URGENT: Will the REAL onion seed please stand up ?

Can any of you offer some urgent advice ?

A month or so ago I 'harvested' some of my seed onions. (e.g. onions that had been allowed to go to seed, and produce seedpods.)

I cut off the "flowerheads", which where now florets of seedpods. I shook them over a tray, and LO !...a host of teeny tiny seeds dropped off, looking like tiny white flakes (see piccy below).

But some of the seedpods where still closed. So on a whim, I decided to dabble with DIY hydroponics, and I stuck the floret stems in a jar of water, in the hope that they would continue to mature, open up, and release their seeds.

Today, I took them out, and gave them a shake. Seeds fell out... BUT... they looked COMPLETELY different to the original seeds. Instead of tiny white flecks, they where small black peppercorns.

So.. my question is...

1. Where the original white flecks a sort of 'immature' onion seed, and if so will they still grow ? Or....
2. Where they just Onion Dandruf ? (e.g. some sort of detritus from the seed pods).

As ever, you can click on the pictures to get a larger version.

Any thoughts would be most gratefully received.