If I'm reincarnated, I sure hope I don't come back as a small insect living on a longleaf pine savanna. Everywhere I'd go, danger would lurk. If I crawled across that red shiny plant, I'd get stuck in goo. If I stepped in that plant that looks like a clam shell, lightning-quick traps would slam shut on me. And if I crawled inside that vaselike plant to hide, I'd drown in an insectivorous brew. In this bizarre world-where the plants eat the animals-nature seems to be orchestrated by a scriptwriter for "B" horror movies.
Worldwide, botanists classify some 600 species of plants as carnivorous, meaning that they consume animals for all or part of their sustenance. The unique characteristics of these plants have made them the subject of scientific study and whimsical delight for centuries. The plants so fascinated Charles Darwin that he wrote an entire book about them. His 1875 Insectivorous Plants was a landmark study and among the first to prove that the plants were actually consuming the insects they were trapping.
The unique nature of carnivorous plants makes many people think they grow only in exotic locales-in some tropical rainforest or perhaps isolated on a Venezuelan tepui. But it might surprise you to learn that nearly three-dozen species live in the Tarheel State. They normally grow in acidic soils that lack the nutrients most plants need to survive, with the wet pine savannas and pocosins of the coastal plain providing ideal habitat. Plants that typically grow in soils that are more basic cannot survive in this type of habitat, thereby allowing the few plants that can live there to thrive. But plant species that are adapted to these nutrient-poor soils must overcome the soil's deficiency in some way. In the case of carnivorous plants, their adaptation allows them to secure additional food from insects.
Carnivorous plants grow in all regions of the state, but only in the coastal plain are they common. A few mountain bogs support small populations of purple pitcher plants, the rare green pitcher plant, and the mountain sweet pitcher plant. Also, the roundleaf sundew and a few bladderworts grow in a number of mountain locations. However, the sensitive nature of these habitats and the rarity of some of the species that grow there mandates that their locations be kept secret, and rightly so. The same scenario exists in the piedmont, where there are even fewer occurrences of carnivorous plants than in the mountains.
The best places for the average North Carolinian to see and take pictures of carnivorous plants in the wild are at a few sites on the coastal plain. While most locations are not publicized, there are several places where anyone can experience the wonders of these plants. The Nature Conservancy's Green Swamp Preserve supports possibly the finest population of carnivorous plants in the state, with at least fourteen species in all five of the state's genera. Another easily accessible site is Carolina Beach State Park, where you can see the Venus flytrap and several other carnivorous species. In addition, the park's visitor center features a hands-on exhibit about carnivorous plants with numerous photos.
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Any site that supports a wild population of carnivorous plants is by nature a sensitive environment, and anyone visiting should exercise care not to disturb the plants that grow there. A good way to see carnivorous plants without disturbing them is to visit an arboretum or botanical garden. The North Carolina Botanical Garden in Chapel Hill has a great collection of carnivorous plants, including the Venus flytrap and pitcher plants.
Unfortunately, we are destroying at an alarming rate the natural environment in which carnivorous plants grow. We continue to drain wetlands for housing developments, golf courses, and pine plantations all across the coastal plain. Without question, habitat loss is the major crisis faced not only by carnivorous plants, but by all other plants and animals as well. But habitat loss can occur in different ways. Many carnivorous plants grow in an ecosystem that is adapted to frequent wildfires. With the Smokey the Bear attitude of our modern society, those environments suffer. Eventually, this fire suppression may cause the ecosystem to reach the point where the native inhabitants can no longer survive-a type of habitat loss just as severe as draining a pocosin and putting in a golf course. Ironically, the U.S. Military-an entity that exists solely for the protection of people-is responsible in large measure for protecting carnivorous plants in North Carolina. Military training facilities such as Fort Bragg and Camp Lejeune experience frequent fires from munitions explosions. This, coupled with the fact that these facilities cover such a large and relatively undisturbed acreage, results in ideal habitat for the plants.
Habitat loss is not the only threat to carnivorous plants. Another one comes from unscrupulous collectors who dig them from the wild. Poaching is such a serious concern for some species, such as pitcher plants and the Venus flytrap, that North Carolina has enacted laws to address the issue. The Plant Conservation Program, a division of North Carolina's Department of Agriculture & Consumer Services created by the Plant Protection and Conservation Act of 1979, is "responsible for the listing and protection of North Carolina's endangered plants and threatened plant species." The green pitcher plant, mountain sweet pitcher plant, dwarf bladderwort, and Venus flytrap all receive special protection under the program.
North Carolina supports some 35 species of carnivorous plants in five different genera. Let's look at each of these five groups and see what makes them so fascinating.
