Coarse, widely branching, annual herb .2 to 1.7 in tall. Leaves alternate, simple, coarsely pubescent, shallowly 3 to 5 lobed. Flowers green inconspicuous, male and female borne in separate clusters. Fruit broadly cylindrical, to nearly spherical, spiny, 1.5 to 3 cm long including spines, two-seeded, greenish to brown at maturity. Found throughout the south; most abundant in fertile soil in gardens, fields, roadsides and other areas having nearly full sunlight.
The toxic principle is the glycoside, hydroquinone. It is concentrated in the seeds and seedlings (cotyledon stage). Mature plants are distasteful to animals and contain less of the toxin.
Swine are the animals most commonly poisoned. They root up and ingest the two-leaf stage of the plant in the springtime. Symptoms include vomiting and gastrointestinal irritation with occasional diarrhea. Large amounts often cause nervous symptoms including spasmodic running movements and convulsions. Chickens and other livestock have also been poisoned.
Treatment is of little or no value once symptoms have been observed.
Perennial, thorny herb, .2 to .8 m tall. Leaves alternate, simple, irregularly pinnately lobed, 7 to 12 cm long, 3 to 8 cm wide, stellate pubescent. Flowers white to purple, 2.3 to 3.1 cm broad; borne in few-flowered, terminal racemes. Fruit green, turning yellow, like a small tomato, 1 to 1.5 cm in diameter. Found throughout the south; common in pastures, old fields, waste places and sometimes in cultivated ground.
A toxic alkaloid, solanine, has been isolated from this group of plants. Toxicity of these plants varies depending upon maturity, environment and portion of plant ingested. The berries are the most toxic part and are more toxic when they have matured. The berries of both Carolina horsenettle and black nightshade are green when immature. However, horsenettle berries turn yellow when mature and nightshade berries become black. Leaves are also toxic, but to a lesser degree.
All classes of livestock and humans have been poisoned. Two syndromes have been described: acute and chronic. The acutely poisoned animal is characterized by irritation of the mouth and gastrointestinal lesions. In the chronic form, unthriftiness, jaundiced mucous membranes, abdominal dropsy and constipation have all been seen.