Wicked Plants: The Weed That Killed Lincoln's Mother and Other Botanical Atrocities - Amy Stewart (2009)

MEET THE NETTLES

How much could the tiny, fine hairs on a nettle possibly hurt? Those delicate trichomes act as hypodermic needles, injecting venom under the skin when you brush against them. Urticaria, the medical term for intense, painful hives, gets its name from the Latin word for nettle, urtica.

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Although any number of painful plants are referred to as nettles, true nettles come from the family Urticaceae. They are mostly weedy perennials that spread by underground rhizomes, and they make themselves at home throughout North America, Europe, Asia, and parts of Africa. A variety of compounds deliver the nettle’s sting, including a muscle toxin called tartaric acid, as well as oxalic acid, which is found in a number of fruits and vegetables and can irritate the stomach. Formic acid, a component of bee and ant stings, is also present in nettles at low levels.

Fortunately, there’s a folk remedy for nettle stings: nettle juice. That’s right, the sap from the crushed leaves is believed to counteract the acidity of the sting. Dock, a weed that often grows near nettles, may also soothe a nettle sting—and dock leaves are blissfully free of sharp, poisonous spines. There’s little evidence about the effectiveness of these remedies, but experts agree that the task of looking for a dock leaf might take one’s mind off the pain.

The news on nettles is not all bad: young nettle shoots, when boiled to remove the hairs, are a nutritious spring delicacy, and sufferers of rheumatism have tried deliberately stinging themselves with nettles to relieve their joint pain. There is even a name for this deliberate flogging of oneself with nettles: uritication.

STINGING NETTLE

Urtica dioica

   

The best-known nettle, growing widely throughout the United States and northern Europe wherever it can find moist soils. A herbaceous perennial, it reaches about three feet in height in summer and dies back to the ground in winter.

DWARF NETTLE

Urtica urens

   

An annual, low-growing herb considered by some to be the most painful plant in the United States. Also called lesser nettle or burning nettle. Grows in most of Europe and North America.

TREE NETTLE OR ONGAONGA

Urtica ferox

   

One of New Zealand’s most painful plants. Causes rashes, blisters, and intense stings lasting several days. There have been reports that full-body contact with the plant has killed dogs and horses, perhaps from the systemic allergic reaction of anaphylactic shock.

NETTLE TREE

Urera baccifera

   

Found in South America from Mexico to Brazil. Ethnobotanists have reported that the Shuar of the Ecuadorian Amazon use the stinging leaves to punish their children when they misbehave.

TREE NETTLE

Laportea spp.

   

Grows in tropical and subtropical regions of Asia and Australia. Unlike most nettles, the sting can last for weeks or months and it can cause breathing trouble. Old, dry branches that have been sitting around for several decades can still do harm.

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DEADLY

Strychnine Tree

STRYCHNOS NUX-VOMICA

Dr. Thomas Neill Cream was a nineteenth-century serial killer who favored strychnine, which comes from the seed of a fifty-foot-tall tree. Those seeds work well for killing rodents and other household pests—strychnine is also used as rat poison—and Cream discovered that it was effective on tiresome spouses and lovers, too.

FAMILY:
Loganiaceae

HABITAT:
Tropical and subtropical climates; prefers open, sunny areas

NATIVE TO:
Southeast Asia

COMMON NAMES:
Strychnine, nuxvomica, quaker button, vomit nut

He got his start in Canada, where he was forced to marry a woman at gunpoint after she became pregnant. He ran off just after the wedding but later returned to Canada. Shortly after he returned, she died mysteriously. He had an affair in medical school that also ended with the death of the young woman.

Later he set up a practice in Chicago. While he was there, a man died of strychnine poisoning, and the man’s wife ratted out Dr. Cream for providing the poison rather than serve time herself.

But that didn’t stop him. Ten years later, Cream was out of jail and offering medical services to unfortunate young women in London whose deaths were often blamed on other ailments such as alcoholism. But the true cause of death was the powdered strychnine seed he slipped in their drink. Dr. Cream’s pride in his work led him to brag about his accomplishments, and that led to his arrest. By the age of forty-two, he was tried, convicted, and hanged.

