Crotalaria spectabilis is native to South and Southeast Asia but has been widely introduced to the Americas and Africa for agricultural purposes. It is an upright annual legume that can reach heights of up to six feet, notable for its striking yellow flowers arranged along vertical stems. These flowers display the classic papilionaceous structure of legumes, with a broad banner petal and two lateral wings enclosing the reproductive parts. The species has been cultivated as a green manure crop because of its ability to fix nitrogen and improve soil fertility, making it valuable in sustainable agriculture. Despite its utility, Crotalaria spectabilis contains pyrrolizidine alkaloids, making it toxic to livestock if consumed, though it is not typically grazed. Photographed in Colombia.