Cycads are an ancient lineage that originated more than 200 million years ago. During their long evolutionary history, cycads have survived tremendous changes in Earth's climate and landscape, yet little is known about how cycads cope with environmental stress. Here, we examine the anatomical, morphological, and physiological determinants of plant function in the ecologically diverse cycad genus, Ceratozamia. Specifically, this study aims to link how anatomical features promote or constrain plant function and how function and stress responses drive ecological patterns of 18 species of Ceratozamia. In a common garden, we measured stomatal and hydraulic anatomy, and gas-exchange response curves, and performed linear regressions in relation to native environmental factors. Linear regressions have shown no correlation between stomatal size (SS) and density (DS), in contrast to most other plant groups. We found that variation in maximum stomatal conductance was driven by stomatal density, not stomatal size. We also found vein density and leaf hydraulic conductance to be strongly correlated with native environmental conditions related to water-availability and drought. These relationships point to underlying traits that have shaped the stomatal function and the regulation of plant water-status in this plant group. Additional analyses will shed light on the mechanisms that drive stomatal responses to rapid changes in environment and the potential adaptive value of variation in stomatal regulation in this group. Stress response data in cycads provide a deeper understanding of the connection between environmental stressors and trait adaptation which could aid in the conservation of this genus.