Thee Temple of Psychic Youth: Look alikes for the San Pedro cactus (Trichocereus pachanoi)

Be Aware, Thee, for the Trichocereus look-alikes!
This compendium of Trichocereus look-alikes includes many sold at nurseries or online, as well as some rarely seen for sale but which are included nonetheless, in case you see one for sale as a "new, rare, different kind of Trichocereus", most of which have NOT been evaluated for safety or mescaline content.
Click-on or download the photos for better detail. This list will be edited as content as found.

Over thousands of years, the civilizations of the Andes and Chaco regions of South America developed cactus for agricultural, ornamental and medicinal purposes, with various nations holding their own cactus in high esteem for the pilgrims on the road. Many cactus were developed from a common ancestor only a few thousand years ago, so similarities abound, and controversy exists over species classifications.

The defining feature for the San Pedro cactus is in the flowers, which begin as tufts of hair from which sprout stalks which burst open with a flower. The flower is in bloom for only 2 or 3 days. Here's an example from Thee Temple's cactus garden (2013-07), showing a flower about to bloom:

San Pedro Fruit -
(photo shows the final part of the cycle as the red seed pod (fruit) lay open the black seeds to be picked by birds)

San Pedro produces fruit, similar to the red fruit produced by Cereus Peruvianus cactus. It is safe to eat raw, without consequence, and is sweet. San Pedro fruit grows there after the flower is gone, but only if the plant has been pollinated. It is egg shaped, green and bumpy with fine white threads. It will become red colored as the pod ripens. Across the world, San Pedro is grown from clones of a few plants, most of which are not self-fertile. Additionally, many places outside of the Andes and Chaco regions lack the appropriate natural pollinators, including large moths and certain bats.

Trichocereus look-alikes -

Browningia altissima (Gymnocereus Altissimus)

Browningia pilleifera (Gymnanthocereus pilleifer; Gymnanthocereus macracanthus)

Browningia utcubambensis

Browningia hertlingiana
photo originally from [Boga.Ruhr-Uni-Bochum.de] [archive.org]:

Stenocereus (Ritterocereus) Griseus

Heliabravoa (Polaskia) chende

Polaskia chichipe

Seticereus chlorocarpus

Subpilocereus repandus

Stenocereus Griseus

Pachycereus

Myrtillocactus geometrizans

azureocereus spp.

Stetsonia coryne

Borzicactus

Corryocactus brevistylus (Colca Canyon Cactus; Cruz del Condor), alongside some Sancayo fruit of the cactus. (photos from [Cactaceae.be/habitat1.php?taal=en] [archive.today] [archive.org])