Right. But do I really know it's E. oxypetalum? That's the question. I think.
Don't remember where I got it. It's rare to find a nursery that sells epiphyllum in the entire Dallas-Ft.Worth area. Maybe I got it from a friend on Facebook. Or wait. I think I got it at a DG Round Up. At one time it was a much bigger plant but I almost killed it. What you see is what I was able to rescue.
EDITED TO ADD: Just got around to looking at the pictures of E. oxy. in the Plants Database. Think it's definitely a match.