Calamus or Common Sweet Flag (Acorus calamus) is a plant from the Acoraceae family, Acorus genues. It is a tall perennial wetland monocot with scented leaves and rhizomes which have been used medicinally, for its odor, and as a psychotropic drug. It is known by a variety of names, including cinnamon sedge, flagroot, gladdon, myrtle flag, myrtle grass, myrtle sedge, sweet cane, sweet myrtle, sweet root, sweet rush, and sweet sedge. 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, Japan, Burma, Sri Lanka, Australia, southern Canada and northern USA.
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.
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; in addition, the root is thought to have been used as an entheogen among the northern Native Americans. In high doses, it is hallucinogenic. Acorus calamus shows neuroprotective effect against stroke and chemical induced neurodegeneration in rat. Specifically, it has protective effect against acrylamide induced neurotoxicity. Shukla PK, Khanna VK, Ali MM, Maurya R, Khan MY, Srimal RC. Neuroprotective effect of Acorus calamus against middle cerebral artery occlusion-induced ischaemia in rat. Hum Exp Toxicol. 2006 Apr;25(4):187-94. PMID: 16696294 Shukla PK, Khanna VK, Ali MM, Maurya RR, Handa SS, Srimal RC. Protective effect of acorus calamus against acrylamide induced neurotoxicity.Phytother Res. 2002 May;16(3):256-60. PMID: 12164272
The plant's roots are often eaten for its effects, which are not very pronounced. Hence, Sweet Flag is not seen as a party drug.
The plant was a favorite of Henry David Thoreau (who called it sweet flag), and also of Walt Whitman, who added a section called the "Calamus" poems, possibly celebrating his love of men, to the third edition of Leaves of Grass (1860). In the poems the calamus is used as a symbol of love, lust, and affection. It has been suggested that the symbology derives from the visual resemblance of the spadix to the erect human penis.
The name Sweet Flag refers to its sweet scent (it has been used as a strewing herb) and the wavy edges of the leaves which are supposed to resemble a fluttering flag.
In Japan, the plant is a symbol of the samurai's bravery because of its sharp sword-like leaves. Even now many families with young boys enjoy "Sweet Flag Bath (shōbu yu)" in the Boy's Festival (Tango no Sekku) on May 5. Also, the legendary Japanese sword Kusanagi was said to resemble a calamus.
From the Latin root "calamus", a number of modern English words arise: