secundine

Etymology
From, from , shortened from  "the second membranes", from. See.

Noun

 * 1)  The second coat, or integument, of an ovule, lying within the primine.
 * 2)  The afterbirth, or placenta and membranes.

Usage notes

 * 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.