The Collaborative International Dictionary of English v.0.48:

Cruciferous \Cru*cif"er*ous\ (kr[.u]*s?f"?r-?s), a. [L. crux,
   crucis, cross + -ferous: cf. F. crucif[`e]re.]
   1. Bearing a cross.
      [1913 Webster]

   2. (Bot.) Of, pertaining to, or resembling, a family of
      plants which have four petals arranged like the arms of a
      cross, as the mustard, radish, turnip, etc.
      [1913 Webster]

WordNet (r) 3.0 (2006):

cruciferous
    adj 1: of or relating to or belonging to the plant family
           Cruciferae