In developing epidermal tissue ofPhaseolus vulgare L. complete plasmodesmatal connections occurred between guard cells and epidermal cells and between sister guard cells of a stoma but they were not seen in fully differentiated tissue. However, incomplete, aborted plasmodesmata were occasionally seen in the common guard/epidermal cell wall, usually connected to the epidermal cell protoplast, in mature tissue. Plasmodesmatal connections between neighbouring epidermal cells were commonly observed in tissue at all stages of development. In all locations, the plasmodesmata were usually unbranched occurring singly or in small pit fields; very rarely branched, incomplete plasmodesmata were also seen in the wall between mature guard and epidermal cells. The significance of these findings were related to stomatal functioning and to the development of plasmodesmata in general.