Crotallaria juncea

Description: Crotalaria juncea, known as brown hemp, Indian hemp, Madras hemp, or sunn hemp, is a tropical Asian plant of the legume family (Fabaceae). It is generally considered to have originated in India. It is now widely grown throughout the tropics and subtropics as a source of green manure, fodder and lignified fiber obtained from its stem. Sunn hemp is also being looked at as a possible bio-fuel. It can be an invasive weed and has been listed as a noxious weed in some jurisdictions. It bears yellow flowers and elongate, alternate leaves.

Flowering and Fruiting: May to September.

Economic Importance: The fibre is made into cordage, fishing nets, sacking fabrics, canvas, and rug yarns and is used to manufacture such paper products as cigarette and tissue papers. The plant is also cultivated in many tropical countries as a green manure crop that is plowed under to fertilize soil. 

Reference: https://en.wikipedia.org/wiki/Crotalaria_juncea