Melocactus zehnerii is a Turk's turban cactus native to the state of Bahia, in north eastern Brazil.

It is also known as melocactus giganteus and Cactus zehntneri.

[1] Like other Turk's Turbans, it has a roundish lower body with typically about eleven vertical ribs which does the photosynthesis and an elongated upper body, the cephalum.

which is a type of capitate inflorescence.

This upper cephalum can grow as much as 29 inches ( 72 centimeters) in length, and displaying as many as sixteen annual rings.