Have yourself a toxic berry Christmas

Science Sushi
By Christie Wilcox
Dec 25, 2016 8:19 AMNov 20, 2019 5:14 AM


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Photo by Heather Cowper It's evening on Christmas Eve, and it's cold. The early sunset was hours ago, and the insulating clouds have vanished, leaving every surface frozen and glittering like the inside of a geode wherever the light from the street lamps touch. A couple braces as they leave their car and step out into the winter air, their ears filled with the sound of the snow creaking and crunching beneath each fall of their boots, each breath precipitating into thin, gray tendrils that slide past their chilled cheeks. They reach the door of their destination; a home glowing and warm, with muffled laughter and the clatter of silverware spilling out into the dry, stratospheric cold of the street. One of them places a round of knocks below a voluminous wreath of holly, its scarlet berries already wearing a film of frost. The door opens abruptly, and after a series of joyous embraces of ugly-sweatered chests, the couple presents their gift of wine and pie. The magnetic pull of heat, smiles, and carbohydrates draws them inside for the night. As they approach the nexus of the living room, they slowly push through a cavalcade of family members, faces flush with inebriation and the radiative heat of a wood-fired stove. One of them finally reaches a table, liberally adorned with sweets and beverages. They pour two mugs of eggnog, taking care to not catch fire on the centerpiece, a gloriously over-done amalgamation of poinsettias, Christmas roses, and candles. The couple rejoins away from the social huddle of guffaws and crosstalk. They take a swig of their viscous treat, and one of them notes the mistletoe pinned on the beam above them. With a wink and smile, they participate in an age-old tradition, and their lips meet.Not once do they stop to ponder the noxious notoriety of every plant they've come across. From the holly on the door to the mistletoe above their heads, they are surrounded by species with toxic reputations. How did these potential poisons come to be symbolic of a holiday celebrating life and good health? Well, that's a good story...

Holly: Ilex aquifolium and I. opaca

Photo by Nanette Turner Holly is probably the most recognizable floral symbol of Christmas, with its bright red berries and deep green leaves. The genus, Ilex, contains some 400 species scattered worldwide in temperate and subtropical latitudes, but holiday fanatics are most familiar with I. aquifolium, the English holly, or perhaps I. opaca, the American holly, which is found natively in the south and eastern U.S. The English holly—sometimes called the Christmas holly or Christ's thorn—is actually a bit of an thorn in the paw of West Coast and Hawaiian conservationists, as the noxious plant has escaped commercial farms and become invasive, crowding out other species in native forests. The association with the holiday comes from early Christian lore, where the bright red fruits were said to represent the blood shed by Christ on the cross while the leaves represented his thorny crown. They may have picked up the some of the symbolism from the Druids, who also saw blood in the red fruits, wore a crown of holly to ward off evil, and cherished the evergreen plant as a reminder of springtime to come during the dark of winter. The Romans, too, used the plant in their wintertime Saturnalia celebrations, decorating with wreaths, sprigs and garlands. Early Christians may have adopted the use of holly for Christmas to avoid persecution by Roman authorities, hiding their illegal celebrations of Christ's birth in plain sight by using Saturnalian decor. While the plant is known for its "berries," the bright red fruits are not technically berries—they're drupes, like peaches, plums and cherries. How does that song go again? Deck the halls with boughs of holly... fa la la la la la la la la... Eat the berries and you'll be sorry... fa la la la la la la la la ... Or something like that, right? Holly has a toxic reputation, but in reality, most cases are mild. In 2014, there were 637 reported cases of exposure to Ilex species in the US, and from 2000 to 2009, there were a total of 5,432 cases of ingestion (including 71 intentional ingestions!), but none were fatal. Most of the cases occur in small children who eat the plant's iconic fruits, which contain alkaloids, caffeine, and theobromine—the chemical in chocolate that makes it dangerous for dogs. But even still, it takes upwards of 20 of the bitter fruits for a person to be in danger of dying—and they aren't tasty enough to eat that many.


