What Lichens Are Not

Alectoria sarmentosa, witch's hair, growing on the trunks of Dougls-fir trees.
Alectoria sarmentosa, witch’s hair, on Douglas fir trees in the Pacific Northwest. Remember not to confuse lichens with moss. Photo courtesy of the U.S. Forest Service.

Cladina arbuscula, also known as reindeer moss, surrounded by real moss.
Cladina arbuscula, also known as reindeer moss, is surrounded by real moss. This species is rare in Colorado. Photo by Gay Austin, U.S. Forest Service.

Isn't lichen that mossy stuff on rocks and trees? When people think of lichens, many of them think of them as a kind of moss. That could not be farther from the truth.

Although moss and lichens are both called non-vascular plants, only mosses are plants. Mosses are included in a group of non-vascular plants called bryophytes. Mosses are believed to be the ancestors of the plants we see today, like trees, flowers, and ferns. Lichens, on the other hand, are not similar in anyway to mosses or other members of the plant kingdom.

unkown moss.
Look closely at this moss. Notice how leaf-like it is. The structures on top produce spores. They are the main mode of moss reproduction. Photo by Charles Peirce, Michigan Wildflowers.

Xanthoparmelia sp. on a rock with a moss.
Xanthoparmelia sp. on a rock with a moss. Can you tell which is the lichen and which is the moss? Photo by Doug Ladd.

Although mosses are very primitive, they still have plant-like structures that look like and function like leaves, stems and roots. They have chloroplasts throughout their entire bodies and can photosynthesize from all sides of their structures.

Lichens, on the other hand, are completely different. They do not have any roots, stems or leaves and their chloroplasts are contained only in the algae on the top surface of the lichen.

What lichens and mosses do have in common are size and habitats. In fact, mosses retain water, which is what lichens use to prolong their growth cycle. That’s why most lichen pictures will have mosses in the photos.

So, the next time you see a bunch of "mossy" stuff hanging from a tree or sitting on a rock, ask yourself, "Is that a lichen or a moss?"

Why are lichens important?…