New Plant Quiz = G. sibiricum

This plant quiz is unrelated to the previous quizzes. In fact, it would be more accurate to call it an unknown. I plan to spend more time researching it, but right now it is still a mystery. Any help is appreciated. The leaves are opposite, uniform, and deeply three-lobed. Habitat - forested floodplain. Location, Wayne County, Indiana, near Richmond. Habit - creeping to semi-erect plant.