'''''Trichocereus macrogonus'' var. ''pachanoi''''' ([[Synonym (taxonomy)|synonyms]] including '''''Trichocereus pachanoi''''' and '''''Echinopsis pachanoi''''') is a fast-growing columnar [[cactus]] found in the [[Andes]] at {{convert|2000|–|3000|m|abbr=on}} in altitude.<ref name="Rätsch">{{cite book |last=Rätsch |first=Christian |author-link=Christian Rätsch |title=Enzyklopädie der psychoaktiven Pflanzen. Botanik, Ethnopharmakologie und Anwendungen |publisher=AT-Verlag |location=Aarau |year=2002 |page=15 |isbn=978-3-85502-570-1 }}</ref>{{sfn|Anderson|2001|p=276}} It is one of a number of kinds of cacti known as San Pedro cactus. It is native to [[Ecuador]], [[Peru]] and [[PeruColombia]],<ref name=POWO_77125731-1>{{Cite POWO|title=''Trichocereus macrogonus'' var. ''pachanoi'' (Britton & Rose) Albesiano & R.Kiesling|id=77125731-1|access-date=2023-09-25|mode=cs1}}</ref> but also found in [[Argentina]], [[Bolivia]], [[Colombia]], [[Chile]] and [[Venezuela]] and cultivated in other parts of the world.<ref name="erowid">{{citation |url=http://www.erowid.org/plants/cacti/cacti_guide/cacti_guide_trichoce.shtml |title=Visionary Cactus Guide |publisher=Erowid.org |access-date=2012-10-24}}</ref><ref>{{Cite web|last=Mchem|first=Benjamin Bury|date=2021-08-02|title=Could Synthetic Mescaline Protect Declining Peyote Populations?|url=https://chacruna.net/synthetic_mescaline_protect_declining_peyote_populations/|url-status=live|access-date=2021-09-21|website=Chacruna|language=en-US|archive-url=https://web.archive.org/web/20210802174233/https://chacruna.net/synthetic_mescaline_protect_declining_peyote_populations/ |archive-date=2021-08-02 }}</ref> Uses for it include traditional medicine and traditional veterinary medicine, and it is widely grown as an ornamental cactus. It has been used for healing and religious divination in the Andes Mountains region for over 3,000 years.<ref>{{cite book |author1=Bigwood, Jeremy |author2=Stafford, Peter J. |title=Psychedelics encyclopedia |publisher=Ronin Pub |location=Berkeley, CA |year=1992 |pages=118–9 |isbn=978-0-914171-51-5
''Trichocereus macrogonus'' var. ''pachanoi'' is native to Ecuador, Peru and PeruColombia. Its stems are light to dark green, sometimes [[glaucous]], with a diameter of {{convert|6|-|15|cm|in|abbr=on|1}} and usually 6–8 ribs. The whitish [[areole]]s may produce up to seven yellow to brown spines, each up to {{convert|2|cm|in|abbr=on|1}} long although typically shorter in cultivated varieties, sometimes being mostly spineless.{{sfn|Anderson|2001|p=276}} The number and length of the spines is a feature that distinguishes ''T. macrogonus'' var. ''pachanoi'' from [[Trichocereus macrogonus|var. ''macrogonus'']], which may have up to 20 spines with three or four longer and more robust central ones up to {{cvt|5|cm|in|1}} long.<ref name=Albe12>{{Citation |last1=Albesiano |first1=Sofía |date=2012 |title=A New Taxonomic Treatment of the Genus ''Trichocereus'' (Cactaceae) in Chile |journal=Haseltonia |volume=18 |pages=116–139 |doi=10.2985/026.018.0114 |s2cid=84425131 }}</ref> The areoles are spaced evenly along the ribs, approximately {{convert|2|cm|in|abbr=on|1}} apart.<ref name="erowid"/> ''Trichocereus macrogonus'' var. ''pachanoi'' is normally {{convert|3|-|6|m|ft|abbr=on|0}} tall and has multiple branches, usually extending from the base but will emerge around broken branches.{{sfn|Anderson|2001|p=276}} The tallest recorded specimen was {{convert|12.2|m|ft}} tall.<ref name="erowid"/> White flowers are produced at the end of the stems; they open at night and last for about two days. Large numbers can be produced by well established cacti and may open new flowers over a period of weeks. The flowers are large, around {{convert|19|-|24|cm|in|abbr=on|1}} long with a diameter of up to {{convert|20|cm|in|abbr=on|1}} and are highly fragrant. There are black hairs along the length of the thick base leading to the flower. Oblong dark green fruits are produced after fertilization, about {{convert|3|cm|in|abbr=on|1}} across and {{convert|5|-|6|cm|in|abbr=on|1}} long,{{sfn|Anderson|2001|p=276}} eventually bursting open to reveal a white flesh filled with small seeds.
