Epiphyte

Often referred to as “air” plants, although epiphytes do exist in water as well. Epiphytes are non-parasitic plants that grow upon another plant. Epiphytes gain moisture and nutrients from the surrounding air. An epiphyte differs from parasitic and semi-parasitic plants in that it does not derive anything other than support from its host plant.

Definition adapted from URL: http://en.wikipedia.org/wiki/Epiphyte