YIBS’ new Program on the Evolution of Flower Form and Function (EF3) brings together diverse scientific disciplines to address the evolution of one of the most innovative and transformative structures on the planet: flowers. Flowers have promoted the rapid diversification of both plants and animals, and they form the basis of the global food supply. Recent evidence suggests that the incredible diversity of flowers apparent today may be due to key innovations that happened early in the evolution of flowering plants. By applying physiological and biomechanical approaches, EF3 will characterize these physiological innovations and elucidate the constraints on floral design that have evolved over the last ~150 million years. Furthermore, it will develop approaches for predicting floral physiological functioning in the future.