Unlikely Bloom

On June 3 I blipped a "bud" on a plant that is a type of epiphyllum. It's a small plant but has one branch that is 2 feet tall. In 10 years (or more) it has never even shown a hint of a flower. That bud, which is almost at the end of the long branch, has been growing progressively bigger, and opened yesterday into this beautiful flower.
The flower and its stalk are so heavy I had to prop it up on another pot because it tipped over the plant. This is about 4 inches across.
It seems like the kind of bloom that will only last a couple of days.