Euphorbia pulcherrima, commonly known as poinsettia or noche buena, is a species of flowering plant indigenous to Mexico and Central America. It is commonly known as poinsettia after Joel Roberts Poinsett, the first United States Minister to Mexico, who introduced the plant into the US in 1825. It is also called the Atatürk flower in Turkey.
Euphorbia pulcherrima is a shrub or small tree, typically reaching a height of 0.6 to 4 m (2 to 16 ft). The plant bears dark green dentate leaves that measure 7 to 16 cm (3 to 6 inches) in length. The colored bracts—which are most often flaming red but can be orange, pale green, cream, pink, white or marbled—are actually leaves; because the flowers are unassuming and do not attract pollinators, brightly coloured leaves developed (aka bracts). The colors come from photoperiodism, meaning that they require darkness for 12 hours at a time for at least 5 days in a row to change color. At the same time, the plants need a lot of light during the day for the brightest color.
In Nahuatl, the language of the Aztecs, the plant is called Cuitlaxochitl (from cuitlatl, residue, and xochitl, flower) meaning "flower that grows in residues or soil." The Aztecs used the plant to produce red dye and as an antipyretic medication. Today it is known in Mexico and Guatemala as Noche Buena, meaning "Christmas Eve". In Spain it is known as Flor de Pascua, meaning "Easter flower". In both Chile and Peru, the plant became known as "Crown of the Andes".
The plant's association with Christmas began in 16th century Mexico, where legend tells of a young girl who was too poor to provide a gift for the celebration of Jesus' birthday. The tale goes that the child was inspired by an angel to gather weeds from the roadside and place them in front of the church altar. Crimson "blossoms" sprouted from the weeds and became beautiful poinsettias. From the 17th century, Franciscan friars in Mexico included the plants in their Christmas celebrations. The star-shaped leaf pattern is said to symbolize the Star of Bethlehem, and the red color represents the blood sacrifice through the crucifixion of Jesus.
Poinsettias are popular Christmas decorations in homes, churches, offices, and elsewhere across North America. In the United States, December 12 is National Poinsettia Day (Wikipedia).
