When a gust of wind plucks a seed from the plant’s fuzzy head, a fluffy structure called the pappus keeps the seed aloft before it ultimately falls to the ground. The pappus creates a swirling bubble of air in the low-pressure region above the structure (seen at right with a seed in a wind tunnel). Some air gets through the pappus, and a pressure gradient forms with low pressure above the filaments and high pressure below them, keeping the bubble stable.