More About Lichens and a Little About Mosses

January 25th, 9 am

This time of the year, because of all the moisture in the ground and on the trees, is the best time to look at the fabulous world of lichens and mosses. The lack of leaves and all the wetness allows these species to grow, reproduce, and be noticed for their color and vibrancy.

Lichens come in many forms. Some are a pale gray-green or yellowish-green mass hanging from trees, and some are orange, yellow, or red patches on rocks or on bark. Lichens can also form blackish crusts on soil. They are a visible and important component of the landscape, dressing up rock faces and outcroppings. They add color and texture to almost any surface that they colonize.

What is a lichen? This has changed since the first time I learned about them many years ago. Research now shows that lichens are not just a fungi and an algae living together in harmony, but according to Stephen Sharnoff from his wonderful book, A Field Guide to the Lichens of California, they are ‘specialized fungi that have become “lichenized,” teaming up with a photosynthetic partner that lives inside of them. This partner is most often a species of alga, but in some lichens, it is a colony of cyanobacteria. When the fungal cells become ‘lichenized,’ it forms an entirely new structure called a ‘thallus.’

Lichens have very important roles in a variety of ecosystems. According to Stephen Sharnoff, ‘they provide food, nesting material, and camouflage for a wide variety of wildlife.’ There are fifty or more species of birds that use lichens in their nest building and many mammals such as mule deer that depend on lichens for winter forage when there is a lack of other plants to eat. They provide a place to live, lay eggs, and hide for many kinds of insects and moths.

Besides all this, lichens are just truly fascinating to look at! They look like underwater coral if looked at closely with a hand-lens or close-up binoculars. They are easy to find and there are about fifteen hundred species of them living in California.

Mosses are non-vascular plants and unrelated to lichens. They produce spores for reproduction instead of seeds and don’t grow flowers or true roots. Instead of roots they have rhizoids that allow them to hold on to rocks and tree bark. They are generally a deep green or a yellow-green and after a few good rains look like lush green carpets wherever they are growing. In the heat of summer, mosses can lie and wait for the rains of winter and practically disappear. But this time of year, their green, verdant carpet gives me no end of pleasure. Mosses are small and for many species it is necessary to look at the cell structure under a microscope to confirm identification. However, there are plenty of common ones that can be studied with just a hand lens to be satisfying!  

If you want to learn more about these fascinating plants, I recommend you read, Gathering Moss: A Natural and Cultural History of Mosses, by Robin Wall Kimmerer, one of my favorite books. This time of year, I reread it to immerse myself in the relatively small but still immense world of mosses.

Go out and enjoy the lichens and the mosses this time of the year while other plants are not very showy!