Symbionts
Lichens, which result from the symbiotic relationship between fungi and green algae, are often seen growing on trees.
Source
Boundless vets and curates high-quality, openly licensed content from around the Internet. This particular resource used the following sources:
"OpenStax College, Nutritional Adaptations of Plants. October 17, 2013."
http://cnx.org/content/m44718/latest/Figure_31_03_06.jpg
OpenStax CNX
CC BY 3.0.
