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Pseudevernia furfuracea

life science Maturity 11-13 Next article →

Pseudevernia furfuracea is a specific type of lichen known as tree moss. A lichen is not a single organism. Instead, it is a partnership between a fungus and a partner called a photobiont. In the case of tree moss, the photobiont consists of green algae from the genus Trebouxia.

Lichen Julian Alps Sovenia 2
Lichen Julian Alps Sovenia 2

This species typically grows on the bark of trees. It prefers trees that are considered "nutrient poor," such as birch, pine, and spruce. Because of its specific needs, tree moss is often used as a biological indicator. Its presence usually suggests that the air in that area is clean and healthy.

This lichen reproduces through a process involving small structures called isidia. Isidia allow the lichen to spread asexually. While isidia are the main method of reproduction, some specimens can also develop structures called soralia. These soralia are whitish and appear on both the top and bottom surfaces of the thallus, which is the main body of the lichen. Scientists have studied how these structures develop. They also investigate how isidia help the lichen manage gas exchange, specifically involving carbon dioxide. This process is vital for the survival of the algae living inside the fungus.

There are two main varieties of Pseudevernia furfuracea. They look identical to the human eye, but they are chemically different. One variety is named var. ceratea Zopf. This variety produces olivetoric acid along with other substances called physodic acids. The second variety is var. furfuracea. This variety produces physodic acid but does not produce olivetoric acid. In the past, some researchers like Hale in 1968 suggested these were two different species. They called the olivetoric acid type Pseudevernia olivetorina. However, most modern science now treats them as two varieties of the same species.

Humans have found many uses for tree moss throughout history. In ancient Egypt, the lichen was used during the process of embalming. It was packed into the body cavities of mummies. Historians are not entirely sure why this was done. It may have been for its aromatic properties, or it might have been for its supposed ability to preserve the body. In modern times, the lichen is highly valued in the fragrance industry. In 1997, approximately 1,900 tons of tree moss were processed in Grasse, France, to create perfumes.

Beyond scent, the lichen has significant medicinal and scientific potential. In Alfacar and Viznar, Spain, people use the lichen to treat respiratory complaints. They prepare a decoction, which is a liquid made by boiling the thallus in water, to be drunk. Research has also shown that water extracts of this species can protect against genotoxicity caused by bismuth compounds. Furthermore, the lichen contains bioactive compounds like atranorin. This compound can inhibit certain enzymes, such as trypsin. Interestingly, the production of these chemicals may be helped by the cooperation of bacteria living on the lichen.

Tree moss also acts as a natural monitor for environmental health. It performs a process called bioaccumulation, where it soaks up heavy metals from the air. It can collect metals like chromium, zinc, cadmium, lead, nickel, iron, manganese, and copper. The amount it collects is often proportional to the concentration of these metals in the air. However, how much metal it holds also depends on how wet the specimen is. The lichen is also very sensitive to ozone. High levels of ozone can cause structural and physiological damage to the organism. In Austria, scientists even used the lichen to monitor levels of Cesium-137 following the Chernobyl nuclear accident.

Finally, scientists are looking at how this lichen might help clean the environment. They have investigated its ability to perform biosorption, which is the absorption of metals from a solution. It has shown potential for treating waste that contains heavy metals like copper(II) and nickel(II). While it shows great promise, we must also focus on conservation. In Iceland, the species is quite rare. It is found in only two locations in the country. Because of this, it is classified as critically endangered in Iceland.

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File:Lichen Julian Alps Sovenia 2.jpg
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