The development of plant leaves.

Most leaves appear simple at first sight and they consist of only a few cell types. Despite that, many developmental processes are involved in leaf ontogeny, including positioning and initiation of leaf primordia, specification of leaf identity, establishment of dorsiventrality, the control of cell division and expansion, and pattern formation. This report highlights and reviews some of what we know about the genetic circuitry that underlies leaf form, as discussed at a workshop on “Leaf Development” held February 11 through 13, 2002, at the Instituto Juan March (Madrid).