Acorus

Taxobox
name = "Acorus"

---

image_width = 240px
image_caption = Sweet Flag ("Acorus calamus") - spadix
regnum = Plantae
divisio = Magnoliophyta
classis = Liliopsida
ordo = Acorales
ordo_authority= Reveal
familia_authority=Martinov
familia = Acoraceae
genus = "Acorus"
genus_authority = L., 1753
subdivision_ranks = Species
subdivision = See text.

"Acorus" is a genus of monocot flowering plants. This genus was once placed within the family Araceae (aroids), but more recent classifications place it in its own family Acoraceae and order Acorales, of which it is the sole genus of the oldest surviving line of monocots. The exact relationship of Acorus to other monocots, however, is still debated by scientists. Some studies indicate that it is placed in a lineage (the order Alismatales), that also includes aroids (Araceae), Tofieldiaceae, and several families of aquatic monocots (e.g., Alismataceae, Posidoniaceae). Common names include Calamus and Sweet Flag. It is known as "vasambu" in Tamil language.

The name 'acorus' is derived from the Greek word 'acoron', a name used by Dioscorides, which in turn was derived from 'coreon', meaning 'pupil', because it was used in herbal medicine as a treatment for inflammation of the eye.

The genus is native to North America and northern and eastern Asia, and naturalised in southern Asia and Europe from ancient cultivation. The known wild populations are diploid except for some tetraploids in eastern Asia, while the cultivated plants are sterile triploids, probably of hybrid origin between the diploid and tetraploid forms.

Taxonomy

Although the family Acoraceae was originally described in 1820, since then "Acorus" has traditionally been included in Araceae in most classification systems, as in the Cronquist system. The family has recently been resurrected as molecular systematic studies have shown that "Acorus" is not closely related to Araceae or any other monocot family, leading plant systematists to place the genus and family in its own order. This placement currently lacks support from traditional plant morphology studies, and some taxonomists still place it as a subfamily of Araceae, in the order Alismatales.

The APG II system recognizes order Acorales, distinct from the Alismatales, and as the sister group to all other monocots.

Characteristics

These grasslike evergreen plants are hemicryptophytes, (i.e. perennial plants of which the overwintering buds are at the soil surface) or geophytes (i.e. the overwintering buds are found underground, usually attached to a bulb, corm, tuber, etc.). Their natural habitat is at the waterside or close to marshes, often found with reedbeds.

The inconspicuous flowers are arranged on a lateral spadix (a thickened, fleshy axis). Unlike aroids, there is no spathe (large bract, enclosing the spadix). The spadix is 4-10 cm long and is enclosed by the foliage. The bract can be ten times longer than the spadix. The leaves are linear with entire margin.

The parallel-veined leaves of some species contain ethereal oils that give a sweet scent when dried. Fine-cut leaves used to be strewn across the floor in the Middle Ages, both for the scent, and for presumed efficacy against pests.

Species

In older literature and on many websites, there is still much confusion, with the name "Acorus calamus" equally but wrongfully applied to "Acorus americanus".

The genus includes as many as six species:
*"Acorus americanus (Raf.) Raf. " (formerly known as "A. calamus" var. "americanus") - American Sweet Flag; fertile diploid (2"n" = 24); occurring in Alaska, Canada and northern USA. Diploid plants in Siberia and temperate Asia may also belong here, but have not been fully investigated ( [http://www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=222000002] ). Recently recognised as a distinct species by the "Flora of North America".
*"Acorus calamus" L. - Common Sweet Flag; sterile triploid (3"n" = 36); probably of cultivated origin. It is native to Europe, temperate India and the Himalayas and southern Asia, widely cultivated and naturalised elsewhere.
*"Acorus gramineus" Sol. ex Aiton - Japanese Sweet Flag or Grassy-leaved Sweet Flag; fertile diploid (2"n" = 18); occurring in the Himalayas to Japan, Myanmar, Thailand, the Philippines.
*"Acorus triqueter" Turcz. ex Schott (syn. "A. calamus" var. "angustatus") - fertile tetraploid (4"n" = 48); occurring in eastern Asia, Japan and Taiwan.
*"Acorus latifolius" Z.Y.Zhu : native to China
*"Acorus xiangyeus" Z.Y.Zhu : native to China

"Acorus" from Europe, China and Japan have been planted in the United States.

Chemistry

Both triploid and tetraploid calamus contain asarone, but diploid does not contain any. Asarone is a possible precursor in the synthesis of the psychedelic phenethylamine TMA-2. The chemical itself is reportedly without activity at doses up to 70 mg.

Regulations

Calamus and products derived from calamus (such as its oil) were banned in 1968 as food additives and medicines by the United States Food and Drug Administration.

Usage

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.

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; Calamus has been used as a "street drug alternative".

Cultural symbolism

The calamus has long been a symbol of male love. The name is associated with a Greek myth: Kalamos, a son of the river-god Maeander, who loved Karpos, the son of Zephyrus and Chloris. When Karpos drowned, Kalamos was transformed into a reed, whose rustling in the wind was interpreted as a sigh of lamentation.

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", celebrating the 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 resemblane of the reed 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.

Etymology of the word Calamus

Cognates of the Latin word "Calamus" are found in both Greek ("kalamos", meaning "reed") and Sanskrit ("kalama", meaning "reed" and "pen" as well as a sort of rice) — strong evidence that the word is older than all three languages and exists in their parent language, Proto-Indo European. The Arabic word "qalam" (meaning "pen") is likely to have been borrowed from one of these languages in antiquity, or directly from Indo-European itself.

From the Latin root "calamus", a number of modern English words arise:
* calamari, meaning "squid", via the Latin "calamarium", "ink horn" or "pen case", as reeds were then used as writing implements;
* "calumet", another name for the Native American peace pipe, which was often made from a hollow reed;
* shawm, a medieval oboe-like instrument (whose sound is produced by a vibrating reed mouthpiece);
* "chalumeau" register, the lower notes of a clarinet's range (another reed instrument)

References and external links

*Govaerts, R. & Frodin, D.G. (2002). World Checklist and Bibliography of Araceae and Acoraceae. 1-560. The Board of Trustees of the Royal Botanic Gardens, Kew.
* [http://www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=100307 Flora of North America: "Acorus"]
* [http://www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=20008 Flora of North America: Acoraceae]
* [http://www.mobot.org/MOBOT/Research/APweb/orders/acoralesweb.htm#Acorales Acorales] in Stevens, P. F. (2001 onwards). [http://www.mobot.org/MOBOT/research/APweb Angiosperm Phylogeny Website] . Version 7, May 2006.
* [http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Tree&id=91812&lvl=3&lin=f&keep=1&srchmode=1&unlock NCBI Taxonomy Browser]
* [http://delta-intkey.com/angio/www/acoracea.htm Acoraceae] in L. Watson and M.J. Dallwitz (1992 onwards) " [http://delta-intkey.com/angio/ The families of flowering plants:] descriptions, illustrations, identification, information retrieval". Version: 27 April 2006. http://delta-intkey.com.
* [http://www.woodlotalt.com/publications/BotNotesv1n2.PDF Taxonomy and distribution of Acorus in Maine]
* [http://www.erowid.org/library/books_online/pihkal/pihkal158.shtml]