1. Acorus Linnaeus, Sp. Pl. 1: 324. 1753.
菖蒲属 chang pu shu
Morphological characters and geographical distribution are the same as those of the family.
Acorus has been considered for a long time to be a member of the Araceae and only recently has it been removed from the family, although the family Acoraceae was already established in 1820. There are a number of significant characters that distinguish Acorus from the Araceae: unifacial leaves, two separate vascular systems in the peduncle, absence of raphides, presence of perisperm and endosperm in the seeds (never a perisperm in Araceae), trichomes on the micropyle of the ovules, and presence of special ethereal oil cells and other anatomical characters; laticifers are also lacking but quite a number of Araceae are also without them. DNA studies show that Acorus is a sister taxon to all other monocots, which means that it is not closely related to the Araceae at all.
The pollination of the Acorus species is not known, but entomophily is likely because the pollen is sticky. Pieces of rhizomes are easily dispersed by water along rivers and creeks. In particular, the sterile triploid Acorus calamus has been dispersed by this means. The seeds also are dispersed by water along streams or river margins.
The rhizomes are used for treatment of neurasthenia, chronic bronchitis, diarrhea, abdominal distention, chills, colds, externally for abscesses, liver disturbance, and stomach and gut disease. Mainly the rhizome of Acorus calamus is used because the content of the essential oil is highest in the rhizome; the leaves are also used, although the roots and leaves have poor oil content and are therefore of no wide or practical use. Other uses are reported as aromatizer for wine and tobacco, as perfume and insecticide, and as medicine for ulcers, kidney disease, and other diseases, though beta-asarone is said to be carcinogenic (Keller & Stahl, Planta Medica 47: 71-74. 1983). Both species are grown as ornamentals in bog gardens.
