Cladonia rangiferina

This is reindeer lichen.

It looks like moss, but it is not. It grows in very cold places. It can live in heat, too.

It grows in open lands and forests. This lichen is food for reindeer. It grows very slowly. It can take many years to grow back. It can even grow on soil after a fire. It is a tough living thing.

Reindeer lichen is a special living thing.

Many people call it reindeer moss. But it is not a moss. It is a lichen. A lichen is made of two partners living together. One partner is a fungus. The other is an alga. They work as a team.

Scientists study how they join. First, the fungus grows toward the alga. Then, the two parts grow together. This makes a new body.

This lichen is very tough. It lives in the cold tundra. It can survive even at -40°C. It can also live in hot places. It grows very slowly. It might grow only 4 millimeters each year. Because it grows slowly, it takes a long time to return. This happens if it is burned or stepped on.

Reindeer and caribou eat this lichen. It is a very important food for them. Some people also use it for food or medicine. It can even grow on burnt soil two years after a fire.

Reindeer lichen is a unique living thing found in many places. People often call it reindeer moss or caribou moss. However, it is not actually a moss. It is a fruticose lichen, which means it has a bushy shape. This lichen grows in both hot and cold climates. It loves open spaces with well-drained soil. You can find it in alpine tundra and boreal pine forests. It is very important because reindeer and caribou eat it. This makes the lichen a key part of their lives.

A lichen is a team of two different living things. One is a fungus and the other is an alga called Trebouxia irregularis. Scientists study how they join together in a process called lichenization. First comes the pre-contact stage where nothing seems to happen. By the eighth day, they reach the contact stage. The fungal tips grow toward the algal cells. They even form swollen tips called appressoria to touch the algae. By day 21, they reach the growth together stage. The algae become part of a network inside the fungus.

Humans have studied this lichen for a very long time. Carl Linnaeus first described it in his 1753 book, Species Plantarum. At that time, he named it Lichen rangiferinus. Later, in 1780, Friedrich Heinrich Wiggers moved it to the genus Cladonia. This is how it got its current scientific name. Today, researchers still look at its special chemistry. They study many compounds like atranorin and fumarprotocetraric acid. Some of these might even help fight certain bacteria.

This lichen is incredibly tough and lives in extreme places.

It can survive temperatures as low as -40°C. It can even handle freezing in liquid nitrogen or very salty water. It grows very slowly, sometimes only 3.9 to 4.4 mm per year. Because it is slow, it can take decades to recover from damage. In Nepal, it grows at high elevations between 3,400 and 4,500 meters. In Sweden, it can start growing on burnt soil just two years after a fire.

Many cultures have used reindeer lichen for many different things. The Inland Dena'ina people have boiled it for food or medicine. They sometimes mix it with berries, fish eggs, or lard. In the West Kameng district, the Monpa people use it as a remedy. It can also be used to make a drink called aquavit. Some people even use it as decoration for glass windows. It is a great source of vitamin D for those who eat it. Just remember that it can be bitter or cause an upset stomach if not cooked well.

Cladonia rangiferina is a unique type of organism known as a fruticose lichen. While many people call it reindeer moss or caribou moss, it is not actually a moss. Instead, it is a lichen, which is a partnership between two different life forms. This specific species is often called reindeer lichen or grey reindeer lichen. It is extremely important to ecosystems because it serves as a vital food source for reindeer and caribou.

Because it supports these large animals, the lichen has significant economic importance in many regions.

A lichen is formed by a symbiotic relationship between a fungus and an alga. In the case of Cladonia rangiferina, the fungal partner works with an alga called Trebouxia irregularis. Scientists study how these two join through a process called lichenization. This process happens in several distinct stages. First is the pre-contact stage, which occurs about one day after the partners are introduced. During this time, there is no visible growth. By the eighth day, the contact stage begins. Here, fungal hyphae—tiny thread-like structures—grow toward the algal cells. They may form swollen tips called appressoria to make contact. By 21 days, the growth together stage occurs. The algal cells become integrated into a network within the fungal matrix.

This lichen has a very specific physical structure. It is fruticose, meaning it has a bushy, branched shape. The branches usually divide into two, three, or four smaller parts. The color of the lichen can range from greyish to whitish or even brownish grey. It forms large, extensive mats on the ground. Unlike some other species, it lacks a thick, protective outer layer called a cortex. Instead, a loose layer of hyphae covers the photobionts, which are the light-capturing algal cells. When the lichen is fertile, its tips may split into small, umbrella-shaped clusters. These clusters hold tiny reproductive discs called apothecia, which are often hidden just below the growing tips.

The history of our scientific understanding of this lichen began in the 18th century. Carl Linnaeus first described the species in his 1753 work, Species Plantarum. At that time, he placed it in his own genus and named it Lichen rangiferinus. In 1780, Friedrich Heinrich Wiggers moved the species to the genus Cladonia. This change gave us the modern scientific name we use today. Since then, researchers have looked closely at its complex chemistry. They have found many bioactive compounds, such as atranorin and fumarprotocetraric acid. Some of these substances have shown the ability to inhibit certain bacteria, like methicillin-resistant Staphylococcus aureus.

Cladonia rangiferina is famous for being incredibly tough and able to survive extreme stress. It can live in both hot and cold climates, often dominating the ground in boreal pine forests and alpine tundra. The lichen can survive temperatures as low as -40°C. It can even continue to breathe after being immersed in liquid nitrogen. It is also highly resistant to dehydration and high salinity. However, its strength is balanced by its very slow growth rate. It typically grows only between 3.9 and 4.4 mm per year. Because it grows so slowly, it may take many decades to recover if it is burned, trampled, or overgrazed.

Different environments change how the lichen grows and reproduces. In humid areas with plenty of water, the lichen often grows taller, reaching about 12 cm. These moist sites also tend to produce more fertile apothecia. In drier locations, the lichen is much shorter, often only 4 to 6 cm tall. The lichen is also a polycarpic species, meaning it can produce sexual spores throughout its 20-to-30-year lifespan. These spores help the lichen spread over long distances. In some parts of the world, like the British Duchy of Cornwall, this lichen is considered an endangered species and receives special protection.

Humans have found many ways to use reindeer lichen throughout history. The Inland Dena'ina people have used it as a food source by boiling or soaking it. They sometimes mix the soft lichen with berries, fish eggs, or lard. It is also a source of vitamin D. In the West Kameng district of the Eastern Himalaya, the Monpa people use it as a traditional remedy for kidney stones. Some cultures even use it to make a drink called aquavit or as decoration for glass windows. However, because of the acids in the lichen, it must be cooked well to avoid an upset stomach.