The seeds themselves can be seen as small dots in the white, and this fluff will carry new plants far and wide from Emthree. They can lie dormant in the soil for ages and are supposed to be stimulated into growth by fire (why are they not consumed?).
It struck me that the seeds are tiny exemplars of James Elroy Flecker's poem To a Poet A Thousand Years Hence. If they could talk, maybe they would be saying to their latent children:
Since I can never see your face,
And never shake you by the hand,
I send my soul through time and space
To greet you. You will understand.
In Finland they use these seeds to stuff pillows - it must be hard work collecting enough.