Commonly known as sweet flag or calamus ( Sanskrit : Haimavati, हैमवती, Vacha, वचा ) and various rushes and sedges, is a plant from the Acoraceae family, in the genus Acorus.
	It is a tall perennial wetland monocot with scented leaves and more strongly scented rhizomes, which have been used medicinally, for its odor, and as an allegedly psychotropic drug. Its Sanskrit name is vacha. Probably indigenous to India, Acorus calamus is now found across Europe, in southern Russia, northern Asia Minor, southern Siberia, China, Indonesia, Japan, Burma, Sri Lanka, Australia, as well as southern Canada and Northern USA, where it may be mistaken for the native Acorus americanus.
Acorus Calamus

Botanical information :

The morphological distinction between the Acorus species is made by the number of prominent leaf veins. Acorus calamus has a single prominent midvein and then on both sides slightly raised secondary veins (with a diameter less than half the midvein) and many fine tertiary veins. This makes it clearly distinct from Acorus americanus.

The leaves are between 0.7 and 1.7 cm wide, with average of 1 cm. The sympodial leaf of Acorus calamus is somewhat shorter than the vegetative leaves. The margin is curly-edged or undulate. The spadix, at the time of expansion, can reach a length between 4.9 and 8.9 cm (longer than A. americanus). The flowers are longer too, between 3 and 4 mm. Acorus calamus is infertile and shows an abortive ovary with a shriveled appearance.

One subspecies, Acorus calamus var. angustatus Besser, Synonyms: Acorus asiaticus, Acorus cochinchinensis, Acorus latifolius, Acorus rumphianus, Acorus spurius, Acorus triqueter, Acorus tatarinowii, Acorus terrestris, Orontium cochinchinense, Acorus calamus var. spurius, Acorus gramineus var. crassispadix.

Chemistry :

Both triploid and tetraploid calamus contain asarone[citation needed]. Other phytochemicals include:

    »    Calamus has been an item of trade in many cultures for thousands of years. Calamus has been used medicinally for a wide variety of ailments, and its smell makes calamus essential oil valued in the perfume industry.

    »    In Bali, Indonesia, calamus is used to give flavour in meat, vegetable and fish dishes. In antiquity in the Orient and Egypt, the rhizome was thought to be a powerful aphrodisiac. In Europe Acorus calamus was often added to wine, and the root is also one of the possible ingredients of absinthe.

    »    Among the northern Native Americans, it is used both medicinally and as a stimulant. It is believed by some that calamus is an hallucinogen. This urban legend is based solely on two pages of a book written by Hoffer and Osmund entitled "The Hallucinogens."

    »    Acorus calamus shows neuroprotective effect against stroke and chemical induced neurodegeneration in rat. Specifically, it has protective effect against acrylamide induced neurotoxicity