Among four species of Clusiaceae (sensu lato) occurring in a mosaic of different types of tropical vegetation, Kielmeyera coriacea Mart. & Zucc. and Calophyllum brasiliense Camb. were C3-species with similar performance at micro-sites of contrasting water supply, Clusia criuva Cambess—although potentially a C3/CAM intermediate species—performed C3-photosynthesis, while Clusia arrudea Planchon & Triana ex Engl. performed C3-photosynthesis or CAM-cycling depending on site characteristics and dry or wet season. Depending on individual species, C3-photosynthesis proves to be a suitable option at a variety of environmental conditions, while CAM-cycling appears to be an escape under more severe stress. In this ecophysiological field work, we investigated possible microhabitat-dependent expression of modes of photosynthesis among species of Clusiaceae (sensu lato) in a mosaic of tropical vegetation. The study site was in the Serra de Sao Jose (21°08’S, 44°17′W; in the municipality of Tiradentes, state of Minas Gerais, SE-Brazil). The mosaic of tropical vegetation types was made up of rupestrian grasslands, cerrado, small rock outcrops, and riverine and gallery forest alongside a small river. Four species were measured, namely C. criuva Camb., C. arrudea Planchon & Triana ex Engl., K. coriacea Mart. & Zucc., and C. brasiliense Camb. K. coriacea and C. brasiliense performed C3-photosynthesis with midday depressions and reversible acute photoinhibition in response to varying environmental conditions related to habitat types and wet and dry seasons, respectively. The C3/CAM intermediate C. criuva also performed C3-photosynthesis with midday depression and acute photoinhibition. It appeared not to be stressed enough to switch to its intrinsic CAM option. In contrast, while C. arrudea under favourable conditions in the gallery forest and the wet season also performed C3-photosynthesis, under drier conditions, it used CAM-cycling. For particular species, realization of CAM-options is a possibility of acclimation. Other species contemporarily may rely on different alternatives such as plastic performance of C3-photoynthesis. At the microsite level, overlapping functional diversity of species and diversity of habitats contributes to the complexity of this vegetation type.