Very yellow gall ... maybe the same kind as these or maybe not.

I had begun to pay less attention to oak species by this day ... too many galls and other things in too little time. For all I know, all the Arizona oaks on which I photographed galls were the same species, but it got too overwhelming to track every detail of every tree.

Also ... thanks to Eric and Margarethe for showing me all these good places with oak galls, beetles, and other good stuff.