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

DUCK AND COVER

Any number of otherwise mild-mannered plants can, if provoked, forcibly eject seeds and scatter them at breakneck velocities. If you get one of these plants angry, back away. They could put your eye out—or worse.

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SANDBOX TREE

Hura crepitans

   

A tropical tree that thrives in the West Indies and in Central and South America, reaching one hundred feet and sporting giant oval leaves, brilliant red flowers, and sharp spines. The sap is so caustic that it can kill fish or be used as an arrow poison. But you have the most to fear from the fruits, which explode with a loud bang when they are ripe. Its poisonous seeds can fly up to three hundred feet, earning it the nickname “dynamite tree.”

GORSE

Ulex europaeus

   

Flourishes on the English moor, where yellow flowers fill the air with a scent that some compare to custard or coconut. Native to Europe and invasive in some parts of the United States, gorse (also called whin or furze) welcomes fire into its dry branches. The flames cause seedpods to burst open, and rejuvenate the roots. On a hot day, sitting near a gorse can be hazardous: the pods explode without warning, ejecting seeds into the air with a noise that sounds like a gunshot.

SQUIRTING CUCUMBER

Ecballium elaterium

   

A most unusual vegetable. While it is in the same family as cucumbers, squashes, and other gourds, it’s hardly something you’d want to add to your diet: the juice can cause vomiting and diarrhea if you swallow it and sting your skin if you come in contact with it. Its two-inch-long fruits are famous for bursting when ripe, squirting a slimy, mucuslike juice and seeds almost twenty feet away.

RUBBER TREE

Hevea brasiliensis

   

An Amazon jungle native that made its way to Europe courtesy of enterprising British plant explorers. Although uses for the sticky latex were not immediately apparent, chemists working in the 1800s quickly realized that the substance could be used to erase pencil lines, coat clothing to make them waterproof, and—thanks to some experimentation by an American named Goodyear—could even be used to make tires. In the wild the tree has another trick: its ripe fruits explode in the fall with a loud crack, sending cyanide-laden seeds several yards in all directions.

WITCH HAZEL

Hamamelis virginiana

   

A beloved North American native that produces star-shaped yellow flowers in late autumn. The extract of the bark and leaves is used as an astringent to treat bites and bruises. The branches have been employed as divining rods to find underground sources of water or mines. In the fall, the dry, brown, acornlike seed capsules snap open and throw seeds up to thirty feet away.

DWARF MISTLETOE

Arceuthobium spp.

   

A relative of the popular Christmastime mistletoe, is a parasite that sucks the life out of conifers in North America and Europe. Its fruit take over a year and a half to ripen, and when they do, the seeds blast off at the astonishing rate of sixty miles per hour—so fast that you might not even be able to see them fly by.

The rubber tree’s ripe fruits explode in the fall with a loud crack, sending cyanide-laden seeds several yards in all directions.

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DEADLY

Water Hemlock

CICUTA SPP.

Widely regarded as one of the most dangerous plants in the United States, water hemlock flourishes in ditches, swamps, and meadows across the country, and its flat, umbrella-shaped clusters of white flowers and lacy foliage resemble that of its more edible relatives like coriander, parsnips, and carrots. In fact, most accidental poisonings from water hemlock come about because people mistakenly believe the roots are edible. Unfortunately, the roots have a slightly sweet taste that might encourage someone to take a second bite.

FAMILY:
Apiaceae

HABITAT:
Temperate climates, usually near rivers and wetlands

NATIVE TO:
North America

COMMON NAMES:
Cowbane, wild carrot, snakeweed, poison parsnip, false parsley, children’s bane, death-of-man

It only takes a nibble or two to get a lethal dose of the plant’s toxin, cicutoxin. It disrupts the central nervous system, and quickly brings on nausea, vomiting, and seizures. One small bite of the plant’s root, which is its most toxic part, could kill a child.

In the early 1990s two brothers on a hike mistook the plant for wild ginseng. One man took three bites and was dead within a few hours; the other took only one bite and suffered seizures and delirium but recovered after a trip to the emergency room. In the 1930s a number of children were killed after making whistles or blow darts out of the plant’s hollow stems. Children have also mistaken the roots for carrots and gone into convulsions after a few bites.

In the 1930s, a number of children were killed after making whistles or blow darts out of the hollow stems of water hemlock.

