I love burr oaks! There is a huge one in my parents' yard and the acorns are so cool looking. It's almost as if they're wearing some sort of Russian hats. The acorns from ours have a really furry rim, though. It might be a variant.
The biggest acorns I've ever seen were from the Alcornoque trees (cork trees) in southern Spain. They're a type of oak and the acorns are just really long. They stick out of the caps about an inch and a half.
Anyway, enjoy the autumn down there in TX!
Yes, I'm sure there are a few different burr oak varieties! I just love displaying a few in a bowl during the fall! How interesting about the alcornoque tree acorns. Have a great day @fotosdenada!