Tonight's mystery was the identity of this clump of oak leaves with one attached acorn that I picked up during this morning's walk in the nearby forest. I am not that good at identifying trees and the oaks, with about 15 possible species in this area, are one of the more difficult groups.
Using Frank Brockman's good ol' Important Trees of Eastern Forests (1968), I narrowed the identity of this specimen down to northern red oak (Quercus rubra), but I am not 100% positive about it.
Here is the acorn.
And here is a close-up of a leaf.
Incidentally, the background in the last picture is the proof for an upcoming paper of mine on the snail Pedipes ovalis. It is scheduled to come out later in the fall. I will write more about it then.