Acorus

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Acorus
Acorus calamus.spadix.jpg
Sweet flag Acorus calamus - spadix
Scientific classification OOjs UI icon edit-ltr.svg
Kingdom: Plantae
Clade: Tracheophytes
Clade: Angiosperms
Clade: Monocots
Order: Acorales
Reveal [1]
Family: Acoraceae
Martinov [1]
Genus: Acorus
L.
Synonyms

CalamusGarsault [2]

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. Some older studies indicated that it was placed in a lineage (the order Alismatales), that also includes aroids (Araceae), Tofieldiaceae, and several families of aquatic monocots (e.g., Alismataceae, Posidoniaceae). However, modern phylogenetic studies demonstrate that Acorus is sister to all other monocots. Common names include calamus and sweet flag .

Contents

The genus is native to North America and northern and eastern Asia, and naturalised in southern Asia and Europe from ancient cultivation. [2] [3] [4] [5] [6] [7] 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.

Characteristics

Habit of Acorus calamus. Acorus calamus1.jpg
Habit of Acorus calamus.

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.

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 III system recognizes order Acorales, distinct from the Alismatales, and as the sister group to all other monocots. This relationship is confirmed by more recent phylogenetic studies. [8] [9] Treatment in the APG IV system is unchanged from APG III. [10]

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).

As of July 2014, the Kew Checklist accepts only 2 species, one of which has three accepted varieties: [2]

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

Etymology

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.[ citation needed ]

Distribution and habitat

These plants are found in wetlands, particularly marshes, where they spread by means of thick rhizomes. Like many other marsh plants, they depend upon aerenchyma to transport oxygen to the rooting zone. [11] They frequently occur on shorelines and floodplains where water levels fluctuate seasonally.

Ecology

The native North American species appears in many ecological studies. Compared to other species of wetland plants, they have relatively high competitive ability. [12] Although many marsh plants accumulate large banks of buried seeds, [13] seed banks of Acorus may not accumulate in some wetlands owing to low seed production. [14] The seeds appear to be adapted to germinate in clearings; after a period of cold storage, the seeds will germinate after seven days of light with fluctuating temperature, and somewhat longer under constant temperature. [15] A comparative study of its life history traits classified it as a "tussock interstitial", that is, a species that has a dense growth form and tends to occupy gaps in marsh vegetation, not unlike Iris versicolor . [16]

Toxicity

Sweet Flag (2006 drawing by USGS Northern Prairie Wildlife Research Center) Acorus calamus illustration.jpg
Sweet Flag (2006 drawing by USGS Northern Prairie Wildlife Research Center)

Products derived from Acorus calamus were banned in 1968 as food additives by the United States Food and Drug Administration. [17] The questionable chemical derived from the plant was β-asarone. Confusion exists whether all strains of A. calamus contain this substance.

Four varieties of A. calamus strains exist in nature: diploid, triploid, tetraploid and hexaploid. [18] 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. [19] The North American Calamus is known as Acorus calamus var. americanus or more recently as simply Acorus americanus. Like the diploid strains of A. calamus in parts of the Himalayas, Mongolia, and C Siberia, the North American diploid strain does not contain the carcinogenic β-asarone. [20] [21] [22] Research has consistently demonstrated that "β-asarone was not detectable in the North American spontaneous diploid Acorus [calamus var. americanus]". [23]

Uses

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.

Related Research Articles

<span class="mw-page-title-main">Alismatales</span> Order of herbaceous flowering plants of marshy and aquatic habitats

The Alismatales (alismatids) are an order of flowering plants including about 4,500 species. Plants assigned to this order are mostly tropical or aquatic. Some grow in fresh water, some in marine habitats. Perhaps the most important food crop in the order is the corm of the taro plant, Colocasia esculenta.

<span class="mw-page-title-main">Flowering plant</span> Clade of seed plants that produce flowers

Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae, commonly called angiosperms. They include all forbs, grasses and grass-like plants, a vast majority of broad-leaved trees, shrubs and vines, and most aquatic plants. The term "angiosperm" is derived from the Greek words ἀγγεῖον / angeion and σπέρμα / sperma ('seed'), meaning that the seeds are enclosed within a fruit. They are by far the most diverse group of land plants with 64 orders, 416 families, approximately 13,000 known genera and 300,000 known species. Angiosperms were formerly called Magnoliophyta.

<span class="mw-page-title-main">Arales</span> Order of flowering plants

Arales is an order of flowering plants. The name was used in the Cronquist system for an order placed in subclass Arecidae, circumscribed as (1981):

<span class="mw-page-title-main">Araceae</span> Family of flowering plants

The 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. Also known as the arum family, members are often colloquially known as aroids. This family of 140 genera and about 4,075 known species is most diverse in the New World tropics, although also distributed in the Old World tropics and northern temperate regions.