Venus flytrap (Dionaea muscipula)
Everyone loves the Venus flytrap-surely the most exciting of all our plants. School children throughout the world recognize it and it's the favorite of plant collectors. It has been the inspiration for everything from a television sitcom character (the disc jockey "Venus Flytrap" on "WKRP in Cincinnati") to the title of a Stevie Wonder song ("Venus Flytrap and the Bug"). The movie "Little Shop of Horrors" featured a Venus flytrap named Audrey II that looked like it was on steroids. The list of flytrap references could fill a book.
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As well known and popular as the Venus flytrap is, few people realize that the plant is native to a small radius around Wilmington, NC and grows naturally nowhere else in the world. Another interesting aspect of the plant is that it is in a monotypic genus, meaning that it is the only species of the genus.
Of course, the trapping mechanism is what makes the flytrap so exciting. The traps (leaves) are shaped like a clam shell, with interlocking teeth that perform much like the bars on a jail cell. On the inside surface of each leaf are three sensitive trigger hairs. When an unfortunate insect touches these hairs in the proper manner, the leaves instantly snap shut, trapping the prey inside. B.W. Wells described it best in The Natural Gardens of North Carolina: "The tension released, the woody springs come into action, the trap snaps shut, and the plant world has a partial revenge for all the vegetation that has been eaten by its minute animal enemies." Despite the plant's name, flies are rarely caught. Most prey consists of ants, small beetles, and other crawling insects, although it is not unheard of for the traps to catch small frogs and lizards.
The flytrap's popularity has also contributed to its decline. Poachers have been caught with thousands of plants in their possession and some populations have been totally wiped out. You can help preserve the Venus flytrap-all plants-by purchasing only artificially propagated ones. Always ask the seller about the plant's origin, and if in doubt, seek another dealer.
Pitcher plants (Sarracenia)
The aptly named pitcher plants have highly modified leaves that form tubular containers (pitchers) that hold water, creating a "witches brew" for any hapless insects that might fall in after being lured to the outer rim by nectar. Downward-pointing hairs along the inside of the pitchers help to prevent the insects from crawling out, and the plant produces enzymes that aid in digesting the insects.
Not all insects that enter the pitchers fall prey to them. In fact, several species are adapted not only to survive, but also to live all or part of their lives within the pitchers. A species of wasp builds its nest inside the pitcher and fills it with stunned crickets for its larvae to feed on. Some insects, as well as bacteria and other microorganisms, are capable of surviving in the water at the base of the tubes, enjoying a veritable all-you-can-eat smorgasbord of trapped critters.
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I've never been able to walk past a pitcher plant without gently lifting up the "hood" and peering down the tube. On one occasion, I was startled to find a small frog peering back up at me. It was easily large enough to climb out, so I can only surmise that it had backed itself down the pitcher to await a free meal from the next hapless insect. Often, I see spiders in the tubes that are employing the same tactic.
Eight species of pitcher plant grow in North Carolina. Most of them grow on the coastal plain; three species occur in the mountains and at least two in the piedmont.
Easily the largest group of carnivorous plants in North Carolina, the bladderworts are also among the least known. Except during the flowering stage, these mostly aquatic plants live out their lives in relative secrecy compared to pitcher plants and the Venus flytrap. But when they flower, the mass of white, purple, or yellow flowers popping up out of the water is an eye-catching sight.
Bladderworts catch prey with minute traps that have sensitive hairs along the outer edges. When a tiny water flea or other critter brushes against these hairs, the trap quickly springs open and the prey is sucked in. Enzymes produced by the plant digest the quarry.
All but one of North Carolina's sixteen species of bladderwort live on the coastal plain, while four of them also are found in the mountains, and one species lives only in the mountains. Only two species are known to occur in the piedmont.
The flowers of butterworts might be mistaken for those of the bladderworts (both are in the same family), but any similarity between the plants ends there. Butterworts are strictly terrestrial, with a basil rosette of leaves. The leaves produce sticky glandular secretions that trap small insects that crawl or fly onto them. The insect is stuck, as if on a piece of natural flypaper, awaiting its inevitable digestion.
Three species of butterwort occur in the state, all of them on the coastal plain.
My favorite carnivorous plant is the sundew. The highly modified leaves of the plant produce copious amounts of sticky secretions that trap any unfortunate insects that happen to land on or crawl across them. But unlike the leaves of butterworts, which mostly remain stationary, the leaves of sundews actually close in on the prey, further aiding in its imprisonment.
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What I like most about the sundews is how stunningly beautiful they are. The glandular secretions contrast markedly with the bright red leaves of some species, looking like sparkling diamonds. As with many carnivorous plants, to appreciate the beauty of sundews you need to see them with some sort of magnification, whether it's a macro lens for taking photographs, or a simple magnifying glass for just viewing.
Five sundew species occur in the state. All of them grow on the coastal plain, while one species also occurs in the mountains, and three species grow in the piedmont.