The Collaborative International Dictionary of English v.0.48:

Mace \Mace\, n. [F. macis, L. macis, macir, Gr. ?; cf. Skr.
   makaranda the nectar or honey of a flower, a fragrant mango.]
   (Bot.)
   A kind of spice; the aril which partly covers nutmegs. See
   Nutmeg.
   [1913 Webster]

   Note: Red mace is the aril of Myristica tingens, and
         white mace that of Myristica Otoba, -- East Indian
         trees of the same genus with the nutmeg tree.
         [1913 Webster]