White Snakeroot – the weed that killed Abraham Lincoln’s mother and changed history.

White Snakeroot proliferates in clearings in the woods.

Common Name: White Snakeroot, Indian or White Sanicle, Richweed – Snakeroot is used as a common name for several plants without clear attribution. It is generally asserted that this would mean that the plant was used to treat snake bites, that it was found in common snake habitats, or perhaps had snake-like roots. The white flowers are distinctly profuse and therefore descriptive.

Scientific Name: Ageratina altissima – The Latin ageraton is taken directly from the Greek word ageratos, meaning ageless. [1] This presumably refers to the persistence of the flowers well into autumn. The species name is, like altitude, derived from the Latin root indicating tallness; white snakeroot is frequently a meter in height. Formerly known as and frequently listed as Eupatorium rugosum. [2]The genus Eupatorium is from Mithridates Eupator [132-62 BCE], who was the governor of Pontus who was accredited with discovering a universal antidote for all poison; several plants of the genus (like boneset) have medicinal properties.

Potpourri: White Snakeroot is unremarkable. While it is attractively festooned with bouquets of small white flowers that extend from the ends of an array of its many branches and reaches heights of five feet, it attracts only small flying pollinators but not people. This is in part because it is one of several plants that are noted for clusters of small white flowers, including Queen Anne’s lace, yarrow, and boneset. But historically, it is a very important weed indeed. It is responsible for one of the most severe and mysterious maladies of the early colonists as they moved west and homesteaded. Many died of what was called the milk sickness. Among its victims was Nancy Hanks Lincoln.

Samuel Lincoln was one of the many thousands of Puritans who sailed from England to the Massachusetts Bay Colony through the Boston port of entry, arriving in 1637, his progeny a microcosm for the westward dispersal of the colonists. Three generations later, his great grandson John Lincoln settled in Virginia, providing 210 acres of his land to his first son, Abraham, who served as a captain of militia in the Revolutionary War. One consequence of the successful war for independence from Great Britain that culminated in the Treaty of Paris in 1783 was the free movement of settlers westward over the Appalachian Mountains into the Ohio River Valley. The pioneering spirit drew Lincoln westward, settling with his wife and five children in a remote farmstead of over 5,000 acres on the Ohio River in what is now Kentucky in 1781. Five years later, he was shot and killed by an Indian, his youngest son Thomas now fatherless and without inheritance or prospect continued west. Consistent with the landless younger sons of his generation, he worked to earn enough money to buy land, where he built a cabin, married Nancy Hanks, and started a family; he named his first son Abraham. Land disputes in Kentucky drove the Lincoln family west into southern Indiana in 1816. Nancy Hanks Lincoln, the mother of President Abraham Lincoln, died of what was called the milk sickness on October 5, 1818. [3]

Frontier living was harsh and mercurial; pioneers required a combination of iron will, good fortune, and ingenuity to survive. Absent any knowledge of microbial malevolence, life could be short and brutal; many children died in infancy and mysterious diseases could strike anyone at any time. For the settlers of the Ohio River Valley, one of the most common and frequently fatal ailments was named according to its symptoms as ‘sick stomach,’ puking illness,’ and eventually ‘the slows and the trembles.’ The first indications of abnormality were usually listlessness and loss of appetite progressing to muscle stiffness, vomiting and trembling over the course of several weeks. In many cases, symptoms did not abate leading to jaundice, prostration and death. Not infrequently, the farm animals of the stricken were observed to succumb with markedly similar symptoms. Cows, sheep and especially horses were all affected, the latter felled with extreme virulence in three days. With little communication among isolated settlements, the similarity of symptoms of those who died was not immediately evident.

