When days get shorter, the memory of spring’s colourful blooms and summer’s tasteful fruits may fade away … leaving space for spooky botanical species that can be protagonists of horror stories told in darker nights. In this blog post, we explore the scary side of Botany by having a look at 10 plants with “magical” properties. Beware the botanicals of fear: most of them are growing wild all around the globe!
POISONOUS PLANTS: Atropa belladonna & Hippomane mancinella
Being unable to move, plants protect themselves from the attack of pathogens and herbivores by developing physical defences (e.g., spines) and a wide range of chemical weapons, which can be toxic or even lethal to animals (including humans) depending on the dose.
Among the deadliest plants, Atropa belladonna (deadly Nightshade) – a perennial shrub of the Solanaceae family original from southern Europe and Asia – produces the alkaloid atropine in most of its structures. Since ancient times, women have used its extracts as cosmetic products to increase attractiveness; indeed, few eye drops containing atropine dilates the eye pupils. Nevertheless, higher concentrations can cause paralysis in the involuntary muscles, including the heart, thus leading to death!
Widespread in central America, Hippomane mancinella – commonly known as “manzanilla de la Muerte” in Spanish or “little apple of death” in English due to its similarities with Malus domestica – is a tree species of the Euphorbiaceae family that produces the diterpene phorbol and other toxic molecules in its sap that cause blisters and irritation upon contact with human skin.
STINKY PLANTS: Stapelia gigantea & Amorphophallus titanum
Several flowering plants attract pollinators by producing floral scents with exciting smells to secure their reproductive success. However, few botanical species attract insects for pollination by mimicking the bad odour of dead animals: they produce the so-called carrion flowers that smell like rotten meat!
Native to southern Africa, Stapelia gigantea – a eudicot plant of the Apocynaceae family that grows well in arid environments – develops big yellow flowers with red stripes of 25-40 cm in diameter. By releasing peculiar floral volatiles (including the diamines putrescine and cadaverine), big reproductive structures attract carrion-flies of the species Musca domestica and Calliphora genus that facilitate its pollination.
Native to Sumatra, Amorphophallus titanum – also known as Titan arum or corpse flower – is a monocot plant of the Araceae family that lives in equatorial rainforests and produces the first bloom after 5-10 years of vegetative growth. According to the Guinness World Records, this species is considered the smelliest plant on Earth and develops the biggest inflorescence scored up to date, being more than 3 metres tall. To attract carrion beetles of the genus Diamesus, its reproductive organs release not only corpse-like odours but also heat at the end of the day when specific pollinators are active.
WITCHY FLOWERING PLANTS: Black Petunia & Tacca chantrieri
The great majority of animals and humans love beautiful and colourful flowers. Nonetheless, new varieties of Petunia with dark names (e.g., Black Magic, Black Cat, Black Mamba) stand out in the ornamental market for their rare black flowers.
Beyond cultivated gardens, a plant species growing wild in tropical regions of Southeast Asia called Tacca chantrieri shows a weird floral morphology that inspires scary names: “devil flower” for dark floral colours, “black bat flower” as the bracts look like wings of flying mammals of the Chiroptera order, or “Tiger’s moustache flower” as bracteoles (i.e., long filiform appendages) resemble feline whiskers. Besides the extravagant reproductive structures, tubers of this monocot plant of the Dioscoreaceae family (related to edible Yam) have wide use in Asian traditional medicine.
VORACIOUS PLANTS: Nepenthes rajah & Nepenthes attenboroughii
Carnivorous species usually live in nutrient-poor ecosystems that lack basic elements for plant growth, such as Nitrogen and Phosphorus. That’s why these plants have evolved clever mechanisms to absorb nutrients from dead animals instead of the soil: specialized structures catch the prey, later degraded by specific enzymes that break down the animal exoskeleton and mobilize macronutrients.
Different from the Sci-Fi images of predator plants with leafy mouths full of teeth, the 170 species of the Nepenthes genus living in the Palaeotropics act like passive killers: insects and small vertebrates fall into cup-shaped modified leaves called pitchers, where they get trapped.
Meat-eating plants use a “cruel” strategy that follows these steps:
- Attraction of the prey in pitfall traps (through nectar, volatiles, colours)
- Retention of the prey inside the pitcher (through slippery surfaces)
- Secretion of a viscoelastic fluid that kills the prey by drowning
- Digestion via specialized enzymes (e.g., chitinases, proteases, phosphatases)
- Assimilation of nutrients for plant development
Among the most spectacular species, N. rajah (from Borneo) and N. attenboroughii (from the Philippines, named after the famous naturalist Sir David Attenborough) have the largest pitchers (containing up to 2-3 litres of digestive liquid) that can trap frogs, birds, and even small mammals like rats.
HUMAN-LIKE PLANTS: Lithops pseudotruncatella & Rumex sanguineus
We conclude this overview of scary plants found all around the planet with two botanical specimens that display structures resembling parts of the human body.
On the one hand, Lithops pseudotruncatella – a small succulent plant endemic to Namibia – develops pairs of leaves of grey to brown colour characterized by a dark staining that recalls features of the two cerebral hemispheres of the human brain
On the other hand, Rumex sanguineus – a perennial angiosperm of the buckwheat family growing in central Europe – forms lance-shaped green leaves with bright purple veins resembling blood. Commonly known as Red Vein Sorrel, young leaves are added to our dishes to give colour and spinach-like taste to salads