Irene, a young biologist from Abbadia San Salvatore, embraces a beech tree growing on the slope of the Amiata Mountain in Tuscany, Italy. Note the white lichens growing on the surface. In addition to being a tree lover, Irene is also a lichen lover. And a holobiont, too.
It is not so easy to find fellow lichen lovers. Lichens are so common and yet so misunderstood and ignored, despite being the quintessential example of a holobiont. They are creatures formed of two completely different species, a fungus and an alga (or a cyanobacterium, not the same thing as an alga, but functioning in a similar way). Algae and cyanobacteria are photosynthetic organisms that provide food for the fungus. The fungus, in turn, digs up mineral nutrients from the substrate and provides them to the algae/cyanobacteria. A perfect example of symbiosis, lichens have existed for hundreds of millions of years, possibly billions of years, and they probably were the first organisms to colonize the land in very ancient times.
Once you discover lichens, you can't avoid being fascinated by their incredible variety of shapes and colors. They can have tiny, leafless branches (fruticose), flat leaf-like structures (foliose); they may form a crust that adheres to the substrate, (crustose), have a powder-like appearance (leprose); and more. They give you some ideas of the overall health conditions of the biome in which they appear, especially if they appear in the foliose state. Some of them are edible and they have been appreciated as food by many traditional culture and also by reindeer. Below, a print shows Japanese lichen collectors
In our culture, lichen lovers are a little rare, but they do exist, and when they find each other they may engage in lyrical appreciations of the lichens they observe, as I did when I met Irene, in the woods of the Amiata mountains. There is a facebook site on lichens (unfortunately it has not been updated during the past three years), an active "società lichenologica italiana", a "British Lichen Society," and you can surely find many more sites on the subject by searching the Web. But the mere fact of seeing these little creatures for what they are is a source of endless wonder. You don't need to be in the wild. You can find plenty of lichens anywhere in urbanized areas.
Here are some white lichens growing on the nearly forgotten tomb of Vernon Lee (1856- 1935) British writer and poet who lived most of her life in Tuscany. Poetry is a form of virtual holobiont growing in the mind.
h/t Irene Mazza, Cinzia Mammolotti, and Miguel Martinez
