It’s a good thing I was looking up, the other day. These look a little more burnished in the late afternoon sun than is their actual lighter color, but they are by no means white.

Here we have something emerging out of a water oak, Quercus nigra, about fifteen feet up. Once again, I’ve got two or three candidates none of which look just like this AND live around here AND grow on the right kind of tree. At first I thought this was a bearded tooth, Hericium erinaceus, which I had similar difficulties with back in March. But these structures look even less like the images I found for that species than the blobs I found then. The only alternatives seem to be one of the toothed polypores. One is Milk-white Toothed Polypore, Irpex lacteus, but again there is a problem. These are thinly spreading, more of a parchment than what we see here, and the set of images I’ve linked to include on that’s a bit out of the norm for this polypore (though it matches mine better).

Here’s another possibility: Spongipellis pachyodon, Soft Toothed Polypore. The latter link says that these do grow on oaks; my Audubon emphasizes conifers. The generic name suggests “spongy” but apparently this mainly applies to the very young emergences. There is some discussion about how that works here.

If the latter species, then this is one of the heart-rot fungi, which will eventually kill this youngish water oak. Oh - and looks like something’s been feasting on them, too.