Here I come!
Yeah cowboy was right
Most of the information below is copy/pasted from a site that is considered a source so I couldn't provide a link, so I have copied/pasted some bits.
You need to find some nice
Trichocereus
there's several Trichocereus genes
there's:
Trichocereus pachanoi (San Pedro)
reported to contain: mescaline (0.11 - 2.3% ), 3,4-dimethoxyphenethylamine, 4-hydroxy-3-methoxyphenethylamine, 3-hydroxy-4,5-dimethoxyphenethylamine, 4-hydroxy-3,5-dimethoxyphenethylamine, anhalonidine, anhalinine, hordenine, tyramine, 3-methoxytyramine.
Trichocereus bridgesii
reported to contain: mescaline (small traces), tyramine, 3-methoxytyramine, 3-4-dimethoxyphenethylamine.
Trichocereus peruvians (Peruvian)
reported to contain: mescaline (0.82% ), 2-chloromescaline (.02% ), tyramine (.009% ), 3-methoxytyramine (.01% ), 3-4-dimethoxyphenethylamine, 4-hydroxy-3-5-dimethoxyphenethylamine (.004% ).
There's many other Trichocereus like spachianus, terscheckii, werdermannianus, etc and they often dont have or tiny traces of mescaline, that contains only a few other psychoactive alkaloids, mainly tryptamines in much lower proportions.
The alkaloids present, including the majority of mescaline reside in the first 1 cm of skin. The green chlorophyl containing tissue under the skin appears to be where the majority of the alkaloids accumulate. The adjacent white tissue is low in, or totally lacking those active ingredients. The woody core is also considered esentially free of active alkaloids.( May contain some alkaloids that might alter the effects of ingestion ).
But if you are looking for a cacti with higher mescaline content, Look around for some
Lophophora the most common is Lophophora williamsii, there's also many other Lophophora's like Loph. jourdaniana, fricii, diffusa, etc
But they are usually expensive to buy because of the time they take to grow.
There have been over sixty alkaloids discovered in this plant which has been described as a " little green chemical factory ". This Cactus is known to contain 56 nitrogen containing compounds derived from a tyrosine base, as well as 20 tyramine-like alkaloids. Mescaline content usually ranges from about 3 - 6%, by dry weight, averaging around 4%, but is highly variable. Most of the alkaloids present can be classified as B-phenethylamines like mescaline or tetrahydroisoquinolines like hordenine. These chemicals differ in structure from LSD in that they don't have a complete indole ring. Mescaline content of fresh, undried cactus is reported at 0.4 %.
Lophophora williamsii (Peyote)
reported to contain: N-acetyl-3-methoxy-4,5-dimethoxyphenethylamine, alanine, anhalamine, anhalidine, anhalinine, anhalonidine (14% of the total alkaloids), anhalonine, anhalotine, 3,4-dihydroxy-5-methoxyphenethylamine, epinine, dopamine, 3,4-dimethoxyphenethylamine, N-acetylanhalamine, N-acetylanhalonine, N-formylanhalamine, N-formylanhalinine, N-formylanhalonidine, N-formylanhalonine, N-formyl-O-methylanhalonidine, N-formyl-3-methoxy-4,5-dimethoxyphenethylamine, glycine (8% of the total alkaloids), hordenine, 3-hydroxy-4,5-dimethoxyphenethylamine (1 to 5% of the total alkaloids), isoanhalamine, isoanhalonidine, 3-hydroxy-4,5-dimethoxy-N-methylphenethylamine, isoanhalidine, isopellotine, lophophorine (5% of the total alkaloids), 3-hydroxy-4,5-dimethoxy-N,N-dimethoxyphenethylamine, lophorine, lophotine iodide, mescaline (30% of the total alkaloids), mescaline citrimide, mescaline malaimide, mescaline maleimide, mescaline succinimide, isocitrimide lactone mescaline , N-acetylmescaline, N-formylmescaline, N-methylmescaline, mescalotam, 3-methoxytyramine, 3-methoxy-N-methyltyramine, 3-methoxy-N,N-dimethyltyramine, O-methylanhalonidine, O-methylpeyoxylic acid, O-methylpeyoruvic acid, N-methyltyramine, pellotine (17% of the total alkaloids), peyoglunal, peyoglutam, peyonine, peyophorine, peyouvic acid, peyotine iodide, peyoxylic acid, tyramine.
Peyotes take years to mature, they can take over 10-15 and over years to mature, and tennis ball sized peyote is like almost 30 or so years old, as the older peyotes have much higher in alkaloids than young plants.
But you can always learn the art of "grafting" which means cutting the top off a couple-several year old peyote and graft them onto the top of Trichocereus, and it will increase the growth rate, but it doesnt mean it will increase the cacti's alkaloids.
Peyotes are beautiful cacti, (look at my avatar, that explains enough

) and there's plenty of enthnobotany forums, you could possiblity find some Australian enthnobotany forums and they will give you more advice and information on identifying the Trichocereus. There's a lot of cacti people "think" they are Trichocereus, but they aren't and some look like them, but they are different spices with no psyhcoactive properties.
There's some enthnobotany forums often happy to help you to ID your cacti plants if you posted some snaps.
If you want further reading I strongly advise you to grab two books:
*
SACRAMENTAL AND MEDICINAL CACTI (Peyote, San Pedro and other Ethnopharmacological Cactaceae) By Michael S. Smith
*
SACRED CACTI By K. Trout
These books can be found by using google, just PM me if you want to know where to get the books, as I am not sure if I am allowed to say the source where to get books..... (Mods - am I allowed to URL to bookstores?)
You will find Michael S Smith in some of enthnobotany forums and he's a very friendly guy and always helpful taking his time giving his advice on plants he loves (and me too

)
Goodluck.
Urbie %)