sought in preference to other food. Horsenettle is believed to have caused the death of a 6-year-old boy in Delaware County, Pennsylvania, in 1963. Solanum carolinense seeds are Restricted Noxious Weed Seeds and must be listed on the tag or label on agricultural seeds sold in Pennsylvania.
Nightshade berries have been cooked and used for plum puddings and in preserves, jams, or pies with no ill effects. Boiling apparently destroys the toxic principle. When three kilograms of green plant were experimentally fed to a horse, no serious symptoms were observed.
The compound solanine has been used as an agricultural insecticide. The LD50 in mice is 42 mg/kg. The cultivated house plant Solanum pseudocapsicum L. (Jerusalem cherry, Natal cherry) is a cardiac depressant. The leaves contain the cardioactive substance solanocapsine, while berries contain the glycoalkaloid solanine and related substances. This ornamental potted plant will affect house pets and children if eaten. If grown too close to the soil surface, ordinary potatoes (S. tuberosum L.) will develop a green skin from exposure to the sun. This green skin, as well as young sprouts, can contain alkaloids that cause human and livestock toxicosis and fatalities. Brown-skinned, unsprouted potato tubers contain 0.009% solanine. Toxicosis is associated with concentrations of 0.049/o. Green potatoes should not be used in food preparation, or the green tissue should be removed before the tuber is used, Symptoms of poisoning are those given above for the alkaloid solanine.