This cluster of papers explores the evolution, diversity, and ecological significance of vascular epiphytes and ferns, with a focus on phylogeny, adaptive radiation, biogeography, and ecological strategies. It delves into the relationships between epiphytes and their host trees, the impact of climate change on canopy communities, and the physiological ecology of vascular epiphytes. The cluster also addresses topics such as polyploidy, gametophyte ecology, and the morphological evolution of ferns.