Epiphytic fungus

An epiphytic fungus is a fungus that grows upon, or attached to, a living plant. The term epiphytic derives from the Greek epi- (meaning 'upon') and phyton (meaning 'plant').

Examples
Many examples of epiphytic microorganisms exist. The ergoline alkaloids found in Convolvulaceae are produced by a seed-transmitted epiphytic clavicipitaceous fungus.