The largest acorn I know is the fruit of the bur oak, and it is borne in a mossy cup, indeed.
In most of its range it is associated with the bur oak from which it is not commonly separated.
For instance, a white oak and a bur oak grow near enough for the wind to "cross-fertilize" their pistillate flowers.
The bur oak is a rugged, ragged tree, compared with the white oak.
In the flats of southeastern Indiana it is generally called white oak, and in some places it is known as bur oak.
In a range of so great geographical extent the bur oak finds it necessary to adapt itself to many kinds of land.
Medium sized trees; bark generally intermediate between that of the swamp white and bur oak; leaves on petioles 5-30 mm.
The weight of bur oak is approximately the same as white oak, and the two woods are much the same in strength and elasticity.
bur oak, because it is a vigorous species, was able to take possession of such burned areas, to the exclusion of most others.
The future of bur oak does not promise much after the trees which now remain have been cut.