We can dismiss this easily.

Fungi and plants were treated in the same category some thousand years ago, but times changed and now are categorized by biologists as new and very different creatures deserving its entire kingdom. The old concept of 'plants' has split into several unrelated lineages.

Fungi have a easily recognizable and unique cell structure than neither animals, nor plants have, so can't be the origin of our brains.

Fungi are the origins of all creatures on earth, humans included it seems. As far as I know, it's still the oldest identified complex organism on this planet.

> Fungi are the origins of all creatures on earth, humans included

Bacteria are older.

Nobody knows if that fossil is a fungus. It looks like one, but to me looks much more like a tiny sponge. I could be wrong and could be perfectly a third different thing. Ctenophora are now the oldest animals I think, so there was a lot of old complexity yet from the start that we don't know well.

I was thinking of Prototaxites which was maybe 470m years old (possibly) and humongous. Sounds like sponges are it (oldest) then. Until we learn otherwise.

I think my brain might be a truffle.