Not all plants crave the sun - some have found other (more sinister) ways to get their meals, often becoming rather strange in the process. Here are at 8 examples of these weird parasitic plants, including...
- The Corpse Flower: Huge, warm and reeking of rotten meat
- The Orchid that Never Blooms: Robbing fungi and keeping its flowers to itself
- The Gnome Plant: A mysterious parasite on the forest floor
- The Crop Strangler: The dodder plant can manipulate genes
- The Double Parasite: A plant that abuses fungi and gnats
- The Vampire of the Plant World: It can lie buried and wait decades for a victim
- The Parasitic Plant Spread by Rare Rabbits: A parasite with a cunning partnership
- The Spectral Orchids: These exotic plants can be parasites too
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| The corpse flower is the biggest bloom in the world... (Colin + Meg) |
The Corpse Flower
Few plants are as strange as Rafflesia. Their blooms are huge (Rafflesia arnoldi produces the biggest flower in the world) and stink like a rotting carcass to attract carrion-eaters - the flower even produces heat to help spread the scent. If that wasn't weird enough, their pollen is a sticky fluid that coats any insect that crawls inside.
To put the rotting cherry on top, these alien-seeming plants are parasites that grow like fleshy strands inside tropical grape vines and siphon off nutrients and fluids. When it's time to flower, the buds force their way through the surface of the vines and erupt into massive, stinking blooms.
But wait, there's more! It turns out that Rafflesia can steal genes from a host plant - it's thought that this "genetic horizontal transfer" can help the parasite blend in and avoid being detected by its victims.
The Orchid that Never Blooms
Orchids are known for their exotic flowers - but on the Japanese island of Kuroshima, Gastrodia kuroshimensis doesn't photosynthesize and never blooms.
Little light reaches the orchid's home on the dark forest floor. Rather than relying on photosynthesis, the orchid parasitizes fungi and draws nutrients from their mycelium.
While this orchid produces flowers, they never actually open - the plant self-pollinates inside each closed bud. This might be a response to the scarcity of pollinating insects where the orchid lives, forcing the plant to take matters into its own hands.
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| Gnome plants steal nutrients from redwood forest fungi... (PublicDomainPictures) |
The Gnome Plant
It's possible to see a "gnome" in the redwood forests of California... but it's a weird parasitic plant rather than any fairytale creature!
Hemitomes congestum grows as a tiny clump of reddish-pink flowers on the forest floor. The flesh or scarlet tones make it stand out from the leaf-litter and are the reason it gets called the "gnome plant." The odd appearance is capped off with a lack of leaves - the plant steals nutrients from fungi beneath the surface.
Nobody actually knows which insect pollinates this weird plant, but there are a few clues. For example, it has long and hair filled flowers that might discourage small insects... but a moth could use its long proboscis to reach the nectar at the base.
The gnome plant also produces fleshy berries with a musky, cheesy scent - which might serve to attract small animals.
The Crop Strangler
A surprisingly common parasite tangles and strangles crops like beans, hops and alfalfa throughout much of the world.
Though related to morning glories, the dodders (Cuscuta) are leafless and lack the chlorophyl needed for photosynthesis. Instead, they produce a spiraling stem as they grow... one that must find a victim within 5-10 days if the dodder is to survive.
Should the dodder find prey, it twines around the host plant and plunges haustoria (basically parasitic roots that act like drinking straws) into the stem. Draining fluids and nutrients, the dodder grows until the host is completely covered - which can prove fatal for the victim.
Dodder has another devious trick - it can manipulate the gene-expression of the host. By injecting microRNA through the haustoria, the dodder can simply "switch off" any defenses the host might use against it.
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| Dodder can parasitize hops - to the dismay of brewers! (Jan Piatkowski) |
The Double Parasite
Like a multicolored, tentacled alien worm bursting from the leaf-litter, Thismia tentaculata has to be one of the strangest looking plants in existence.
This leafless parasite stands out from the crowd because it seems to abuse not one but two different organisms. Like many other parasitic plants, it siphons nutrients from fungal mycelium in the soil... but researchers have also suggested that it attracts fungal gnats for pollination - and it may not give them nectar as a "reward."
Thismia tentaculata produces complex and colorful scented flowers to lure the gnats. It also seems to exude droplets on hairs inside the flower - while it's unknown if these benefit the gnats, we do know that the flowers "trap" visitors for a short while to ensure pollination.
The Vampire of the Plant World
Lurking beneath the soil and draining fluid and nutrients from victims, the Orobanche (or broomrapes) sound more like something out of a horror movie rather than a pest-plant.
Like a slumbering vampire, broomrape seeds can remain dormant for years until they detect molecules released by the roots of a potential victim. The plant itself remains underground throughout its life, with the only above-surface activity being flower spikes that punch up through the soil.
Broomrape targets the root systems of its victims, puncturing them with haustoria (these root-like organs have evolved independently at least eleven times in different parasitic plants) to drain water and nutrients.
These plants can and do attack crops - and because they live underground, it can be very hard to detect them before a harvest is ruined!
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| Broomrapes are the vampires of the plant world.. (u_1ue8d3w012) |
The Parasitic Plant Spread by Rare Rabbits
Rabbits usually spell doom for plants, but the parasitic Balanophora yuwanensis uses them to spread itself to new trees.
The Balanophora are mushroom-like plants that attach themselves to underground tree roots. They use haustoria to steal resources and only pop up from the soil to fruit. They also contain a waxy substance that resists fire - some regions have used them as an impromptu candle.
Balanophora yuwanensis is found on the Ryukyu Archipelago of Japan and resembles a mushroom crossed with a strawberry. It has also evolved to take advantage of the local Amami rabbits when dispersing seeds.
Rather than a fleshy lump, the parasite produces a dry fruiting body that suits the leaf-based diet of the rabbits. The hungry herbivores gobble up their meal and return to their burrows... where the seeds are "deposited" conveniently near to tree roots!
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| The ghost orchid thrives in this kind of environment... (Andriy Nestruiev) |
The Spectral Orchids
Did you know that some orchids are parasitic?
The leafless snow (or phantom) orchid Cephalanthera austiniae hails from America and steals its meals from fungi beneath the soil. It grows in shady conditions where fungi flourish and seems to have a preference for alkaline soils - it's been seen on old shell middens and limestone mines. The only visible bit of the orchid is a startling white (including the stem) flower spike with a few splashes of yellow on the blooms.
Britain has its own version, the ghost orchid Epipogium aphyllum. Like the phantom, it lacks leaves and leeches off fungi. It's not as visually striking as the phantom (in fact, it's highly unusual to see one at all thanks to a diminutive size and love of darkness) but it does have a habit of confounding botanists - disappearing for decades only to pop up in unexpected places!
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