The molecular mechanisms whereby leaf founder cells initiate from shoot apical meristems (SAMs) and differentiate along three developmental axes in plant systems is the focus of this project. Leaves are the ground state lateral organs of plant shoots; inflorescence and floral organs result from modification(s) of the leaf developmental blueprint. However, the mechanisms of leaf organogenesis are not well understood. This project is utilizing higher-order mutations of WOX3 genes in maize (the duplicate genes NS1 & NS2 and the paralogs WOX3a and WOX3B), clonal analyses of WOX3 function during shoot ontogeny, and live imaging of tagged WOX3~reporter homologs in Brachypodium to understand the mechanisms whereby leaves grow wide and flat.