In piecemeal sharing of individual experience anecdotes, it eventually emerged that the proximate cause for humans was the consumption of milk from poisoned cows leading to the assignation milk sickness, the name that has persisted. According to an Indiana historian “milk sickness killed many, frightened more, and caused local economic distress. Villages and farms were abandoned, livestock died, entire families were killed.” Discovering the root cause was a matter of some serendipity; many logically concluded that it must have something to do with what the farm animals were eating and where they ranged to get it. As early as 1809, a doctor named Barbee came to the Ohio River Valley from Virginia and described what he observed among those entrusted to his care, noting the similarity of the human symptoms to those of proximate farm animal stock. An 1811 article in a Cincinnati newspaper reported the observation that the problem seemed to originate from cows allowed to wander outside established pastures into oak woods and valleys. [4]

While lore and legend inevitably augment the historical record. (John Chapman cum Johnny Appleseed a case in point), it is plausible that the hypothesis that milk sickness was caused by a specific plant originated with Doctor Anna Pierce Hobbs Bixby (1812 – 1873), probably the first female physician in Illinois. Her life story is a compelling saga of pioneer spirit. Anna Pierce came to Illinois from Philadelphia as a youth and became a teacher, returning to her city of origin to train in midwifery and other medical practices to return as a frontier doctor, where she met and married Isaac Hobbs. In the heart of milk sickness country, she was immediately involved both professionally and personally as her mother and sister were felled by the malady. When the proximity of sick cows and sick people became a matter of observation, it is alleged that while she was searching the fields where the cows grazed looking for a plausible cause, she encountered a Shawnee woman who pointed out a tall weedy plant with small white flowers as one known to her people as poisonous. We don’t know what they called it at that encounter but probably the Algonquin name for the plant; it is now known as white snakeroot.

The etymology of snakeroot is unclear, as is the case with many plants and animals of the New World that were first named by its original denizens; colonists frequently translated the Indian name into its Anglicized form (e. g. woodchuck comes from the Cree wuchak) It may then have originally been an Algonquian word that sounded like snake or a translation of the Algonquian word for snake. It is also feasible that snake was used as something of a metaphor – some snakes are poisonous so plants that poison are like snakes. There are several plants also commonly called snakeroot. Whatever white snakeroot was originally called, Dr. Pierce initiated a local program to eradicate the weed and to warn those within the range of her practice of its consequence. However, due to the remoteness of settlement and the lack of communication technology, the correct identification of white snakeroot as the cause of milk sickness did not transcend throughout the midwestern region. When Isaac Hobbs died of pneumonia, Anna married a man named Eson Bixby who turned out to be a horse thief intent on stealing her money. Legend has it that he tied her up and threw her off a cliff and then set fire to the surrounding woods. She survived. Milk sickness continued to be a major problem; an Indiana doctor named Bunnel reported that he typically had five patients with milk sickness continuously through the 1830’s and one county reported that fully half of all deaths during this period were due to milk sickness. [5]

Native American had a substantive knowledge of plants that poisoned, plants that healed, and plants that could be eaten. The Eurasians that migrated to the Americas thousands of years ago survived according to tribal oral tradition of accrued lore; the western civilization that unsettled their lives is only about two thousand years old. While the lack of a written record detracts from historical surety, documented testimonials of tribal practices report that white snakeroot was used by many tribes, notably the Cherokee and the Iroquois for a variety of purposes ranging from antidiarrheal to warming tonic; there is no recorded use of the plant to treat snakebite although it may have been [6]. In general, Indian plant remedies are not tested to modern standards of controlled drug assessment as it is too expensive relative to any gains that might accrue; it is known that it was used but not that it worked The Algonquin Shawnee people of the Ohio River Valley left no oral tradition of snakeroot use, but this is surely a matter of omission and not commission; they frequently crossed paths with their Iroquoian neighbors to the east. It is certainly more plausible that Shawnee pointed out the plant to Dr. Pierce, as it would have been most unlikely that she would have picked it from the bouquet of diverse wildflowers that grow in scattered patches throughout the forest.

