[1] : The Collaborative International Dictionary of English v.0.48

helianthus \helianthus\ n.
   any plant of the genus helianthus having large flower heads
   with dark disk florets and showy yellow rays.

   syn: sunflower.
        wordnet 1.5
see also:
helianthus 

[2] : WordNet (r) 2.0

helianthus
     n : any plant of the genus helianthus having large flower heads
         with dark disk florets and showy yellow rays syn: sunflower
see also:
sunflower 

Helianthus >> H Words
Helianthus, definition of term: Helianthus
helianthus_pag1.html