aka field mint, corn mint
Mentha arvensis
Lamiaceae

Pretty little thing, isn’t it?  Not a very remarkable plant.  It looks like mint, it smells like mint.  It grows to two feet tall in moist soils in the sun; in the shade it can be somewhat sprawling.  But it has those wonderful whorls of flowers in the leaf axils.

Wild mint can be found through most of the US and Canada except for parts of the South.  There are no conservation issues, but Nebraska considers it weedy/invasive.