White snakeroot qualifies as a weed which is defined as an uncultivated pioneer plant that is undesirable, an anthropocentric notion that ignores the role of nature as the true arbiter of what grows and what doesn’t. As the cynosure of the milk sickness epidemic, it is surely an evil weed – the pejorative sobriquet of smoking tobacco – if ever there was one. The scenario for ‘man meets plant’ is clearly (pun intended) evident. As migrating farmers cleared new land from the forest for their fields, the copious wind driven snakeroot seeds ringed the open areas where shade prevailed to establish dense patches interconnected by underground rhizomes. The plant is about two feet tall with large, toothed green leaves topped with terminal clusters of small white flowers. As the hardscrabble frontier farm progressed, livestock were introduced to augment dietary protein. The stage was thus set for the milk sickness drama to unfold, as grazing cows browsed around the edges of clearings where the lush green plants flourished at a convenient muzzle high elevation. The cows ate the snakeroot, the farmers milked the cows, and their families perished from the milk sickness. Case closed? Not quite’

It is easy to see why herbivores like cows would be drawn to the verdant pastures of white snakeroot.

It took over a half century to determine the proximate cause of milk sickness and another half century to understand its physiological effects. While local remedies had reduced the pernicious effects of snakeroot in some areas (in addition to Dr. Pierce, there had been some successes achieved by keeping their cows behind fences), the syllogistic relationship between snakeroot and sickness remained a mystery. By the middle of the 19^th century, it was widely accepted that some type of plant was involved but there were numerous candidates including poison oak, wild parsnip, and white snakeroot. In 1841, the Kentucky legislature offered two thousand dollars to anyone who discovered the true cause of the milk sickness; it was never collected. In the 1850’s both Indiana and Ohio initiated statewide medical and agricultural surveys to gather information from which regulatory policy could be based. Based on these surveys, which included instances of feeding trials conducted with animals that developed the characteristic symptoms of trembles, it was generally concluded by 1850 that milk sickness was caused by cows eating white snakeroot. It appeared in the 5^th edition of George P. Woods medical textbook in 1858, affording the hypothesis official medical certification as fact. [7]

The prevalence of milk sickness as one of the most malevolent of frontier maladies faded during the second half of the 19^th century until it had almost disappeared by 1900. This is attributed to an increasing public knowledge of the problem but also and probably more importantly due to the simple fact that the frontier had largely disappeared as fences around established pastureland predominated. A 1909 National Institutes of Health report stated, “with the advance of civilization, as forests were cleared, and pastures fenced the disease became less frequent.” [8] The last documented case of milk sickness was in 1963 when two infants were admitted to a Saint Louis, Missouri hospital and determined by blood testing to have a severe condition known as metabolic acidosis, which was remediated with intravenous infusion of bicarbonate to lower the PH to the normal neutral range. One of the older staff physicians suggested a diagnosis of milk sickness based on dim memories of his early practice. Subsequent inquiry proved that the infants had been given milk from cows who had been allowed to wander into infested areas, the theory presumably being that this was more natural and therefore more wholesome. [9] Those who forget or ignore history are doomed to repeat it, and, according to Ecclesiastes, “whatever is has already been and what will be has been before.”

The physiological nature of milk sickness and the mechanisms by which it was induced by white snakeroot could not be fully explained without the knowledge and laboratory acumen of chemistry that began in earnest in the early 20^th Century. A researcher named Couch first isolated a straw-colored oil from white snakeroot in 1929; he named it tremetol in recognition of the ‘trembles’ that it caused. The toxic dose for animal ingestion was estimated at ten percent of body weight. While this seems to be more than a grazing animal might possibly eat, the amount is cumulative with tremetol building up over time. White snakeroot is still a problem for grazing animals; In 1983, four horses in Ohio died with symptoms of trembles. Investigation by Ohio State University veterinarians confirmed that their pasture was filled with white snakeroot. There is no antidote for tremetol poisoning in animals, supportive care is prescribed but death is frequent and permanent disability likely. [10] The chemical nature of white snakeroot poisoning was not established until 1971. It disrupts the very essence of life.

