Abstract
The localization of callose in the cell walls of megasporocytes and megaspores was studied by means of fluorescence microscopy. It was found that the part of the meiocyte cell wall in which callose begins to appear corresponds to the region of active megaspore formation. During the whole megasporogensis more of callose was found in walls of such cells which differentiate afterwards. For different species the pattern of callose distribution in walls during megasporogenesis is a constant specific trait.