Dry, Wet and Mixed Counties, What's the Difference?

I was reading the Wikipedia entry on dry counties in the U.S. and it also talks about wet and mixed. It doesn’t really explain the differences.

The map, for example, shows Michigan as mixed, but what makes it different from a wet (blue) state? I live in Michigan and don’t know of any restrictions that other states don’t have. What could they be?

In TN they have what are called moist counties, which means IIRC restaurants can serve alcohol and/or a city inside a county can sell alcohol.

More precisely, it shows Michigan as a blend of wet and mixed counties.

From the text, and from exposure to mixed counties elsewhere, I conclude that means those counties contain either significant restrictions on alcohol sales or contain cities that have such restrictions, or at least the statutory authority to enact such restrictions.

This http://en.wikipedia.org/wiki/Alcohol_laws_of_the_United_States reference indicates Michigan state law permits counties or localities to restrict Sunday sales beyond the state’s standard. I suspect those yellow counties have at least one municipality which has done so. Or the county has done it entire.

Looking at that list, it appears that the blue (wet) states have no restrictions at the state level. The yellow ones do. I’d thought the ban on Sunday morning sales applied to everyone.