EPPO Global Database

The plant originally described in Europe as Acorus calamus is a sterile triploid, naturally occurring in Asia, which has spread naturally or been introduced by human agency into Europe, South Africa, North America and Australia. The cut foliage was used in earlier centuries as a fragrant floor covering, a use which has now virtually disappeared, so that A. calamus is now much less frequent in its introduced range than it was in the past. In eastern Asia, a fertile tetraploid form exists in the wild, known as A. calamus var. angustatus. Wild diploid forms are also known in Asia, as putative parents for the triploid. The plant known as Acorus americanus, in North America, is also a diploid. Some authors consider all these forms to be simply A.calamus. Used medicinally