I found these berries growing in an alley next to somebody's shed or garage or something last year at around this time (1 October) and thought they were sort of neat, so I took pictures, but then I didn't post the pictures because I didn't know what they were. I checked Wikipedia recently, and based on that, I'm pretty sure about the genus (Solanum), but there are quite a few possibilities for the species, including S. americanum, S. nigrum, and S. ptychanthum.
I realize that it would probably be easier to make an ID if there were a picture of the leaves too. (At the time, I figured I'd be easy to identify from the berries alone and didn't think I'd need anything more than that.) If it can't be determined from these photos, does anybody at least know which of the three species in question would be most abundant in Eastern Iowa?