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 and they only list Odontarrhena obovata as a known species.