Nutrition type

Mycorrhizal

For the best-known forest mushrooms, the "Nutrition type" column always says "Mycorrhizal" (or forms mycorrhiza). It means the mushroom can't live on its own — it lives in a close, mutually beneficial symbiosis with a living tree.

The word "mycorrhiza" literally means "fungus-root". The mushroom's mycelium wraps tightly around the tree's fine rootlets, creating a single system for exchanging nutrients.

24 species in the database.

How does this exchange work?

As M.Ya. Zerova explains, it's the perfect biological trade:

- What does the mushroom give the tree? Fungal mycelium is thousands of times thinner than tree roots. It works like a giant sponge, soaking up water, phosphorus and nitrogen from the tiniest pores in the soil and passing them to the tree. Without mycorrhiza, trees grow much worse and often die in droughts.

- What does the tree give the mushroom? A mushroom has no chlorophyll and can't make sugar. The tree (through photosynthesis) shares the carbohydrates it produces, and the mushroom feeds on them.

The main mycorrhizal mushrooms

Almost all the classic "forest" delicacies (and the most poisonous mushrooms) are mycorrhizal. They are tightly bound to their partner trees:

1. All boletes: porcini, aspen boletes, birch boletes, slippery jacks. (That's why the birch bolete grows only under birch, and the slippery jack under pine.)

2. All amanitas: the fly agaric, the death cap (often forms mycorrhiza with oak or hazel).

3. Milk caps: saffron milk caps, other milk caps, woolly milk caps.

4. Chanterelles and brittlegills.

5. Truffles: The most expensive mycorrhizal mushrooms, which form an alliance with oak roots.

Questions and answers

Why don't supermarkets sell fresh porcini the way they sell button mushrooms?

Because porcini are a mycorrhizal species, they can't be grown in a greenhouse on a substrate (the way button mushrooms are). To harvest porcini, a farmer would have to plant an entire oak or pine forest, inoculate it with mycelium and wait 15-20 years for the trees to grow and the mycorrhiza to start fruiting. That makes no economic sense. All the porcini in the world are gathered exclusively in the wild.

If the tree is cut down, will the mycorrhizal mushroom die?

Yes. Once a tree is felled, its roots stop producing sugars. Having lost its food source, the mycelium weakens very quickly and dies. That's why porcini and chanterelles never grow on fresh clearcuts.

Sources

1.Зерова М.Я. та ін. Визначник грибів України. 1979
2.Roger Phillips. Mushrooms (Roger Phillips)
3.David Arora. Mushrooms Demystified
4.Index Fungorum