Photo by me at McHose Park, Boone, IA (no web info found as of today)
I heard nuts falling off a hickory tree this evening while the kids were playing. Unfortunately, the undergrowth was too thick and full of poison ivy for me to pursue the newly fallen nuts. They are yummy. You can ask Double-O Tiny ("I" of GAIN), she loves them.
Here is a photo of a nut that fell a while ago. Newly fallen nuts have bright yellow-green husks. My grandmother told me that her family would go hunting for walnuts with her dad's cousin's family. If they found a hickory, they felt special. After tasting one, I would agree. Especially after having black walnuts, hickories would be really appreciated.
The shagbark hickory tree is pretty easy to spot, and is one of the only trees I know by sight. I don't see bark like that and not remember it. We had a class with State DNR foresters, and when I asked how they identify trees, they stated that they can tell most trees by their bark. Despite the class description and my question to prompt them, they did not share that knowledge, or any ID hints, with us.