> ayahuasca, DMT
Listing both is redundant, as DMT is the active ingredient in ayahuasca (the MAOI component in this plant extract is there to prevent the DMT from being destroyed in the gut by monoamine oxidaze, and its psychoactive effect is miniscule in comparison to the DMT -- if MAOIs had a strong psychoactive effect they probably wouldn't be used as antidepressants).
The harmala component in ayahuasca is there (mostly) to facilitate ingestion, yes, but DMT can be used without it when smoked or snorted (which I think was the original use, powder processed from yopo bark).
Anyway, it might be a regional thing, but my impression is that to the extent that is to be found at all, "DMT" here in the EU refers to synthetic stuff meant to be smoked in a base pipe, and probably is not the 5-MeO-DMT variant found in ayahuasca. Is this use of the terms different in the US?
Listing DMT would have been sufficient; listing both is kind of like listing mescaline and peyote both, which doesn't make sense -- one comes from the other.
Mescaline can come from peyote, of course, but also from San Pedro. The effects are reported to be distinct, to some extent, due to the various other components in either plant. Which presumably make both slightly different from synthetic mescaline. I can't actually say this from personal experience though, these things are not at all commonplace or easy to procure where I'm at.