It's a Dryadella for sure, possibly D. edwallii.
That could be a choice, or D. simulis
Do you know any more about the plant? Source? Country of origin? How it's being grown? D. simula is an obligate cool grower. I've killed it pretty quickly trying to grow it intermediate. My plant started as a 30+ growth specimen and went down to probably 7 growths in a month or so. It stabilized with 55F nights but never grew a root or leaf. I moved it to a spot with a bit more humidity but was a tad warmer and it was leafless in a month.
On the other hand, D. edwallii can easily be grown intermediate to warm and humid. These both like really good water and a good bit of it.
It came from Orchid Trail in NC. 65-85 F days, no lower than 65 at night. It was in a hoop house covered in thick plastic, so no direct sunlight, but enough that the leaves color up. Probably edwallii then. They had it for 2 years before selling it.
Also, here's a few pictures where you can easily compare the two: https://picasaweb.google.com/1115658...8532/Dryadella
Notice that the lateral sepals on D. edwallii taper to a point, whereas the more rounded lateral sepals with just an abrupt point on D. simula. I can't really tell from your pictures what the plant in question's sepals look like. This link should also give you a bunch more possibles to look through.