In plants, recruitment of leaf founder cells from the shoot apical meristem(SAM) coincides with development and differentiation along the three axes -mediolateral, proximodistal and dorsoventral - of the leaf primordium. How these axes form remains unclear but on p. 2827 Nardmann et al. report that a homeobox gene function, which is conserved between monocots and dicots, initiates meristematic cells to become founder cells in a specific lateral domain of the SAM. The researchers identify this homeobox gene function in the monocot maize, where it is encoded by narrow sheath1and narrow sheath2 (ns1 and ns2), through the homology of these genes to PRESSED FLOWER (PRS), a homeobox gene involved in flower development in Arabidopsis, a dicot plant. Their observation that Arabidopsis leaves lacking PRS function have a previously unreported subtle abnormality contrasts with the obvious narrow sheath phenotype of maize mutants, and these divergent roles provide new insights into the evolution of leaf morphology