Cereus peruvianus
With an often tree-like appearance, its cylindrical gray-green to blue stems can reach 10 metres (33 feet) in height and 10–20 cm in diameter as a self-supporting plant. However, if supported by a scaffold, C. repandus has grown to a height of 110 feet (34 meters) at the SDM College of Dental Sciences at Dharwad, Karnataka, India, technically making this the tallest cactus plant in the world, although no cactus under natural conditions exceeds eighty-two feet (25 meters) in height in the case of Cereus stenogonus. There are nine to ten rounded ribs that are up to...