That's a beautiful flower. If no one is able to ID it here, you might contact the folks at the link below

Here is a link that might be useful: Epis are Cactus, Too

It's almost impossible to tell one hybrid from another; this one looks like it's got a lot of epi. ackermanii (which has a newer name, I think).

Enjoy it -- great growing!

Jim

There are several hybrids, as jimshy said, & it is hard to pin down an ID. You might also try posting a picture on the Yahoo epi forum. There are some very knowledgeable people over there who specialize in these plants lurking on that forum. They also have good material on growing, propagation, and troubleshooting not found elsewhere.
EpiÂs can almost be a forum in and of itself. Some of the GW members at one time proposed a separate forum for GW users, but it did not go through.

baci
A few of us have migrated here
Nice place ;)))

Here is a link that might be useful: Epiphyllum talk ;)