The scientific name for the poinsettia, the vibrant plant widely used in holiday decorations, is Euphorbia pulcherrima. This binomial nomenclature provides a precise, universally recognized label for the species, eliminating the confusion that can arise from its many regional common names. Scientific classification is essential for botanists and horticulturalists to accurately identify the plant and distinguish it from other related species worldwide.
Taxonomy and Nomenclature
The poinsettia belongs to the expansive genus Euphorbia, which contains over 2,000 species of flowering plants, and is part of the spurge family, Euphorbiaceae. The genus name, Euphorbia, likely honors Euphorbus, a first-century physician to the King of Mauretania. The specific epithet, pulcherrima, is a Latin word meaning “most beautiful,” a clear nod to the plant’s striking appearance.
This formal name, Euphorbia pulcherrima, was first described in 1834 by the German botanist Johann Friedrich Klotzsch. The common English name, poinsettia, emerged shortly after and honors the man who introduced the plant to the United States. The plant’s classification within the Euphorbia genus is a matter of ongoing scientific study, but E. pulcherrima remains its accepted species designation.
Origins and Cultural Significance
The poinsettia is native to the tropical forests and dry deciduous areas of Mexico and Central America. In its native habitat, it can grow as a shrub or small tree, reaching heights of up to 13 feet. The Aztecs, who cultivated the plant, called it cuetlaxochitl in their Nahuatl language, meaning “flower that withers” or “flower that grows in the residues”.
The Aztecs used the plant for practical purposes, extracting a reddish-purple dye for textiles and cosmetics, and utilizing its milky sap to treat fevers. After the Spanish conquest, Franciscan friars in the 17th century began using the plant in Christmas celebrations, renaming it flor de Nochebuena (“Flower of the Holy Night”) because it blooms around Christmastime. Its journey to becoming a global holiday staple began when Joel Roberts Poinsett, the first U.S. Minister to Mexico, encountered the plant in the 1820s. Poinsett sent cuttings back to South Carolina, and the plant was subsequently named in his honor.
Botanical Structure and Coloration
The most distinctive feature of Euphorbia pulcherrima is its intense coloration, often mistakenly identified as the flower. The bright red, pink, or white structures are not petals but modified leaves known as bracts. These showy bracts function primarily to attract pollinators to the plant’s true flowers.
The actual flowers are the small, yellow, berry-like structures located in the center of the bract cluster, called cyathia. The bracts develop their vivid color through photoperiodism, a physiological response to the length of day or night. To induce coloration, poinsettias require a minimum of 14 hours of uninterrupted darkness daily for six to eight weeks. This extended period of darkness triggers the chemical changes that cause the bracts to transform from green to their characteristic bright hues.
Addressing Common Toxicity Myths
For decades, the poinsettia has been wrongly rumored to be highly poisonous, a misconception stemming from an early 20th-century urban legend. Extensive studies have since demonstrated that Euphorbia pulcherrima is not deadly, and exposure rarely results in serious effects. Research showed that a 50-pound child would need to ingest over 500 bracts to reach a potentially toxic dose.
The plant is officially classified as having low-severity poisonous characteristics. If any part is ingested by children or pets, it may cause only minor symptoms such as mild gastrointestinal irritation, vomiting, or diarrhea. The plant’s milky white sap, or latex, contains diterpenoid euphorbol esters and saponin-like detergents, which can cause a skin rash or contact dermatitis in sensitive individuals. It is prudent to keep the plant out of reach of small children and pets, as with any household ornamental.