<span class="mw-page-title-main">Monocotyledon</span> Clade of flowering plants

Monocotyledons, commonly referred to as monocots, are grass and grass-like flowering plants (angiosperms), the seeds of which typically contain only one embryonic leaf, or cotyledon. They constitute one of the major groups into which the flowering plants have traditionally been divided; the rest of the flowering plants have two cotyledons and are classified as dicotyledons, or dicots.

<i>Acorus calamus</i> Species of plant

Acorus calamus is a species of flowering plant with psychoactive chemicals. It is a tall wetland monocot of the family Acoraceae, in the genus Acorus. Although used in traditional medicine over centuries to treat digestive disorders and pain, there is no clinical evidence for its safety or efficacy – and ingested calamus may be toxic – leading to its commercial ban in the United States.

<span class="mw-page-title-main">Juncaceae</span> Family of flowering plants commonly known as rushes

Juncaceae is a family of flowering plants, commonly known as the rush family. It consists of 8 genera and about 464 known species of slow-growing, rhizomatous, herbaceous monocotyledonous plants that may superficially resemble grasses and sedges. They often grow on infertile soils in a wide range of moisture conditions. The best-known and largest genus is Juncus. Most of the Juncus species grow exclusively in wetland habitats. A few rushes, such as Juncus bufonius are annuals, but most are perennials.

<span class="mw-page-title-main">Juncaginaceae</span> Family of aquatic plants

Juncaginaceae is a family of flowering plants, recognized by most taxonomists for the past few decades. It is also known as the arrowgrass family. It includes 3 genera with a total of 34 known species.

<span class="mw-page-title-main">Commelinids</span> Clade of monocot flowering plants

In plant taxonomy, commelinids is a clade of flowering plants within the monocots, distinguished by having cell walls containing ferulic acid.

<span class="mw-page-title-main">Najadales</span> Order of flowering plants

Najadales is the botanical name of an order of flowering plants. A well-known system that used this name is the Cronquist system (1981), which used this name for an order in subclass Alismatidae with this circumscription:

<span class="mw-page-title-main">Tofieldiaceae</span> Family of flowering plants

Tofieldiaceae is a family of flowering plants in the monocot order Alismatales. The family is divided into four genera, which together comprise 28 known species. They are small, herbaceous plants, mostly of arctic and subarctic regions, but a few extend further south, and one genus is endemic to northern South America and Florida. Tofieldia pusilla is sometimes grown as an ornamental.

<i>Acorus americanus</i> American sweet flag, a species of plant

Acorus 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 arise directly from the rhizomes and sheath into each other at the base. Additionally the blades have 2-6 raised veins, and a swollen center when viewed in cross section. The foliage has a citrus-like spicy aromatic quality, and can be used to flavor beer. It is a flowering plant with inconspicuous flowers that are arranged on a lateral spadix and the fertilized flowers produce berries with a jelly inside. This plant is protected as a state endangered species in Pennsylvania.

<span class="mw-page-title-main">Asarone</span> Chemical compound

Asarone is chemical compound of the phenylpropanoid class found in certain plants such as Acorus and Asarum. There are two isomers, α and β. As a volatile fragrance oil, it is used in killing pests and bacteria.

<i>Butomus</i> Genus of flowering plants

Butomus is the only known genus in the plant family Butomaceae, native to Europe and Asia. It is considered invasive in some parts of the United States.

<span class="mw-page-title-main">Basal angiosperms</span> Descendants of most extant flowering plants

The basal angiosperms are the flowering plants which diverged from the lineage leading to most flowering plants. In particular, the most basal angiosperms were called the ANITA grade, which is made up of Amborella, Nymphaeales and Austrobaileyales.

<i>Arisarum</i> Genus of flowering plants

Arisarum is a genus of flowering plants in the family Araceae. It is native to the Mediterranean region, east to the Caucasus and west to Macaronesia.

<span class="mw-page-title-main">Mesangiospermae</span> One of two clades of flowering plants

Mesangiospermae is a clade of flowering plants (angiosperms), informally called "mesangiosperms". They are one of two main groups of angiosperms. It is a name created under the rules of the PhyloCode system of phylogenetic nomenclature. There are about 350,000 species of mesangiosperms. The mesangiosperms contain about 99.95% of the flowering plants, assuming that there are about 175 species not in this group and about 350,000 that are. While such a clade with a similar circumscription exists in the APG III system, it was not given a name.

<span class="mw-page-title-main">Lilioid monocots</span> Grade of flowering plant orders, within Lilianae

Lilioid monocots is an informal name used for a grade of five monocot orders in which the majority of species have flowers with relatively large, coloured tepals. This characteristic is similar to that found in lilies ("lily-like"). Petaloid monocots refers to the flowers having tepals which all resemble petals (petaloid). The taxonomic terms Lilianae or Liliiflorae have also been applied to this assemblage at various times. From the early nineteenth century many of the species in this group of plants were put into a very broadly defined family, Liliaceae sensu lato or s.l.. These classification systems are still found in many books and other sources. Within the monocots the Liliaceae s.l. were distinguished from the Glumaceae.

