Harvesting seed.
You are looking at the first seed collected this year from the Canada hawkweed (Heiracuim canadense). The dark part is the seed, the fluff is to carry the seed on the wind if it isn't harvested soon enough. I will be checking daily for the next few weeks as the flowers bloom then go to seed individually.
On the canada hawkweed a seedhead is ready to collect. You can see it has turned fluffy and sort of light tan. The flowers are yellow they close , the seed forms and the seedhead opens and dries then flies with the wind. Except I'll be there to pinch off and save. Comes loose very easily.