5. Lichens, mosses and fungi

Lichens

Lichens are unique organisms, as they actually consist of two different organisms: an alga and a fungus. 

Algae are microscopically small plants that are capable of photosynthesis. They provide the fungal part of the lichen with sugar, whereas the fungal part provides the algal part of the lichen with water and protection! In other words, both organisms benefit from their co-operation. 

The co-operation of algae and fungi has reached a point where it has become hard to distinguish between the two different organisms. This is why we consider lichens single organisms. 

Lichens thrive best in rocky areas, where plants cannot grow. They can also grow on tree trunks. Lichens grow very slowly and they are sensitive to air pollution. 

Mosses

Mosses are primitive plants. They lack two parts that other plants have: they have no roots or flowers. Mosses attach themselves to the ground or a tree trunk with small rhizoids. It collects water with its whole body, like a sponge. 

Because mosses do not have strong stems, they cannot grow very tall. This is why mosses can only be found growing near the ground or on tree trunks in wet locations. 

Mosses can often cover the forest floor completely, especially in spruce forests. Mosses reproduce by releasing spores. 

Fungi

The fungi of the forest live mostly in the form of underground mycelia networks. During the autumn, the mycelia grow visible fruit bodies on the ground. The fruit body consists of a stem and a cap. The cap releases spores, which the fungi uses to reproduce and spread into new areas. 

Because the fruit bodies of various fungi have different shapes, colors and structures, you can learn to identify mushrooms. This is especially important if you plan to collect mushrooms to eat. 

Fungal cells do not contain chloroplasts, which means that they cannot photosynthesize. Instead, they gain their energy from green plants, just like animals do. This means that fungi are consumers. 

Some fungi collect sugar from tree roots. In return, some fungi species give the tree some of the water collected by the mycelia. This kind of a mutually beneficial co-operation is known as symbiosis. 

Some fungi are decomposers that break down dead plant parts. Bracket fungi, for example, live on fallen or dead tree trunks and act as decomposers. 

Some fungi are inedible, whereas others are dangerously toxic. Such fungi include the destroying angel and the fly amanita (pictured). In contrast, other fungi, such as boletes and chanterelles, are widely used in cooking.

Terminology

Lichens, mosses and fungi
Terminology Explanation
lichen A small organism that consists of an alga and a fungus.
moss A small, primitive plant that has no roots and flowers. Mosses usually inhabit the forest floor.
fungus An organism that lives as a mycelium underground and occasionally grows a reproductive fruit body above ground.