Final Activity Report Summary - MODELLING FLOWERS (Examining Arabidopsis floral organ number patterning using a dynamic computer model) The overall aim of the project was to gain a detailed understanding of floral growth and build a virtual model of this growth. In the long run, such models, infused with sufficient detail and complexity, should provide a way to make predictions about floral growth, e.g. about the diverse floral forms existing in nature, that could not easily be experimentally tested. In order to simplify a complex task, the initial phase of the project focused on sepal development, which is the very first morphological feature to arise on a flower. The early stages of floral growth were somewhat akin to an expanding balloon, and my first challenge was to be able to follow events on every side of the balloon as it grew in size. I developed a way to follow cell behaviour on every aspect of a developing flower over several days. In collaboration with computer scientists, these data were used to create detailed three-dimensional images of each stage of floral growth at cellular resolution. The next step of the experiment was to integrate differentiation data into these models and attempt to use simplified growth hypotheses to simulate the growth of this realistic flower on a computer.