An attempt is made to investigate the formation of the exine pattern with SEM, during pollen development after release from the tetrad inHemerocallis middendorffiiTrautv. & Meyer var.esculenta(Koidz.) Ohwi. The microspore wall immediately after release from the tetrad is verrucose. It develops gradually into a reticulate structure by elongation and longitudinal division of the muri, in relation to an increase in volume of the microspore after dissociation of the tetrad.