Acorus
Encyclopedia
Acorus is a genus
of monocot flowering plant
s. 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.
. 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.
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 flower
s 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 pest
s.
Four varieties of Acorus calamus strains exist in nature; diploid, triploid, tetraploid and hexaploid.
Diploids do not produce the carcinogenic β-asarone. Diploids are known to grow naturally in Eastern Asia (Mongolia and C Siberia) and North America. The triploid cytotype probably originated in the Himalayan region, as a hybrid between the diploid and tetraploid cytotypes. The North American Calamus is known as Acorus Calamus var. Americanus or more recently as simply Acorus Americanus. Like the diploid strains of calamus in parts of the Himalayas, Mongolia, and C Siberia, the North American diploid strain does not contain the carcinogenic β-asarone. Research has consistently demonstrated that “β-asarone was not detectable in the North American spontaneous diploid Acorus [Calamus var. Americanus]”.
The genus includes as many as six species
:
Acorus from Europe, China
and Japan have been planted in the United States
.
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
of monocot flowering plant
Flowering plant
The flowering plants , also known as Angiospermae or Magnoliophyta, are the most diverse group of land plants. Angiosperms are seed-producing plants like the gymnosperms and can be distinguished from the gymnosperms by a series of synapomorphies...
s. This genus was once placed within the family Araceae
Araceae
Araceae are a family of monocotyledonous flowering plants in which flowers are borne on a type of inflorescence called a spadix. The spadix is usually accompanied by, and sometimes partially enclosed in, a spathe or leaf-like bract. Also known as the Arum family, members are often colloquially...
(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
Tofieldiaceae
Tofieldiaceae is the botanical name of a family of flowering plants in the monocot order Alismatales. The family is divided into five genera, which together comprise 20 or 21 species. They are small, herbaceous plants, mostly of arctic and subarctic regions, but a few extend further south, and...
, and several families of aquatic monocots (e.g., Alismataceae, Posidoniaceae). Common names include Calamus and Sweet Flag
Sweet Flag
Acorus calamus, commonly known as Sweet Flag or Calamus and erroneously as "rush" or "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...
. It is known as vasambu in Tamil language
Tamil language
Tamil is a Dravidian language spoken predominantly by Tamil people of the Indian subcontinent. It has official status in the Indian state of Tamil Nadu and in the Indian union territory of Pondicherry. Tamil is also an official language of Sri Lanka and Singapore...
..
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
Herbalism
Herbalism is a traditional medicinal or folk medicine practice based on the use of plants and plant extracts. Herbalism is also known as botanical medicine, medical herbalism, herbal medicine, herbology, herblore, and phytotherapy...
as a treatment for inflammation
Inflammation
Inflammation is part of the complex biological response of vascular tissues to harmful stimuli, such as pathogens, damaged cells, or irritants. Inflammation is a protective attempt by the organism to remove the injurious stimuli and to initiate the healing process...
of the eye
Human eye
The human eye is an organ which reacts to light for several purposes. As a conscious sense organ, the eye allows vision. Rod and cone cells in the retina allow conscious light perception and vision including color differentiation and the perception of depth...
.
The genus is native to North America
North America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...
and northern and eastern Asia
Asia
Asia is the world's largest and most populous continent, located primarily in the eastern and northern hemispheres. It covers 8.7% of the Earth's total surface area and with approximately 3.879 billion people, it hosts 60% of the world's current human population...
, and naturalised in southern Asia and Europe
Europe
Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...
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 systemCronquist system
The Cronquist system is a taxonomic classification system of flowering plants. It was developed by Arthur Cronquist in his texts An Integrated System of Classification of Flowering Plants and The Evolution and Classification of Flowering Plants .Cronquist's system places flowering plants into two...
. 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
Alismatales
Alismatales is an order of flowering plants including about 2500 species. Pleants assigned to this order are mostly tropical or aquatic.-Description:...
.
The APG II system recognizes order Acorales, distinct from the Alismatales, and as the sister group to all other monocots.
