Wicked Plants (24 page)

Another early discovery was made by a farmer named William Jerry in Madison County, Illinois, in 1867, who realized that the disease occurred after his cattle grazed on white snakeroot, but it was not until the 1920s that white snakeroot was widely recognized as the cause. Eventually farmers learned to fence their cattle or eradicate the weed from pastures to prevent the disease.

White snakeroot grows to four feet tall and produces small, white clusters of flowers similar in shape to Queen Anne’s lace. The plant is still found in the woods across eastern North America and throughout the South. The toxic ingredient, tremetol, remains active even after the plant has dried, making it a threat in hayfields as well as pastures.

Meet the Relatives
     Joe-pye weed,
Eupatorium purpureum
, a popular plant in butterfly gardens, and boneset,
E. perfoliatum
, which was once used as a laxative and as a treatment for fever and flu are both related to white snakeroot.

Some plants get around by hitching a ride on an animal or an unsuspecting hiker. These plants are the most aggressive in the plant kingdom, practically leaping out to sink their teeth into a bare ankle or grab the tail of a golden retriever. The tiny, fishhook-like barbs mean that the more you pull on them, the more embedded they will become.

Cacti native to the southwestern United States. Hikers swear that the plants reach out and grab boots and pants legs. But in fact the spines are so strong that even the slightest grip is enough to cause one segment
of the plant to break away. Don’t try pulling it out; it will only stick to your hand. Experienced travelers carry a comb and use it to brush the plant away in one swift, painful motion.

A tough, perennial vine found in South Africa. Its barbed seedpod can reach several inches in diameter, and each spine resembles a grappling hook, earning it its name. The plant produces beautiful pink flowers that resemble morning glory, but its oversized and painful seeds make it a menace for farmers and ranchers grazing livestock. Grapple plant does try to make up for the pain it causes: extracts of the roots have become a popular alternative remedy for treating pain and inflammation.

Native to the southern and western United States, this plant sprawls along the ground and resembles a squash vine. It sports showy pink or yellow trumpet-shaped blossoms that produce a seedpod with long, curved hooks that easily attach to shoes or hooves. The seed itself is covered in smaller, sharp spines. Also called devil’s claw, devil’s horn, or ram’s horn

A small tree native to Madagascar, popular among tropical plant enthusiasts and found in botanical gardens throughout the United States. It produces gorgeous three-inch-long yellow flowers that give way to green fruit covered in otherwordly spines. Each spine has a tiny hook on the end; as the fruit dries, the remaining seedpod becomes a real hazard.
It could certainly snare a mouse, and humans who have been caught in its grip report that attempting to remove the seedpods is like getting caught in a Chinese finger trap.

A species of wild barley that produces the long, barbed seed heads that get embedded in dogs’ fur in summer. However, the common name “foxtail” is also applied to a number of grasses that have similar seed heads. For example, ripgut grass
(Bromus diandrus)
is so tough that it can perforate the stomach lining of animals and actually kill them.

Foxtails sport tiny barbs that once embedded under the skin can be impossible to see and difficult to remove. The outer coating of the seed-pods contains a bacterium that makes it easier for the barbs to work into the skin and even travel through the body. Dogs are the most susceptible; veterinarians have found foxtails inside their brains, lungs, and spinal cords.

A widespread summer weed in the aster family; it is native to North America but has become invasive worldwide. Cocklebur produces small seedpods covered in thorns, and although the pods are not difficult to remove, they have been known to ruin the wool of grazing sheep. The seeds are poisonous, and while most humans would not be tempted to munch on them, they can kill livestock.

Produces thistle-shaped burrs that grab clothing and fur; leaves and stems irritate the skin. Burdock burrs are comparatively easy to remove,
but they have the same fishhook structure of other stickers and grapples. This structure caught the attention of George de Mestral, the Swiss engineer who based his invention, Velcro, on the burdock burrs he found in his dog’s fur after a walk.

