Derick,
I see a seed pod, coloured by the autumn, opened in the sun and finally dropped off the plant.
However, I'd not want to peek in, there might be a face-hugger hiding in there!
Pete,
I had a similar discussion some years ago over a piece Mark Sanger posted. I had to learn that sometimes the timber is just the hanger for the art. You don't look at a vase and think 'where's the ceramic', you don't look at the Mona Lisa and think where's the wood (it is painted on a board not canvas).