The cell wall at the tetrad stage in <em>Convallaria majalis</em> L. has been studied by light microscope histochemical techniques. The standard PAS reaction has shown the persistence of the primary pecto-cellulosic pollen mother cell wall localized around the callosic special wall (determined both by Bauer's reaction and the fluorescence technique with aniline blue) of individual tetrcds. A PAS-positive spore precursor wall (primexime) is formed while the tetrad of microspores is still enclosed by intact callose and pollen mother cell walls. The pecto-cellulosic wall and callose layer dissolve simultaneously to release the microspores into another loculi.