Treated Bittergreen Petals are an alchemical ingredient in The Elder Scrolls III: Morrowind. They have the same effects as Bittergreen Petals, simply in a different order. They are used in Mephala's Quest.
Speaking to either Tendris Vedran or Anarenen, both Alchemists, will cause the Nerevarine to learn the following: Bittergreen is a red flowering plant with modest magical properties. It grows in the Red Mountain region.