Ferns are the second most diverse group of vascular plants and are globally distributed across a wide variety of habitats including deserts, savannahs, temperate understories, and montane cloud forests. Numerous studies have shown that ferns have evolved a diverse array of adaptive forms and functions that drive species ecology and spatial fern biodiversity patterns.  However, the majority of research has focused on the sporophyte generation and relatively less attention has been paid to contribution of fern gametophyte form and function to fern biodiversity patterns. Here, I present preliminary evidence for the global convergence in fern gametophyte functioning from 10 fern species distributed among continents and diverse biomes. Specifically, I show that fern gametophyte photobiology can be predicted by a species’ native climate including water, temperature, and soil related factors. In addition, I uncovered aspects of fern gametophyte physiology that have not been observed in fern sporophytes such as the strong relationships between key aspects of carbon and water dynamics. The clear and strong relationships among physiological traits in fern gametophytes may represent a novel dimension of fern function, and ongoing work will shed light on the structural and physiological mechanisms that underlie these trait and ecological patterns in ferns.