Maybe another will grow Beverly, and yes there is a possibility a cross has occurred. I think Ipomoea cross fairly readily, those who want to keep pure varieties have to bag them to stop cross pollination. Correct me if I'm wrong!
I also think it's impossible to say for sure what this one is, I seem to recall those who specialise in Ipomoea mentioning variability.
Thankfully, you won't have to beat yourself up for pulling one you know you wanted.
