American sweetflag is stately, aromatic plant, to 1,8 m tall. Leaves are gladiate, 50 to 100 cm long, bright green, with 2 to 6 parallel veins. Redish-brown ground rhizomes are white inside, 2 to 5 cm wide, more than 1 m long. Flower spike is 5 to 10 cm long, at firtst green, later yellow-green to brownish. It contains tiny flowers. It blossoms late late spring to mid summer. Seeds are tan, narrowly oblong to obovate, 2 to 4 mm long. American sweetflag grows on muddy shores of stagnant or slowly flowing waters and in wet drains. It is native in northeast Asia, wider area of the Great Lakes (in South Dakota as far as Missouri River), and belt around USA-Canada border line to British Columbia. This species is closely related to common sweetflag or calamus (Acorus calamus) introduced by European settlers (today in the Eastern USA; isolated presence in northern Colorado or Cleveland and Stephens County in Oklahoma). Calamus contains carcinogenic β-asaron. Both species appear together today and they are frequently confused.
Grinnell wrote that Cheyennes obtained sweetflag from Lakota people in the past and they knew it as a plant growing on Lakota territory. Root was chewed and smeared on the skin "for any illness." According to Northern Cheyennes Alex Black Horse and Wilson Brady, infusion of the root was drunk on chill. Tea of sweetflag operated as a laxative on belly-ache. Also, it was diuretical and was used in the sweatlodge (émaome or vonȧhéome). The root was pulverized and mixed with inner bark of red osier dogwood (Cornus stolonifera) and afterward smoked. It was used for smoking by night. This mixture with sweetflag was preferred by people who favored something stronger for smoking. Cheyennes smoked sweetflag roots in mixture of other herbs for relieving chill, head-ache, and breathing troubles caused by blocked airways (Grinnell 1923 II: 171; Hart 1981: 7; Tallbull 1993: 1).
According to Wesley Whiteman, Northern Cheyenne, Cheyennes called sweetflag "ghost medicine" sometimes because it had power to ward off ghosts. They believed a bit of sweetflag root tied to a child’s necklet, dress or blanket would drive night spirits away. According to Northern Cheyenne Ben Black Wolf, only Sun Dance priests could collect this plant and it required ceremonial offerings. According to Northern Cheyenne herbalist William Tallbull, whole plant had to be dug ceremonially. He wrote too: "This plant has been lost to us" (Grinnell 1923 II: 171; Hart 1981: 7; Tallbull 1993: 1).
