The serendipitous discovery that salinity stress can induce a switch from C3 photosynthesis to Crassulacean acid metabolism (CAM) in the Aizoaceae Mesembryanthemum crystallinum has instigated a wide range of ecophysiological, biochemical, and molecular genetic studies aimed at understanding the mechanistic basis of this phenomenon. The underlying changes in gene expression that initiate CAM induction are influenced by the interaction of environmental and developmental factors resulting in an extremely plastic adaptation. M. crystallinum holds the notable distinction of being one of the few true halophytes among inducible CAM species. The peculiarity has resulted in M. crystallinum becoming a favored model for genetic and molecular genetic studies.