Abstract
At the stage of diakinensis and metaphase of the first meiotic division, conjugating chromosomes in the form of bivalents were always observed. At the pre-meiotic stage some of .the mother pollen cells underwent degeneration (in 'Australian' var. 17% in 'Warminska' 20%, in 'Kleszczewska' 23%, in 'Grimma' 30% and in 'Miechowska' 40%). In the degenerating mother pollen cells no meiotic division were observed. In the surviving mother pollen cells, meiotic division were found to be normal. The mature pollen grains were trinucleate.