American black nightshade

Solanum americanum grows up to 1–1.5 metres (39–59 in) tall and is an annual or short-lived perennial. The leaves are alternate on the branch, and vary greatly in size, up to 10 centimetres (4 in) long and 7 cm (3 in) broad, with a 4 cm (1+1⁄2 in) petiole and a coarsely wavy or toothed margin. The flowers are about 1 cm diameter, white or occasionally light purple, with yellow stamens. The fruit is a shiny black berry 5–10 millimetres (1⁄4–3⁄8 in) diameter, containing numerous small seeds.

It has a wide but uncertain native range. The certain native range encompasses the tropics and subtropics of the Americas, Melanesia, New Guinea, and Australia. The plant is widely naturalised around the tropical Pacific and Indian Oceans, including Hawaiʻi, Indochina, Madagascar and Africa, possibly via anthropogenic introduction in these locales.

Despite the toxic compounds that they contain, cooked greens and ripe berries of S. americanum are eaten throughout their range. The ripe fruit is cooked into jams and preserves, or eaten raw. In Africa, South America, New Guinea and Oceania the young green shoots of S. americanum are cooked and eaten as greens, after boiling in water. The cooking water used for boiling the leaves is discarded as it contains the soluble alkaloids. In Kenya, Cameroon and Papua New Guinea the leaves are sold as a leaf vegetable in the markets. The leaves are used in a West Indian stew, and it is known as branched calaloo. In Mauritius it is cultivated and eaten as a pot-herb and used in bouillon. Experts warn that care should be taken since numerous toxins are reported with levels varying with local conditions and varieties.

It is used as a medicine in Cameroon, Kenya, Hawaiʻi, Panama, Sierra Leone, Tanzania and Pakistan. In China a tea from the whole plant is used to treat cancer of the cervix. It is used as folk medicine for a wide range of conditions, being applied topically and internally.