Crotalaria pallida Aiton var. obovata (G. Don) Polhill

Smooth Rattlebox

Herb

Annual

Vascular

Smooth Rattlebox is an introduced herbaceous annual in the Bean family (Fabaceae). It is native to tropical Africa, but has been introduced in many parts of the world. In Alabama it can be found at scattered locations across the state. Smooth Rattlebox occurs around fields, on roadsides, along railroad tracks, and in other ruderal sites. It is an annual with a tap root. Stems are erect, 2-6 feet in height, branched or unbranched, green in color, and pubescent. Leaves are alternate, petiolate, and trifoliate. The leaflets are obovate in outline, entire, and pubescent below. Flowers are produced in racemes. The racemes are usually well exserted and the flowers dense along the stem. The calyx is pubescent. The corolla is papilionaceous, yellow in color, often with the veins reddish. The fruit is a slightly inflated, falcate, shortly pubescent legume. Smooth Rattlebox has a long history of cultivation as a green manure or cover crop. It contains pyrrolizidine alkaloids which can damage the liver when consumed. Large doses can be toxic to birds and mammals. The toxins are slow acting and symptoms may only appear weeks or months after the animal has eaten the plant. The alkaloids are most concentrated in the seed. Smooth Rattlebox has been used in traditional medicine to treat urinary problems, skin rashes, and to reduce fevers and joint swellings.--A. Diamond

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Not Native

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