epiphyte

noun2

1. •
   A plant that grows on another, using it for physical support but obtaining no nutrients from it and neither causing damage nor offering benefit.

   • The nature of the surface of a plant also determines the number and sort of Epiphytes which lodge on it. — 1893
2. •
   A fungus that grows on a plant but does not feed upon it saprotrophically (an epiphytic fungus). (The science of detecting and studying any such symbiosis as may be involved in this relationship is still developing.)