Xanthoria parientina is a lichen consisting of fungus and algae that produces a yellow dye to protect itself from UV radiation. The species is common in places where there is enough nitrogen in the air. Therefore, it is also used as an indicator of nitrogen pollution.
Xanthoria parientina is a lichen consisting of fungus and algae that produces a yellow dye to protect itself from UV radiation. The species is common in places where there is enough nitrogen in the air. Therefore, it is also used as an indicator of nitrogen pollution.
Growth in a variety of places
Xanthoria parietina is a lichen consisting of a fungus and algae. The species is common on a variety of places: living trees, brick, concrete, cement and asphalt. Thus, it is often found on human structures such as walls, roads and roof tiles. The species has a high tolerance for salt, so you'll also find it a lot on sea dikes.
Indicator of air pollution
Xanthoria parietina is an ammonia-loving species and grows wherever there is enough nitrogen. You'll therefore find the species most often near farms and major roads. But this is not a very good sign. More lichen means more nitrogen pollution, which is bad for nature. Since the 1980s, the species has become increasingly common in the Netherlands. The growth of big harvester moss and other ammonia-loving lichens is sometimes used as an indicator of nitrogen pollution.
Yellow dye
The yellow color of Xanthoria parietina is usually bright yellow to orange. This acid acts as a sunscreen and protects the moss from harmful UV rays. When the moss grows in the shade, therefore, very little of this dye is produced and it is also more green in color. Parietic acid derived from big yolk moss used to be widely used as a dye to turn textiles yellow. When it comes into contact with potassium hydroxide, the color changes from yellow to red/purple. This type of color reaction is widely used in lichenology (study of lichens) for identifying the correct species.