Ah. Lophophora williamsii. Never heard that term for it before.

It used to be cheap and plentiful but that was a half a century ago. My buddy bought 1.5"-2.5" dried buttons for $0.15 each in New Mexico and mailed them to Toronto strung as necklaces. He sold them to me for $0.25 each. USD and CAD were pretty much at par back then. A typical button weighed about a quarter ounce and was considered a standard psychedelic dose. Once I ate 15 whole buttons and crossed over into a different reality.

Most so-called mescaline tablets were bogus. I could tell the real synthetic mescaline by its flavor. It tasted like natural peyote even though it was a white powder. A tiny amount (an eighth of a tablet) gave you a pleasant invigorating high without being psychedelic.

Those were the days.