Rye (Secale cereale), a cereal grass, probably native to South-Eastern Europe, the flour of which forms the black bread which is the staple food of most of Northern Europe. It is still cultivated to a small extent in our eastern counties, but mainly as green fodder. Its grain is imported for malting. In structure it nearly approaches wheat, but differs in having two flowers and a stalked rudiment of a third in each of its spikelets. It is peculiarly liable to the attacks of the fungus ergot (q.v.), which is known in pharmacy as Secale cornutum or "horned rye."