hemp Cannabis sativa, is cultivated mostly as a source of fibre for rope-making and illegally for various narcotic products; but it also has edible seeds which are not narcotic and from which an oil can be pressed. Its leaves are occasionally grown as a vegetable.
Hemp grows wild in C. Asia, and was first cultivated in China from 3000 BC for its fibre and seeds. The plant has males and females. The males are taller and provide better fibres from their stems, while the females are stronger in narcotic substances; these are concentrated in a gummy resin which exudes from the flowers and are present in smaller amounts in the top leaves.