A poppy is a flowering plant in the subfamily Papaveroideae of the family Papaveraceae. Poppies are herbaceous plants, often grown for their colourful flowers. Poppies have long been used as a symbol of sleep, peace, and death: Sleep because the opium is a sedative, and death because of the common blood-red colour. In Greek and Roman myths, poppies were used as offerings to the dead - Morpheus and Hades were brothers. Poppies used as emblems on tombstones symbolize eternal sleep, and have become a symbol of remembrance of soldiers who have died during wartime.