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spurge (spûrj), common name for members of the Euphorbiaceae, a family of herbs, shrubs, and trees of greatly varied structure and almost cosmopolitan distribution, although most species are tropical. In the United States the family is most common in the Southeast.
Many plants of the spurge family have reduced fleshy leaves, in particular the vast Euphorbia genus of approximately 1,600 subtropical and warm-temperate species. These cactuslike plants, comprising most of the species commonly called spurge, have spiny, jointed stems and are among the most common Old World desert succulents. The euphorbias and the cacti illustrate the biological phenomenon of convergent evolution, in which unrelated groups of organisms, subject to the same environmental pressures, gradually develop similar structures. The euphorbias exhibit another family trait: “naked flowers” (i.e., flowers lacking petals and sometimes sepals) that are enclosed in a bract envelope, from which they emerge during the flowering period to permit pollination.
Many species are cultivated for their brilliant, showy bracts as well as for their frequently colorful foliage. These include snow-on-the-mountain (E. marginata), native to the United States; the cypress spurge (E. cyparissias), a favored cemetery plant that was introduced from Europe and naturalized; the scarlet-bracted greenhouse plant crown-of-thorns (E. splendens), native to Madagascar; and the poinsettia (for J. R. Poinsett), an ornamental shrub native to Central America. The poinsettia (E. pulcherrima), whose several species are sometimes considered a separate genus (Poinsettia), is a popular Christmas decoration with its large rosettes of usually bright-red bracts.
Other Spurges and Their Uses
Many spurges are of great economic importance as a source of food, drugs, rubber, and other products. The sap of most species is a milky latex, and the source of a very large part of the world's natural rubber is the latex of the Pará rubber tree. Pará rubber and several other latexes also come from plants of the spurge family. The tropical American Manihot genus includes the cassava, the source of tapioca and the most important tropical root crop next to the sweet potato.
Other valuable commercial products of this family are castor oil and tung oil, expressed from the seeds of Ricinus communis and Aleurites fordii respectively. The castor bean, the source of castor oil, is native to tropical Africa, where it grows as a tree, but is now widespread and is sometimes cultivated in temperate regions as an annual ornamental. The tung tree, indigenous to E Asia and Malaysia, is the only important plant of the spurge family cultivated commercially in the United States. The candlenut tree (A. moluccana) and the Japanese wood oil tree (A. cordata), of the same genus as the tung tree, also yield oils, as does the Chinese tallow tree (Sapium sebiferum), a source of grease for candles and soap.
Various spurges provide medicines, dyes, oils, and other products; primitive peoples utilized the poisonous saps of other spurges on arrow tips and to poison fish. The presence of poisonous substances in many euphorbias and in a number of other spurges has led these to be classed as noxious pests, especially when they grow as weeds on livestock ranges.
The poinsettia originally hails from Mexico. The leaves that crown the end of each poinsettia stalk undergo a seasonal color change in December, turning from green to red. As Christianity spread across Mexico during the colonial era, this color change turned poinsettias into a popular Christmas decoration. The Mexicans call the plant florde la Nochebuena, or "Christmas Eve flower."
A Mexican folktale explains this name. Many years ago on Christmas Eve a poor girl sought a gift to offer to the Christ child. She realized, however, that she owned nothing beautiful enough to give the infant. She began to cry, but eventually her desire to pay tribute to the child overcame her shame. She plucked a branch of an ordinary green plant that grew beside the road and humbly brought it to the manger. As she laid it beside the crib the leaves of the plant burst into a brilliant red in recognition of the child's humility and Jesus' pleasure with the gift.
The poinsettia's popularity in the United States can be traced back to the initial interest of one man, Dr. Joel Roberts Poinsett. Appointed the first U.S. ambassador to Mexico, Dr. Poinsett also maintained an interest in botany. While stationed in Mexico in 1825 he noticed a plant whose ordinary green leaves turned a brilliant red in December. Intrigued by these tongues of fire he sent samples home to South Carolina where he maintained a greenhouse. Other horticulturists soon adopted the plant. Botanists named the plant Euphorbia pulcher-rima, but the public called it "poinsettia" in honor of the man who first imported it to the United States. By the last quarter of the nineteenth century New York shopkeepers were offering poinsettias at Christmas time. By the twentieth century Americans had fully adopted the plant as a Christmas symbol. The current popularity of the poinsettia as a Christmas decoration can be measured in numbers. In 2000 Americans bought more than 65 million of these potted plants.
The leaves of the poinsettia are very sensitive to light. During the darkest weeks of the year the leaves at the end of each stalk react to the shortage of sunlight by changing color. Although people commonly refer to the poinsettia's scarlet blooms as "flowers," in fact only the yellow buds at their centers are flowers. The red halos that surround them are composed of a special kind of leaf known as a bract.
Americans seem to favor red poinsettias as Christmas decorations, but other less well known varieties of the plant sport leaves that change from green to white, yellow, or pink. A number of these varieties were developed by the Ecke family. In the early part of this century Paul Ecke, a flower farmer located near Los Angeles, California, played a major role in developing new varieties of poinsettias and championing these hardier and more attractive plants as Christmas decorations. His cross-country promotional tours eventually paid off. Not only has the poinsettia become a Christmas symbol, but also the Ecke family farm, now located in Encinitas, California, continues to supply a large percentage of America's demand for the potted plants and the cuttings from which they grow (see also Urban Legends).
Christmas in Mexico. Chicago: World Book, 1976. Christmas in the American Southwest. Chicago: World Book, 1996. Comfort, David. Just Say Noel. New York: Fireside Books, 1995. Del Re, Gerard, and Patricia Del Re. The Christmas Almanack. Garden City, N.Y.: Doubleday, 1979. Hottes, Alfred Carl. 1001 Christmas Facts and Fancies. 1946. Reprint. Detroit, Mich.: Omnigraphics, 1990.
"Poinsettia: The Christmas Flower," an article by D. Michael Benson, et al., through the American Phytopathological Society, located in St. Paul, Minnesota. Published in the December 2000 - January 2001 issue of their online journal, APSnet, at: http:www.apsnet.org/online/feature/xmasflower/
(Euphorbia pulcherrima), a shrub native to Central America. This plant reaches a height of 1.5 m and contains a milky juice. The leaves are ovate-oblong with notched margins, and the inflorescences of unisexual flowers are encircled by large flaming red lanceolate bracts. The poinsettia blooms in December and January; it requires short periods of light (no more than ten hours) for normal development. It is cultivated in greenhouses, where it is kept in darkness for a certain number of hours and treated with substances to retard stem growth. Varieties with pink, white, and orange bracts have been produced.