Houstonia c[oe]rulea

from The Collaborative International Dictionary of English v.0.48

Bluets \Blu"ets\, n. [F. bluet, bleuet, dim. of bleu blue. See
   {Blue}, a.] (Bot.)
   A name given to several different species of plants having
   blue flowers, as the {Houstonia c[oe]rulea}, the {Centaurea
   cyanus} or bluebottle, and the {Vaccinium angustifolium}.
   [1913 Webster]