Dottie, those are two different genus of plants. Which are you looking for? The Epiphyllum is often called the orchid cactus, whereas the Aporocactus is often called the rat-tail cactus. I don't think there are hybrids, but I guess, why wouldn't there be?

Seems there is an hybrid between the 2 maybe. I bought this one a long time ago (pic from the day I bought it) with an Epiphyllum X Aporocactus on the tag.

And here is the flower,

That's all I know about it and sorry, I don't remember where I bought it. Definitely locally.

I have seen them but not for sale...beautiful. Thank you for your reply. Dottie