Seen unlabelled at a Botanical Garden

[SunnySmiles]

Heya

I've seen this one last week at a botanical garden, unfortunately without a label. It was growing in the tropical zone attached to the bark of a tree (by means of a cut-up pantyhose - thought that was a nice touch). Individual flowers are probably the size of a fingernail.
I've never seen anything like it and all my books seem to cover mostly orchids that are widely available as houseplants. Anyone got an idea what it is?
(Apologies for the photo to be sideways - I haven't figured that one out yet)

Thanks folks - you're brilliant!