<Li> Dendromecon--tree poppy </Li> <P> The flowers of most poppy species are attractive and are widely cultivated as annual or perennial ornamental plants . This has resulted in a number of commercially important cultivars, such as the Shirley poppy, a cultivar of Papaver rhoeas and semi-double or double (flore plena) forms of the opium poppy Papaver somniferum and oriental poppy (Papaver orientale). Poppies of several other genera are also cultivated in gardens . A few species have other uses, principally as sources of drugs and foods . The opium poppy is widely cultivated and its worldwide production is monitored by international agencies . It is used for production of dried latex and opium, the principal precursor of narcotic and analgesic opiates such as morphine, heroin and codeine . Poppy seeds are rich in oil, carbohydrates, calcium and protein . Poppy oil is often used as cooking oil, salad dressing oil, or in products such as margarine . Poppy oil can also be added to spices for cakes, or breads . Poppy products are also used in different paints, varnishes, and some cosmetics . </P> <P> Poppies have long been used as a symbol of sleep, peace, and death: Sleep because the opium extracted from them is a sedative, and death because of the common blood - red color of the red poppy in particular . In Greek and Roman myths, poppies were used as offerings to the dead . Poppies used as emblems on tombstones symbolize eternal sleep . This symbolism was evoked in the children's novel The Wonderful Wizard of Oz, in which a magical poppy field threatened to make the protagonists sleep forever . </P> <P> A second interpretation of poppies in Classical mythology is that the bright scarlet color signifies a promise of resurrection after death . </P>

Where did the symbol of the poppy come from
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