After several years of drought in northern California, this winter has been especially exciting for observing lichen and moss, due to recent rains.
Moss is a flowerless, living plant — very different than lichen.
Lichen are actually a union of two separate organisms: fungi and algae. It is a symbiotic relationship in which a fungus pairs up with algae. Algae produce food by photosynthesis, for the fungus; and the fungus in turn gives the algae a place to live.
Lichen grows on almost any surface: bark, moss, leaves, other lichen, walls, gravestones, roofs. It grows in forests, arctic tundra, deserts, and cities; it can even survive unprotected in space. For more info about lichen click here.
Lichen species vary depending on the host environment. For instance, we have a lot of oakmoss lichen, Evernia prunastri, where I live.
It grows on the trunks and branches of oak trees. It is found in many temperate mountain forests throughout the Northern Hemisphere, including other parts of North America, as well as France, Portugal, Spain, and much of Central Europe.
On my morning walks, especially after a windy night, I often find many small branches that have broken off the oak trees and blown to the ground. They’re loaded with oakmoss lichen. One year I found a hummingbird nest, made of this lichen, in an oak tree directly above a lot of these branches.
About 6% of earth’s land surface is covered by lichen. They are a pioneer species, meaning they are one of the first organisms to begin growing in an area that has been denuded by disaster.
Last month California became the first state with an official state lichen: Ramalina menziesii, also known as lace lichen. It ranges from Alaska to Baja California.
Lichen is eaten by some animals, used for nesting, contributes nitrogen to soils, and was once used as a form of dye. In the past humans used it for food, but it is generally indigestible and mildly toxic. It also serves as a sort of litmus for testing levels of air pollution.
And for those of us who like to get silly in the woods, forest growth is an excellent source of entertainment.
Photo credit: Athena Alexander unless otherwise noted