Lichen

Here is an example of lichen. Lichen is a slow growing composite organism. This means that it is actually a group of different organisms that symbiotically combine to become a new and different organism. Lichen is comprised of fungus, alga, and/or cyanobacterium. It has the ability to photosynthesize but it does not have a root system to receive nutrients. However, this does not pose a problem for the lichen and the lack of roots means it can grow on rocks without threatening its livelihood. This also means it can grow on organisms like this tree and it won't become parasitic or harmful to the host.