Orchid Cactus [Epiphyllum ackermanii] blossom

My wife pointed this blossom out to me this morning. It's a good thing too. The sun was so harsh this afternoon that the top of it got burned! This is on our biggest Orchid Cactus. It has been blooming non-stop for about a month which is pretty impressive since even in the shade each blossom only lasts for a few days.