(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 produced 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.