I am trying to identify a vine found on a black walnut tree along the
side of our road. It has single leaves, heart shaped, with parallel
veins, about 2 inches wide and 3 inches long. It has a ball shaped
cluster of berries or nuts that are green to purple, about 1 1/2 inch
ball, each berry has a stem that is like a radius and they are all
attached at the center, making it sort of a hollow ball of berries or
nuts. This is in northwest Indiana.