i guess it could be a seed, but it looks a little big to me. not to mention, usually there is not just one seed to be found.

it looks like a swollen calyx. i've read somewhere that the pistils can get stuck in there a bit or something like that. leave it be for a bit and see if any pistils emerge. if not, after a bit, i would pluck it.

that's a damn good looking plant by the way!


-shake