Fluffy

No not the large, three-headed dog who was once cared for by Hagrid in Harry Potter.
This is the seed from willow. It is everywhere along the stretch of the Kennet & Avon canal (which is where I escaped from work for a short walk today). The water had a white covering and the air was full of the seed floating around.
Willow has many uses it is grown for biomass or biofuel; used in arts and crafts for weaving, living sculptures and made into charcoal; used for biofiltration and white willow is used for cricket bats. Probably not much comfort to hay fever suffers.
According to urban dictionary willow can also mean another word to describe a overweight person. Not sure I get that perhaps it is an age thing.