An account is presented of the results of crossing O. sativa (2n=24) with O. latifolia (2n=48), the characteristics of the F, hybrids as compared with those of the parents, and cytological observations on the F1 hybrids. The F1. plants and three F2 plants which were raised were highly sterile. All F 1 plants examined had 2n=36 chromosomes. Degeneration of archesporial and pollen mother cells and various meiotic abnormalities were observed.