Premise of research. Structure-function relationships of xylem in tropical fern species remain poorly explored despite the taxonomic diversity and ecological importance of ferns in tropical environments. The aim of this study is to broaden our understanding of how tropical fern morphology and anatomy are influenced by light availability.Methodology. Nine fern species, including six shade-tolerant species, two sun-exposed species, and one species with representatives in both light conditions, were studied in order to investigate the impact of light exposure on leaf morphology and xylem anatomy. Measured parameters included water potential and micromorphology based on light and electron microscopy.Pivotal results. Canopy openness was significantly correlated with specific leaf area, basic specific gravity, venation density, pit membrane area, pit aperture area, and pit membrane thickness. Intraspecific variation within Pteris quadriaurita showed that leaf morphological features such as petiole length and di...