Taxonomy & identification

• The concept of T. pachanoi is taxonomically problematic: plants of widely varying morphology from Cochabamba (Bolivia) to Huancabamba (Peru), Ecuador and elsewhere are all recognized as "pachanoi," and one cultivar is even labeled T. pachanoi cv. 'peruvianus Huancabamba,' suggesting the current species concept is poorly resolved. [WVC 2011 San Pedro talk]
• Trichocereus pachanoi is also known as (treated as a synonym of) Echinopsis pachanoi. [Mescaline reported in Trichocereus species assembled by Keeper Trout (EntheoGenesis Australis, 2011)]
• T. santaensis (Echinopsis santaensis) is probably a form of Echinopsis pachanoi (T. pachanoi). [Mescaline reported in Trichocereus species assembled by Keeper Trout (EntheoGenesis Australis, 2011)]
• Britton & Rose (The Cactaceae, 1920, p.134) described pachanoi with the ovary covered with black curled hairs and the axils of scales on the flower-tube and fruit bearing long black hairs. [Pachanoi or Pachanot? (Keeper Trout, Trout's Notes)]
• Curt Backeberg's 1931 description (for Cereus pachanoi, Werdermann) in Neue Kakteen (p.79) described the ovary and tube as bearing long brown woolly hairs ('mit langen, braunen Wollhaaren'). [Pachanoi or Pachanot? (Keeper Trout, Trout's Notes)]
• John Borg (Cacti, 1937, p.183) described pachanoi with ovary and tube covered with long brown hairs. [Pachanoi or Pachanot? (Keeper Trout, Trout's Notes)]
• By 1959 Backeberg's description (Die Cactaceae, p.1118) had shifted toward Britton & Rose, describing the ovary and tube as set with blackish hairs ('schwärzlichen Haaren'). [Pachanoi or Pachanot? (Keeper Trout, Trout's Notes)]
• Carlos Ostolaza (Cactus & Succulent Journal US 56, 1984, p.102) described the pericarpel (ovary) as covered with scales bearing brownish hairs 15 mm long on the axils, the floral tube with fewer scales but more hair on axils, and the fruit covered with scales and black hairs. [Pachanoi or Pachanot? (Keeper Trout, Trout's Notes)]
• Edward Anderson (The Cactus Family, 2001, p.276) described pericarpels and floral tubes with black hairs. [Pachanoi or Pachanot? (Keeper Trout, Trout's Notes)]
• David Hunt (New Cactus Lexicon, 2006, p.98) described the pericarpel and hypanthium (tube) with black hairs. [Pachanoi or Pachanot? (Keeper Trout, Trout's Notes)]
• Bona fide pachanoi near Cuzco shows smooth-edged ribs, deeply indented/sunken areoles set planar to the median of the rib, and when short-spined the spines are consistently much shorter than the already short spines of the pachanot. [Pachanoi or Pachanot? (Keeper Trout, Trout's Notes)]
• The basionym Trichocereus pachanoi Britton & Rose was published in The Cactaceae 2: 134-135, fig. 196, on 9 September 1920. It is now treated as a synonym of Echinopsis pachanoi. [https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:257116-2; https://www.ipni.org/n/257116-2; https://trichocereus.net/trichocereus-pachanoi-britton-and-rose-1920-echinopsis-pachanoi/]
• The 1920 original description characterized the plant as a columnar cactus 3-6 m high with numerous strict branches, slightly glaucous when young and dark green in age, with 6-8 broad obtuse ribs bearing a deep horizontal depression (notch) above each areole, and spines often absent or few (3-7, unequal, the longest 1-2 cm). [https://trichocereus.net/trichocereus-pachanoi-britton-and-rose-1920-echinopsis-pachanoi/]

Native range

• Trichocereus pachanoi is documented in Ecuador (e.g., Vilcabamba, where it grows with vilca, and at Quito). [WVC 2011 San Pedro talk]
• Britton & Rose initially reported pachanoi from Ecuador, and Backeberg expanded its reported range into Peru in the 1930s, encountering it at Huancabamba where it was called San Pedro. [Pachanoi or Pachanot? (Keeper Trout, Trout's Notes)]
• Bona fide pachanoi is documented growing in Ecuador (including Quito and Vilcabamba) and Peru (including Huancabamba, Matucana, and shaman's gardens near Cuzco), with many wild collections and herbarium vouchers made. [Pachanoi or Pachanot? (Keeper Trout, Trout's Notes)]

Habitat

• In Ecuador (at Vilcabamba, Loja Province), Trichocereus pachanoi grows intimately among stands of Anadenanthera (vilca) trees — the place-name Vilcabamba derives from the vilca tree. [WVC 2011 San Pedro talk]

Growing & propagation

• The 'pachanot' cultivar is much faster growing, more cold tolerant, more rot resistant and more water tolerant than bona fide Trichocereus pachanoi; this intense vigor plus simple vegetative propagation and popularity as an ornamental explain its rise to near-uniform dominance in the US market (possibly within a few decades), now grown from California to Florida. [Pachanoi or Pachanot? (Keeper Trout, Trout's Notes)]
• Assorted horticultural pachanoi exist in European (German) cultivation, including a cultivar originally collected in Peru by a German collector named Kaiserwerth that is sold under the name Trichocereus peruvianus. [Pachanoi or Pachanot? (Keeper Trout, Trout's Notes)]
• San Pedro (T. pachanoi) thrives on heavy watering when hot and tolerates thorough daily watering during summer, but is rot-prone if wet during cold weather; watering should be discontinued in cool or cold weather. [Trout's Notes on the Cultivation & Propagation of Cacti]
• T. pachanoi has minimal spination, making it a common preferred grafting stock; it is hardy, fast-growing, and has a longer life as a grafting stock than most cacti. [Trout's Notes on the Cultivation & Propagation of Cacti]
• Fat pachanoid forms that naturally occur under heavy tree cover develop best girth with only partial sun and dappled light rather than full sun. [Trout's Notes on the Cultivation & Propagation of Cacti]
• Intermediate forms of pachanoi-peruvianus have shown the most problems with cold and wet conditions in cultivation. [Trout's Notes on the Cultivation & Propagation of Cacti]

Clone genealogy

• The pachanot is propagated entirely vegetatively (clonally) despite freely flowering and readily hybridizing; it is the predominant cactus sold as Trichocereus pachanoi in US horticulture, comprising well over 90% (possibly over 99%, and 100% in most retail outlets) of available horticultural pachanoi in the USA. [Pachanoi or Pachanot? (Keeper Trout, Trout's Notes)]
• A second T. pachanoi collected at Huancabamba, Peru entered horticulture as a distinct clone. [WVC 2011 San Pedro talk]