Melocactus azureus is a blue bodied globular cactus from Bahia, Brazil. It can grow to 8 inches tall and 6 inches around. The sky blue body and white cephalium make this one of the prettiest of Melos. Mine has yet to form a cephalium, it may be a few more years yet. the picture below is of a nice old specimen with rare top growing offsets. it was taken at B&B Cactus Farm.