A weedy legume with sickle-shaped seed pods, common on farmland and waste ground.
Sicklepod (Senna obtusifolia, family Fabaceae) is very variable in form: an annual or perennial herb, or a shrub, up to 2 metres tall. It is used locally in many ways, especially as food and medicine, and is occasionally grown for these purposes; its decorative flowers mean it is commonly planted near towns as an ornamental. It is found throughout the tropics, along rivers, on lake shores and on farmland, up to 1,700 metres.
It prefers a deep, well-drained, moderately fertile sandy loam in full sun. It spreads freely and is considered a weed in many parts of the world; an estimated 600,000 hectares are infested in Queensland, Australia. It is a self-pollinating, short-day plant. It is closely related to Senna tora, and S. obtusifolia, S. occidentalis (coffee senna, tsetsa in this archive) and S. tora are often confused: their names have been misapplied and local names may cover all three, and records of S. tora in Africa probably refer to S. obtusifolia. African farmers already select plants that taste less bitter, are less fibrous and have leaves that are easy to pick. Soaking the seed in warm water for 12 hours, or rubbing it with sand, improves germination.
Source: Useful Tropical Plants database (Fern, K.).
Seeds and leaves have laxative properties; large doses are toxic and can cause diarrhoea and tremors.
Young leaves are fermented and used as a meat substitute in parts of Africa; roasted seeds have served as a coffee substitute.
A fast-growing weed of disturbed and cultivated ground.