In humans and other mammals, it is our bones that give form to our bodies and enable our muscles to exert force. Insects have a hard exoskeleton for the same reason. But plants?from flowers to trees?are different. Their structure comes from bundles of cellulose biomolecules that form microfibers, which combined with other materials including lignin make up the walls of plant cells. These walls are so strong that they essentially act as a skeleton. Indeed, cellulose-rich cell walls enable a slender stalk of corn to grow 6 or 8 feet tall and a giant Sequoia to tower more than 300 feet, dwarfing any other life form. Cellulose is the most abundant (and arguably the most important) long-chain biomolecule on earth. Until recently, however, cellulose?both its structure and how plants make it?was a mystery. That?s why the U.S. Department of Energy?s Office of Science funded an Energy Frontier Research Center (EFRC) to explore the topic and its implications for advanced plant-based materials and biofuels. The Center for Lignocellulose Structure and Formation included a dozen principal investigators spread across a number of universities, including physicists and engineers as well as plant biologists.