Is this an orchid?

[DanW]

Hi everyone,

I found this plant after a tenant moved out. It was thrown away and was not in any pot. I decided to try and grow it. I kept it in potting soil for about a year. It seemed OK but did not really grow much. After my wife brought home some sad looking orchids I started reading about how to take care of them. I am now thinking my found plant is actually an orchid. I repotted it in some medium bark and have been using the MSU fertilizer. It has not done much in the last few months since repotting. Just a week ago the leaves on one of the pseudobulbs turned yellow and fell off. Now the second to last pseudobulb with leaves has the leaves rapidly turning yellow. Shining a light down at the base I see a couple of very green roots starting to grow. Also at least one of the roots has a new green bit emerging from about halfway down the root.

Is this plant even an orchid? When I repotted it I was thinking it could be a Zygopetalum. Anyway, if anyone can offer a guess as to what type of orchid this is I would really appreciate it. I just trying to figure out what this plant needs.

Thanks,
Dan