Poinsettia

The poinsettia (/pɔɪnˈsɛtiə/; Euphorbia pulcherrima) is a commercially important flowering plant species of the diverse spurge family Euphorbiaceae. Indigenous to Mexico and Central America, the poinsettia was first described by Europeans in 1834. It is particularly well known for its red and green foliage and is widely used in Christmas floral displays. It derives its common English name from Joel Roberts Poinsett, the first United States minister to Mexico, who is credited with introducing the plant to the US in the 1820s. Poinsettias are shrubs or small trees, with heights of 0.6 to 4 m (2.0 to 13.1 ft). Though often stated to be highly toxic, the poinsettia is not dangerous to pets or children. Exposure to the plant, even consumption, most often results in no effect, though it can cause nausea, vomiting, or diarrhea.

Wild poinsettias occur from Mexico to southern Guatemala, growing on mid-elevation, Pacific-facing slopes. One population in the Mexican state of Guerrero is much further inland, however, and is thought to be the ancestor of most cultivated populations. Wild poinsettia populations are highly fragmented, as their habitat is experiencing largely unregulated deforestation. They were cultivated by the Aztecs for use in traditional medicine. They became associated with the Christmas holiday and are popular seasonal decorations. Every year in the United States, approximately 70 million poinsettias of many cultivated varieties are sold in a six-week period. Many of these poinsettias are grown by Paul Ecke Ranch, which serves half the worldwide market and 70 percent of the US market.

The poinsettia was described as a new species in 1834 by the German scientist Johann Friedrich Klotzsch. Klotzsch credited Carl Ludwig Willdenow with the species name "pulcherrima", and the authority is given as Willd. ex Klotzsch. The holotype had been collected in Mexico during an 1803–1804 expedition by Alexander von Humboldt and Aimé Bonpland.

It was known by the common name "poinsettia" as early as 1836, derived from Joel Roberts Poinsett, a botanist and the first US Minister to Mexico. Possibly as early as 1826, Poinsett began sending poinsettias from Mexico back to his greenhouses in South Carolina. Prior to poinsettia, it was known as "Mexican flame flower" or "painted leaf".

Although its story has been debunked, poinsettias are known in Turkey as Atatürk çiçeği (Atatürk flower). The name originated from a report by the newspaper Cumhuriyet, which claimed that while a professor was searching for a name for the newly introduced plant, another professor who had seen Mustafa Kemal Atatürk during his visit to the Talas American College in Kayseri suggested naming the flower Gazi Atatürk.

Euphorbia pulcherrima is a shrub or small tree, typically reaching a height of 0.6–4 metres (2–13 ft). The plant bears dark green dentate leaves that measure 6–16 centimetres (2.4–6.3 in) in length. The colored bracts—which are normally flaming red, with cultivars being orange, pale green, cream, pink, white, or marbled—are often mistaken for flower petals because of their groupings and colors, but are actually leaves. The colors of the bracts are created through photoperiodism, meaning that they require darkness (at least fourteen hours at a time for 6–8 weeks in a row) to change color. The plants also require abundant light during the day for the brightest color. Semi-evergreen, they generally lose most of their leaves during winter.

The flowers of the poinsettia are unassuming. They are grouped within the cyathia (small yellow structures found in the center of each leaf bunch, or false flowers). Nothing is known about pollination in wild poinsettias, though wasps are noted to occasionally visit the cyathia. All flowers in the Euphorbiaceae are unisexual (either male or female only), and they are often very small in size. In Euphorbia, the flowers are reduced even more and then aggregated into an inflorescence or cluster of flowers. Extrafloral nectaries in E. pulcherrima were first reported by Zimmerman in 1932.

Poinsettias are popularly, though incorrectly, said to be toxic to humans and other animals. This misconception was spread by a 1919 urban legend of a two-year-old child dying after consuming a poinsettia leaf. In 1944, the plant was included in H. R. Arnold's book Poisonous Plants of Hawaii on this premise. Though Arnold later admitted that the story was hearsay and that poinsettias were not proven to be poisonous, the plant was thus thought deadly. In 1970 the US Food and Drug Administration published a newsletter stating erroneously that "one poinsettia leaf can kill a child", and in 1980 they were prohibited from nursing homes in a county in North Carolina due to this supposed toxicity.