Lichens

What are Lichens? They aren't animals, they aren't plants, they aren't moss and they aren't mushrooms- so what are they?

"Fungi that have discovered agriculture!"- Trevor Goward

Lichens are a combination of two organisms, fungi and photosynthetic symbionts (algae or cyanobacteria), that work together. The cells of the cyanobacteria or green algae are surrounded by fungal filaments; these filaments comprise the majority of the mass of the lichen. The photobionts produce sugars and other carbohydrates for the fungi, while the fungi helps to keep the photobiont moist while shielding it from too much light.

Lichens are part of the cryptobiotic crusts in arid regions, helping to stabilize the soil. They also promote the production of new soils in arid regions by colonizing bare rock and other harsh habitats, and by adding organic materials to the soil.

Lichens are extreme!

Lichens are hardy, and can survive in extreme environmental conditions in the arctic and in hot deserts. They survive drought by completely drying out and becoming dormant. When moisture is available they can react quickly and absorb it to become pliable and photosynthetic again.

You say you have a lichen up your nose?

Lichens reproduce using a number of different methods:
-through spores that have a multitude of different colors and shapes
-the thallus (body) of the lichen can break into pieces and scatter and become new lichens -and through a process unique to lichens that produces soridia. Soridia are algae cells that are surrounded by fungal filaments and can form new lichens.

Soridia and spores are extremely small and have a powdery appearance- most can only be seen through a slide-microscope. Because spores and soridia are so small, they can easily travel on slight breezes in the air- this helps lichens to colonize new habitats.

Lichen growing on columnar basalt- Palisades, WA.