That does look really strange, Alice. Like some kind of gall, but galls can be caused by insects and also by disease. The channel running up between the galls is curious too, looks like something a termite might make.
Being the curious person I am, I wouldn't be able to leave them alone. I'd take a sharp instrument and cut into one just to see if there's something in there. Or cut one off, take it into the house (as long as nothing crawls out first) and look at it with a magnifier. Hope your Clemson boffins have an answer for you!
