zinnia

from WordNet (r) 3.0 (2006)

zinnia
    n 1: any of various plants of the genus Zinnia cultivated for
         their variously and brightly colored flower heads [syn:
         {zinnia}, {old maid}, {old maid flower}]

from The Collaborative International Dictionary of English v.0.48

Zinnia \Zin"ni*a\, n. [NL. So called after Professor Zinn, of
   G["o]ttingen.] (Bot.)
   Any plant of the composite genus {Zinnia}, Mexican herbs with
   opposite leaves and large gay-colored blossoms. {Zinnia
   elegans} is the commonest species in cultivation.
   [1913 Webster]