Acorus calamus L. has a nearly global distribution, with representative varieties in nearly every continent with the exception of Australia and Antarctica. The plant grows from a rhizome, has reed-like leaves and a whitish-green spadix. It has three accepted varieties; A. c. var. americanus Raf. (syn. A. americanus) in Canada, the northern United States, and Russia; A. c. var. angustatus Besser from Siberia, China, Russia, Japan, Korea, Mongolia, the Himalayas, the Indian Subcontinent, Indochina, the Philippines, and Indonesia; and A. c. var. calamus L. in Siberia, Russia, Mongolia, Manchuria, Korea, and the Himalayas.
Also known as Calamus or sweet flag, the rhizome and leaves of some varieties is used in herbal medicine as a digestive aid. The dried rhizome was also dried and smoked by some indigenous cultures, and the leaves were used in basketry by Native Americans.
Illustration below from Prof. Dr. Otto Wilhelm Thomé, Flora von Deutschland, Österreich und der Schweiz 1885, Gera, Germany.