Abstract: Structural details of the megaspores both in situ, preserved within one kind of spore-bearing organs previously assigned to Annalepis zeilleri Fliche, and in dispersal, found from the samematrix as these plant remains preserved in, have been investigated based on the fossil specimens from one bed in the bottom of the mid-Triassic Ermayin Formation at only one locality in Wupuxian district of Shaanxi Province, China. A continutous succession in morphological and structural changes of the megaspores has been obtained and as a result, a series of megasporegennic stages might be preliminarily elacidated as follows: the immature "nexine" stage, the mature Dijkstraisporites stage, the germinating Banksisporites stage when the sporodermis loosing after the megaspore had detached. In addition, Laevigatisporites-type megaspore may be abortive.