The Collaborative International Dictionary of English v.0.48:

Chrysophyceae \Chrysophyceae\ n.
   a class of yellow-green algae, all of which have flagella of
   unequal length.

   Syn: class Chrysophyceae, Heterokontae, class Heterokontae.
        [WordNet 1.5]

WordNet (r) 3.0 (2006):

Chrysophyceae
    n 1: all the yellow-green algae having flagella of unequal
         length [syn: Chrysophyceae, class Chrysophyceae,
         Heterokontae, class Heterokontae]