Professor Marilyn Ball has an international reputation based on achievements in an unusually wide range of topics, all aimed at linking physiological mechanisms of stress tolerance with larger scale patterns in whole plant structure and function along complex environmental gradients. Her work has advanced understanding of plant function in complex, highly variable environments. Her research achievements include seminal studies of salinity tolerance in relation to mangrove ecology, the first linkage of cold-induced photoinhibition with regeneration in temperate evergreens, the discovery that elevated CO2 enhances freezing stress, and discovery of a novel interaction between plants, namely that alteration of the thermal environment can be a major component of competitive interactions between grass and trees.