How does a fungus get to be so big? And what exactly is a fungus, anyway?
What weighs about the same as 200 blue whales, is as big as the Mall of America, and yet is almost invisible? Oh, yeah, it’s also several thousand years old, alive, and parasitic.
This is no joke.
It’s the Humongous Fungus, a single specimen of Armillaria ostoyae, or more simply, a honey mushroom that’s been growing for thousands of years. The Humongous Fungus (its nickname) spreads out over about four square miles (the size of some international airports!) in Oregon’s Malheur National Forest. Its weight is estimated at 7,500 tons (half the weight of the Brooklyn Bridge!), though some scientists think it could be as heavy as 35,000 tons. And it’s still growing, expanding outward under the ground in thin networks of mycelia, root-like filaments. Yikes!
So, how does a fungus get to be so big? And what exactly is a fungus, anyway?
Much Ado About Mushrooms
Question: What’s not a plant, not an animal, not a bacterium, and yet is still alive?
Answer: Fungus. A fungus is part of the family that includes the mushrooms on your supper table (and some less familiar mushrooms, too), the yeast in your challah (and other kinds of yeast), and microorganisms like the mold growing in your shower (eww).
Although mycology, the study of fungi, is a branch of botany (the study of plants), fungi are actually more closely related to animals than plants — at least genetically speaking. They’re found all over the world. Most of them have never been properly studied and classified, but there are one and a half to five million species of them. And they’re essential to the environment: they play a role in the decomposition of dead things and replace important nutrients in the soil. We eat some of them. They can be used in various medicines. Researchers are always finding other fascinating uses for them. And lots of them are extremely poisonous.
But most of them are not the size of a mall. So how did the Humungous Fungus grow so large?
The Humongous Fungus (a.k.a. the not-so-sweet honey mushroom taking over Oregon’s forest) most likely grew to its Guinness-record proportions due to human error. That’s right. Our fault. Bad forest management is to blame. And it’s a Humongous problem.
Ever heard the joke about the mushroom who wasn’t allowed into a café? He argues with them, saying, “Why not? I’m a fun guy!” (Get it, fun guy, fungi?) Well, the Humongous Fungus may be a fungi, but it’s certainly not a fun guy. In fact, it’s an insidious, parasitic killer. And it’s at least 2,400 years old. It doesn’t have a birth certificate or even age rings like a tree. But scientists estimate its age based on its average growth rate each year.
As this fungus spreads, it creeps up trees, hiding right under their bark. The parasite then slowly sucks away at its unfortunate host, killing the tree, and then continues chomping away on its dead wood for tens of years to come. The killing is done in extremely slow motion, taking 20 to 50 years to complete the process.
How do the fungus investigators know the Humongous Fungus is all one big creepy mushroom and not millions of separate ones? DNA fingerprinting. Scientists have checked samples of the fungus across the spread and have found they all have the same genes.
Chernobyl’s Radiation-Munching Mushrooms
You’ve probably heard of the Chernobyl nuclear disaster. In April 1986, at the Chernobyl nuclear power plant in Pripyat, Ukraine (then part of the Soviet Union), one of the worst nuclear accidents in history occurred when there was a nuclear meltdown and massive quantities of radioactive particles were released into the air. Hundreds of thousands of people were forced to flee their homes, and many people in the area got sick and died.
Everything in the area was abandoned. But something else crept in…
Discovered in the area in 1991 by robots exploring the area, Cryptococcus neoformans is a jet-black fungus that’s pretty familiar to scientists. It can even cause quite a vile infection, called cryptococcosis, in people. It leads to chest pain, dry cough, headache, nausea, confusion, blurred or double vision, fatigue, fever, unusual and excessive sweating at night, swollen glands, and more. Yikes!
But the Cryptococcus neoformans found in Chernobyl post-nuclear disaster was doing something very interesting. It was eating radiation. In fact, it was growing inside the defunct nuclear reactors! A type of extremophile, a microorganism that can live in extreme conditions (temperature, acidity, alkalinity, radioactivity, and so on), this fungus might actually be able to play an important role in helping protect us from radiation. In fact, the fungus can survive not just in radioactive places, but in extremely hot environments, too.
