It must look like a traditional mushroom, with a central stalk and a cap above it. (A puffball counts if it actually has a visible stalk.) It must rise at least 1 meter from the point where it's last supported by the ground or another object. (The cap is counted in this height). This refers to actual vertical height as found in the wild, not the length of the stem when stretched out.
Resolves YES if anyone provides a credible example, otherwise resolves NO at close. Any mushroom that existed at any point before close counts, even in the distant past. (I must be highly confident that it actually existed, was a fungus, and looked something like a modern-day mushroom.)
Related questions
So the world record for edible mushrooms is 59cm and that includes parts that would likely be supported, so would not count in full for the purpose of this market. All of the big mushroom species I know of are edible, so don't think including inedible should change much. There are some photos of presumably a bit taller (70cm) Macrocybe Titans specimen, but it is hard to verify. So I'd say unlikely for extant species. Hard to evaluate the historical record... https://www.guinnessworldrecords.com/world-records/97463-longest-edible-mushroom
https://m.facebook.com/photo.php/?photo_id=3647530488616453
@IsaacKing here's a different source with the same photo https://www.forestfloornarrative.com/blog/2019/1/4/the-giant-fungus-among-us-macrocybe-titans
This is for a mushroom that exists at any moment from now to 2035, right?
@IsaacKing I was more thinking about strong evidence of tall mushrooms in the past. https://www.smithsonianmag.com/smart-news/long-before-trees-overtook-the-land-earth-was-covered-by-giant-mushrooms-13709647/
@NoaNabeshima Prehistoric examples do count, but I need to be highly confident that they actually existed and it's not an error of fossil reconstruction.
That particular example doesn't look much like a mushroom unfortunately.
@IsaacKing I'm not sure that the drawing is a good representation of what prototaxites looked like. I'm not sure humans have actually found tops that looked like that, I think it might have been an artistic addition from the drawer who thought that prototaxites were an early conifer. Even still, it seems unlikely that they'd look like a classic mushroom.