Real Dictionary

poinsettia
countable noun: 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.

poinsettia in American English
a Mexican and Central American plant (Euphorbia pulcherrima) of the spurge family, with yellow flowers surrounded by tapering red leaves resembling petals
noun: a plant, Euphorbia (Poinsettia) pulcherrima, of the spurge family, native to Mexico and Central America, having variously lobed leaves and brilliant scarlet, pink, or white petallike bracts

poinsettia in British English
noun: a euphorbiaceous shrub, Euphorbia (or Poinsettia) pulcherrima, of Mexico and Central America, widely cultivated for its showy scarlet bracts, which resemble petals