The molecular mechanisms that direct chloroplast division are poorly understood. One clue regarding the constitution of the plastid division apparatus came with the recent discovery of an Arabidopsis nuclear gene that encodes a plastidic homolog of FtsZ, a major cytoskeletal component of the bacterial cell division machinery. On pages 1991-2004, Osteryoung et al. now show that Arabidopsis expresses a second form of FtsZ. Like the plastid-localized form, this putative cytosolic form is required for chloroplast division in higher plants. This point is illustrated on the cover, which depicts the mesophyll cell phenotypes typical of transgenic Arabidopsis plants expressing antisense constructs of either FtsZ form (bottom images) together with that of a cell from a wild-type plant (top). The authors postulate that the two forms of FtsZ act coordinately on opposite sides of the chloroplast envelope membranes to achieve constriction and division of the organelle. (Image generated by Stanislav Vitha.)