Night bloomer

[cactuswatcher]

When I came back from having lunch with a friend yesterday I looked at this cactus out front. It's never bloomed before as far as I know. I noticed there were drooping buds like on the branch to the top right and healthy looking buds like the one darkly seen on the opposite side of the same branch. I said to myself, "Yikes, it's a night bloomer!" I meant to go out last night but forgot all about it till early this morning.

There was one bloom open as pictured below. No very colorful, but exciting to me since I thought I'd missed it. The plant is a mass of branches like this, currently about a meter tall.