Oryza sativa

Rice ( Oryza ) is a plant genus of the family Gramineae ( Poaceae ) with 24 species. It is distributed in warm regions worldwide.

Of great importance for the production of the food rice has mainly the type of rice Oryza sativa; As the only other rice species Oryza glaberrima is an endemic to Africa kind, grown mainly in West Africa.


The plants grow annual or perennial, the stems are erect or upward growing in tufts or short rhizomes. The broad - linear, flat leaf blades grow mainly on the upper part of the culm, the membranous ligule is found sometimes extended.

The inflorescence is a composed of numerous spikelets composing, often nodding panicle with short flower stems, which is either not or only slightly branched at the bottom of or arranged in whorls. The spikelets have only vestigial glumes and consist of three florets, the lower two of which are sterile and consist of only a small per lemma near the base of the fertile flower. This is laterally strongly flattened and is located in the armpit of a boat-shaped, keeled and striking five-core lemma, which is usually leathery and papillose, sometimes pointed, and in some species bears a long, straight awn. The palea is the lemma similar but narrower, three-core and runs like a beak to. There are six stamens present in two circles. The fruit is a caryopsis, whose shape varies greatly between species. The spikelet is thrown above the glumes, which remain as lobate hem after seed maturity, except in the cultivated varieties, where it remains on the plant.

The chromosome number is x = 12


The species of the genus are native to the warm regions of Africa, Asia, Australia and Central and South America.

Types (selection)

The genus includes 24 species, including:

  • Oryza australiensis
  • Oryza barthii
  • Oryza brachyantha
  • Oryza eichingeri
  • Oryza glumaepatula
  • Oryza glaberrima
  • Oryza grandiglumis
  • Oryza latifolia
  • Oryza longiglumis
  • Oryza longistaminata
  • Oryza meridionalis
  • Oryza meyeriana
  • Oryza minuta
  • Oryza neocaledonica
  • Oryza Nivara
  • Oryza officinalis
  • Oryza punctata
  • Oryza rhizomatis
  • Oryza ridleyi
  • Oryza rufipogon
  • Oryza sativa
  • Oryza schlechteri