From creepy to dangerous, some plants a perfect Halloween fit

Looking for scary plants? Many fill the bill as 'boo-tanical' horrors

Even plants can get into the spirit of Halloween.

Kyle Martin sees it all the time. He's a doctoral candidate in plant biology at Cornell University whose specialty is brood-site deception. That's when a plant masks itself, sending misleading signals to fool a pollinator.

In other words, when you can't say it with flowers, say it with stench.

"The flowers I study usually smell like rotting substrates, like fruit or carrion, to attract insects," he says.

It's a horticultural twist on trick or treat.

"A lot of flowers provide a treat, like a sweet-smelling treat or a nectar reward for the service of pollination," Martin says. "But all the flowers I study are tricksters. They trick their pollinators and don't give a treat back."

For example, Dracula orchids. Native to South America, they tend to be purple or maroon and hairy, Martin says. "They mimic fungal fruiting bodies. They smell like mushrooms or other fruiting fungi. ... They attract flies looking for a spot to lay their eggs."

Once pollination is achieved, the rendezvous is over. The pollinator gets no treat, no sweet nectar as a reward.

Other plants are a nice fit with Halloween. Some are scary-looking. Some are ugly. Others have a creepiness about them. Still others are just, well, ewwww.

Here's a rundown of some of what's out there. Approach them at your own risk. Wash your hands afterward.

Scary-looking

Titan arum: Also known as the corpse flower, the titan arum (Amorphophallus titanum) has it all — it's gigantic (up to 10 feet tall), it grows quickly and it exudes a foul odor (a combination of cheese, rotting flesh, old socks and ammonia). Chicago-area plant groupies are especially familiar with this plant, courtesy of Alice and Spike, two famous specimens from the Chicago Botanic Garden that have attracted thousands of onlookers. It's quite the package. Martin says it's the scariest plant he has ever encountered. "Just looking at it — it's this massive plant, taller than a lot of us. (When it blooms) it smells like rotting meat. When you see it, at first you're cautious. When I'm showing the flower to the public, even adults are wary to look into it. They don't want to touch it."

Doll's eyes: How'd you like to go for a walk in the woods and find a bush full of these watching you? Doll's eyes (Actaea pachypoda), also known as white baneberry, is a native plant found in eastern North America. It grows up to 2 feet tall and produces the small, white, poisonous fruit that gives it its name.

Nepenthes rajah: This colorful, endangered plant from Borneo boasts huge traps nearly the size of a football, according to Devin Dotson, public affairs and exhibits specialist at the U.S. Botanic Garden in Washington. "The lurid traps entice insects to a watery death, along with the occasional lizard or rat," Dotson says. Interestingly, the same liquid welcomes an array of creatures resistant to the digestive juices, including mosquito larvae.

Dangerous

Poison ivy: Jacob Burns, curator of herbaceous perennial plants at the Chicago Botanic Garden, says Toxicodendron radicans gets his vote for scariest plant. "Every part of the plant is toxic," Burns says. "Urushiol is the oil on it. It causes a long-lasting rash on most humans. ... You don't even have to touch the plant to get the rash, because that oil is so easy to get on your boots, your dog, the lawn mower. And that oil can remain on items for years." Because it's everywhere — dry areas, wet areas, roadsides, riverbanks, woods — it's easy to come in contact with. Burns recalls the old rhyme "Leaves of three, let it be," to help identify this foliage fiend. Says Burns: "It even sounds like a horror-movie tag line."

Apples: Well, not what you'll find in the store today. "The really, really old varieties of apples — I'm talking from 100 years ago — the seeds are laced with cyanide," says Karl Niklas, the Liberty Hyde Bailey professor in the section of plant biology at Cornell University. "They can kill you. Of course, people don't eat the core of the apple, but still. (In) the new cultivars, what we find today in grocery stores, that intensity of poison has been bred out."

Stinging nettle: Found in North and South America, Europe and Asia, the nettles plant (Urtica dioica) has hollow stinging hairs on its leaves and stems. On contact, they inject chemicals that produce a stinging sensation. "Anyone who has walked through a patch of stinging nettles doesn't do it again," says Niklas.

