Here are some photos showing the Trichocereus sp. SAN MARCOS, which belongs into the wider context of Trichocereus santaensis. These plants are also closely related to the plants known as Trichocereus huanucoensis and Chavin de Huantar. They look very similar to Trichocereus cuzcoensis, but actually don´t belong to that species. The spines are extremely long, the rib count is variable and the flowers are similar to the flowers of Trichocereus bridgesii. The white hairs on the flowers are very unique in the sense that most Peruvian San Pedros have brown flower hairs, while the Bolivian species like Trichocereus bridgesii and Trichocereus scopulicola are known to be covered with white hairs. This is particularly interesting because Trichocereus santaensis is often mislabeled as Trichocereus bridgesii and both can be extremely similar. I would love to see some cladistic studies comparing Trichocereus santaensis and Trichocereus bridgesii to investigate this some more.
Well yeah, Trichocereus sp. SAN MARCOS is the type of plant that is sometimes misidentified as Trichocereus cuzcoensis, especially when dealing with young plants. As seedlings, these plants look very much like Trichocereus cuzcoensis and it takes a lot of experience to recognize them.
Once again, many thanks to my friends from Chavin for providing some new photos. I am proud that I can share these wonderful plants with you.