Strychnine takes control of the nervous system, flicking on a switch that leads to a flood of painful, unstoppable signals. With nothing to stop the nervous system from firing, every muscle in the body goes into violent spasm, the back arches, breathing becomes impossible, and the victim dies of respiratory failure or sheer exhaustion. Symptoms start within half an hour and death comes a few agonizing hours later. By the end the face of the deceased is fixed in a rigid, terror-stricken grin.

It is rumored to be the sort of poison one could develop a gradual tolerance for. The Greek king Mithridates is believed to have slowly built up a resistance to an entire bouquet of poisons, including strychnine, so that he could survive a sneak attack from an enemy. He tested his potions on prisoners before swallowing them himself; from this legend A. E. Housman wrote these lines:

They poured strychnine in his cup
And shook to see him drink it up:
They shook, they stared as white’s their shirt:
Them it was their poison hurt.
—I tell the tale that I heard told.
Mithridates, he died old.

In The Count of Monte Cristo Alexandre Dumas writes of brucine, another poison found in the seed of the strychnine tree, and suggests that after taking minute amounts and gradually building up a tolerance, “at the end of a month, when drinking water from the same carafe, you would kill the person who drank with you, without your perceiving, otherwise than from slight inconvenience, that there was any poisonous substance mingled with this water.”

Meet the Relatives     Strychnos toxifera bark can be boiled down and used as an arrow poison. S. potatorum is used in India to purify water by killing harmful microbes.

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DEADLY

Suicide Tree

CERBERA ODOLLAM

The humid, brackish lagoons of the Kerala backwaters on the southwestern coast of India play host to lion-tailed macaques, Malabar giant squirrels, and a race of small but sturdy goats called Nilgiri tahrs. Here, in the low-lying waterways populated by vipers, pythons, and stinging catfish, grows Cerbera odollam, the suicide tree. Its narrow, dark green leaves resemble those of its cousin, the common oleander. Sprays of starry white flowers release a perfume as sweet as jasmine. The fleshy, green fruits are like small, unripe mangoes, except that they conceal a nasty surprise: the seeds’ white nut meat contain enough cardiac glycosides to stop the heart within three to six hours.

FAMILY:
Apocynaceae

HABITAT:
Mangrove swamps and riverbanks in southern India, as well as southeast Asia

NATIVE TO:
India

COMMON NAMES:
Othalanga maram, kattu aralia, famentana, kisopo, samanta, tangena, pong-pong, butabuta, nyan

The advantages of such a powerful natural resource are not lost on the locals. The suicide rate in Kerala is about three times India’s average, with about one hundred Keralites attempting suicide, and twenty-five to thirty succeeding, every day. Poisoning is a popular method, preferred by 40 percent of the despondent. Women in particular favor a dessert of mashed odollam nut mixed with jaggery, an unrefined sugar drawn from palm sap, as their final meal. However, the nut’s bitter taste is also easily concealed in one of the popular local curries, which are usually served with coconut and rice.

Because the symptoms of odollam poisoning resemble that of a heart attack, the seeds have been used as a murder weapon. In 2004 a team of French and Indian scientists conducted liquid chromatography and mass spectrometry analyses to prove that many of those who had died under mysterious circumstances had actually been fed odollam by some homicidal acquaintance.

The genus Cerbera is named after Cerberus, the hound of Hades from Greek mythology, a vicious three-headed dog with a snake for a tail. He guarded the gates to hell, keeping the dead perpetually trapped inside and preventing the living from entering. But its success as an instrument of suicide is what earned the tree its common name.

“To the best of our knowledge,” the scientists analyzing the forensic data wrote, “no plant in the world is responsible for as many deaths by suicide as the odollam tree.”

Meet the Relatives     Cerbera is a cousin of the poisonous oleander. The blossoms of C. manghas resemble plumeria. While all the trees and shrubs in the Cerbera genus are fragrant and beautiful, they will nonetheless kill you. Even smoke from the burning wood is considered dangerous.