[+][+] Leaves not dilated upward, generally entire; acorn globose.
18. Q. imbricària, Michx. (Laurel or Shingle Oak.) Leaves lanceolate-oblong, thickish, smooth, and shining above, downy underneath, the down commonly persistent; cup between saucer-shaped and top-shaped.—Rich woodlands, Penn. to Ga., west to S. Wisc., Iowa, E. Neb., and N. Ark.—Tree 30–90° high. The specific name is in allusion to its early use for shingles.
19. Q. Phéllos, L. (Willow-Oak.) Leaves linear-Lanceolate, narrowed to both ends, soon glabrous, light green (3–4´ long); cup saucer-shaped.—Bottom lands or rich sandy uplands, Staten Island to N. Fla., west to S. Ky., Mo., and Tex.
In addition to the above, the following hybrids have been recognized:—
Q. alba × macrocarpa; N. Ill. (Bebb); central Ill. (Hall).
Q. alba × stellata; N. Ill. (Bebb); D. C. (Vasey); S. C. (Mellichamp).
Q. alba × prinus; near Washington, D. C. (Vasey.)
Q. imbricaria × nigra (Q. tridentata, Engelmann); S. Ill. (Engelmann).
Q. imbricaria × palustris; Mo. (Engelmann).
Q. imbricaria × coccinea (Q. Leana, Nutt.); Ohio to Mo., and near Washington, D. C.