Saab: Saab 900 1997, gasoline vapors, saab 900

Question
I was filling my car up and somehow broke the small plastic flap that sits just down inside the mouth of the hole. The plastic disc fell into the tank.

I think it would be fairly involved to get it out, so what might happen if I just leave it there? Would it matter very much if I drove the car without this plastic flap in place?

Your help is most appreciated!

Answer
Clara:
 I am pretty sure that the errant piece of plastic will do absolutely NO harm where it is; it is made of a plastic designed to be unaffected by gasoline.
 The reason for it is to help keep gasoline vapors from escaping during any time that the gas cap is removed..admittedly a relatively a relatively short period during normal use.

  Hope this helps,
                      Jerry