• Rice -;
  • Oryza -;
  • biosystematics -;
  • evolution -;
  • variability.

In order to clarify the taxonomy and the interrelationships among Asiatic cultivated rice, Oryza sativa, and its related wild species (O. rufipogon, O. nivara and O. barthii), 41 morphological characters were examined. Numerical taxonomic methods were used to analyse the data and to illustrate species relationships.

Distinctive differences among the materials studied suggest the retention of O. rufipogoon, O. nivara and O. sativa as three distinct species. The origin of O. sativa from O. nivara through domestication is discussed. An annual wild taxon from Australia, which had been classified as a form of O. nivara, is shown to be distinct from typical O. nivnra and is raised to specific rank. This species has been named O. meridionalis Ng.