Chamaecrista nigricans

Chamaecrista nigricans is part of Fabaceae, the pea family. Its native range spans Cape Verde, tropical Africa, and Arabia. Records place it in India and northern Australia too. Two of its common names are Diola and Diala. Older sources use the name Cassia nigricans for this plant. People in Africa gather wild plants for medicine and pest control.

This upright plant grows about 1–5 feet [0.3–1.5 metres] tall. Most plants complete their life cycle in one year. Some form a woody base and live for longer. It grows in grassland and savannah with scattered trees. It also spreads into roadsides, farm fields, and waste ground. It grows on disturbed soil too. Its habitats range from sea level to 3,937 feet [1,200 metres]. Sources warn that it can grow as a weed.

It grows in the tropics, where each year has a dry spell. It does well with yearly rain of 950–1,400 millimetres. In these areas, rain falls over five or six months. It often grows on heavy soils of the lateritic type. Plants For A Future lists USDA hardiness zones 10–12. Bacteria form nodules, or small lumps, on its roots. They fix nitrogen, which helps the plant grow. This supply can help nearby plants grow as well. Seeds sprout with ease, though hard seed coats can cause delays. Scarification means making a break in the seed coat. This and soaking may help seeds take up water.

Mature leaves taste bitter, but people add them to food. Reports say that they help people feel like eating. Useful Tropical Plants lists no known hazards for this species. This does not mean that every use is safe. Many records describe leaf use in traditional medicine. People use leaves for fever, coughs, stomach pain, and worms. They also use them for diarrhoea, ulcers, and malaria. They wash wounds and skin complaints with leaf washes. These records show past and current practices, not proven health benefits.

The leaves also help guard stored grain and pulses against insects. People use dried leaves, powder, ash, and extracts for this. Useful Tropical Plants cites research on the leaf powder. That study found that it hinders insect hatching. The source says to remove this material before eating treated food. People also use leaf mixtures against ticks and head lice. These uses give it local value beyond its limited food use.