The Collaborative International Dictionary of English v.0.48:

Bilamellate \Bi*lam"el*late\, Bilamellated \Bi*lam"el*la`ted\,
   a. [Pref. bi- + lamellate.] (Bot.)
   Formed of two plates, as the stigma of the Mimulus; also,
   having two elevated ridges, as in the lip of certain flowers.
   [1913 Webster] Bilaminar