Kathi - I know Bruce looked up for you, but I have a 'Rhein Moonlight' and it's called either a Galeopetalum or Zygosepalum. I posted it on a thread in a thread in Orchids of Other Genera IN BLOOM a couple months ago - I spent ages looking it up and finally found it. Mine has rather larger blooms than the usual zygo, though, so maybe there's a smaller 'Rhein Moonlight' floating around. You might want to check the RHS register.
I REALLY mean this to be possibly helpful - NOT to contradict anyone or create confusion -

Maura