Sasha did write a blog article stating that psilocybin mushrooms would selectively 4-hydroxylate tryptamines. It's one of those reactions that plants can do very selectively quite easily, but if you try to do in a lab, it's difficult to prevent hydroxylation at other sites.

E.g. (well, not a real example, but the idea of the reaction). You could put DPT in the growing media of mushrooms, and get 4-OH-DPT in the mushroom.

Keep in mind that you could put DMT in the media and get 4-OH-DMT, but that would be pointless, that's what the mushrooms make anyway!

Aha, that's what I was thinking of. I believe it's mentioned in passing in TIHKAL.

I think you're confusing N,N-DMT (commonly referred to as DMT) with either 4-PO-DMT (psilocybin) or 4-HO-DMT (psilocin). _Very_ different substances.