A poinsettia is a plant with groups of bright red or pink leaves that grows in Central and South America. Poinsettias are very popular in Britain and the United States, especially at Christmas. a tropical plant with groups of large red or white leaves that look like flowers (Joel R. Poinsett (1775-1851), U.S. diplomat and plant scientist). Popular flowering plant (Euphorbia pulcherrima), best-known member of the diverse spurge family. Native to Mexico and Central America, it grows in moist, wet, wooded ravines and on rocky hillsides. What appear to be flower petals are actually coloured leaflike bracts that surround a central cluster of tiny yellow flowers. Cultivated varieties are available with white, pink, mottled, and striped bracts, but the solid red varieties are in greatest demand during the Christmas season. Milky latex in the stems and leaves can be irritating to sensitized persons or animals, but the claim that poinsettias are deadly poisonous is greatly exaggerated