There are seven species of Cauliflower Mushroom in the genus Sparassis. They grow from the roots or bases of various trees in North America, Europe, Asia and Australia.
Some of them are parasitic on the tree. Being a brain, I guess that makes them an emotional vampire? Others feed on decaying matter, completely inverting the zombie thing. Let that be a hopeful message to you: even if the Zombie Apocalypse happens, brains will rise again from the mush of rotting leaves. This assumes that zombies don't suddenly become quite smart and set it up as a kind of "brain agriculture"...
|Image: tedreese via Flickr|
Man smiles as he handles a brain in the woods, yesterday
Their normal size is up to 25 cm (10 in) in height or about half that. This is not bad at all, but pales in comparison to certain reports of them reaching over 50 cm (20 in) tall and 14 kg (31 lb) in weight. That's nuts! Especially since they're not lumbered with a great big body; they can devote themselves totally to a life of the intellect. Oh, what they could tell us if only they were lumbered with a great big mouth!
Alas, for all their braininess, they didn't think to make themselves inedible. Not only can you cook them up and eat them, there's no poisonous mushroom that looks quite like them. Like all brains, you just have to make sure you clean out all the filth from the nooks and crannies first.