This is the fruit from one of my favorite native trees, Ostrya virginiana. You can see why its common name is American Hophornbeam. This fruit comes from some very old ones nearby on a parkway. They are stunted by years of full sun (they are a lowland, dry shade tree) and the neglect that comes with being city property on a rental building...not that any multi-owner building would do any better, in my opinion.
Being in its last legs, the plant is fruiting heavily.
No picture of the parkway trees, but they are about half the size of this better-placed and managed one in our backyard.