Source : Webster's Revised Unabridged Dictionary (1913)

Secundine \Sec"un*dine\, n. [Cf. F. secondine.]
   1. (Bot.) The second coat, or integument, of an ovule, lying
      within the primine.

   Note: In the ripened seed the primine and secundine are
         usually united to form the testa, or outer seed coat.
         When they remain distinct the secundine becomes the
         mesosperm, as in the castor bean.

   2. [Cf. F. secondines.] The afterbirth, or placenta and
      membranes; -- generally used in the plural.