''Oryza'' is a

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nom ...

of plants in the grass family. It includes the major food crop

rice Rice is the seed of the grass species '' Oryza sativa'' (Asian rice) or less commonly ''Oryza glaberrima'' (African rice). The name wild rice is usually used for species of the genera '' Zizania'' and '' Porteresia'', both wild and domesticat ...

(species ''

Oryza sativa ''Oryza sativa'', commonly known as Asian rice or indica rice, is the plant species most commonly referred to in English as ''rice''. It is the type of farmed rice whose cultivars are most common globally, and was first domesticated in the Yan ...

'' and ''

Oryza glaberrima ''Oryza glaberrima'', commonly known as African rice, is one of the two domesticated rice species. It was first domesticated and grown in West Africa around 3,000 years ago. In agriculture, it has largely been replaced by higher-yielding Asian r ...

''). Members of the genus grow as tall,

wetland A wetland is a distinct ecosystem that is flooded or saturated by water, either permanently (for years or decades) or seasonally (for weeks or months). Flooding results in oxygen-free (anoxic) processes prevailing, especially in the soils. The p ...

grasses, growing to tall; the genus includes both

annual Annual may refer to: *Annual publication, periodical publications appearing regularly once per year ** Yearbook ** Literary annual *Annual plant *Annual report *Annual giving *Annual, Morocco, a settlement in northeastern Morocco *Annuals (band), ...

and

perennial A perennial plant or simply perennial is a plant that lives more than two years. The term ('' per-'' + '' -ennial'', "through the years") is often used to differentiate a plant from shorter-lived annuals and biennials. The term is also wid ...

species. ''Oryza'' is situated in tribe

Oryzeae Oryzeae is a tribe of flowering plants in the true grass family, Poaceae. It contains 11 genera, including both cultivated rice ('' Oryza'') and wild rice Wild rice, also called manoomin, Canada rice, Indian rice, or water oats, is any of ...

, which is characterized morphologically by its single-flowered spikelets whose

glumes In botany, a glume is a bract (leaf-like structure) below a spikelet in the inflorescence (flower cluster) of grasses (Poaceae) or the flowers of sedges (Cyperaceae). There are two other types of bracts in the spikelets of grasses: the lemma and ...

are almost completely suppressed. In ''Oryza'', two sterile lemma simulate glumes. The tribe Oryzeae is in subfamily Ehrhartoideae, a group of Poaceae tribes with certain features of internal leaf anatomy in common. The most distinctive leaf characteristics of this subfamily are the arm cells and fusoid cells found in their leaves.Heywood, V.H. Flowering Plants of the World 1993 Oxford University Press One species, Asian rice ( ''O. sativa''), provides 20% of global grain and is a food crop of major global importance. The species are divided into two subgroups within the genus.

Species

Inside the genus ''Oryza'', species can be divided by their genomes types. They include the diploid (2n = 24) of cultivated rice and their relatives, , , , and as well as the

tetraploid Polyploidy is a condition in which the cells of an organism have more than one pair of ( homologous) chromosomes. Most species whose cells have nuclei (eukaryotes) are diploid, meaning they have two sets of chromosomes, where each set contains ...

(4n = 48) , , , and . Species of the same genome type cross easily, while hybridizing different types requires techniques like embryo rescue. Over 300 names have been proposed for species, subspecies, and other infraspecific taxa within the genus. Published sources disagree as to how many of these should be recognized as distinct species. The following follows the World Checklist maintained by Kew Garden in London. * '' Oryza australiensis'' (EE) – Australia * '' Oryza barthii'' (AA) – tropical Africa * '' Oryza brachyantha'' (FF) – tropical Africa * '' Oryza coarctata'' (KKLL) – India, Pakistan, Bangladesh, Myanmar * '' Oryza eichingeri'' (CC) – tropical Africa, Sri Lanka * ''

'' (AA) – African rice – tropical Africa * '' Oryza grandiglumis'' (CCDD) – Brazil, Venezuela, Fr Guiana, Colombia, Peru, Bolivia * '' Oryza latifolia'' (CCDD) – Latin America + West Indies from Sinaloa + Cuba to Argentina * '' Oryza longiglumis'' (HHJJ) – New Guinea * '' Oryza longistaminata'' (AA) – Madagascar, tropical + southern Africa * '' Oryza meyeriana'' (GG) – China, Indian Subcontinent, Southeast Asia * '' Oryza minuta'' (BBCC) – Himalayas, Southeast Asia, New Guinea, Northern Territory of Australia * '' Oryza neocaledonica'' (GG) – New Caledonia * '' Oryza officinalis'' (CC) – China, Indian Subcontinent, Southeast Asia, New Guinea, Australia * '' Oryza punctata'' (BB) – Madagascar, tropical + southern Africa * '' Oryza ridleyi'' (HHJJ) – Southeast Asia, New Guinea * ''

Oryza rufipogon ''Oryza rufipogon'', known as brownbeard rice, wild rice, and red rice, is a member of the genus ''Oryza''. It is native to East, Southeast and South Asia. It has a close evolutionary relation to ''Oryza sativa'', the plant grown as a major rice ...

'' (AA) – brownbeard or red rice – China, Indian Subcontinent, Southeast Asia, New Guinea, Australia * ''

'' (AA) – Asian rice – China, Indian Subcontinent, Japan, Southeast Asia; naturalized many places * '' Oryza schlechteri'' (HHKK) – New Guinea

Formerly included

Many species now regarded as better suited to other genera: *

Echinochloa ''Echinochloa'' is a very widespread genus of plants in the grass family and tribe Paniceae. Some of the species are known by the common names barnyard grass or cockspur grass. Some of the species within this genus are millets that are grown ...

* Leersia * Maltebrunia * Potamophila * Prosphytochloa *

Rhynchoryza ''Rhynchoryza'' is a genus of plants in the grass family.Rosengurtt, B., B. R. A. Maffei & P. I. Artucio. 1970. Gramíneas Uruguayas –vii 1–489. Universidad de la República, Montevideo The only known species is ''Rhynchoryza subulata'', nat ...

References

Poaceae genera Taxa named by Carl Linnaeus {{Poaceae-stub

Species

Formerly included

See also

References