Sulphur or sulfur?

Did you know there are two different spellings of that funny yellow stuff that was decorating the rocks along the Sulphur Banks trail?

Denise saw two different spellings on the National Park Service web site (at least she thinks she did...) and then she caught herself using both spellings. That's not like her, so I went off to see which spelling is correct.

The definitions I found were a bit confusing; one spelling appears to be British, the other US English. But it's a little weird.

sul⋅phur
1. Chiefly British. sulfur


sul⋅fur
1. Also, especially British, sulphur.
A nonmetallic element that exists in several forms, the ordinary one being a yellow rhombic crystalline solid, and that burns with a blue flame and a suffocating odor.

I think what that's saying is that the spelling sulphur is a British spelling, but I'm really not sure. Funny thing is, the spellings on the Hawaii Volanoes National Park site mostly use sulphur.

Hey, I wonder who gets to decide on spellings? No matter, I think the puzzle is solved - Denise can use whichever spelling she'd like!

--- Rover