Fistulina hepatica

Fistulina hepatica, also called liver mushroom or ox tongue, is a tree mushroom in the liverwort family (Fistulinaceae).

Fistulina hepatica is a xylobiont and lives as a weakling parasite almost exclusively on oaks, rarely also on sweet chestnuts or even more rarely on other deciduous trees such as walnut or ash. Injuries to the tree bark serve as an entry portal for the spores. Inside the trunk, the fungus spreads parasitically, initially hardly harming its host because it life process remain unaffected. Only the heartwood of the central cylinder – which is dead anyway – is affected. This wood decomposition occurs very slowly as the fungus breaks down the tanning-containing heartwood, utilizing the tannis from the parenchyma cells. Wood decomposed in this way eventually shows brown rot.

Since this process proceeds slowly and, due to the preferential tannin decomposition, the structure-giving wood components cellulose and hemicelluloses are almost not attacked at all, trees attacked by ox-tongue are still break-proof and stable for a long time; only late does cube breakage occur. The annual fruiting body appears in June/August to October/November mostly on the lower section of the trunk. Initially it pushes out of the trunk like a tongue, in adult specimens the fruiting body stands out from the growing point as a semicircular or fan-shaped bracket.

In the past, the Fistulina hepatica was known in Anglo-Saxon-speaking countries as “poor men’s beefsteak”, because it was found in abundance in the forests and served as a meat substitute when fried in a pan.

Preparation of the Substrate

Materials Needed:

• Hardwood sawdust (oak, chestnut, or beech are ideal)
• Wheat bran or other nitrogen supplements
• Water

Substrate Preparation:

• Mix hardwood sawdust with wheat bran in a ratio of about 5:1.
• Hydrate the mixture until it reaches a moisture content of about 60-65%. The substrate should feel damp but not dripping wet.

Sterilization

• Sterilize the substrate mixture by placing it in autoclavable bags or jars.
• Autoclave at 15 PSI for 90-120 minutes to ensure all contaminants are eliminated.

Inoculation

• Once the substrate has cooled to room temperature, inoculate it with Fistulina hepatica mycelium.

Spawn Rate:

• Use about 5-10% of the total substrate weight in grain spawn.
• Mix the spawn thoroughly with the sterilized substrate to ensure even distribution of the mycelium.

Incubation

• Place the inoculated substrate in a dark, warm area with a temperature range of 20-25°C (68-77°F).
• Allow the mycelium to colonize the substrate fully. This may take several weeks, typically around 4-8 weeks.
• During this period, ensure proper ventilation to avoid CO2 buildup.

Formation of Fruiting Block

• Once the substrate is fully colonized, it will form a solid fruiting block.

Initiation of Fruiting:

• To initiate fruiting, lower the temperature.
• Increase humidity
• Provide indirect light to simulate a natural environment, about 12 hours of light per day.
• Ensure proper air exchange to avoid stagnation and promote healthy growth.

Fruiting

• After a week or two under fruiting conditions, you should start to see the formation of fruiting bodies.
• Keep the environment humid and well-ventilated to support the development of the mushrooms.

Harvesting:

• Harvest the fruiting bodies when they reach a desirable size. The Beefsteak Fungus is best when young and tender.
• Use a clean knife to cut the mushroom at the base.
• Tips for Successful Cultivation

Patience: This species may take longer to fruit compared to other mushrooms, so patience is key.

1. Dissolve the ingredients and agar in distilled water.
2. Sterilize the solution by autoclaving at 121°C for 15-20 minutes.
3. Pour the sterilized media into petri dishes or other containers under sterile conditions.
4. Yeast and Peptone are optional, but you can add them to any recipe for nutritions.

Mixing Ratios: Typically, the substrate can be supplemented with 5-10% bran, 1-2% gypsum, and other additives depending on specific requirements. For instance, a substrate mix might include 90% hardwood sawdust, 5% bran, 3% soybean meal, and 2% gypsum.

Sterilization/Pasteurization: To prevent contamination, substrates should be sterilized or pasteurized before inoculation with Fistulina hepatica spawn.

Moisture Content: Maintain a moisture content of around 60-65% for optimal mycelial growth.

• Hardwood Logs: Preferred species: Oak, Chestnut, Beech, and other hardwoods.
• Hardwood Chips: Used in outdoor beds or mixed with other substrates.
• Sawdust: Hardwood sawdust is preferred over softwood due to nutrient content.
• Straw: Can be used alone or mixed with other substrates like sawdust.
• Paper and Cardboard: Recycled paper and cardboard, though less common, can be used effectively.
• Compost: A mixture of decomposed organic matter, though not as typical for Fistulina hepatica, can support growth.

• Bran: Wheat bran, rice bran, or oat bran can be mixed into substrates to increase nutritional content.
• Soybean Meal: Adds a significant amount of protein and nitrogen, aiding in vigorous mycelial growth.
• Cornmeal: Another source of carbohydrates and proteins.
• Cottonseed Meal: Provides a high protein content.
• Alfalfa Meal: Adds nitrogen and other micronutrients.
• Chicken Manure: High in nitrogen but must be used sparingly due to its high concentration.
• Fish Emulsion: Provides a balanced nutrient profile but should be used carefully to avoid over-saturation.

The biological efficiency (BE) of Fistulina hepatica, also known as the beefsteak fungus, typically ranges between 60% to 80%. This means that for every 100 grams of substrate, 60 to 80 grams of mushrooms can be harvested. Factors affecting BE include substrate quality, environmental conditions, and the method of cultivation. Optimal substrate moisture, adequate aeration, and proper temperature control are crucial for maximizing yield. This species' ability to break down lignin and cellulose in hardwood substrates contributes significantly to its efficient fruiting.

Weakness parasite, secondary decomposer, brown rot trigger

Fistulina hepatica has a nearly cosmopolitan distribution and occurs in Europe preferentially in thermophilic mixed deciduous forests, especially on calcareous soils. Its distribution area follows that of the oak or sweet chestnut. In Germany the occurrence of the ox-tongue is not frequent, but scattered. The frequency varies regionally and in some places shows a slight tendency to decline. Nevertheless, this fungus should be protected, since due to the declining area of near-natural oak forests (in a forest used for forestry purposes as well as in parks, diseased trees and dead wood - the hosts of the oak liverwort - are removed), an endangerment of the species can be assumed. Outside of Europe, this fungus is native to North America, South America, where its host trees include false beech (Nothofagus), and the subtropical montane forests of India. There are also populations in Australia growing on eucalyptus.

Mixed forest, floodplain forest, mainly on deciduous trees, preferably oaks, beeches, willows, needs stands of old oaks, also on eucalyptus, likes areas with calcareous soil conditions, summer to late fall.

Fistulina hepatica has a bitter and slightly bitter taste that can be mitigated by preparation. Beefsteak mushrooms are edible when young, although they are not poisonous; However, despite the fleshy appearance of the mutilated bodies, they had a nasty bitter taste. Older specimens become mature and "woody." It can be prepared in a variety of ways and is considered a raw food, but it is not considered a great food mushroom. Due to the high amount of tannin, the mushroom is difficult to digest and has a bitter taste.

Fistulina hepatica, commonly known as beefsteak fungus, stands out in the fungal kingdom for its unique composition. This mushroom is notably rich in an unusual pigment called "fistulin," which gives it its distinctive red coloration. Beyond its aesthetic appeal, Fistulina hepatica contains significant amounts of polysaccharides, particularly beta-glucans, known for their immune-modulating properties. It also provides a range of essential minerals such as potassium, phosphorus, and magnesium, along with vitamins B1 (thiamine) and B2 (riboflavin).