It comes from the poplar tree and looks like little tufts of white cotton.
At best, the wind picks it up and swirls it around, creating an effect of dandelion fluff in a beautiful meadow.
At worst, the wind sends it into your mouth and nose and open windows; several pieces settle in your hair.
We noticed this "pukh" as students in St. Petersburg one summer and were amused by this summer "snow." Unfortunately, it does not always seem so charming...