Genus of Brassicaceae plants
Odontarrhena is a large genus of flowering plants in the family Brassicaceae. They were originally a separate genus and then were amalgamated into the "Alyssum" genus, but then morphological and molecular evidence has reseperated them. Some of the genera are nickel (Ni) hyperaccumulators (a plant capable of growing in soil or water with very high concentrations of metals).
Description.
It is similar in habit to "Alyssum" and has small yellow flowers, except that it has a suborbicular pouch and one seeded cells.
The plants are characterised by inflorescences that are usually compound, subumbellate racemes. There is a single ovule per loculus, and the fruit valves are at most only slightly inflated.
Range.
Its widespread native range is from temperate Eurasia to subarctic America. It is found in Europe (within Albania, Bulgaria, Corsica, Crete, Czechoslovakia, East Aegean Islands, France, Greece, Hungary, Italy, Romania, Sardina, Sicily, Switzerland and Yugoslavia), Eastern Europe (within Central European Russia, Crimea, East European Russia, North European Russia, South European Russia and Ukraine), Siberia (within Altai, Buryatiya, Chita Oblast, Irkutsk Oblast, Krasnoyarsk Krai, Tuva, West Siberia and Yakutskiya), the Russian Far East (within Amur Oblast, Khabarovsk Krai and Magadan Oblast), Central Asia (within Kazakhstan and Turkmenistan), the Caucasus (North Caucasus and Transcaucasus), Western Asia (Afghanistan, Cyprus, Iran, Iraq, Lebanon, Palestine, Saudi Arabia, Syria and Turkey), China (Inner Mongolia, Manchuria and Xinjiang), Mongolia and also Subarctic America (within Alaska, Northwest Territories and the Yukon).
The Balkan Peninsula is a major diversity center. Greece has the largest number of species; next, Albania is known to have 7 species. It is also found on the serpentine soils of Lesbos Island (in Greece).
Taxonomy.
"Odontarrhena" was a taxonomically difficult genus of the tribe "Alysseae". However, recent morphological and molecular evidence (DNA analysis) clearly showed that "Alyssum" and "Odontarrhena" are monophyletic clades within the tribe "Alysseae", deserving separate generic status (Warwick et al. 2008; Cecchi et al. 2010; Rešetnik et al. 2013; Li et al. 2015).
The genus name of "Odontarrhena" is derived from two Greek words; "odous" meaning tooth and "arrhen" meaning male.
It was first described and published by Carl Anton von Meyer in Flora Altaica (edited by Carl Friedrich von Ledebour) Vol.3 on page 58 in 1831.
The genus is recognized by the United States Department of Agriculture and the Agricultural Research Service, but they still list it as synonym of "Alyssum" L. and they only list "Odontarrhena obovata" C. A. Mey. as a known species.
Known species.
The following list includes all species recognised by either Plants of the World Online (as of January 2022) or by "BrassiBase" (version 1.3, June 2020). Of these, 80 species are recognised by both databases, with the remaining 16 accepted by only one of them (this is indicated in each entry).
Uses.
About 48 members of the "Odontarrhena" species, are known to be nickel (Ni) hyperaccumulators (a plant capable of growing in soil or water with very high concentrations of metals). The accumulation of nickel was first discovered in the Italian endemic "Odontarrhena bertolonii" (Desv.) Jord. and Fourr. (syn. "Alyssum bertolonii" Desv. by Minguzzi and Vergnano in 1948, Of the 168 or so species of "Alyssum", 45 species were determined to be hyperaccumulators of nickel, all from the Odontarrhena section. The metal is found in the roots, stem, leaves and flowers of the plant.
References.
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