The attached bristles of the pappus serve as a cotton-like tuft, which promotes dispersal of the seeds by the wind.
(The attached bristles of the pappus; serve; as a cotton-like tuft) (a cotton-like tuft; promotes; dispersal of the seeds)
The attached bristles of the pappus a cotton-like tuft
serve promotes
as a cotton-like tuft
dispersal of the seeds