Are the leaves about twice as long as wide, tapered at the tip; bark has high, corky ridges?
CLUE: the fruit is purple and berry-like.
It is a hackberry.
- OR -
Are the leaves heart-shaped and about as wide as long?
CLUE: the fruit is small and nut-like, attached to a wing-like leafy bract.
These are basswood or linden trees.