bipinnate

from WordNet (r) 3.0 (2006)

bipinnate
    adj 1: of a leaf shape; having doubly pinnate leaflets (as
           ferns)

from The Collaborative International Dictionary of English v.0.48

Bipinnate \Bi*pin"nate\, Bipinnated \Bi*pin"na*ted\, a. [Pref.
   bi- + pinnate; cf. F. bipinn['e]. Cf. {Bipennate}.]
   Twice pinnate.
   [1913 Webster]