Cannabis leaf. Kirlian photograph of a leaf of the hemp plant (Cannabis sativa), showing the electromagnetic discharge around the edges. This luminous discharge is the result of high-energy interactions between the leaf and a powerful applied electric field. This plant is native to Asia, and is a valuable source of tough natural fibres. As well as this, the leaves and flowering heads of the plant are dried to produce marijuana. This preparation is smoked as a euphoriant drug. For this reason, growing hemp is illegal in most countries without a licence.