Wicked Plants (4 page)

This Indonesian tree produces a toxic sap that’s also useful as an arrow poison. It was once (falsely) believed to produce narcotic fumes, and tales circulated that prisoners were being put to death simply by tying them to the upas tree and letting its sap and fumes slowly poison the condemned.

ERYTHROXYLUM COCA

In 1895 Sigmund Freud wrote to a colleague that “a cocainization of the left nostril had helped me to an amazing extent.” A modest, medium-sized shrub had transformed Freud’s entire outlook on life. “In the last few days I have felt quite unbelievably well,” he wrote, “as though everything had been erased . . . I have felt wonderful, as though there never had been anything wrong at all.”

Archaeological evidence shows that coca leaves were placed between the cheek and gum as a mild stimulant as early as 3000 BC. When the Incas came into power in Peru, the ruling class seized control of the coca supply, and when Spanish conquistadores arrived in the sixteenth century, the Catholic Church banned the use of the devilish plant. Eventually, practical considerations won out, and the Spanish government realized that it would be better off regulating and taxing the use of coca, while making it available to slaves who had been forced to work in gold and silver mines. The Spaniards found that, with enough coca, the natives could work quickly, for long hours, with very little food. (Never mind the fact that most died after a few months of this treatment.)

An Italian doctor named Paolo Mantegazza promoted the medicinal and recreational use of the leaves of the coca plant in the mid-nineteenth century. He was so enthralled by his discovery that he wrote: “I sneered at the poor mortals condemned to live in this valley of tears while I, carried on the wings of two leaves of coca, went flying through the spaces of 77,438 words, each more splendid than the one before . . .”

Cocaine, an alkaloid that can be extracted from coca leaves, has been used as an anesthetic, a pain reliever, a digestive aid, and an all-around health tonic. Trace amounts were present in early versions of the soft drink Coca-Cola; while the company’s recipe is a closely guarded secret, coca extract is still believed to be a flavoring, just without the cocaine alkaloid. The leaves are legally imported by an American manufacturer, which buys it from Peru’s National Coca Company, transforms it into Coca-Cola’s secret flavoring, and extracts the cocaine for pharmaceutical use as a topical anesthetic.

The coca plant’s ability to inspire humans to go to war, both against each other and against the plant, may be its most deadly quality. A healthy shrub can produce three crops a year of fresh, glossy leaves. The cocaine and other alkaloids in the leaves serve as a natural pesticide, helping to ensure that the plant flourishes even when it’s under attack. Although a few different species can
be used to extract cocaine, the plant used most often for this purpose is
Erythroxylum coca
, which grows along the eastern slope of the Andes mountain range.

In native Andean communities, coca leaves are still chewed as a mild stimulant. Some pharmacological studies suggest that this provides a much milder and nonaddicting stimulation that works on a different part of the brain than cocaine does. The leaves are surprisingly nutritious and very high in calcium, prompting a minister in Bolivia’s new pro-coca government to suggest that instead of milk, coca leaves should be fed to schoolchildren.

The shrub has also survived attacks from another kind of enemy: the drug war’s aerial spraying of the herbicide glyphosate. Drug eradication programs have been foiled by a new, resistant variety of coca called
Boliviana negra
. It emerged, apparently, without any help from scientists in laboratories. Instead, naturally resistant plants have simply been discovered in the fields and passed from farmer to farmer.

Advocates of traditional coca farming point out that coca is an Andean crop dating back several thousand years, while cocaine was invented in Europe 150 years ago. The problems created by cocaine use, they suggest, should be solved within those countries and not at the expense of the coca plant.

Meet the Relatives
   
Erythroxylum coca
is the best-known member of this family of angiosperms, but
E. novagranatense
also contains the cocaine alkaloid.
E. rufum
, or false cocaine, can be found in some botanical gardens in the United States.

KARWINSKIA HUMBOLDTIANA

Coyotillo is a modest shrub of the Texas plains, rarely reaching more than five or six feet in height. The bright green, untoothed leaves and pale green flowers make it an entirely forgettable shrub. But the round black berries it produces in fall would be impossible to forget.

