The southern blue-flag, (Iris virginica), is a beautiful purple-blue flower. It is found in the Okefenokee Swamp. The iris (Iridacea) is a family of perennial herbs. Other familiar plants in the family are crocuses, freesia and gladioli. The iris is characterized by thickened stems and sword-shaped leaves. The swamp or purple iris stem or rhizome is extremely poisonous when dried. The Indians often used small amounts as a diuretic and cathartic. The wild iris is common in the temperate and sub artic regions of North America. These wild irises are often called flags. The iris is thought to be the source of the fleur-de-lis and possibly the flower of the Greek youth Hyacinth.