The fungus contains a lot of melanin. That’s a pigment that turns skin darker. The melanin in the fungus feeds on radiation and turns it into a kind of energy, sort of like the photosynthesis cycle in plants. (Scientists are calling this radiosynthesis.) Amazingly, the closer the fungi were to the source of radiation, the more melanin they produced. The black fungi were not growing despite the radiation. They were growing due to it. And just like plants display phototropism, growing toward the sun, these fungi are exhibiting something called positive radiotropism. They somehow “sense” radioactivity and grow and expand toward it.
NASA has been studying the Chernobyl fungus to see if there’s a way to use its good properties to protect astronauts in space from radiation — basically making a “space sunscreen” out of it. (There is some radiation on the International Space Station and lots of cosmic radiation in space.) Of course, this extremophile fungus could also be used to help protect people on Earth. Maybe it could also be used to process radiation in a safe way and turn it into usable energy.
The sick, dying, and dead trees (mostly firs) in Malheur are a symbol of what’s at risk. They’re also easier to see than the fungus itself, which is mostly hidden underground. When the trees in the area are tested (by chipping away a bit of bark with a forestry tool called a Pulaski), foresters can see cream-colored, fanlike shapes on the bare wood. That’s evidence of the fungus’s deadly spread. That fungus spreads under the tree’s bark and rots its roots.
Most of the Humongous Fungus’s growth is underground. Similar to other fungi, Armillaria sprouts tiny root-like threads underground. Unlike most fungi, however, these little threads fuse together, forming strings the width of shoelaces. These grow and expand over tremendous distances to munch on dead and weak wood. In a smaller form, the Humongous Fungus species (Armillaria ostoyae) is actually an important part of the decomposition process. It eats up sick and dead wood and helps it return to soil.
Wildlife specialists actually blame fire management over the last 100 years ago or so for the problem of the fungus’s spread. Because naturally occurring forest fires (from lightning strikes) would have burned down unhealthy trees (which are most susceptible to fungal spread), the Humungous Fungus would have had nowhere to go and grow. Natural fires used to burn up all scrub and brush on the forest floor, “cleaning up” the forest, and leaving the healthy trees room to spread. (They were strong, thick trees, and were healthy enough to resist fire.)
But one of the most devastating fires in history changed the way humans managed forest fires, ultimately leading to the crazy growth of the Humongous Fungus.
It Grows on Your Toes
It’s definitely not the most appetizing topic, but it’s certainly relevant: toenail fungus. Ewwww. While toenail fungus isn’t a mushroom growing on your toes, it’s in the same fun(gus) family. It’s an infection caused by fungi growing on your feet. The most common culprit is the dermatophyte (dehr-muh-toe-fite) fungus. But yeast and molds can also cause toenail problems. Nails with fungal issues often look chalky white or yellowish under the edge. And the nail can thicken and crumble at the tip.
Toenail fungus can affect anyone at any age, but it’s most common in older people. In fact, about 50 percent of people over 70 have to deal with it from time to time. When people get older, their nails can become dry and easily breakable. If the nails crack, the fungi can creep in!
Athlete’s foot (your un-friend from camp and community pools) is an infection caused by foot fungus. It can also spread to your toenails. Yuck.
Want to keep these freaky fungi away? Here are some tips:
Wear flip-flops/Crocs/sandals (and don’t go barefoot!) when using public showers, in locker and dressing rooms, and at swimming pools.
Don’t share nail clippers with friends.
Don’t share towels or footwear with friends.
Make sure your feet are fully dry after showering or swimming and before putting on socks and shoes.
Wash your feet every day.
Change your socks every day.
Don’t wear socks when you sleep, to allow your feet to “breathe.”
Marvelous, Mysterious Mushrooms
If your local grocer sells more than portobello and button mushrooms, you’ve probably seen cremini and shiitake mushrooms, too. But there’s a lot more out there than these four in the world of mycology. Check out some of the most unusual.
NOTE: Never, ever pick, touch, or eat wild mushrooms. Many are deadly and look similar or nearly identical to edible varieties.
Black Witches’ Butter (Exidia Glandulosa)
Looks like: Lumps of charcoal (when dry) or globs of black jelly (when wet)
Found: On decaying logs and fallen branches
Selected because: They’ve got such a weird color and texture. And they’re apparently edible, but they don’t taste anything like butter.
