''Oryza'' is a

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

of plants in the

grass family Poaceae ( ), also called Gramineae ( ), is a large and nearly ubiquitous family of monocotyledonous flowering plants commonly known as grasses. It includes the cereal grasses, bamboos, the grasses of natural grassland and species cultivated in ...

. It includes the major food crop

rice Rice is a cereal grain and in its Domestication, domesticated form is the staple food of over half of the world's population, particularly in Asia and Africa. Rice is the seed of the grass species ''Oryza sativa'' (Asian rice)—or, much l ...

(species ''

Oryza sativa ''Oryza sativa'', having the common name Asian cultivated rice, is the much more common of the two rice species cultivated as a cereal, the other species being ''Oryza glaberrima, O. glaberrima'', African rice. It was History of rice cultivation ...

'' 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 In agriculture, it has largely been replaced by higher-yielding Asian ric ...

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

wetland A wetland is a distinct semi-aquatic ecosystem whose groundcovers are flooded or saturated in water, either permanently, for years or decades, or only seasonally. Flooding results in oxygen-poor ( anoxic) processes taking place, especially ...

grasses, growing to tall; the genus includes both annual and

perennial In horticulture, the term perennial ('' per-'' + '' -ennial'', "through the year") is used to differentiate a plant from shorter-lived annuals and biennials. It has thus been defined as a plant that lives more than 2 years. The term is also ...

species. ''Oryza'' is situated in tribe

Oryzeae Oryzeae is a Tribe (biology), tribe of flowering plants in the true grass family, Poaceae. It contains 11 genera, including both cultivated rice (''Oryza'') and wild rice (''Zizania''). Genera There are 11 genera classified in two subtribes: ...

, 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 an ...

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 (listed after each species name below). They include the

diploid Ploidy () is the number of complete sets of chromosomes in a cell, and hence the number of possible alleles for autosomal and pseudoautosomal genes. Here ''sets of chromosomes'' refers to the number of maternal and paternal chromosome copies, ...

(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 two paired sets of ( homologous) chromosomes. Most species whose cells have nuclei (eukaryotes) are diploid, meaning they have two complete sets of chromosomes, one fro ...

(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 ''Oryza australiensis'' is a wild rice species native to monsoonal northern Australia. Also known as Australian rice or Australian Wild Rice, it is a perennial plant that uses the C3 photosynthesis pathway. ''O. australiensis'' is unique among ot ...

'' (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 ''Oryza longistaminata'' is a perennial species of grass from the same genus as cultivated rice (''O. sativa''). It is native to most of sub-Saharan Africa and Madagascar. It has been introduced into the United States, where it is often regarded ...

'' (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 ''Oryza officinalis'' is species of flowering plant in the genus ''Oryza'' (rice) native to India, Nepal, the eastern Himalaya, southeast Asia, south-central and southeast China, Hainan, the Philippines, New Guinea, and the Northern Territory and ...

'' (CC) – China, Indian Subcontinent, Southeast Asia, New Guinea, Australia # '' Oryza punctata'' (BB) – Madagascar, tropical + southern Africa # ''

Oryza ridleyi ''Oryza'' is a genus of plants in the grass family. It includes the major food crop rice (species ''Oryza sativa'' and ''Oryza glaberrima''). Members of the genus grow as tall, wetland grasses, growing to tall; the genus includes both annual a ...

'' (HHJJ) – Southeast Asia, New Guinea # ''

Oryza rufipogon ''Oryza rufipogon'' is a species of flowering plant in the family ''Poaceae''. It is known as brownbeard rice, wild rice, and red rice. In 1965, ''Oryza nivara'' was separated off from ''O. rufipogon''. The separation has been questioned, a ...

'' (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 are 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 ''Leersia'' is a genus of plants in the grass family which includes species known generally as cutgrasses. The genus is widespread across many countries on all the inhabited continents. It was named for the German botanist Johann Daniel Leers ...

'' *'' Maltebrunia'' *''

Potamophila ''Potamophila'' is a genus of Australian plants in the Poaceae, grass family. The only known species is ''Potamophila parviflora''.Ge, S., et al. (2002)A phylogeny of the rice tribe Oryzeae (Poaceae) based on matK sequence data.''American Journ ...

'' *'' Prosphytochloa'' *'' Rhynchoryza''

References

{{Authority control Poaceae genera Taxa named by Carl Linnaeus

Species

Formerly included

See also

References