This book provides a general presentation of knowledge and methods in mathematical modelling and simulation of individual plants. The chapters mainly describe the algorithms of mathematical modelling, simulation and computer visualization and prospective aspects related to future developments of plant models. The book highlights the concepts coming from different disciplines and their mathematical integration to build robust, calibrated, and realistic integrative modeling solutions. Its original and groundbreaking focus is on the integration of structural and functional modeling for a living system such as a whole plant (or a crop field, a forest): most of the time, it has been believed among modeling practitioners that choices have to be made between the two, this belief no more prevails in the era of integrative (well-conceptually grounded) simulations. The content of this book is sufficient for a non-specialist to understand the fundamentals of mathematical modelling of plant architecture. Readers or even software developers can supplement their knowledge by consulting the book.