Due to increased humidity, lower to moderately warm temperatures, and an abundance of organic material, this season becomes ideal for the growth and development of fungi, which we often know as mushrooms. These unique organisms can be observed in forests, meadows, and other natural environments.
Slovenia, with its diverse geographical position and varied climate, provides a home to a wide range of these organisms. It is estimated that about 5,000–6,000 species of fungi grow in our country, of which around 2,500 form visible fruiting bodies known as mushrooms.
Among these mushroom species are edible as well as poisonous ones, and many that are inedible or have no culinary value. Mushrooms are spread across a variety of habitats, including forests, meadows, wetlands, and even urban areas.
Forests, which cover a large part of Slovenia, offer particularly favorable conditions for numerous mushroom species, especially deciduous and mixed forests, where some popular species thrive—such as porcini, chanterelles, morels, parasol mushrooms, and many others frequently used in Slovenian culinary recipes. Porcini are especially popular among mushroom gatherers for their rich flavor, while chanterelles and parasol mushrooms are excellent for preparing a variety of dishes, such as sauces or baked meals.
Edible morel (Morchella esculenta), parasol mushroom (Macrolepiota procera), and porcini (Boletus edulis). (Photo: Tine Schein)
When collecting mushrooms, we must be very careful, as among the edible species there are also quite a few dangerous poisonous ones that can cause severe poisoning. Some of the most poisonous mushrooms include the death cap, the fly agaric, the panther cap, and the sickener. If misidentified, these species can cause serious health problems or even death.
Because of these dangers, caution and precise knowledge of mushrooms are essential when foraging, as even a small mistake can lead to serious health consequences. It is important that mushroom gatherers always consult experienced experts or mycological societies before consuming their harvest.
Biological characteristics of fungi
Fungi belong to a separate kingdom, distinct from plants and animals. Although at first glance they may resemble plants, their biological characteristics are very different. They are eukaryotic organisms, meaning their cells contain a nucleus where their genetic material is stored. Unlike plants, fungi do not perform photosynthesis and instead depend on organic matter in their environment for nutrients, which classifies them as heterotrophs.
Their bodies are made up of an interwoven network of microscopic filaments called hyphae, which together form the mycelium. The mycelium represents the main “body” of the fungus, hidden beneath the surface, while the fruiting body we see above ground (the mushroom) is only a small part of the organism, serving as a means of reproduction. Fungi reproduce through spores, which are dispersed by wind, water, or animals. Spores are extremely resistant to unfavorable conditions and can survive for long periods in a dormant state until they find a suitable environment for germination.
Structure of the fungus. (drawing – adapted from online template: Ana Mia Bedjanič)
Fungi as decomposers
The main ecological role of fungi is the decomposition of organic matter, which is why they are called decomposers. In forest ecosystems, fungi are the main decomposers of dead wood, leaves and other plant and animal debris. Through this activity, fungi release important nutrients, such as nitrogen, phosphorus and potassium, which become available to plants and other organisms. Without fungi, dead organic material would accumulate, reducing nutrient availability in soils.
One of the most important tasks of fungi is the degradation of lignin, a complex polymer that is a key component of wood. Wood would decompose very slowly without fungi, which would affect nutrient cycling in ecosystems. Species of fungi that feed on dead wood efficiently break down lignin and enable rapid return of wood to the cycling of matter in soils.
Sulphur shelf (Laetiporus sulphureus). (photo: Tine Schein)
Mycorrhiza: Symbiosis between fungi and plants
In addition to decomposing organic matter, fungi are also important because of their symbiotic role with plants. One of the most significant forms of this symbiosis is mycorrhiza, in which fungi live in close partnership with plant roots. In this relationship, fungi help plants absorb water and minerals from the soil, while the plants provide fungi with carbohydrates produced through photosynthesis.
Mycorrhiza is extremely important for the growth of many plant species, especially trees in forests. Through this partnership, plants can make better use of nutrients in the soil, particularly in poor or depleted environments. Studies show that without mycorrhizal fungi, many plants would not be able to survive or would grow much less successfully.
Summer mushroom (Boletus reticulatus) in symbiosis with plants. (photo: Tine Schein)
Lichens: Symbiosis of fungi and algae
Fungi also play a key role in the formation of lichens, which are a unique symbiosis between fungi and algae or cyanobacteria. In this relationship, fungi provide structure and protection, while the photosynthetic partner uses light energy to produce nutrients.
Lichens thrive in a wide range of environments, including rocky surfaces, tree trunks, and even extreme habitats such as deserts and arctic regions. They are sensitive indicators of air quality and important for the ecological stability of many ecosystems.
Bradovec (Usnea sp.) (photo: Primož Žižek)
Fungi in everyday life
In addition to their roles in ecosystems and as a source of food, fungi also play an important role in human daily life. The best-known fungus used in households is yeast (Saccharomyces cerevisiae), which is indispensable in baking bread and fermenting alcoholic beverages, such as wine and beer. Yeasts are unicellular fungi that release carbon dioxide during fermentation, which allows the dough to rise and the production of alcohol.
Fungi also have medical significance. The antibiotic penicillin, which revolutionized the treatment of infections, is a product of molds from the genus Penicillium. In addition to penicillin, fungi are the source of many other medicines, including immunosuppressants and cholesterol-lowering drugs.
Jelkina pološčenka (Ganoderma carnosum) (photo: Tine Schein)
Final thought
Fungi are extraordinarily important organisms whose role in natural ecosystems is indispensable. As decomposers, symbiotic partners, and sources of food and medicine, they have a profound impact on both nature and humans. Their ability to survive and adapt in diverse environments, along with their complex biological structure, highlights their invaluable place in the natural world. All this makes them among the most important organisms on our planet, even though they are often overlooked.
Slime porcelain (Mucidula mucida). (photo: Tine Schein)
Note prepared by Primož Žižek, biologist on the LIFE FOR SEEDS project.
