coronule

from The Collaborative International Dictionary of English v.0.48

Coronule \Cor"o*nule\ (k?r"?-n?l), n. [L. coronula, dim. of
   corona crown.] (Bot.)
   A coronet or little crown of a seed; the downy tuft on seeds.
   See {Pappus}. --Martyn.
   [1913 Webster]