Found with a group specifically seeking this species with permission from land managers. Female found in leaf litter.
Quercus × filialis (Q. phellos × Q. velutina).
Photos taken on a few days from October 2012 through October 2013.
A large, cultivated tree at Duke University with somewhat narrow, small acorns (around 1.5 cm long).
The second-to-last photo is a modified screenshot from Google Street View (Sep. 2014 picture) showing the tree, and I added the red arrow. The last photo is a modified screenshot (again, I added the arrows) of this tree when young and recently-planted in the early 1930s. The original and enlargeable photo can be found here: https://www.flickr.com/photos/dukeyearlook/6900485120/in/album-72157621179687840/
Duke's historical photos can be found here: https://www.flickr.com/photos/dukeyearlook/albums
and here: https://library.duke.edu/rubenstein/uarchives/history
This tree was cut down in 2020, not sure why.