As much as I love the gray green lichens my absolutely favorite lichen is orange. Sunburst lichens grow from the coast of Maine to New Mexico. When I lived on Monhegan island I was surrounded by these lichens which grow on rock outcroppings near the sea. I don’t recall where I have seen any sunburst lichen around here except in graveyards. Parietin, the pigment that colors sunbursts intensifies under sunlight. The stronger the solar irradiance, the denser the pigment. When growing in the woods most sunburst lichens don’t need sunblock so they are more yellow than orange. Parietin protects the sensitive algal partner from exposure to ultraviolet rays. This pigment also protects the slow growing lichen from slugs and other herbivores who otherwise might denude them because of the way the pigment tastes.

On the porch of the casita in New Mexico I have a slightly squared stone that a friend found on a hike and gave me a couple of years ago that has a thin crust of orange lichen on it. I have watered it from time to time noting that despite my attention the color has dimmed. Is this because it came from the high country where the air is less congested with particles? I don’t know.

For a naturalist like me sunburst lichens help me to get a reading on who might have once been in the area. At the seacoast the color orange suggests that seabirds were present; farther inland the presence of orange lichen over a crevice might indicate a coyote or fox den. Orange lichen appearing on a branch of spruce or balsam provides me with evidence that an owl might have roosted here for a time. Newly laid dung will provide the substrate for a colony of orange lichen to appear in a few years.

Lichens are usually described as having a leaf -like (like my fringed friend), crusty, or branching and shrub -like forms. Lichens often play an important part in the weathering of rocks. When lichens attach to rocks, they retain moisture and are instrumental in breaking down the stone. This process is an essential component for producing soil in a barren environment, but it takes years.

In the desert it is easy to spot dark clumpy soil areas, which are actually a layer that can include cyanobacteria, lichens, mosses, green algae, microfungi, and bacteria. This living biomass binds particles of soil, reduces erosion, fixes nitrogen, and can add organic matter. These areas are very fragile and even a footstep reduces their functioning which can take years to rebuild. In Abiquiu, the local cattle trample this delicate ground with impunity.

Lichens are widely used for many different purposes throughout the world. The most common use is dye production. Litmus paper is made from a dye mixture extracted from the Rocella species which is then applied to filter paper. Dyes used for clothing were used in the Scottish Highlands and produced red, orange, brown, and yellow. Purple dyes used throughout Europe from the 15ththrough 17thcenturies were extracted from lichens.

Many lichens have been used medicinally. A lichen’s usefulness as a medicine is often related to the lichen secondary compounds that are abundant in most lichen. It is estimated that 50-percent of all lichen species have antibiotic properties. Many lichen extracts have been found to be effective in killing the bacteria that cause boils, scarlet fever, and pneumonia.

Lichen are sensitive to atmospheric pollution including nitrogen and sulfur emissions that lead to acid rain, as well as toxic lead and mercury emissions. This sensitivity makes lichen a valuable biological indicator of air quality

Some sensitive lichen species develop structural changes in response to air pollution including reduced photosynthesis and bleaching. Pollution can also cause the death of the lichen algae, discoloration and reduced growth of the lichen fungus, or kill a lichen completely. The most sensitive lichens are shrubby and leafy (like the lichen pictured above) while the most tolerant lichens are crust-like lichens.

Lichens have been around for 400 million years and have learned how to cooperate and live in harmony. These fascinating and sometimes diminutive animal – plant ‘beings’ with their antibiotic/antiviral properties could be powerful teachers helping humans to develop medicines that could help with our current pandemic, as well as modeling the ability to cooperate despite ‘difference’ something our dominate culture has yet to learn.