By David Brown
England, 1614: The crop was in ruins. The food plants were desiccated, brown, and brittle. There would be no harvest this year. Despair descended upon the farmers for winter was coming and their food stores would not be replenished. They cursed the monster that stalked their land…
Our species grew up in a world of monsters. Sailors feared being swallowed whole by savage sea serpents. Travelers shivered at howls echoing through the night, terrified of becoming a werewolf’s next meal. Villagers dreaded possibly having their life forces drained from them by blood-sucking, soul-stealing vampires.
As we better explored and understood the world, the monsters shrank away.
Vampires now only haunt us in our movies, books, and other forms of imagination – at least the undead, mythological kind of vampires that drain the life force from humans.
Deep in the sea lurks a squid with blood red skin and glassy demonic blue eyes. A web of skin connects each of its arms. When the squid fans its arms out it looks like the cape of a vampire. So startling was the appearance of this creature that scientists named it Vampyroteuthis infernalis, the Vampire Squid of Hell. For many years very little was known about the vampire squid or what it ate. Surely such a creature must live by grabbing unsuspecting fish with its tentacles and drawing it to its jaws to suck out their blood? Alas the human imagination exceeds the cold reality of the vampire squid, which turns out to be a scavenger, helping clear the deep seas of dead sea jellies and other organic matter. This animal is a vampire only in our minds.
Yet, vampires are real. They fly and creep and stalk across the Earth, as they have for millions of years before the vampires of human imagination existed.
Perhaps the most famous real life vampires flutter through the forests of Central and South America, sucking blood from birds and mammals (including humans sometimes). Europeans first saw vampire bats in the 1600s as they explored the New World. Tales of the blood-sucking bats were sewn into the mythology of vampires. Dracula, perhaps the most famous vampire of all, transformed himself into a bat in the novel by Bram Stoker, inspired by the existence of real vampire bats.
In the Pacific Ocean, 600 miles off the coast of South America, is the Galapagos Archipelago. These islands arose from the volcanic engines powering the movement of continental plates. Over time an ecosystem of animals arose found nowhere else on the planet featuring giant tortoises, tropical penguins, iguanas that swim in the ocean nibbling seaweed, and genuine vampires – vampire birds. On two of the Galapagos Islands, Wolf and Darwin, lives a species of finch that makes its living by drinking the blood of other birds. The vampire finch, also known as the sharp-beaked ground finch, pierces the skin of sea birds called boobies, drawing blood. Like the vampires of myth the vampire finch slurps up the blood, using the life force of others to its nourishment.
We have banished the monster vampires of legend to our art and literature. We know that some real vampires lurk in the animal kingdom. Our consideration of vampires usually ends there. Yet, there is another kingdom of the vampires beyond these boundaries.
These vampires do not stalk us directly, but they have clashed with humans throughout our history and they shape the world around us. These are the vampires of the plant kingdom.
The vampires of imagination sustain themselves by plunging their fangs into their victims and sucking out their blood. Botanical vampires operate in similar fashion, only without fangs and they are not drinking blood. Plants need to move water, nutrients, and sugars throughout their bodies. Vascular plants are plants with a circulatory system of tissues called xylem and phloem. Xylem is a highway of canals moving water throughout a plant’s body. Phloem does the same thing for sugars. These tissues are analogous to the circulatory system moving blood throughout the human body. They make a very tempting target for the vampires of the plant world.
If a plant dreaded a vampire attack, it is not the bite of a fang that it would fear but the deadly grasp of the haustorium. A haustorium is a modified root that seeks not to draw water and nutrients from the soil, but to find a victim and penetrate deeply into its tissue. A vampire plant unleashes a swarm of haustoria into its victim to tap into its xylem and phloem. Once inside, the haustoria directly connect the circulatory system of victim and vampire. The victim plant literally has the life sucked away from it as the vampire hijacks its water and nutrients.
The vampires of myth dwell in the shadows, pouncing on their victims only in the depths of night. Vampire plants operate out in the open in the full light of day. Nobody knows for sure how many kinds of botanical vampires there are. There are between 300,000 and 400,000 species of vascular plants (plants with xylem and phloem) in the world. Some scientists have estimated that perhaps 1% of these species are vampires, known technically as parasitic plants to botanists. This means that there may be 4000 or more species of plants seeking to sink their haustoria into their fellow plant species.
One of the most famous botanical vampires has a starring role as a holiday decoration.
Mistletoe is a vampire, and there are over 1000 different kinds of it. The vampiric life cycle of mistletoe begins with a bird being attracted to a luscious berry on a mistletoe plant. The bird unknowingly swallows the vampire in the form of a seed within the berry and transports it to a new victim plant, a tree. The vampire seed emerges from the bird unharmed and deposited on a tree branch where it germinates. Haustoria writhe from the mistletoe seedling and infest the tissue of the tree hosting it. The xylem and phloem of vampire and host are connected and the mistletoe feeds on its host for years. The victim is weakened by the vampire feeding upon it for decades, but likely will not be killed by it. It is in the interest of the vampire not to destroy its victim by overfeeding on it. Eventually the mistletoe will flower and produce a seed embedded in a berry. Another bird will feed on it and the vampire attack will start anew.
Vampire plants do not attack humans directly, but in medieval Europe one species did cause real horror. Yellow rattle is a plant species that lives in meadows and grasslands. It has beautiful yellow flowers. When the seeds mature they rattle around within the fruit pod of the plant. This rattling would not be a welcome sound for European farmers. Yellow rattle is a hemi-parasite. This means that the plant sometimes lives freely on its own, absorbing water and nutrients from its roots like a normal plant does. Other times yellow rattle becomes a vampire, engulfing the roots of surrounding plants with haustoria and sucking dry their water and nutrients. Yellow rattle was known by the curse “stealer of bread” in medieval Europe. It would infest fields and vampirize entire crops of wheat so that nothing was left.
As vampire hunters of legend arose to fight off the vampires of our imaginations, the farmers of Europe figured out how to defeat the real life vampirism of yellow rattle. They discovered that yellow rattle does not produce enough seeds to remain in the ground over time and start a seed bank, a repository of seeds that survives over years and replenishes a plant species’ numbers. If the yellow rattle was destroyed before seeds were produced then the vampire threat could be eradicated from the fields and the crops would be plagued no more. By the 1800s farmers no longer considered yellow rattle a threat to their crops. The stealer of bread had been defeated.
Yellow rattle was once seen as vampiric scourge that preyed upon other plants with evil intent. Today we know more about its role in its grassland ecosystems. In England scientists are restoring agricultural fields back into natural grasslands. Sometimes a few species of grasses will dominate a field and reduce the biological diversity, the number of species present, of the restored grassland. When yellow rattle is added in these ecosystems it helps preserve biological diversity by preventing any one species from taking over by vampirizing the most abundant species and controlling its numbers. Just as our increasing knowledge and exploration of the world transported us out of a world of imaginary monsters, our increased understanding of vampire plants now shows us that they are not really monsters. They are important parts of the ecosystems that they live in and help conserve biological diversity.
The sea serpents and werewolves have disappeared from the world, but we really do live in the garden of the vampires.
The author thanks Dr. Duncan B. Westbury for his help with this story.