These invasive grasslike plants have naturalized across the southern United States. They conceal themselves in lawns and produce small, sharp stickers that torture picnickers and punish children who dare to run across the yard barefoot. The burrs flourish in sandy soil with low fertility. They can irritate the eyes and lips of livestock, causing ulcers that can get infected. Control is difficult; some Southerners exact revenge by brewing sand burr wine with the burrs, grape juice, sugar, and Champagne yeast.

TAXUS BACCATA

In 1240 Bartholomaeus Anglicus described the yew in his encyclopedia,
On the Properties of Things
, as “a tree with venim and poison.” It’s fitting, perhaps, that this highly toxic tree has come to be known as the graveyard tree in England. The plant earned that name not for its ability to send people to an early grave, but because Roman invaders began offering church services in the shade of yew trees, hoping that this would appeal to the pagan population. Today ancient yew trees are still found near churches in the English countryside.

The sight of these yew trees in cemeteries inspired Alfred, Lord Tennyson, to write, “Thy fibres net the dreamless head / Thy roots are wrapt about the bones.” In fact, an ancient churchside yew growing in the English village of Selborne was toppled during a storm in 1990, and the bones of the long-ago dead were found tangled in its roots.

The yew is a slow-growing evergreen that can live two or three centuries, but it is difficult to date mature trees because
the dense wood doesn’t always produce rings. The fine, needlelike leaves and red fruit make it an attractive landscape tree that can easily reach seventy feet in height. In England yews are often pruned to form a formal hedge; the Hampton Court Palace’s legendary three-hundred-year-old hedge maze is now planted almost entirely with yew.

Every part of the yew is poisonous with the exception of the flesh of its red berrylike fruit (called an aril), and even that contains a toxic seed. The aril itself is slightly sweet, making it a temptation for children. Eating just a few seeds or a handful of leaves will bring on gastrointestinal symptoms, a dangerous drop in pulse rate, and possible heart failure. One medical manual mournfully noted that “many victims never described their symptoms” because they were found dead. Yews pose a particular hazard to pets and livestock. A veterinary medicine article stated that “often, the first evidence of yew toxicosis is unexpected death.”

In Caesar’s
Gallic Wars
, suicide by yew became a way to avoid facing defeat. Catuvolcus, king of a tribe who lived in what is now Belgium, was “worn out by age . . . unable to endure the fatigue either of war or flight” and “destroyed himself with the juice of the yew-tree.” Pliny the Elder wrote that “travelers’ vessels” made of yew wood and filled with wine could poison people who drank from them.

But before ripping that yew tree out of the garden, consider this: In the early 1960s a team of researchers from the National Cancer Institute discovered that yew extract had potent antitumor properties. Now the drug paclitaxel, or Taxol, is used to fight ovarian, breast, and lung cancers and shows promise for many others. Companies like Limehurst Ltd. collect hedge clippings from English gardens for the pharmaceutical industry. Research indicates that yew trees even secrete the drug into the dirt, opening up the possibility that cancer-fighting compounds can be extracted without harming the trees.

Meet the Relatives
Relatives include Japanese yew,
Taxus cuspidata
, which is native to Japan but grows throughout North America, Pacific or western yew,
T. brevifolia
, found in the western United States, and Canadian yew,
T. canadensis
, found in Canada and the eastern United States, which is also called American yew or ground hemlock.

Throughout the twentieth century, syrup of ipecac was recommended as a treatment for accidental poisoning. Ipecac is made from the roots of
Psychotria ipecacuanha
, a flowering shrub in Brazil. The syrup proved to be a powerful emetic, causing violent vomiting that might bring up the poison. Ipecac syrup eventually made its way into the medicine chest of every family with young children as a remedy for accidental poisoning.

However, the American Academy of Pediatrics and other medical groups now discourage the use of ipecac except if recommended by a doctor or poison control center. The syrup is abused by people with bulimia; in fact, it contributed to the death of singer Karen Carpenter. Ipecac has also been used in a few high-profile poisoning cases in which parents poison their children to get attention, a syndrome called Munchausen syndrome by proxy. Doctors also have more effective treatments for poisoning cases and believe that home use of ipecac may delay better treatment and mask symptoms. Instead, they recommend calling a poison control center or seeking immediate medical attention.