Many pitchers are over a foot. I'm not talking about different growers, etc. I'm talking about optimal conditions. Asking me how I know for sure is like asking me how I know sumatrana is bigger than bellii...it just is. Merrilliana is the biggest, hands down.
I remember seeing a picture somewhere where a little child is holding a N. raja pitcher and it is as big as his head. They can get to the size of a football or bigger in good conditions.
xvart.