<span class="mw-page-title-main">Alismatid monocots</span> Grade of flowering plant orders within Lilianae

Alismatid monocots is an informal name for a group of early branching monocots, consisting of two orders, the Acorales and Alismatales. The name has also been used to refer to the Alismatales alone. Monocots are frequently treated as three informal groupings based on their branching from ancestral monocots and shared characteristics: alismatid monocots, lilioid monocots and commelinid monocots. Research at the Royal Botanical Gardens, Kew is organised into two teams I: Alismatids and Lilioids and II: Commelinids. A similar approach is taken by Judd in his Plant systematics.

References

  1. 1 2 Reveal, James L. (17 February 2011). "Indices Nominum Supragenericorum Plantarum Vascularium – S, Solanales". Indices Nominum Supragenericorum Plantarum Vascularium Alphabetical Listing by Genera of Validly Published Suprageneric Names. University of Maryland and Cornell University.
  2. 1 2 3 Kew World Checklist of Selected Plant Families
  3. ↑ Flora of North America: Acorus
  4. ↑ Flora of China, Vol. 23 Page 1, 菖蒲属 chang pu shu, Acorus Linnaeus, Sp. Pl. 1: 324. 1753.
  5. ↑ 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.
  6. ↑ Boyce, P.C., Sookchaloem, D., Hetterscheid, W.L.A., Gusman, G., Jacobsen, N., Idei, T. & Nguyen, V.D. (2012). Flora of Thailand 11(2): 101–325. The Forest Herbarium, National Park, Wildlife and Plant Conservation Department, Bangkok.
  7. ↑ Nooteboom, H.P. (ed.) (2011). Flora Malesiana 20: 1–61. Noordhoff-Kolff N.V., Djakarta.
  8. ↑ Soltis et al 2011.
  9. ↑ Givnish et al 2010.
  10. ↑ Angiosperm Phylogeny Group (2016). "An update of the Angiosperm Phylogeny Group classification for the orders and families of flowering plants: APG IV". Botanical Journal of the Linnean Society. 181 (1): 1–20. doi: 10.1111/boj.12385 .
  11. ↑ Keddy, P.A. 2010. Wetland Ecology: Principles and Conservation (2nd edition). Cambridge University Press, Cambridge, UK. Chapter 1.
  12. ↑ Gaudet, C.L.; Keddy, P.A. (1988). "Predicting competitive ability from plant traits: a comparative approach". Nature. 334 (6179): 242–243. doi:10.1038/334242a0. S2CID   4284026. Figure 1.
  13. ↑ van der Valk, A. G.; Davis, C. B. (1978). "The role of seed banks in the vegetation dynamics of prairie glacial marshes". Ecology. 59 (2): 322–35. doi:10.2307/1936377. JSTOR   1936377.
  14. ↑ Leck, Mary Allessio; Simpson, Robert L. (1995). "Ten-year seed bank and vegetation dynamics of a tidal freshwater marsh" (PDF). American Journal of Botany. 82 (12): 1547–1557. doi:10.2307/2446183. hdl: 2027.42/141113 . JSTOR   2446183.
  15. ↑ Shipley, B.; Keddy, P.A.; Moore, D.R.J.; Lemky, K. (1990). "Regeneration and establishment strategies of emergent macrophytes". Journal of Ecology. 77 (4): 1093–1110. doi:10.2307/2260825. JSTOR   2260825. Appendix 3.
  16. ↑ Boutin, C.; Keddy, P. A. (1993). "A functional classification of wetland plants". Journal of Vegetation Science. 4 (5): 591–600. doi:10.2307/3236124. JSTOR   3236124. Figure 2
  17. ↑ "Code of Federal regulations, title 21".
  18. ↑ Ginwal, HS, An efficient genomic DNA isolation protocol for RAPD and SSR analysis in Acorus calamusL.
  19. ↑ Evstatieva et al., Fitologiya 48: 19–22. 1996; Löve & Löve, Proc. Genet. Soc. Canada 2: 14–17. 1957
  20. ↑ Marongiu, L.B; Piras, A; Porcedda, S (2005). "Chemical composition of the essential oil and supercritical CO2 extract of Commiphora myrrha (Nees) Engl. and of Acorus calamus". Journal of Agricultural and Food Chemistry. 53 (20): 7939–43. doi:10.1021/jf051100x. PMID   16190653.
  21. ↑ (Rost and Bos, 1979)
  22. ↑ Antimicrobial activities of the crude methanol extract of Acorus calamus Linn., S Phongpaichit, N Pujenjob, J. Songklanakarin
  23. ↑ Radušienė, J.; Judžentienė, A.; Pečiulytė, D.; Janulis, V. (2007). "Essential oil composition and antimicrobial assay of Acorus calamus leaves from different wild populations". Plant Genetic Resources. 5: 37–44. doi:10.1017/S1479262107390928. S2CID   86085313.

Bibliography

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