Coyotillo berries contain a compound that causes paralysis—but not immediately. The unlucky subject may not realize that he or she has been poisoned for several days or even weeks. But then, the paralysis sets in—and if this were a murder mystery, it would happen just as the unlucky victim was driving through a dark mountain pass or trying to sneak past the jewelry store’s security alarm. What author could invent a more devious drug?

Animals have been known to lose control over their hind legs, or to lurch backward for no reason they could understand, under the influence of this harmless-looking berry. In the laboratory, administering just the right dose to animals would cause quadriplegia. Livestock browsing freely on the shrub could eventually lose control of their limbs entirely, and death would not be far behind.

Coyotillo goes to work on the feet first and then moves to the lower legs. Once the limbs are still, it brings the respiratory system to a halt, and then it silences the tongue and throat. The plant thrives along the border between Texas and Mexico. Ironically, the name
coyotillo
is the diminutive of the Spanish word
coyote
, given to a person who helps illegal immigrants make the dangerous border crossing into the United States. One study counted about fifty people in Mexico who died from eating the berries during a two-year period.

Coyotillo thrives in the canyons and dry riverbeds of southern Texas, New Mexico, and northern Mexico, where it can tolerate the mean heat and scorched earth. Give it the right conditions and it may reach twenty feet, the size of a small tree.

Meet the Relatives
   Coyotillo is a member of the buckthorn family; many shrubs in this family play host to butterflies. Most produce berries, but they don’t pose the same threat.

Some of the most popular houseplants are surprisingly toxic. They were chosen not for their suitability as a snack for pets and small children, but for their ability to thrive in a year-round climate of 50 to 70 degrees Fahrenheit. That’s why many houseplants are actually tropical plants that come from the jungles of South America and Africa.

The poinsettia, one of the most reviled indoor plants, is not nearly as toxic as its reputation would lead one to believe. As a member of the Euphorbiaceae family, the sap is mildly irritating, but that is the extent of it. While the poinsettia gets plenty of bad press around the holidays, many other houseplants escape notice in spite of their more toxic qualities.

A South American plant with simple white flowers that resemble calla lilies. In 2005 more people called poison control centers about possible peace lily poisoning than any other plant. (This may have more to do with how popular the plant is than how poisonous it is.) The plant contains calcium oxalate crystals that can bring on skin irritation, burning of the mouth, difficulty swallowing, and nausea.

This ubiquitous European vine grows outdoors as a ground cover but is also one of the most popular indoor potted plants. The berries are bitter enough to discourage people from eating them, but they could cause severe gastrointestinal problems and possible delirium or respiratory problems. Sap from the leaves can cause serious skin irritation and blisters.

An ivylike plant native to South America in the West Indies. All parts of the plant contain calcium oxalates. Nibbling on a leaf might only bring about mild burning in the mouth or a little nausea, but ingesting it could lead to severe abdominal pain, and repeated skin contact may cause serious allergic reactions. Poison control centers in the United States got over sixteen hundred calls in 2006 related to philodendron poisoning.

A tropical South American plant well known for its ability to temporarily inflame vocal cords, leaving people unable to speak. Some species are believed to have been used as an arrow poison in combination with
other plants. Most poisonings involve severe irritation of the mouth and throat, swelling of the tongue and face, and stomach problems. The sap is also irritating to the skin, and can cause light sensitivity and pain if it gets in the eyes.

These two indoor trees are closely related species in the mulberry family. The latex from these plants can provoke severe allergic reactions. One case history describes a woman who developed anaphylactic shock and other frightening symptoms that disappeared promptly after her ficus tree was removed from her home.

This African plant is not actually a cactus, but it gets its name from the long, skinny stems that resemble a succulent. Pencil cactus has become popular in modern interior design for its striking, architectural shape. But like other euphorbia, it produces a corrosive sap that causes severe rashes and eye irritation. It requires some pruning to keep it down to a reasonable size indoors, and gardeners are often surprised that a single pruning session can bring on such a painful reaction.