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Stem

Rooting

Rooting — mushrooms with the trait «Rooting»

There are no true roots (like those of plants) in the mushroom kingdom. What foragers often call a "root," or a root-like extension of the stem, has a mycological term: pseudorhiza (pseudorhiza).

It is a special, strongly elongated, tapering base of the stem that reaches deep into the substrate (soil or rotting wood). Its main purpose is to connect the fruiting body (the cap on the surface) with its food source (the mycelium), which is hidden very deep underground.

5 species in the database.

Classic mushrooms with a "root"

Roger Phillips and M.Ya. Zerova give striking examples of this stem structure:

1. Rooting shank (Hymenopellis radicata): This is the textbook "rooting" mushroom. Its visible stem above ground can be 10 cm tall, but if you carefully dig up the soil, you'll find the stem continues underground for another 15–20 cm! This long "root" stretches down until it attaches to a deeply buried rotting tree root, which is what the mushroom feeds on.

2. Strobilurus: Small early-spring mushrooms that grow only on deeply buried pine or spruce cones. Their stem has a very long root-like extension that stretches through the layer of soil and needles straight to the cone.

3. Spindle toughshank (Gymnopus fusipes): Its stem narrows sharply at the base and stretches into a spindle shape, burrowing into the soil near oak roots.

Why does this matter?

David Arora stresses that a root-like extension is an excellent diagnostic trait. If you cut a rooting shank off with a knife, you'll see just an ordinary mushroom on a thin stem and won't be able to identify it. But if you pull it out whole, the extra-long pseudorhiza will instantly tell you the exact species.

That is why mycologists always insist on digging out the base of the stem when collecting mushrooms for identification.

Questions and answers

If you break off the pseudorhiza, will the mushroom die?
A mushroom's fruiting body (the part we pick) is only its temporary reproductive organ. If you break off the "root," you simply separate the fruiting body from the mycelium. The mycelium underground won't die from this and will grow new mushrooms next year.
Do amanitas or porcini ever have a root?
No, that isn't typical for them. Porcini and amanitas form mycorrhiza (a symbiosis) with the fine surface roots of living trees, so their mycelium sits close to the surface. Their stem base is more often bulbous or even, without deep "roots."

Sources

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