Viscum album and Phoradendron tomentosum

Photo by Flickr user designatednaphour Mistletoe is my favorite Christmas tradition. Whenever I'm hosting for the holidays, I love to hide springs of mistletoe with their green leaves and white berries throughout my apartment in advance of the annual Christmas eve 

festa dei sette pesci

(feast of seven fishes), an Italian-American holiday custom where seven or more kinds of seafood are consumed (my menu deviates pretty far from the classic Italian dishes to include things like poke, but I maintain the theme!). Under the table, on the inside of a cupboard, or anywhere that a pair of guests might serendipitously find themselves underneath, I place the traditional plant (kisses always optional, of course!). Mistletoe is actually a parasitic plant which grows into other trees to steal their water and nutrients. Its name reflects its less than glamorous nature—it comes from the combination of "mistle," old English for dung, and "tan," for twig. "Mistletan"—which later became mistletoe—represented how the plant sprung to life from bird poop on tree branches (romantic, right?). The widespread European species, Viscum album, is the more traditional holiday decoration, though the US's Phoradendron tomentosum (synonym P. flavescens) is sometimes used. The kissing tradition stems, like many Christmas customs, from pagan beliefs. It is thought that the Norse in particular gave the plant its romantic symbolism, as it was custom to kiss below it as a sign of friendship. It, like holly, was also associated with the Roman festival of Saturnalia and related weddings, as its evergreen nature symbolized fertility. In Norse, Druidic and Roman traditions, the plant was also a symbol of peace, and in many early European cultures, it was considered forbidden to fight beneath its boughs. At first, mistletoe was actually shunned by the church, as the plant was considered too pagan. There is a medieval legend that mistletoe was once a proper tree, and that its wood was used to construct Christ's cross. Because of its contribution to the crucifixion, God punished the plant, making it into a parasite that would never again grow on its own. But despite initial disapproval, some early Christians adopted the use of wintertime mistletoe decor, and the association between it and Christmas emerged. As a green plant in the winter, it is now said to symbolize Christ's rebirth. How exactly the reclamation of mistletoe as a Christmas decoration led to the kissing custom isn't clear, but by the 18th century, there were well-known rules in place regarding mistletoe's romantic side. Those who agreed to lock lips beneath its boughs were said to have good luck in love for the next year, while those that refused to kiss would end up alone. But according to etiquette, men could only give a lady as many kisses as there were berries, as they had to pluck one for each smooch. According to the Roman historian Pliny the Elder (23-79 AD), the druids "held nothing more sacred than the mistletoe and the tree that bears it." In his encyclopedic Naturalis Historia (Natural History), he wrote about a sacred tradition where the plant is collected by priests clad in all white using a golden sickle. "It is the belief with them that the mistletoe, taken in drink, will impart fecundity to all animals that are barren, and that it is an antidote for all poisons," he explained. Which is kind of ironic, really, given that the leaves and berries are very, definitely poisonous. Mistletoe (the European variety) contains several toxins, including a lectin similar to ricin that has an intraperitoneal LD50 in mice of 2.4 µg/kg (putting it on par toxicity-wise with batrachotoxin, the killer poison of poison dart frogs, and the nerve gas VX). Unlike holly, there have been recorded deaths from mistletoe in the last few decades—though all are associated with people who, believing deeply in the plant's curative lore, drank tea steeped from the leaves and berries (mistletoe extracts are commonly used in alternative medicine, but they are injected). There were 1,138 recorded ingestions of mistletoe in the U.S. from 2000 to 2009, a surprising 7.5% of which were intentional. Luckily, the American variety is considered less toxic; according to a 1986 study of mistletoe in the US, eating less than three berries or two leaves is unlikely to do more than give you an upset stomach.