Giant hogweed: Growing up to 18 feet in height, Heracleum mantegazzianum has spread from Asia to Europe, England and North America. Its sap causes phytophotodermatitis — irritation triggered when the affected area is exposed to sunlight — in humans. It can result in blisters, scars and blindness.

Creepy

Bat flower: Niklas has been teaching for 37 years, and when he says something is "really creepy looking," you listen. This plant is native to southeast Asia. Its bloom is black — unusual for a flower — and up to a foot across, with "whiskers" as long as 2 feet. And the flower seems to hover, almost menacingly, above the plant's green leaves.

Aristolochia: This plant, which has 500 varieties (its members are often called Dutchman's pipe and pipevine), captures and imprisons pollinators before releasing them. "They tend to be very large, and they have this surface that looks like rotting meat, really," Martin says. "Once the pollinators are attracted to Aristolochia flowers, by a combination of scent and visual display, they are directed through a tube into the chamber which houses the plant's reproductive organs. Downward facing hairs line the tube, which prevents the insects from leaving once they have entered the chamber. Any Aristolochia pollen that was on the insect body is passively deposited on the female parts of the flower on the first day while the female parts are receptive. The insect is held captive overnight until the male part of the flower matures and showers pollen on the captured insects. Once this happens, the hairs on the inside of the tube wilt and the insects are released. If the insects are tricked again by another Aristolochia flower, then cross-pollination will occur."

Other insectivorous varieties: Bug eaters come in numerous shapes and sizes: the Venus flytrap, sundews (drosera), pitcher plants. "They've always fascinated people," Niklas says. "Since the time of Darwin. He even wrote a book on them ('Insectivorous Plants'). ... They're kind of intriguing because they eat insects, and one doesn't normally think of plants as capturing and eating animals." The sundews are especially interesting. "They show a sort of split personality, or Dr. Jekyll and Mr. Hyde-type lifestyle," Martin says. "Drosera leaves produce a sticky mucilaginous substance that contains digestive enzymes. When an insect is attracted to the leaves and gets stuck, the leaves biomechanically fold around the insect and it is eventually digested for its nitrogen-rich nutrients. But drosera also produce flowers that have typical pink and white displays. In some cases, they use the flowers to attract pollinators, cross-pollination happens, and the plants produce seeds and reproduce. The interesting part is the plant needs to attract different subsets of insects to digest versus insects they use for pollination, because it doesn't make sense to eat your pollinator, because they are providing a reproductive service for you. Therefore you have this scary, sticky, dangerous leaf for digesting insects and also a beautiful, benign flower for attracting pollinators."

Ewwww

Prairie dodder: This parasitic vine (Cuscuta) has a "creepy, alien look," according to Burns of the Chicago Botanic Garden. Like most other parasitic plants, it doesn't have foliage. "They don't need leaves, don't need chlorophyll because they're sucking the life out of other plants. It's an orange twining vine that lacks leaves, thus needing zero water. It sucks water and nutrients from the host plants. Each tendril has suckers that give the vine a warty appearance." The vine can grow to 7 feet before it strangles and smothers the host plants. It's also known as devil's guts, strangleweed and witch's hair.

Cobra lily: Darlingtonia californica puts up tall green pitchers complete with hollow, inflated tops, each bearing a striking resemblance to a cobra poised to strike, according to Dotson. "A maroon landing pad shaped like a forked tongue completes the picture and offers a place for its insect victims to perch — before they fall to their deaths," he says. The carnivorous plant lives only in the wet meadows of coastal California and Oregon.

Bleeding tooth fungus: The name says it all. The fruit bodies secrete a red liquid that resembles blood. With spikes and a bitter taste that makes it inedible, this fungus (Hydnellum peckii) belongs on any scary plant (or fungus) list. It is found in North America and Europe, though in recent years it has been discovered in Iran and Korea. Its goal is to take over the world.

bhageman@tribpub.com

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