Barry, I think that there are no "range restrictions" on utricularia.
Those aquatics can grow almost anywhere, it is just a matter of getting
there. I bet if you threw some U. inflata in your Flagstaff lake, it
would probably do quite well. So few good collections of Utrics have
been made (and properly id'ed) we cannot really trust estimates of their
distribution (in most cases).
MJC