Anthers of Allium cepa and Rhoeo discolor , excised at leptotene-zygotene and diplotene-diakinesis, have been cultured in modified White's medium supplemented with different concentrations of ribonucleic acid and desoxyribonucleic acid. The best development was obtained with ribonucleric acid in which there was a 100 per cent. survival of the microspore mother cells up to the formation of 1-celled microspores. In R. discolor , the time taken by the microspore mother cells to form tetrads in vitri was half of that required in nature. All attempts to induce division of the microspore nucleus in vitro failed.