Origin and Habitat: This four ribbed form is a selected cultivated variety. The wild species occurs over a considerable range from the mountains of Peru, Ecuador, Bolivia and northern Argentina.

• Echinopsis pachanoi f. quadricostatus hort.
• Trichocereus pachanoi f. quadricostatus hort.

• Echinopsis pachanoi (Britton & Rose) H.Friedrich & G.D.Rowley
• Cereus pachanoi (Britton & Rose) Werderm. in Backeb.
• Trichocereus pachanoi Britton & Rose
• Echinopsis pachanoi f. cristata aurea hort.
• Trichocereus pachanoi f. cristata aurea hort.
• Echinopsis pachanoi f. cristata hort.
• Trichocereus pachanoi f. cristata hort.
• Echinopsis pachanoi f. quadricostatus hort.
• Trichocereus pachanoi f. quadricostatus hort.

• Echinopsis pachanoi f. monstruosa cv. Gianfra
• Trichocereus pachanoi f. mostruosa hort.

Description: Echinopsis pachanoiSN|8470]]SN|8470]] more often known as: Trichocereus pachanoiSN|8471]]SN|8471]] or "San Pedro cactus" usually has 6-8 ribs, but ribs number can vary from 4 to 14 ribs as it have been reported observed on the occasional Trichocereus pachanoiSN|8471]]SN|8471]] by commercial growers, botanists travelling extensively in Peru and other reliable sources.
The cactus in full bloom is found depicted cryptically on two thousand-year-old shamanic textiles of the Chavin culture, albeit in its idealized form, with only four ribs. It is still believed by Peruvian shamans to this day that the four ribbed San Pedro cactus is the most potent, however, no actual modern-day specimens have ever been documented in nature. The sacred four ribbed “Cactus of the Four Winds” is sometime observed in cultivation, but four ribbed growth is an anomaly and this plant is quite uncommon.

Bibliography: Major references and further lectures
1) Curt Backeberg “Die Cactaceae: Handbuch der Kakteenkunde.” Volume 3, 1959
2) Ostalaza, C., Cáceres, F. & Roque, J. 2013. Echinopsis pachanoi. In: IUCN 2013. "IUCN Red List of Threatened Species". Version 2013.2. <www.iucnredlist.org>. Downloaded on 29 March 2014.
3) Britton & Rose "The Cactaceae" 4: 273, 1923
4) Edward Anderson “The Cactus family” Timber Press, Incorporated, 2001
5) James Cullen, Sabina G. Knees, H. Suzanne Cubey "The European Garden Flora Flowering Plants: A Manual for the Identification of Plants Cultivated in Europe, Both Out-of-Doors and Under Glass" Cambridge University Press, 11/Aug/2011
6) David R Hunt; Nigel P Taylor; Graham Charles; International Cactaceae Systematics Group. "The New Cactus Lexicon" dh books, 2006
7)Dobkin de Rios, M. “Trichocereus Pachanoi: a Mescaline Cactus Used in Folk Healing in Peru.” Economic Botany 22 (1968): 191–194.
8) Cordy-Collins, A. “Psychoactive Painted Peruvian Plants.” in: Journal of Ethnobiology 2, no. 2 (1982): 144–153.
9) Torres, D., and M. “San Pedro in the Pressure Pot.” Yearbook for Ethnomedicine and the Study of Consciousness 1995, no. 4 (1996): 283–284.
10) Davis, E.W. “Sacred Plants of the San Pedro Cult.” Botanical Museum Leaflets 29, no. 4 (1983): 367–386.
11) Hofmann, A., Ratsch, C., Schultes, R., “Plants of the Gods: Their Sacred, Healing, and Hallucinogenic Powers.” Rochester: Healing Arts Press, 1992.
12) Furst, P.T. “Shamanism, Transformation, and Olmec Art.” In The Olmec World: Ritual and Rulership. Princeton, N.J.: The Art Museum, Princeton University, 1996.
13) Polia, M., and A. Bianchi. “Ethnological Evidences and Cultural Patterns of the Use of Trichocereus Pachanoi Britt. Et Rose Among Peruvian Curanderos.” Integration 1 (1991): 65–70.
14) Ratsch, Christian., “The Encyclopedia of Psychoactive Plants: Ethnopharmacology and its Applications.” Rochester: Park Street Press, 1998.