From southern Brazil, Discocactus zehntneri is the smallest of the Discocactus at only 4 inches across. Small clumps of the finely spined cactus form in time. The creamy white flowers appear from a cephalium at the crown of the plant. They flower in April and flowers last only a day and only open at night. This plant came from B&B Cactus farm. I'm hoping it's a heavy offsetter. The best I can do for a flower pic is a pic of the buds. Unfortunately my camera doesn't do low light well and the flowers close and die well before morning.