Also known as the Peruvian fence post. This cactus is fast becoming popular, as it is almost as fast growing as San Pedro, but with a higher content of mescaline. Very fast growing, huge when mature, columnar. Is readily available in Peru but is rare as an ornamental in the U. S. This species is also known to grow on ledges and let its heavy arms, that may be up to 5 meters long, dangle over the edge of cliffs.

Some studies reported up to 10% mescaline content by dry weight but a more reasonable and believable figure is in the 1 - 3% range. It contains only a few other psychoactive alkaloids, mainly tryptamines in much lower proportions.