Blue Milk Mushroom (Lactarius Indigo)
Looks like: Regular mushrooms, but blue
Found: Eastern North America, East Asia, and Central America on the ground in forests
Selected because: Their “milk” (the latex-like “juice” that oozes from it) is indigo blue. And that’s just cool. Also, that blue milk slowly turns green when exposed to oxygen. They’re also apparently edible, if blue mushroom milk appeals to you.
Bleeding Tooth Fungus (Hydnellum peckii)
Looks like: Red and oozy
Found: Pacific Northwest, Europe, Iran, and South Korea, among the mosses and pine needles of conifer forests
Selected because: They looks like they’re oozing blood, but that’s really just part of how the fungus excretes extra fluids. They’re not toxic, but they supposedly taste so bitter that they’re inedible. They’re used in dyes and also in creating some medicines.
Golden Jelly Fungus (Tremella mesenterica)
Looks like: Globs of earwax
Found: On dead and recently fallen branches in temperate and tropical forests of Africa, Asia, Australia, Europe, North and South America
Selected because: They look so weird and unnatural. They’re edible, though thought to be bland and flavorless.
Glow-in-the-Dark Mushrooms (Mycena chlorophos)
Looks like: Creepy, eerie, green-glowing mushrooms
Found: Southeast Asia
Selected because: They glow in the dark and how cool is that?! There are actually numerous species of fungi that exhibit bioluminescence (glow-in-the-dark properties) but these were discovered first.
The Wrinkled Peach (Rhodotus palmatus)
Looks like: A fruit from another planet
Found: Eastern North America, Northern Africa, Europe, and Asia, on the stumps and logs of rotting hardwoods
Selected because: It’s very rare and looks so strange
Chicken of the Woods (Laetiporus Sulphureus)
Looks like: Chicken nuggets or stacks of schnitzel
Found: In Europe and North America on tree trunks and branches
Selected because: They can grow to be up to 100 pounds. They’re edible, but they have a look-alike that’s poisonous. And I doubt they taste like chicken.
Hat Thrower (Pilobolus Crystallinus)
Looks like: Reverse water drop with a black hat
Found: China, growing in animal dung
Selected because: It’s the fastest organism on Earth, which is pretty crazy considering that fungi don’t move. These fungi launch their spores at an acceleration rate of 1.7 million m/s2 — faster than rockets!
Basket Fungi (Ileodictyon cibarium)
Looks like: A strange basket-like orb
Found: In Australia, New Zealand, South Africa, and Chile in woody debris, cultivated soil, and even lawns
Selected because: They’re cool structural mushrooms. They absolutely stink. They have a smelly, slimy layer that attracts flies. And they start out egg-shaped and only turn into baskets when they mature.
Devil’s Fingers (Clathrus Archeri)
Looks like: A creepy black claw
Found: Originally from Australia and New Zealand, this species has spread throughout the world in leaf litter, decaying stumps, and woodchips.
Selected because: It looks pretty weird, and the fingers are really smelly.
The Big Burn
In 1910, the Big Burn blazed across a staggering three million acres of Idaho, Montana, and Oregon, killing more than 80 people. Officials at the US Forest Service say it was this fire, the Big Burn, that created the idea that forest fires are bad and must be extinguished no matter what.
Meanwhile, as loggers chopped down trees in the Northwestern United States (many of which were hundreds of years old and could naturally resist fires and fungus), new trees were planted to “replace” them. But the Douglas firs and grand firs that were planted couldn’t resist fires or fungus. In fact, they were highly susceptible to fungal growth.
Although the Humongous Fungus is way older than 20th century forest management (like, thousands of years older), it wouldn’t have gotten so big if nature had been allowed to run its course the way Hashem intended. And now that fungus is chomping its way through the forest, leaving fallen, hollowed out, and dying trees in its wake.
The Humongous Fungus is growing at a rate of around five feet per year in all directions. It’s eating up all those fir trees, leaving expanses of empty space. Maybe the fire- and fungus-resistant species can move back in?
Forestry experts are trying to help things along by doing some controlled burns: small fires that are set on purpose and carefully monitored. When the ground is clear of debris, healthier species can be brought in.
There could be more humongous fungi out there, too. We just don’t know about them. Yet. In the meantime, the world’s largest known living organism (and one of the oldest), the Humongous Fungus, just keeps on growing.
(Originally featured in Mishpacha Jr., Issue 920)
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