Everything animals do requires energy which comes from what they eat. Carbohydrates, protein and fats are broken down into their constituent molecules by digestion and absorption. The chemically complex process of metabolism is to animals what photosynthesis is to plants, oxidation of carbohydrates forming the carbon dioxide that keeps the cycle in balance. What tremetol from white snakeroot does is to interfere with the citric acid enzyme in the liver to disrupt the operation of the Krebs cycle. [11] In somewhat simplistic terms, glucose derived from food digested in the stomach and absorbed in the small intestine is transported to the hepatic portal vein and thus to the liver. The breakdown of glucose that ultimately releases energy in the form of adenosine triphosphate (ATP) formation in cell mitochondria by the Krebs cycle is facilitated or catalyzed by the citric acid enzyme. The action of tremetol thus disrupts the basic operation of glucose metabolism; the body then reverts to the ketosis backup mode, using ketones produced by the liver from fatty acids. The trembling symptoms are due to energy disruption. As the amount of tremetol accumulates, probably in the liver, the metabolic engine gradually shuts down, and the acidity of ketones results in ketoacidosis, which is life threatening.[12] One of the ketones is acetone which has a distinctive smell, reported to be quite evident in the respiration of milk sickness victims. And that is how white snakeroot became the plant that killed Abraham Lincoln’s mother.

And that is how white snakeroot became the weed that killed Abraham Lincoln’s mother. One year later, Thomas Lincoln married Sarah Bush Johnston, a widow with three small children. Her strength of character and shared affection were the silver lining of the ominous clouds of the slough of despond; her nurture restored the sanctity of hearth and home. Abraham Lincoln was quoted by a relative as having said “She had been the best friend in the world …and no man could love a mother more than he loved her.” [13]

References:

1. Webster’s Third New International Dictionary of the English Language, Unabridged, Volume 1 Encyclopedia Brittanica, Inc. Helen Benton Publisher, Chicago, 1971 p. 41.

2. Niering, W. and Olmstead, N. National Audubon Society Field Guide to North American Wildflowers, Alfred A. Knopf, New York, 1998, p. 379.

3. Donald, D. Lincoln, Simon and Schuster, New York, NY, 1995. Even though the Lincoln family got off to an auspicious start, Abraham did not get along all that well with his father Thomas and worked at odd jobs along the Ohio River until he was of age and could make his own way.

4. Daly, W. J. “The Slows: The Torment of Milk Sickness on the Midwest Frontier” Indiana Magazine of History Vol 102 No.1 March 2006 pp 29-40. A thorough historical review of the milk sickness problem in the Ohio River Valley.

5. Allen, John W, “It Happened in Southern Illinois”, Southern Illinois University Press 23 February 1968. The section of interest is entitled: The Legend of Dr. Anna Bixby.

6. http://naeb.brit.org/ An excellent ethnobotany database is available at It is searchable by tribe, by common name and by scientific name with full reference attribution.

7. Daly Op. cit.

8. Tabler, D. “The Curse of the Milk Sickness” Appalachian History, 16 June 2011

9. Daly Op. cit.

10. Daly Op. cit.

11. Wu, C. H. “Metabolic disturbances induced by Eupatorium urticaefolium,” PhD Thesis University of Miami 1971. This was the first evaluation of the physiology of milk sickness in interrupting the normal metabolic process.

12. Starr, C. and Taggart, R. Biology, The Unity and Diversity of Life 5th ed. Wadsworth Publishing Company, Belmont, California 1989.

13. Donald Op. cit.

Mistletoe

Common Name: Mistletoe, Birdlime, All-Heal, Golden Bough- The common name “mistletoe” is derived from a blend of Old English and Old High German roots, reflecting the linguistic transition of Anglo Saxons. The first component, mistel, has an uncertain origin; it may refer to either the herb basil or animal dung. The second root, tan, translates to “twig.” This peculiar combination—”dung-twig”—is believed to arise from the observation that mistletoe often sprouts from the droppings of birds perched on tree branches.