There were about a hundred cases of water hemlock fatalities in the United States during the twentieth century, although experts believe the actual number is probably much higher because the victims don’t usually survive to report on what they ate.

Water hemlock also poses a threat to pets and livestock. Because the plant’s fragrance is not as unpleasant as other poisonous plants, animals are more tempted to graze on it. When mature water hemlock plants are uprooted by tractors, the exposed tap roots can be tempting to hungry animals. Usually the poison works so quickly that animals are near death by the time they’re discovered. A single root is toxic enough to kill a sixteen-hundred-pound cow.

The weed grows to seven feet tall and sports purple splotches on the stem. The fleshy roots produce copious amounts of the poison in the form of a thick, yellowish liquid that oozes out when the roots are cut. The most widespread species is Cicuta maculata.

In the western United States and Canada, C. douglasii thrives in pastures and swamps. It produces unusually thick stems and its flowers are so large and sturdy that they are sometimes picked as cut flowers. This is a very dangerous decorating idea; even a small amount of toxic juice on the hands could find its way into the bloodstream.

Meet the Relatives     Poison hemlock, Conium maculatum, which killed Socrates is one relative; others include parsley, carrots, parsnips, and dill.

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DESTRUCTIVE

Water Hyacinth

EICHHORNIA CRASSIPES

This South American native is not hard to recognize. It grows to about three feet tall in water and sports luscious lavender blooms with a distinctive yellow spot on just one of its six petals. Although it is beautiful, the crimes that this aquatic plant has committed are so great that it should be locked away forever—if only that worked.

FAMILY:
Pontederiaceae

HABITAT:
Tropical and subtropical lakes and rivers

NATIVE TO:
South America

COMMON NAMES:
Floating water hyacinth, jacinthe d’eau, jacinto de aqua

Water hyacinth forms dense, sprawling mats on the water’s surface that even commercial boats can’t penetrate. Those mats become islands of their own, providing the perfect environment for other semiaquatic plants and grasses to sprout. It is freakishly prolific, doubling its population every two weeks. While natural predators kept the plant from taking over its native Amazon, it has gone on a crime spree in Asia, Australia, the Americas, and other parts of Africa. The plant is so horrible that it has earned its own Guinness World Record as the world’s worst aquatic weed.

Its offenses include:

CHOKING WATERWAYS. The plant will quickly take over a lake, pond, or river, slowing the flow of water, sucking up all the oxygen, and strangling native plants.

CLOGGING POWER PLANTS. A vigorous infestation of water hyacinth can shut down a hydroelectric power plant or dam, making the lights go out for thousands of unsuspecting homeowners.

STARVING THE LOCALS. In parts of Africa, fishermen have seen their catches decline by half because of water hyacinth. The people of Papua New Guinea were unable to fish, get to their farms, or go to market because this floating menace stood in their way.

STEALING WATER. Clean drinking water is actually in short supply in some parts of Africa because the greedy water hyacinth slurps it up.

STEALING NUTRIENTS. Although water hyacinth has received cautious praise for its ability to absorb pollutants such as heavy metals, its voracious appetite makes it hard for other tiny water-dwelling creatures to get enough to eat. It devours nitrogen, phosphorus, and other critical plant nutrients until there’s nothing left for the others.

BREEDING NASTY PESTS. Water hyacinth can be a breeding ground for mosquitoes, which are a vector for transmission of malaria and West Nile virus. It also provides food and shelter for a particular species of water snail that, in turn, is a particularly friendly host for a few different species of parasitic flatworms. Those flatworms emerge from their snail hosts and swim around until they find a human to infest. The disease, widespread in developing countries, is called schistosomiasis, or snail fever. The little worms travel freely in the body, laying eggs in the brain, around the spinal column, and on any organ that looks inviting. Over one hundred million people are infected worldwide.

The people of Papua New Guinea were unable to fish, get to their farms, or go to market because this floating menace—water hyacinth—stood in their way.

PROVIDING COVER FOR SEA MONSTERS. One report blames water hyacinth for offering convenient hiding places for snakes and crocodiles, giving it an unfair advantage over unsuspecting boaters, bathers, and tourists.

Scientists are looking at the possibility of introducing insects to eat the wicked weed, but they fear they might just be introducing another environmental thug into the mix. Stay tuned—and stay away from water hyacinth.

Meet the Relatives     There are seven different species of water hyacinth, most of which are invasive.