Here's a picture of my tree when I repotted it last Februaury. Gray bark, but no cork on the trunk. I was told it was a cedar elm when I bought it. It was collected in '95 and planted in a club members back yard. A friend bought it from him and dug it out of the yard about ten years ago. There were no wings on the branches when I bought it, but it was weak and hadn't been repotted in many years. The potting soil it had been grown in was compacted and the tree was rootbound. I fertilized heavily and this year it sent vigorous 3 foot shoots with the color and corking that you see. Cedar elm make wings too, but not like this in my experience - so I think it's probably a winged elm. Additionally, the leaf bottoms did not feel as rough as on my cedar elms. But who knows - maybe it something else?
I'm curious to see yours, Si.
Scott