Scientific Name: Phoradendron serotinum – The genus is a combination of the Greek words phor, meaning thief, and dendron, meaning tree. Mistletoes are parasites, stealing nutrients from trees, and are therefore tree-thieves. Serotinous means “coming late” from the Latin word serotinus. This is likely to refer to the appearance of mistletoe in tree branches long after the tree from which it sprouts became established. Synonymous with P. leucarpum, from leuk karpos meaning “white fruit” in Greek. Mistletoe has sticky white drupes, which are incorrectly called berries. Drupes have a pit or stone in the center in lieu of the embedded seeds of true berries. [1]

Potpourri: The suspension of a bough of mistletoe over a doorway to elicit a kiss is one of the more esoteric and enduring of Christmas traditions. The annual celebration of Christ Mass started as a religious holiday (holy day) that was placed on the calendar close to the winter solstice (21-22 December) by the nascent Catholic Church to take advantage of the extant feasting and reveling of the Roman Saturnalia (17 December). The German tradition of the Christmas tree became established in 19^th Century Victorian England as an unintended consequence of the accession of the German prince-elector of Hannover to the throne as King George I. [2] Saint Nicholas became the reindeer sleigh-riding Santa Claus due to the popularity of Clement Moore’s poem “A Visit from Saint Nicholas” caricatured as a white-bearded, portly cherub introduced by the German-American editorial cartoonist Thomas Nast. Presents are the gifts of the Magi; “Rudolf the Red-Nosed Reindeer” was created by Montgomery Ward, a department store, so that people would buy more gifts as part of the business of Christmas business comprising about one fifth of annual retail sales.

The earliest documented reference to the mistletoe kiss tradition dates to 1740, when a poem, describing three men kissing a young woman, “not turn’d of twenty,” under a sprig of mistletoe was written. Although this account may appear somewhat risqué by modern me-too standards, it provides historical context for a custom that is believed to be much older. The precise origins of the practice remain uncertain, but it is commonly thought to have begun when a bold young man—possibly a servant—initiated the act as a way to publicly show affection toward a virtuous woman, circumventing the social constraints of the era. In America, the tradition evolved with fewer restrictions. In 1820, Washington Irving, wrote that each mistletoe berry represented a kiss, and that a man’s opportunity for kissing continued until all the berries had been plucked. [3] This enthusiasm is evident in modern festivities. The official United States National Mistletoe—measuring 600 pounds and 10 feet in diameter—is located at Anthem Row near Chinatown in Washington, DC. It was the venue for an attempt to break the Guinness World Record for the most simultaneous kisses induced by mistletoe’s mysterious power. The nation’s capital now holds the record with 1,435 couples, besting the previous record set by Anheuser-Busch at a 2019 beer festival promotion in Saint Louis by almost a thousand. [4] Virginia is for lovers, Maryland is for crabs, and DC is for mistletoe.

For thousands of years, mistletoe has played a significant role in religious ceremonies in Europe. The Druids, who were priest-like sages of the Celtic tribes that originally inhabited the British Isles, used it extensively for spiritual purposes. While this is speculative since Druids left no written account, their practices have survived as oral history. A first century CE account by the Roman historian Gaius Plinius Secundus, better known as Pliny the Elder, provides one of the earliest written descriptions of Druidic ceremonies involving mistletoe. Pliny wrote that, to the Druids “nothing [was] more sacred than the mistletoe and the tree that bears it.” He described a ritual in which a priest, clad in white robes, climbed an oak tree and carefully cut the mistletoe with a golden sickle. The ceremony was consummated by the sacrifice of two white bulls. [5] The mistletoe collected during such sacred rites was believed to impart magical powers that protected its possessor from evil. To share these blessings, acolytes would carry mistletoe branches from house to house at the beginning of the new year, offering them as annual tokens meant to promote health and prosperity. It is plausible that these ancient customs laid the foundation for the later use of mistletoe as a Christmas decoration [6].

