Nutmeg is the actual seed of the tree, roughly egg-shaped and dried. Mace is the dried “lacy” reddish covering or arillus of the seed. This is the only tropical fruit that is the source of two different spices.
The mace is removed from the shell and its broken parts are known as blades.Because the yield of mace is much less than nutmeg, it has had greater value. A pile of fruit large enough to make one hundred pounds of nutmeg produces a single pound of mace. While Nutmeg and Mace are related, they are 2 different spices. Mace has a stronger flavor and is preferred in medieval English cooking. Nutmeg was preferred in French cooking. Arabic and Asian cultures used the spices equally.
Personally I love the smell of mace over nutmeg. Sweet, pungent, spicy (not heat, but bite) all at the same time. I bought some mace blades at Pennsic, 4 precious ounces, and have fallen in love all over again. I have not been this excited about a spice since I put cardamon in the baklava. I am working on building my regional spice libraries. While there are commonalities across cultures, everyone has a different spin on things. Herbs are next on the research hit list.