Borzicactus (now Cleistocactus) samaipatanus
I bought this as another genus entirely but it has just flowered, so I know what it actually is. “Cleisto” in Cleistocactus means “closed”, referring to the flowers of most species, which are not closed but tubular. In some species, such as this, the tube opens up wide near the tip.
Olympus EM-1, (aperture priority), Olympus 4/3 50mm f2 macro, 1/160 at f11 ISO 400, hand-held.
Stereos will be uploaded tomorrow