Abstract: A collection made in October showed two well developed mi-crosporangia, borne on the ventral surface of each microsporophyll. A mass sporogenous cells wwere dividing within the microsporangium. In the following spring, at end of January to early February, the microspore mother cells were beginning for reduction division. During the reduction division period, the distribution of starch grains change. The formation of tetrads at the early February, and tapetal were gradually disintegrated. The formation of uninu- cleate pollen grain at the middle of February. The pollen grain soon develops two extensions of the exine whlich form the two wings. lt is heteroplar and radiosymtnetric. The pollen in shed at the four-celled stage in March.

Key words: P. yunnanensis