Spotting

You're right! I missed it on scrolling down. Too bad they didn't group them together.

Yes it does, looking at it right now. http://www.herpnet.net/Iowa-Herpetology/...

Probably. It's interesting that the Iowa frog list doesn't include Hyla versicolor.

Best to leave it at Gray/Cope's gray tree frog with Hyla versicolor/chrysoscelis as the scientific name.

However... Amphibiaweb shows that both Hyla chrysoscelis http://amphibiaweb.org/cgi/amphib_query?...
and Hyla versicolor (Gray Treefrog) http://www.amphibiaweb.org/cgi/amphib_qu...
may occur in this area. As stated on Herp.net, http://www.herpnet.net/Iowa-Herpetology/...
The Cope's gray treefrog is identical in appearance to the eastern gray treefrog. There is (as of now, anyway) no reliable way to distinguish these frogs based on appearance on a consistent basis. The pattern on the backs of each species is unreliable as they both may or may not have a pattern; observations based on positive identification indicates that one has a pattern more often than the other. The only steadfast differences between these two species is the number of chromosomes (the Cope's gray treefrog is a diploid, the eastern gray treefrog is a tetraploid), and that the Cope's has smaller red blood cells than the eastern gray treefrog, and differences in the advertisement calls of the males (see habits).'
Their calls differ slightly - you can hear them here --- http://wwknapp.home.mindspring.com/docs/...