The genus Echinopsis, in its wide sense, comprises somewhere between 100 - 150 species of cactus. There has been considerable disagreement amongst taxonomists as to how this group of species should be treated, with some favouring housing them all in the genus Echinopsis and others favouring separating them into several smaller genera. We are following the conclusions of Schlumpberger and Renner (Molecular Phylogenetics of Echinopsis (Cactaceae): Polyphyly at all levels and Convergent Evolution of Pollination Modes and Growth Forms; American Journal of Botany 99(8): 1335-1349. 2012) in which it is concluded that the most sensible answer is to group these specis into several distinct genera. If this species were to be retained in Echinopsis, it wuld be as Echinopsis macrogona, or even as Echinopsis peruviana (see list of synonyms for authors)

Common Name: San Pedro Macho

General Information

Trichocereus macrogonus is a spiny, evergreen, succulent, shrubby to tree-like cactus with several erect or prostrate branches. It can grow 1 - 4 metres tall, with stout, cylindrical stems around 6 - 20cm in diameter[].
The plant is frequently cultivated in Bolivia, Colombia, Chile, Ecuador and Peru, as an ornamental, for living fences, and for medicinal or magical purposes. Its most plausible wild origin is the medium to high valleys of the Peruvian Andes, at elevations from 2,000 − 3,000 metres.
Trichocereus macrogonus has a relatively wide range and the population seems to be stable. However, it is not abundant where it occurs, is used due to its hallucinogenic action, and does not occur in any protected area. The plant is classified as 'Least Concern' in the IUCN Red List of Threatened Species(2017)[].

Known Hazards

None known

Botanical References

Range

S. America - Bolivia to western and southern Peru

Habitat

Shrubland, in inter-Andean valleys; at elevations from 3,000 - 3,500 metres[].

Properties

Conservation Status	Least Concern
Medicinal Rating
Other Uses Rating
Habit	Evergreen Shrub
Height	3.00 m
Self-fertile	No
Cultivation Status	Wild

Cultivation Details

Trichocereus macrogonus is native to semi-arid climates at moderate to high elevations in the Andes. It has moderate cold tolerance, being able to survive occasional short periods with temperatures falling as low as -9°c so long as the climate is fairly dry. It requires hot summers and a mean annual temperature of at least 10°c.
In cultivation, Cactus plants generally will not succeed in moist climates. They usually require a sunny position in a well-drained, circumneutral soil and to be kept more or less dry in the dormant season[].

Edible Uses

None known

Medicinal

This species contains mescaline-derived alkaloids that have a strong effect on the mind, senses and emotions. Like the San Pedro cactus (see the entry for Trichocereus macrogonus pachanoi) it is used for medicinal and magical-religious purposes[]
Some forms of this plant, known as San Pedro macho, can contain up to 10 times the mescaline content of the San Pedro cactus, with levels sometimes as high as that in the N. American species peyote (Lophophora williamsii)[].
A common error embedded in the literature is reference to this species as being 10 times more 'potent' than the San Pedro cactus. Results in this study indicate that San Pedro contains a considerably higher concentration of mescaline than this species. Maximum concentrations (dry weight) for the various forms of this species that were tested were in the range zero to 0.82%, whilst some forms of San Pedro had up to 5%[].

Agroforestry Uses:

The plant is used for making living fences to act as boundary markers and barriers.

Other Uses

None known

Propagation

Seed -

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