Keith — I looked at your vase soon after you posted, and thought, no, it's not a floral pattern I recognise. Then I thought about it some more, and realised that your vase was considerably stretched, and twisted at the top. There was nothing I could do about the twisting from the single side view, but I could squash it. So I dropped it into IrfanView and squashed it. See the outcome below.
About an hour ago I found a Walsh mother of pearl example, and tried to match it to your squashed image. Similar, but not the same. I then realised that your vase might have a completely new base, i.e. the bottom part of the full pattern might have been removed with the pucellas in the process of forming the bulbous base, which would also explain the twisting at the top of the vase. Success at last. Your floral pattern matches the top two thirds of mine, with a small part of the pattern at the top missing as well.
I can't see any hints of a thin inner layer of opal glass, nor can I see any iridescence. If so, it is Walsh canary opalescent. Dating is a little tricky — I suggest late Victorian to early C20.
Interesting piece, Keith.
ps — note that I have not kept any copies of your image file on my PC, normal or squashed.