USC Title 21 (Food and Drugs)
Chapter 13 (Drug Abuse Prevention and Control)
Section 802
(16) The term 'marihuana' means all parts of the plant Cannabis
sativa L., whether growing or not; the seeds thereof; the resin
extracted from any part of such plant; and every compound,
manufacture, salt, derivative, mixture or preparation of such
plant, its seeds or resin. Such term does not include the mature
stalks of such plant, fiber provided from such stalks, oil or
cake made from the seeds of such plant, any other compound,
manufacture, salt, derivative, mixture or preparation of such
mature stalks (except the resin extracted therefrom), fiber, oil
or cake or the sterilized seed of such plant, which is incapable
of germination.