Debunking the “World’s Largest Mushroom” Photo

A photo of a giant mushroom - large enough to eclipse a group of people - allegedly shows the largest living thing in the world. It is real or just another internet hoax?

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The story is real but the photo is fake.

The Real Story

As first reported in August 2000, the world’s “largest living thing” is the honey mushroom (Armillaria ostoyae) of Oregon. It covers 2200 acres and is estimated to be over 2400 years old. A paragraph from the story linked above has been circulating online for years, which is an accurate description of the “world’s largest thing.” The shared story, however, often includes a fake photo of a single, giant mushroom that completely misrepresents the story and the honey mushroom. The story included with the photo reads:

Oregon’s monster mushroom is world’s biggest living thing

The largest living organism ever found has been discovered in an ancient American forest. The Armillaria ostoyae, popularly known as the honey mushroom, started from a single spore too small to see without a microscope. It has been spreading its black shoestring filaments, called rhizomorphs, through the forest for an estimated 2,400 years, killing trees as it grows.

The Fake Photo

The caption fails to mention that the fungus is not a single, massive growth, but actually covers many square miles of land. The giant mushroom depicted in the photo is a digital creation, and does not show the honey mushroom of Oregon.

Digital Manipulation

The first step we took in debunking this photo was to look closely for obvious signs of manipulation. The person in the red shirt, for example, appears to be using binoculars, which wouldn’t be necessary for an object only about 20-feet high. The edges of the mushroom indicate that a photo of a mushroom was cut out and enlarged (see below). It would also stand to reason that if such a massive mushroom did exist, there would be more photos of it. Such an amazing sight would have been well-documented by scientists and journalists, yet the photo above is the only image in existence of this large mushroom.

Honey Mushroom

The massive mushroom in the fake photo doesn’t even appear to depict the honey mushroom of Oregon. Take a look at the actual honey mushroom (right) and compare it to the one in the manipulated photo above.

According to the website by Tom Volk, Professor of Biology at University of Wisconsin-La Crosse, “The largest fungal fruiting bodies known are… only about 300lbs.”

Edge Analysis

There are several signs of digital manipulation of the image. Take, for example, how the edges of the stem change when background changes to the forest behind it. The edge changes from a smooth, slightly blurry line to a very sharp edge. This indicates that the image of the mushroom was likely cut out and placed there. See the enlargement below.

True source: “Boletus photoshopus”

Although we felt our “edge analysis” was enough to debunk the hoax, we decided to dig a little deeper and ask around to see if any “mushroom experts” could tell us anything else about the image. We first contacted Professor Volk to see if he had any insights, and he was familiar with the popular image. His response was:

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“This picture was out of Tom Bruns’ lab at Berkeley. Definitely photoshopped. Apparently believably. Hope this helps. —tom”

We then sent an email in January 2013 to Tom Bruns at UC Berkeley, who responded immediately. His quirky response included the subject of Boletus photoshopus with a single statement:

Pictured in its natural habitat – the digital photo. – Tom Bruns

In other words, the “natural habitat” of the mushroom in the image is in a digital photo.  We love the name he gave the mushroom in the picture: Boletus photoshopus.

Bottom Line

The giant mushroom pictured above is a digital creation and does not depict the world’s “largest living thing.” The image originated from the lab of Tom Bruns from UC Berkeley, apparently as a joke.

We’d like to thank Thomas Volk and Tom Bruns for helping us debunk the image once and for all. Who knew that fungi experts could be so cool? 

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  • BIBO

    I thought it was a tree carved to look like a mushroom. Interesting story, although there was a similar story of a fungus across the upper peninsula of Michigan 30 years ago – which would have been much larger than either of these western varieties!

    • Rob Foe

      Umm,I HIGHLY DOUBT the fact that just a couple years ago there was ANOTHER fungus in michigan that would have Dwarved the largest living thing on earth.Think about the picture of the honey mushroom,And then remember that those trees are GIANT REDWOODS.So even though they arent 20 ft tall they are STILL apparently fairly large,But hey thats just my opinion.Oh and btw,What happened to the fungus???

  • shroomer

    lol the guy who made this post is an idiot. This was obviously a practical joke.

    • waffles

      Thank you for your enlightened comment. The purpose of this post is to clear up the origin of this image which continues to be passed off as real.

  • Shirley

    I think it’s great! I am from Oregon and have seen very large mushrooms! fake pic but made me feel like I was back home!

  • Caveman Chuck

    Of course Thomas Volk and Tom Bruns could be so cool… They’re a couple of fungis!

  • sara

    I was hoping it was some sort of wood carved tourist attraction.

    • waffles

      That would actually be very cool!

  • sandra

    I found a article by jeff barnard from ABC news that he published back in 2006. I find ABC news to be a credible media. I live in Oregon so Iam going to go see it for myself since the real question is if the photo is fake. In the article it depicts that the mushroom is as big as 3 football fields. Now Im no expert in photography but seems there would be no way you would be able to capture a mushroom that big into a photo and be able to see the whole thing or is this possible?

  • Marc

    When they say the ‘largest living thing’, they’re more referencing the underground portion, how far it spans. It’s not going to be a 3 football field mushroom, I’m sorry to say.

    • waffles

      Good clarification!

  • matthew

    I want more pictures of the mushrooms.

  • Ferit

    plus there are trees and mammals larger than this fake photo.

  • vedant

    If you carefully look at the trees it is apparent that the lightsource (sun) is at the right side of the photo, but that should imply that the left side of the upper lobe of the mushroom should’ve been darker. Secondly the shadow that the mushroom should’ve cast on the ground is also nowhere to be seen.

  • noel b. liban

    hahaha..at first sight, the it made me think that the picture is fake…look at the surroundings…it doesn’t match the color or the texture of the mushroom.the next time around i hope its not super mario’s mushroom…^_^

  • SpinalTrap

    Marie certainly did.

  • bmark

    haaaaaa
    i get it
    good show, sir.