Poinsettia: Euphorbia pulcherrima

Photo by Rachel Andrew Unlike most holiday plants, poinsettias are not native to Europe. They come from Central America, and have only become prominent in the US and Canada as Christmas decor in the last century. The name comes from the man who brought them to America, Joel Roberts Poinsett, who served as the first US ambassador to Mexico in 1825. When he saw the plants on a visit in 1828, he fell for their bright, red star-shaped "flowers," and brought them back with him to South Carolina (the red parts are actually modified leaves called bracts—the plant's true flowers are the small and yellow, and can be found at the center of the star of red). He bred and sold the plants to friends and botanical gardens, and they soon became easy to obtain in the U.S. Poinsettia are now the top-selling potted plant in the US and Canada, with more than 65 million of the festive plants sold annually. In their native range, there are about 100 species of poinsettias, some of which stand over 10 feet tall. They were known to the Aztecs as "cuetlaxochitl," and because of their red color—which symbolized purity—were used in religious ceremonies. The plants were also used to produce a colorful reddish dye for clothes, and the sap to treat fevers. The poinsettia became associated with Christmas sometime in the 16th century, soon after Catholicism reached the part of the new world where the plants are native. Poinsettias were probably used in holiday decor because they bloom in the winter and are Christmas-colored and star-shaped, but the legends of how they came to be associated are much more entertaining. Most tell of a poor girl named Pepita or Maria who couldn't afford a gift to give the baby Jesus during Christmas services. Inspired by her brother or an angel, depending on whom you ask, she gathered weeds from the side of the road to the church into a bouquet, and laid it on the altar. To everyone's amazement, the weeds sprouted into big red blossoms, and in honor of the miracle, poinsettias became known as "La Flor de la Nochebuena" (Flower of the Holy Night, or Christmas Eve). Another variation says that it was a poor boy, and the flowers sprouted where his tears fell when he began to cry because he had no gift for Jesus. Whatever the origins, Franciscan friars in Mexico have included the plants in their Christmas celebrations since at least the 17th century. It is often said the red color represents the blood of Christ's sacrifice, while the white leaves on some variants symbolize his purity. Others claim the starry shape is reminiscent of the Star of Bethlehem. Oddly enough, in Spain, the plant is associated with another Christian holiday—there, the poinsettia is known as "Flor de Pascua" (Easter flower). It is often repeated that poinsettias contain deadly toxins, originating from a story from around 1920 of an Army officer in Hawaii who's two-year-old daughter supposedly died from eating one the leaves. Soon, scientists in Hawaii reported hearing of similar deaths, such as this one of a child dying on Kauai from "suckling the freshly cut stems of the Poinsettia." But contrary to the popular myth, poinsettias are not deadly, or even really considered poisonous by medical standards. A study in rats estimated that a 50 lb child would have to eat more than 500 leaves to be in any real danger, and they reportedly taste terrible. Between 2000 and 2009, there were a whopping 19,862 cases of ingestion of poinsettias reported to American Poison Centers—17,419 of which were in children under the age of 5, only one of which had a "major effect" and none of which were fatal. In a study of more than 22,000 cases, 92.4% didn't develop any symptoms of exposure at all, and 96.1% were not even seen by a doctor, leading the authors to conclude "Most patients do not require any type of therapy and can be treated without referral to a health care facility." Consuming the plants can cause nausea and vomiting, and pets don't seem to react as strongly to the foul taste as we do, so pet owners are often cautioned to keep an eye on their fur-babies if they bring poinsettias into the home. That all said, there are some people that react strongly to contact with the plant: the sap contains latex-like proteins, and those with latex allergies can also be allergic to poinsettias.

Christmas rose: Helleborus niger

Photo by Flickr user Paleokeittiö Christmas roses, sometimes called winter roses or snow roses, are not roses at all. Instead, the plant is related to buttercups. The most accurate common name, black hellebore, reflects the plants dark roots. Native to mountainous parts of Switzerland, Bavarian Germany, Austria, Northern Italy and Croatia, the small white flowers somtimes tinted with pink are a common staple in holiday floral arrangements. The Christmas rose has evergreen leaves and blooms in January or February, which likely led to its popularity as winter decor. Depending on which calendar you use, Christmas day is either December 25th or January 7th, so the Christmas rose is said to bloom just in time for the later celebrations. Its connection to the holiday comes from the legend of Madelon, a shepherd that lived near the birthplace of Christ. As the story goes, Madelon ran into the three wise men and the swarm of pilgrims on their way to present their gifts to the baby Jesus. Saddened that she had no gift to give the newborn king, she began to cry. Unknown to Madelon, an angel was watching over, and was moved by her tears. Suddenly, beautiful white flowers erupted from the snow where her tears fell, a gift from the angel for Madelon. Excitedly, she gathered them up and presented them to Jesus, who smiled with joy at the sight of the stunning bouquet. In Christian lore, the Christmas rose is also associated with Saint Agnes, who was only 12 or 13 years old when condemned by the Roman emperor Diocletian. As a "Bride of Christ," Agnes refused to marry her Roman suitors, and out of spite, they outed her as a Christian. The tender white blossoms of the Christmas rose, which are supposedly "whiter" than other flowers, are said to emulate her purity. Like the other holiday plants listed here, Christmas roses are notoriously toxic. Chronic exposure can lead to heart trouble, drowsiness, headaches, delirium, hallucinations and visual disturbances. More acute poisonings can cause cardiovascular disorders, convulsions, and death due to circulatory and/or respiratory failure. In ancient times, the plant was used criminally (for attempts at murder), as well as to poison arrows. Cardiac glycosides as well as a diversity of other toxins have been extracted from the plants. Despite its toxic nature, the Christmas rose has been used for centuries in traditional medicine, and is still taken by adventurous patients for a diversity of conditions, including nausea, colds, and to induce miscarriage.

Special thanks to Jake Buehler for his narrative contributions

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