Mistletoe also played an important role in Norse Mythology. Baldur or Baldr, the god of light, was the son of the principal god Odin and his wife the goddess Frigg. Much like Apollo in Greek and Roman mythology, Baldur was universally loved—except by Loki, the mischievous trickster god.. Baldur’s troubles began when he was plagued by ominous dreams, which he shared with his mother, Frigg. In a protective effort, Frigg sought out every entity in the world, from the elements of fire and water to every living thing, extracting promises from each that they would never harm her son. However, Loki, using deception disguised as an old woman, approached Frigg and inquired if she had overlooked anything. Frigg admitted that she had not secured an oath from mistletoe, believing it was too young and insignificant to pose any danger. Seizing on this oversight, Loki collected mistletoe and fashioned its woody branches into a spear. He then orchestrated the fatal attack by having the spear hurled at Baldur, striking him and sending him to the realm of Hel, the Norse equivalent to Hades. Despite all efforts, the other gods were unable to restore Baldur to Asgard, as Loki prevented his return, again using subterfuge. [7]

Many mistletoe genera including P. leucarpum, the primary variant in North America, and Viscum album, its counterpart in Europe are members of Santalaceae, the Sandalwood Family, noted for the aromatic oils of its wood that have been used for centuries in perfumes and balms. The taxonomic association is due in part to the fact that many sandalwoods and all mistletoes are parasitic. The technical term is hemiparasitic, half parasitic. Mistletoes are green and therefore have chlorophyl for hydrocarbon formation of photosynthesis. Evolution favored an augmentation to its food sources in the form of a root-like structure called a haustorium that penetrates the bark of the host tree to withdraw water and nutrients. As many of the 1,500 species of mistletoe grow in the upper branches of trees, it is evident that one of the key evolutionary factors must be some mechanism to position seeds in these remote locations for germination. [8] Phylogenic analysis has shown that mistletoe haustorial parasitism evolved on five separate occasions starting in the Oligocene era when trees spread to form savannahs. [9]

Mistletoe produces small, sticky white drupes that are attractive to a variety of birds, particularly the thrush; the European missel thrush named for this behavior. When the birds feed on the berries, they excrete seeds that then adhere to the branches in the vicinity due to the viscous and sticky berries. This explains why infestations of mistletoe typically occur in clusters in the upper branches of trees where birds perch. At some point, the removal of water and nutrients from the host tree will result weakening and ultimately death. The only way to remove them is mechanically (like the golden sickle of the Druids), which is impractical in most cases.

Mistletoe grows from seeds deposited by perching birds.

The genus of the European species, Viscum, is Latin for both mistletoe and birdlime. In that the words are analogous in Latin; it is certain that mistletoe was widely used to make birdlime in Europe. Birdlime is something of a misnomer. It is essentially an adhesive applied to roosting branches to trap birds that land there. While this seems unorthodox, it is legal in most jurisdictions and not far removed from the practice of animal trapping for fur. Fowl have been staples of European cuisine for millennia. Other than large ground birds that can be hunted like other animals, those that fly are much more of a challenge. Smaller birds were a common component of a meal. The nursery rhyme “Sing a Song of Sixpence” with four and twenty blackbirds baked into a pie is testimony to the cultural norm. Although any substance that is sticky can be used to make birdlime, the gooey berries of mistletoe were considered the best, at least according to the notable herbalist John Gerard, who wrote “the white translucent berries … are of a clammy or viscous moisture, whereof the best birdlime is made.” [10] There is some irony in the use of sticky mistletoe “berries” to trap birds that promote mistletoe germination by consuming and defecating the entrained seeds.

The use of mistletoe as medicine also has deep roots in European history. This extended to, as is the case with many compounds, for its use as a poison. The range from a beneficent cure to a deadly poison is a matter of dose. The term overdose marks the line of demarcation between the two. Most field guides and herbal references have cautionary notes about mistletoe’s alleged toxicity without direct evidence. These range from “unconfirmed reports of deaths have been attributed to eating berries” [11] to “use only under the guidance of a qualified [herbalist] practitioner.” [12] Chemical analysis in the modern era has revealed the mistletoe does indeed produce a cytotoxin (cell killer), now known as viscumin. Its primary action is to inhibit protein synthesis from amino acids which results in interruption of the circulatory system. Varying doses of viscumin were administered to laboratory mice to demonstrate a range based on dosage that caused deaths almost immediately to as long as one week later. [13] Mistletoe can kill but it also can heal. It is apparent that foraging birds are not affected by the dose of a few berry-drupes.

