The word Epiphyllum comes from the Greek meaning "upon the leaf" as the flowers look like they come right on the leaf. They are native to Central America and the flowers come in all colors. Epiphyllum bloom mostly in Spring and Summer and like part shade. Under trees is a preferred habitat.
This Epiphyllum is called "Grand Falls". I saw it in bloom at Sherman Library & Gardens a few years ago. I was impressed at how compact it was. I would have bought one had it been available for sale. Instead I was forced to use the Grandma method of acquiring it ;-) Don't tell anyone. It took 2 years to grow and this is it's first bloom.
Let us hope I do not succumb to the Epiphyllum addiction of acquiring any more. One will do.