Characteristics
The inconspicuous flower
Flower
A flower, sometimes known as a bloom or blossom, is the reproductive structure found in flowering plants . The biological function of a flower is to effect reproduction, usually by providing a mechanism for the union of sperm with eggs...
s are arranged on a lateral spadix
Spadix
In botany, a spadix is a type of spike inflorescence having small flowers borne on a fleshy stem. Spadix are typical of the Family Araceae known as arums or aroids...
(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
Leaf
A leaf is an organ of a vascular plant, as defined in botanical terms, and in particular in plant morphology. Foliage is a mass noun that refers to leaves as a feature of plants....
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 pest
Pest (animal)
A pest is an animal which is detrimental to humans or human concerns. It is a loosely defined term, often overlapping with the related terms vermin, weeds, parasites and pathogens...
s.
Regulation
Products derived from Acorus calamus were banned in 1968 as food additives by the United States Food and Drug Administration.The questionable chemical derived from the plant was β-asarone. Confusion exists whether all strains of Acorus Calamus contain this substance.Four varieties of Acorus calamus strains exist in nature; diploid, triploid, tetraploid and hexaploid.
Diploids do not produce the carcinogenic β-asarone. Diploids are known to grow naturally in Eastern Asia (Mongolia and C Siberia) and North America. The triploid cytotype probably originated in the Himalayan region, as a hybrid between the diploid and tetraploid cytotypes. The North American Calamus is known as Acorus Calamus var. Americanus or more recently as simply Acorus Americanus. Like the diploid strains of calamus in parts of the Himalayas, Mongolia, and C Siberia, the North American diploid strain does not contain the carcinogenic β-asarone. Research has consistently demonstrated that “β-asarone was not detectable in the North American spontaneous diploid Acorus [Calamus var. Americanus]”.
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 (formerly Acorus calamus var. americanus).The genus includes as many as six species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
:
- Acorus americanusAcorus americanusAcorus americanus, the American Sweet Flag, is an emergent wetland plant native to the northern United States and Canada. This perennial plant has bright green blade-shaped leaves that arising directly from the rhizomes and sheath into each other at the base. Additionally the blades have 2-6 raised...
(Raf.) Raf. (formerly known as A. calamus var. americanus) - American Sweet Flag; fertile diploid (2n = 24); occurring in Alaska, Canada and northern USA. Diploid plants in SiberiaSiberiaSiberia is an extensive region constituting almost all of Northern Asia. Comprising the central and eastern portion of the Russian Federation, it was part of the Soviet Union from its beginning, as its predecessor states, the Tsardom of Russia and the Russian Empire, conquered it during the 16th...
and temperate Asia may also belong here, but have not been fully investigated . Recently recognised as a distinct species by the Flora of North America. - Acorus calamus L. - Common Sweet Flag; sterile triploid (3n = 36); probably of cultivated origin. It is native to EuropeEuropeEurope is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...
, temperate IndiaIndiaIndia , officially the Republic of India , is a country in South Asia. It is the seventh-largest country by geographical area, the second-most populous country with over 1.2 billion people, and the most populous democracy in the world...
and the Himalayas and southern Asia, widely cultivated and naturalised elsewhere. - Acorus gramineusAcorus gramineusAcorus gramineus Sol. Aiton is a botanical species belonging to the family of Acorus.-Origin:Native to Japan in eastern Asia, where it usually occurs in wetlands and shallow water.-Description:...
Sol. ex Aiton - Japanese Sweet Flag or Grassy-leaved Sweet Flag; fertile diploid (2n = 18); occurring in the Himalayas to Japan, Myanmar, Thailand, the Philippines. - Acorus triqueter Turcz. ex Schott (syn. A. calamus var. angustatus) - fertile tetraploid (4n = 48); occurring in eastern Asia, Japan and Taiwan.
- Acorus latifolius Z.Y.Zhu : native to China
- Acorus xiangyeus Z.Y.Zhu : native to China
China
Chinese civilization may refer to:* China for more general discussion of the country.* Chinese culture* Greater China, the transnational community of ethnic Chinese.* History of China* Sinosphere, the area historically affected by Chinese culture...
and Japan have been planted in the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
.