Epiphytes are plants which depend on other plants for

Epiphytes are plants that grow on other plants but do not derive nutrition from their hosts; instead the host is used solely for physical or mechanical support. Textbook descriptions state epiphytes live “supported physically but not nutritionally by the structures of other plants,” attaching to trunks, branches or foliage while obtaining moisture and nutrients from air, rain and accumulated debris rather than from the host itself [1]. Authoritative references also define epiphytes as growing upon other plants merely for physical support and not parasitically, and note their prevalence in forest canopies where roots are not grounded in soil [3]. Hence, epiphytes depend on other plants mainly for mechanical support.

Sources

1. [1] Environment and Ecology, Majid Hussain (Access publishing 3rd ed.) > Chapter 3: MAJOR BIOMES > 1. Tropical Evergreen Rainforest Biome > p. 7
2. [2] https://www.britannica.com/plant/epiphyte
3. [3] Environment and Ecology, Majid Hussain (Access publishing 3rd ed.) > Chapter 3: MAJOR BIOMES > 1. Tropical Evergreen Rainforest Biome > p. 5