Cuzco, Trichocereus cuzcoensis (1 ft Tip cutting)
Trichocereus cuzcoensis syn. Echinopsis cuzcoensis. There are vendors out there (that will remain nameless), that sell this exact cultivar as T. peruvianus to this day. The entire community begs to differ ;) There are many traits that make this plant clearly a cuzco: the notching, central main outward spine, etc. Cuzco's are known for that intense central spine, I know I used to get stabbed by it all the time before I got my HexArmor ThornArmor Cactus Gloves :)
A beautiful cactus and I know from personal experience that it makes an excellent grafting stock.