Mystery Solved!
Velvet Leaf, AKA Butter Print, China Jute, Indiann Mallow
Abutilon theophrasti
Malvaceae — Mallow family
This is an exotic plant that originated in India.
It is considered a noxious weed in many places
because it overtakes and crowds out crops. I can
confirm that it is a vigorous re-seeder. The empty
pods turn completely black in the fall.