This study investigated the foliar plasticity in Schwartzia brasiliensis in restinga formations (shrub and shrub-tree
restinga) in southern Brazil. In each area, 10 individuals were selected and leaves in sunlight were collected for
an analysis of functional leaf traits, including: fresh and dry leaf mass, leaf area, specific leaf area, succulence,
stem diameter, plant height and tissue thickness. Environmental variables were measured considering soil
mineral nutrition, water availability and photosynthetically active radiation. Phenotypic plasticity index was
calculated for studied attribute. We compared means with a Student’s t-test and the weight of environmental
variables with a PCA. Results showed that the main leaf traits that differentiated the populations were leaf dry
mass, specific leaf area, lamina thickness and plant height, while the main predictor environmental variables
were gravimetric humidity, solar radiation, soil CEC, phosphorus content and salinity. In the shrub restinga,
there is greater investment in mechanical support as a water saving strategy due to greater exposure to solar
radiation. In the shrub-tree restinga, there is greater investment in photosynthetic production, since the shade
provided by the treetops of other species attenuates the radiation effect. Despite the low plastic potential, the
populations present structural adjustments that respond to the environmental heterogeneity.

Palavras-chave: ecological anatomy, environmental heterogeneity, functional leaf traits.