| Story by Megan McMahon |
What looks like a plant and grows anywhere a plant can — and then some — but is definitely not a plant? A lichen.
Like fungi, lichens are neither plant nor animal. These common organisms exist virtually everywhere on Earth, but they are unique in how they form and live.
Lichens exist as a symbiotic relationship between two species: an alga and a fungus. The fungus provides the organism with minerals, shelter and water, while the alga or bacteria provides nutrients it creates through photosynthesis, according to National Geographic.
Diversity among lichens is impressive, both in their physical appearance and their habitats. Because we often think of lichens as being similar to plants, we think of them as green. Many are, but they can also be yellow, orange, red, black, brown, silver and gray, according to the Arizona State University Biodiversity Knowledge Integration Center. And they live almost everywhere, from the coldest corners of the Arctic to the hottest spots in our deserts. One place where lichens do not commonly grow is in aquatic habitats, but they aren’t totally absent. They actually have been found growing on barnacles in the water.
Compared to many things, lichens seem complicated and aren’t well understood, but they are present in our lives in some unexpected ways. Read on to learn more about lichens.