In celebration of the Halloween holiday this week, let’s learn something new about some spooky plants. Some are scary because of their macabre uses. Some are frightening merely for the ambiance they create. Others are disturbing because they engage in behaviors wholly unbecoming for plants.
I’ve mentioned before that plants are consummate biochemists. This means that they have the potential to be quite dangerous to humans. Many of you may immediately recognize poisonous plants like the strychnine tree, hemlock, foxglove, or castor (ricin), but don’t be fooled by plants with seemingly innocent names like Doll’s eyes or Angel Trumpet. They are deadly beautiful. Think that Aconitum aka Wolf’s bane only works on werewolves? Think again. This plant with its delicate purple flowers is related to buttercups, but it’s just as fatal to humans as it is to were-creatures. The roots synthesize large amounts of the alkaloid pseudaconitine, a potent neurotoxin that inhibits the enzyme acetylcholinesterase.
Other spooky plants are not as traditionally beautiful. Take, for example, Spanish moss- the ubiquitous gray accessory of live oak and cypress trees in the Deep South. Despite what its name may lead you to believe, it is not a moss, but a true plant that makes its own tiny flowers and seeds. Nor is it a parasite to the trees on which it grows, yet it doesn’t have roots. It is an epiphyte that directly absorbs its nutrients from the water and air it encounters in its environment. Southerners know that Spanish moss is the perfect environmental punctuation for our heavy, humid days adding a sense of slowness to any scenery. However, its prevalence in our swamps makes it the ideal plant if you are looking to add some spookiness to your landscape design.
Not all plants play so well with others. There are some true parasitic plants that suck the life out of their photosynthetic hosts. These include the aptly named for today’s discussion- witchweed and the ghost plant. Witchweed belongs to the Striga genus, but it isn’t all warts and crooked noses. It actually produces lovely small flowers, but its establishment as a plant comes at the expense of others. Developing witchweed seeds parasitize the roots of other grass plants (sometimes important crop plants like corn, millet, and sorghum) and steal the host plant’s nutrients until it has developed sufficiently to support itself as a proper self-respecting photosynthetic organism. Other parasitic plants never change their ways. The ghost plant got its name from its pure white color and its lack of chlorophyll indicates it never has the intention of becoming photosynthetic. Found in the dark understory of wooded areas, it is the bottom feeder of bottom feeders in the parasitic plant world. It doesn’t even derive its nutrients directly from a host tree. Instead, it parasitizes a fungus. Mycorrhizal fungi engage plants in a beneficial symbiosis whereby the fungi provide nitrogen to plant roots in exchange for some of the sugars the plant can make via photosynthesis. Ghost plants steal nutrients from mycorrhizal fungi associated with tree roots. The tree probably doesn’t notice, but for a member of the plant kingdom, the ghost plant leads a shameful existence.
Other plants engage in even more unnerving behaviors. Carnivorous plants like pitcher plants, flytraps, sundews, and bladderworts dine on other heterotrophs to supplement their nitrogen nutrient needs. They use a variety of tortuous mechanisms to lure and trap their prey from irresistibly sticky leaves and flowers to incredibly slippery surfaces over pits of digestive juices to hair-triggered mouth-like traps of the aerial or submersible variety.
We commonly think of the unfortunate insects eaten by such sinister plants, but it’s more common than you would think for them to trap larger prey like frogs and mice. Don’t believe me? Watch the video. It’s not exactly Audrey II, but impressive nevertheless.
So while you are on the lookout for other-worldly creatures and the fantastical monsters of the animal kingdom, don’t take the plant kingdom for granted.