The distribution of highly de-esterified homogalacturonans (HGs) in dividing protodermal cells of the monocotyledon , the dicotyledon , and the fern was investigated in order to examine whether the cell wall region adjoining the preprophase band (PPB) is locally diversified. Application of immunofluorescence revealed that de-esterified HGs were accumulated selectively in the cell wall adjacent to the PPB in: (a) symmetrically dividing cells of stomatal rows of , (b) the asymmetrically dividing protodermal cells of , (c) the symmetrically dividing guard cell mother cells (GMCs) of and , and (d) the symmetrically dividing protodermal cells of . A common feature of the above cell types is that the cell division plane is defined by extrinsic cues. The presented data suggest that the PPB cortical zone-plasmalemma and the adjacent cell wall region function in a coordinated fashion in the determination/accomplishment of the cell division plane, behaving as a continuum. The de-esterified HGs, among other possible functions, might be involved in the perception and the transduction of the extrinsic cues determining cell division plane in the examined cells.