Thank you everybody. I got this plant from Wendy shortly after the freeze last March. That's the second flower on the stem. The first flower opened in the last week of August; but, as often happens with this cross, it only lasted 5 days. When this second flower on the same stem was opening, I took it into the house, where the air is less humid. It lasted 7 days. It is stunningly beautiful; but, I'd really like to get one that holds it's flowers for a couple months, like Kyle has mentioned are available now.
This second flower on the stem was about 3 1/2"; the first flower was a tiny bit larger.