Epiphytes are a distinct group in the Earth's carbon cycling ecosystems. Most vascular epiphytes are from the particularly species-rich orchid family (Orchidaceae), with about 70% of Orchidaceae species being epiphytes. Crassulacean Acid Metabolism (CAM) is a water-conserving carbon dioxide (CO2) fixation pathway, and Epiphytes with CAM photosynthesis are widespread in vascular plants.
