The Evolution of CAM Photosynthesis in Australian Calandrinia Reveals Lability in C3+CAM Phenotypes and a Possible Constraint to the Evolution of Strong CAM

Australian Calandrinia has radiated across the Australian continent during the last 30 Ma, and today inhabits most Australian ecosystems. Given its biogeographic range and reports of facultative Crassulacean acid metabolism (CAM) photosynthesis in multiple species, we hypothesized (1) that CAM would be widespread across Australian Calandrinia and that species, especially those that live in arid regions, would engage in strong CAM, and (2) that...