what is it?

I'm trying to find out what the deal is with this hat, it was my uncle's and was passed down to me when he died at the age of 89, the leather label inside says "Brent" and its sized 7 1/4 has a small bow on inside back, it seems to be made out of straw, he also had a mallory from the 40's, so i'm guessing this is from around then, any help appreciated!