By all accounts, mistletoe is closer to panacea than to quack medicine. From Hippocrates in ancient Greece to Paracelsus in Germany during the Middle Ages, V. album has been prescribed for a variety of ailments including epilepsy, diseases of the spleen, and fertility problems. Native Americans used P. serotinum for a variety of purposes, indicating that the medicinal value of mistletoe is not limited to one species, but is more generally applicable globally. Cherokee of the east used it not only for epilepsy but also after vomiting for four days to cure “love sickness.” Navaho of the west used it to treat warts and to relieve distress caused by “eating too much meat.” [14] While some folk remedies are dubious, modern medical research has confirmed that mistletoe has many validated uses, particularly in the treatment of cancer. It has been clinically evaluated as ameliorating bladder, breast, colorectal, and lung cancer by both shrinking tumors while at the same time improving the quality of life of cancer patients. Mistletoe has also been shown to benefit the central nervous system, providing affirmation of its use as a treatment for epilepsy. [15]

What all this has to do with mistletoe as yuletide kiss talisman is speculative. More likely, hanging it in the rafters as a part of New Year’s celebrations was symbolic, promising health in the coming year as a recognized elixir of good cheer. The kiss was possibly added later as a means to pass the blessing of good health along directly in union at the start of the new year.

References:

1. Webster’s Third New International Dictionary of the English Language, Unabridged, G. C. Merriam and Company, Philippines, 1971.

2. https://www.english-heritage.org.uk/learn/histories/christmas-greenery-history/

3. Anderson, S. “How Mistletoe Became a Christmas Kissing Tradition” Smithsonian Magazine, December 2024. https://www.smithsonianmag.com/history/how-mistletoe-became-christmas-kissing-tradition-180985450/

4. Uber, E. “D.C. aims for an epic kiss under mistletoe” Washington Post, 12 December 2025

5. Bostock, J. “Historical Facts Connected with Mistletoe”, Pliny the Elder, Natural History, Book XVI, Chapter 95.

6. https://www.botanical.com/botanical/mgmh/m/mistle40.html

7. Tonnelat, E. “Teutonic Mythology” New Larousse Encyclopedia of Mythology, The Hamlyn Publishing Group, Ltd, Middlesex, England, 1973, pp 245-280

8. University of California Division of Agriculture and Natural Resources Integrated Pest Management https://ipm.ucanr.edu/home-and-landscape/mistletoes/#gsc.tab=0

9. Vidal-Russell, R. and Nickrent, D. “The first mistletoes: Origins of aerial parasitism in Santalales”. Molecular Phylogenetics and Evolution. May 2008 Volume 47 Issue 2 pp 523–537.

10. Gerard, J. The Herball or Generall Historie of Plantes, John Norton, London, 1597

11. Duke, J. and Foster, S. Peterson Field Guide to Medicinal Plants and Herbs, 2^nd Edition, Houghton Mifflin Company, Boston, Massachusetts. 2000, p. 333.

12. Polunin, M. and Robbins, C. The Natural Pharmacy, Macmillan Publishing Company, New York, 1992, p. 130.

13. Olsnes, S et al. “Isolation and characterization of viscumin, a toxic lectin from Viscum album L. (mistletoe)”. The Journal of Biological Chemistry. 25 November 1982 Volume 257 Issue 22 pp 13263 – 13270

14. Ethnobotany Data Base at http://naeb.brit.org/uses/search/?string=mistletoe

15. Szurpnicka, A. et al. “Biological activity of mistletoe: in vitro and in vivo studies and mechanisms of action”. Archives of Pharmacal Research. 1 June 2020 Volume 43 Issue 6 pp 593–629.