NOUN (2)

1. the flower of a chrysanthemum plant;

2. any of numerous perennial Old World herbs having showy brightly colored flower heads of the genera Chrysanthemum, Argyranthemum, Dendranthema, Tanacetum; widely cultivated;

The Collaborative International Dictionary of English v.0.48:

Chrysanthemum \Chrys*an"the*mum\, n. [L., fr. Gr. ?; chryso`s
   gold + ? flower.] (Bot.)
   A genus of composite plants, mostly perennial, and of many
   species including the many varieties of garden chrysanthemums
   (annual and perennial), and also the feverfew and the oxeye
   daisy.
   [1913 Webster]

WordNet (r) 3.0 (2006):

chrysanthemum
    n 1: the flower of a chrysanthemum plant
    2: any of numerous perennial Old World herbs having showy
       brightly colored flower heads of the genera Chrysanthemum,
       Argyranthemum, Dendranthema, Tanacetum; widely cultivated