Spend a warm summer day on a slow river or along a gravel road in Iowa and you will likely see little tufts of cottony threads floating through the air.
These carry the tiny seeds of cottonwood trees. Cottonwood trees can be majestically large, but can also be hollow and sometimes fall down or break off limbs in storms.
The tiny fluffy threads can pile up alongside the road or float down a river.
The threads get entangled in the vegetation.
Even insects can be inconvenienced by the threads.